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Comparative analysis of Late Jurassic sauropod trackways from the JuraMountains (NW Switzerland) and the central High Atlas Mountains(Morocco): implications for sauropod ichnotaxonomyDaniel Martya; Matteo Belvedereb; Christian A. Meyerc; Paolo Miettob; Géraldine Parattea; ChristelLovisa; Basil Thüringc

a Office de la culture, Section d'archéologie et paléontologie, Porrentruy 2, Switzerland b Dipartimentodi Geoscienze, Università degli Studi di Padova, Padova, Italy c Naturhistorisches Museum Basel, Basel,Switzerland

First published on: 19 April 2010

To cite this Article Marty, Daniel , Belvedere, Matteo , Meyer, Christian A. , Mietto, Paolo , Paratte, Géraldine , Lovis,Christel and Thüring, Basil(2010) 'Comparative analysis of Late Jurassic sauropod trackways from the Jura Mountains(NW Switzerland) and the central High Atlas Mountains (Morocco): implications for sauropod ichnotaxonomy',Historical Biology, 22: 1, 109 — 133, First published on: 19 April 2010 (iFirst)To link to this Article: DOI: 10.1080/08912960903503345URL: http://dx.doi.org/10.1080/08912960903503345

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Comparative analysis of Late Jurassic sauropod trackways from the Jura Mountains(NW Switzerland) and the central High Atlas Mountains (Morocco): implications forsauropod ichnotaxonomy

Daniel Martya*, Matteo Belvedereb, Christian A. Meyerc, Paolo Miettob, Geraldine Parattea, Christel Lovisa and

Basil Thuringc

aOffice de la culture, Section d’archeologie et paleontologie, Paleontologie A16, Hotel des Halles, P.O. Box 64, 2900 Porrentruy 2,Switzerland; bDipartimento di Geoscienze, Universita degli Studi di Padova, Via Giotto 1, 35137 Padova, Italy; cNaturhistorischesMuseum Basel, Augustinergasse 2, 4000 Basel, Switzerland

(Received 2 October 2009; final version received 22 November 2009)

Late Jurassic sauropod trackways from the Jura Mountains (NW Switzerland) and the central High Atlas Mountains(Morocco) are described and compared. Emphasis is put on track preservation and trackway configuration. The trackwaysare similar with respect to preservation and the pes and manus track outlines, but they show a large range of trackwayconfiguration. Only one of the trackways reveals digit and claw impressions, and thus differences in trackway gauge and theposition of pes and manus tracks are the most explicit characters for their distinction. The Late Jurassic to Early Cretaceousichnotaxa Brontopodus, Parabrontopodus and Breviparopus are reviewed and a differential diagnosis is given for thetrackways studied. The reference trackway of Breviparopus corresponds to one of the studied trackways of Morocco.Parabrontopodus and Breviparopus are considered to be both valid ichnotaxa, even though we recommend the latter to beformally erected based on better-preserved tracks than those currently exposed. The analysed trackways and ichnotaxasuggest that trackway configuration, notably trackway gauge (width), is not decisively influenced by extrinsic factors such asontogenetic stage, locomotion speed and substrate properties. However, it cannot be excluded that it is related to otherfactors such as individual behaviour or even sexual dimorphism.

Keywords: Sauropod footprint; trackway configuration, trackway gauge; Late Jurassic; Switzerland; Morocco

Introduction

The present paper describes in detail Late Jurassic

sauropod trackways from the Jura Mountains (NW

Switzerland) and the central High Atlas Mountains

(Morocco), with particular emphasis put on track

preservation, track morphology and trackway configur-

ation, notably trackway gauge (width). The major issues

are (1) to compare the trackways, (2) to explain similarities

and differences between the trackways (e.g. substrate

properties, trackmakers and behaviour) and (3) to evaluate

their ichnotaxonomical assignation. We also comment on

the ichnotaxon Breviparopus Dutuit and Ouazzou (1980)

since one of the analysed trackways from Morocco (i.e.

trackway Deio-D) is the reference trackway for this

ichnotaxon. The term ‘reference’ is used instead of ‘type’

throughout this paper, because this ichnotaxon is not

formally emended (see below).

In the description of dinosaur ichnotaxa, trackway

configuration is traditionally used. This is also the case for

sauropod trackways, and a good example is Brontopodus

birdi, which is based on both track morphology and

trackway parameters (Farlow et al. 1989). More

particularly, Farlow (1992) proposed that sauropod track-

ways could be classified according to trackway width. He

introduced the term trackway gauge stressing that

sauropod trackways can generally be described as narrow

gauge when pes tracks are ‘close to or even intersecting the

trackway midline’ or wide gauge when they are ‘well away

from the trackway midline’. Because not all trackways

could unambiguously be classified into one or the other

category, Lockley et al. (1994b) and Meyer et al. (1994)

proposed an intermediate category (i.e. medium gauge),

but they also stated that a formal classification of sauropod

trackways on gauge alone was premature and that there is

‘a need to carefully describe well-preserved trackways and

refine sauropod ichnotaxonomy . . . ’. Nonetheless, track-

way gauge is commonly used for the classification of

sauropod trackways and the identification of their track-

makers (e.g. Lockley et al. 1994a, 1994b, 2002a, 2002b;

Moratalla et al. 1994; Lockley and Hunt 1995; Dalla

Vecchia and Tarlao 2000; Lockley and Meyer 2000; Day

et al. 2002, 2004; Marty et al. 2003; Moreno and Benton

2005; Gonzalez Riga and Calvo 2009 and dos Santos et al.

ISSN 0891-2963 print/ISSN 1029-2381 online

q 2010 Taylor & Francis

DOI: 10.1080/08912960903503345

http://www.informaworld.com

*Corresponding author. Email: martydaniel@hotmail.com

Historical Biology

Vol. 22, Nos. 1–3, March–June–September 2010, 109–133

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2009) and also for ichnofacies (e.g. Lockley et al. 1994c;

Mannion 2008) or herding behaviour (Day et al. 2002).

When Farlow (1992) introduced the trackway gauge

concept, he stressed that trackway configuration including

gauge may also be related to substrate properties and

locomotion (speed), in a way that the trackmakers of the

wide-gauge trackways may have angled their legs inward

with respect to the sagittal plane, and if so that trackway

gauge would have little systematic value. This was also

discussed by Wilson and Carrano (1999), but they

concluded that ‘it is unlikely that any single sauropod

was able to produce both wide- and narrow-gauge

trackways’, because they assumed that skeletal mor-

phology is responsible for trackway gauge and that the

wide stance was a synapomorphy of the titanosaurids.

More recently, Wright (2005) has suggested that trackway

gauge also seems to be influenced by other characteristics

such as locomotor style and ontogeny. Carpenter (2009)

suggested that trackway gauge could also be related to the

degree of lateral motion of the trackmaker, i.e. wide-gauge

trackways were produced by trackmakers that had less

lateral motion than the makers of the narrow-gauge ones.

However, despite the importance of trackway gauge in

the classification of sauropod trackways and the proposed

link with the anatomy of the trackmakers, a quantification

for trackway gauge was provided only recently by

Romano et al. (2007) introducing the trackway ratio

(TR) and by Marty (2008) introducing a ratio between the

width of the angulation pattern and the corresponding

track length (i.e. the [WAP/PL] ratio for pes tracks).

An important part of this work is the characterisation

of trackway gauge, and therefore, the two trackway gauge

ratios mentioned above are compared. This is also

presented for three sauropod ichnotaxa Breviparopus,

Brontopodus and Parabrontopodus, contributing towards

their better characterisation. Finally, we test whether

sauropod trackway gauge is influenced by parameters such

as substrate consistency, behaviour (locomotion speed)

and ontogenic stage (pes length).

General setting

NW Switzerland

The four studied trackways were documented on four

different tracksites near Porrentruy, Ajoie district, Canton

Jura (Figure 1(D) and (E)): Chevenez–Combe Ronde

(CHE-CRO), Courtedoux–Pommerat (CTD-PMM), Cour-

tedoux–Sur Combe Ronde (CTD-SCR) and Courtedoux–

Tchafoue (CTD-TCH). In this tracksite naming system, the

community is indicated first followed by the name of the

tracksite. The excavations of the tracksites started in 2002

and are carried out by a paleontological survey project (the

Paleontologie A16) on or close to the future course of the

Figure 1. Geographical setting of Europe and North Africa (C) exhibiting the location of the studied tracksites in the central High AtlasMountains, Morocco (A and B), and in the Jura Mountains, NW Switzerland (D and E).

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Swiss federal highway A16, also named Transjurane (e.g.

Marty et al. 2004, 2007). By the end of 2009, over 50

ichnoassemblages (i.e. an association of true tracks found

on a single paleosurface) revealing over 8000 tracks,

including 234 trackways of tridactyl dinosaurs (mainly

attributed to theropods) and 177 sauropod trackways, have

been excavated and documented.

The sauropod trackways occur in three track-bearing

laminite intervals (named lower, intermediate and upper

levels) interbedded between shallow marine carbonate

platform sediments (Marty 2008). These laminites were

deposited in inter- to supratidal paleoenvironments, which

is indicated by macroscopic (stromatolitic lamination,

desiccation cracks, wave ripples and invertebrate burrows)

and microscopic (e.g. cryptmicrobial lamination, fenestrae

and brecciation) sedimentological features (Marty 2008;

Marty and Pacton 2009) (Figure 2(C) and (D)). Each

laminite interval bears several distinct track-bearing

levels, whereas the intermediate levels with a thickness

of 1 m and at least 15 track-bearing levels are the track-

richest interval (Marty et al. 2007). In total over 30 distinct

levels, some of which (notably the main track levels at the

base of each laminite interval) can be correlated between

the different tracksites, have been identified so far. The

sequence with the three track-bearing intervals is part of

the Reuchenette Formation (Thalmann 1966; Gygi 2000),

and it can be precisely dated with ammonites to the

Tethyan Divisum to Acanthicum ammonite zones, i.e. late

Early to early Late Kimmeridgian (Marty et al. 2003; Jank

et al. 2006a, 2006b).

During the Late Kimmeridgian, the localities were

located at the northern margin of the oceanic Ligurian

Tethys as a large, structurally complex carbonate platform

(e.g. Thierry et al. 2000a, 2000b and Stampfli and Borel

2002). This platform was at a paleolatitude of around 308N,

at the threshold between the Paris Basin to the northwest

and the Tethys Ocean to the south (Figure 3) and, thus,

influenced by both the Tethyan and Boreal realms (e.g.

Ziegler 1988; Thierry 2000a, 2000b and Jank et al. 2006a).

During the Kimmeridgian, the climate of the Jura carbonate

platform was subtropical and is generally considered semi-

arid to arid (e.g. Hallam 1984, 1985; Frakes et al. 1992;

Ross et al. 1992; Weissert and Mohr 1996 and Bertling and

Insalaco 1998).

Morocco

The analysed trackways are from two different tracksites

located in the western part of the Iouaridene Valley near

the village of Taghbalout, i.e. in the central High Atlas

Mountains, around 15 km east of the town of Demnat and

120 km east of Marrakech (Figure 1(A) and (B)). Known

since 1930s (Plateau et al. 1937), the Iouaridene tracksites

became important with the work of Dutuit and Ouazzou

(1980) because of their description of a narrow-gauge

trackway with very large tracks, which they named

Breviparopus taghbaloutensis. Later, Ishigaki (1985a,

Figure 2. Typical macroscopic and microscopic features of the studied tracksites in Morocco (A and B) and NW Switzerland (C and D).(A) Cross section of the track RP3 of the Deio Lav-A trackway. The dashed line indicates the track outline. Note the absence ofundertracks indicating that the subjacent sediment was already consolidated at the time of track formation. (B) Thin section with planarcryptmicrobial lamination and laminoid fenestrae of level 3 near Taghbalout. (C) The lower track-bearing laminites at the CHE-CROtracksite. The laminite interval is capped by a shallow marine, massif limestone bed. Hammer (33 cm in length) for scale is put on themain track level (level 500). (D) Thin-section CRO004-132a of layer 545 from the CHE-CRO tracksite exhibiting crinkled cryptmicrobiallamination, characterised by an alternation of clotted micrite and irregular seams enriched in organic matter.

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1985b, 1985c, 1986, 1989) published several papers on

some of the sauropod tracksites of the Iouaridene Valley,

but only recently more complete studies have been

achieved by Nouri (2007) and Belvedere (2008). The latter

reported around 800 tridactyl tracks, mostly attributed to

theropods, 200 sauropod tracks and 2 tracks attributed to

the stegosaur ichnogenus Deltapodus (Belvedere and

Mietto 2010). Consequently, sauropod tracks represent

about 20% of the studied tracks of the Iouaridene

ichnosite, even though it has to be considered that the very

long Breviparopus reference trackway (i.e. Deio-D)

accounts for a large part of the sauropod tracks.

All tracksites of the Iouaridene basin are located in the

lower member (sensu Charriere et al. 2005) of the

Iouaridene Formation (Jenny et al. 1981), in which

Belvedere (2008) identified 21 track-bearing levels.

The sequence with the track-bearing levels is composed

of a cyclic alternation of siliciclastic mudstones and

carbonate-cemented mudstones to very fine sandstones

topped by mud cracks sometimes associated with

symmetrical ripple marks and often bearing dinosaur

tracks. Fluvial channels, with fining upward sequences,

climbing ripples and herringbone cross-stratification, are

present at the top of the sequence with the track-bearing

levels. Dinosaur tracks are never deeper than 15 cm, even

for the largest sauropod tracks, indicating a coherent

and/or well-laminated (e.g. due to microbial mats)

sediment. In thin sections, the carbonate-cemented levels

often exhibit a pronounced microbial lamination with

laminoid fenestrae and birds eyes (Figure 2(B)). The

presence of evaporitic minerals, concertina-like veins and

pseudo-anticlines with evaporitic infillings suggest an arid

to semi-arid environment (Belvedere 2008).

The track-bearing sequence has long been attributed to

the Middle Jurassic (e.g. Jenny et al. 1981; Jenny and

Jossen 1982 and Jenny 1985). However, Charriere et al.

(2005) identified charophytes (Prochara kimmeridgiensis,

Dictyoclavator ramalhoi) that indicate a Late Jurassic

Figure 3. Paleogeographical setting of the studied localities during the Late Jurassic. The central High Atlas Mountains (Morocco) wereformerly located at the north-eastern part of the Sahara Craton (1), and the Jura Mountains (NW Switzerland) on the Jura carbonateplatform (2) between the Massif Central to the southwest and the Rhenish Massif to the north. Redrawn after Thierry et al. (2000a, 2000b).The paleogeographical position of Corsica and Sardinia is interpreted differently in other reconstructions (e.g. Stampfli et al. 2002). (1)Exposed land; (2) hypersaline; (3) aeolian, fluviatile, lacustrine and fluvio-lacustrine; (4) shallow-water environments with fluctuatingsalinities; (5) coastal marine and shallow marine (terrigenous); (6) shallow marine (carbonate); (7) deeper carbonates and (hemi)pelagicoozes; (8) deep marine; (9) deep oceanic basins (mid ocean ridge) and (10) major faults.

D. Marty et al.112

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(Oxfordian to Kimmeridgian) age to the track-bearing

sequence, i.e. the upper part of the lower member of the

Iouaridene Formation. This is further supported by the

occurrence of a Barremian lacustro-marine ostracod

assemblage (Globator trochiliscoides, Atopochara trivol-

vis triquetra) in the upper member of the Iouaridene

Formation (Charriere et al. 2005).

During the Late Jurassic, the domain of today’s central

High Atlas Mountains was located at the northeastern part

of the Sahara Craton at a paleolatitude of about 208 N

(Figure 3), and continental red beds (couches rouges) were

deposited, whereas in the western area of the High Atlas, a

more coastal-marine deposition prevailed due to the

opening of the central Atlantic (e.g. Ziegler 1990;

Charriere et al. 2005 and Haddoumi et al. 2009).

Methods and terminology

Only quadrupedal trackways or pes-dominated trackways

(i.e. trackways with some but not all manus tracks missing

due to overprinting) with tracks considered as true tracks

(for definition see below) are studied. For all trackways,

track and trackway data were systematically measured

(Figure 4) following commonly used ichnological

terminology (e.g. Leonardi 1987 and Thulborn 1990),

and the mean parameters are given in Table 1. Tracks

directed outward with respect to the line connecting it with

the consecutive track (the stride) have an outward

(positive) rotation and those directed inward an inward

(negative) rotation. For the quantification of sauropod

trackway gauge, two quantitative ratios are used: the TR

and the ratio between the width of the angulation pattern

and the corresponding track length.

Trackways are illustrated by outline drawings exhibit-

ing the distinct and essential characters of the tracks

(Figure 5) and photographs (Figure 6). In the trackway

outline drawings, the internal track outline marks the

actual imprint of the foot and defines the track dimensions,

whereas the external track outline and the external limit of

the displacement rim define the extramorphological

features of the tracks (Figure 5).

Preservation terminology

True track

Lockley (1991) called the track emplaced on the actual

tracked surface true track, and the term true track is used

here in this sense. The track bottom or true track sensu

Figure 4. Schematic sauropod trackway showing the essentialpes and manus track and trackway parameters measured: PL, peslength; PW, pes width; a, pes rotation; LPP, left pes pace length;RPP, right pes pace length; PS, pes stride length; g, pes paceangulation; WAP, width of the pes angulation pattern; ML, manus

length; MW, manus width; b, manus rotation; LMP, left manuspace length; RMP, right manus pace length; MS, manus stridelength; d, manus pace angulation; WAM, width of the manusangulation pattern; SW, side width; OW, overall width; LP, leftpes; RP, right pes; LM, left manus and RM, right manus track.

R

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stricto may, under appropriate substrate conditions and

if the foot is placed in an ideal way, reveal anatomical

details of the trackmakers’ foot. Such tracks were also

named elite tracks, which have the connotation of well

preserved, visually clear true tracks that are not

distorted (e.g. Lockley and Hunt 1995 and Lockley and

Meyer 2000).

Underprint

A special case of a true track, which is produced when the

foot penetrates or breaks through the uppermost or through

several layers of sediment and leaves the true track on

sediment below the initially exposed sediment surface

(Marty et al. 2009). If in this case the sediment is split open

at successively deeper layers, the overall track will be

found to be less and less complete (Thulborn 1990), while

the track bottom (or the true track sensu stricto) may still

reveal anatomical details of the foot.

Undertrack

A track that is formed in (bio-) laminated and plastic

substrate when the foot does not penetrate the sediment

but compresses it in a way that it creates a miniature

stratigraphic sequence or stack of transmitted prints

(stack of casts and moulds) (Thulborn 1990;

Lockley 1991).

Trackway ratio

The TR is defined as the ratio between the side width (SW)

and the overall width (OW) of a trackway (Figure 4),

expressed as a percentage (Romano et al. 2007):

TR ¼ ðSW=OWÞ £ 100%:

Both measurements (SW and OW) are taken

perpendicular to the trackway axis of the trackway: as

such SW may not correspond to the true width of the

track, which is measured at right angles to the length of

the track. Only in cases where the track is oriented

parallel to the long axis of the trackway the SW

represent the true track width. The higher the TR, the

narrower the trackway gauge is; the provisional

boundary between wide gauge and medium gauge is at

35% and that between medium gauge and narrow gauge

is at 50% (Romano et al. 2007).

The TR is calculated for both pes (pes TR, PTR)

and manus (manus TR, MTR) tracks. Only the SW

and OW of the Moroccan trackways were measured in

the field. For the studied Swiss trackways, SW and OW

were measured on magnifications of outline drawings,

and for the ichnotaxa from magnifications of published

outline drawings or the TR was taken from Romano et al.

(2007) as indicated in Table 2.

Ratio between the width of the angulation pattern and thecorresponding track length

Defined for both pes and manus tracks as (Marty 2008):

(1) width of the pes angulation pattern/pes length

(i.e. [WAP/PL] ratio)

(2) width of the manus angulation pattern/manus width

(i.e. [WAM/MW] ratio).

In the case of manus tracks, the manus width is used

instead of its length because manus tracks are often

incomplete due to overprinting by the subsequent pes or

due to a more digitigrade impression of the manus. Thus,

manus length is subjected to a high variability, and width

better represents the size of the manus than the length. If

the [WAP/PL] ratio equals one (i.e. PL ¼ WAP), the pes

tracks are likely to touch the trackway midline. If the ratio

is smaller than one, tracks intersect the trackway midline,

which corresponds to the definition of narrow gauge

(Farlow 1992). Accordingly, a value of 1.0 separates

narrow-gauge from medium-gauge trackways, whereas the

value 1.2 is arbitrarily fixed between medium-gauge and

wide-gauge trackways, and trackways with a value higher

than 2.0 are considered as very wide gauge (Marty 2008).

For the studied trackways, all measurements (Table 1)

were made at the outcrops, and for the ichnotaxa included

in the discussion (Table 2), they were taken from

published data or measured on magnifications of published

outline drawings.

Ratio between the widths of the pes and manusangulation patterns

This ratio is introduced here and is defined as

(1) width of the pes angulation pattern/width of the manus

angulation pattern (i.e. [WAP/WAM] ratio).

This ratio is used to characterise whether manus tracks

are closer or farther away from the trackway midline than the

pes tracks. If this ratio equals one, pes and manus tracks are

located in a line at the same distance from the trackway

midline; if the ratio is smaller than one, manus tracks are

located farther away from the trackway midline than pes

tracks and if the ratio is higher than one, the manus tracks are

located closer to the trackway midline than the pes tracks.

Heteropody

Heteropody is defined as the difference in area (total track

area) between the pes and manus tracks in a given trackway

of a quadrupedal animal (Lockley et al. 1994b). Lockley

et al. (1994b) noted that differences in heteropody could be

used to distinguish ichnotaxa, even if heteropody is not

considered as a character in the phylogenetic taxonomy of

sauropods (e.g. Salgado et al. 1997; Wilson and Sereno

1998; Wilson and Carrano 1999 and Wilson 2002, 2005).

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Detailed calculations of total track areas and of the

heteropody ratio are not in the scope of this work, because

manus tracks are often incomplete due to overprinting or a

digitigrade stance, and their surface area is thus subjected

to an important variation and difficult to calculate.

Therefore, heteropody values should be considered only

as a gross approximation. The ratio between the indices of

pes and manus track size may also be used as an

approximate estimation of heteropody, and this ratio is

indicated in Table 1. The higher this ratio, the smaller the

manus with respect to the pes track is. The definition of the

index of track size follows Thulborn (1990, p. 234), and it

is calculated with the mean pes and manus lengths and

widths, respectively.

Locomotion speed

Calculation of locomotion speed (Tables 1 and 2) derives

from the relationship obtained by Alexander (1976). Because

of several shortcomings of this empiric relationship due to

the estimation of hip height based on tracks and the a priori

unknown precise trackmaker (e.g. Coombs 1978 and

Rainforth and Manzella 2007), as well as the unknown

precise relationship between relative stride length (S/h) and

the Froude number (speed2/leg length £ gravitation con-

stant) for dinosaurs (Alexander 2006), speed calculations are

considered as rough approximations only (Hutchinson et al.

2005; Alexander 2006). Nonetheless, Alexander’s (1976)

method is at least informative providing an estimation for the

magnitude of the locomotion speed of a dinosaur and, more

importantly, for the relative speed of a given sample of

trackways. Locomotion speed is used here in this way to test

whether it has an influence on trackway configuration,

notably trackway gauge.

Description of studied trackways

NW Switzerland

Four typical trackways from four different ichnoassem-

blages and from all three track-bearing laminite intervals

are described. The trackways of NW Switzerland are

either protected in situ (CHE-CRO-500-S10, CTD-SCR-

1000-S10, CTD-PMM-1505-S1) or the original trackways

were extracted and displaced (CTD-TCH-1055-S4) or

casted (CTD-SCR-1000-S10, CTD-PMM-1505-S1) and

are now housed in the collection of the Natural History

Museum of Porrentruy (Musee jurassien des sciences

naturelles MJSN).

Trackway CHE-CRO-500-S10

This straight, 8.5 m long trackway (Figures 5(A) and 6(A))

was described by Marty (2008) who, based on its very

wide gauge and rather small heteropody, tentatively

assigned it to the ichnotaxon Brontopodus.

The trackway is characterised by a very wide gauge,

a pes-dominated pattern (some manus tracks are

completely overprinted), an irregular configuration

(variable position of manus tracks with respect to the

pes tracks) and a relatively small heteropody coefficient

(Figure 5(A)). Manus tracks, undeformed by the pes, are

in front of the pes tracks with their centre located

slightly to the inside of the prolongation of the pes’ long

axis. Pes and manus tracks have a similar high mean

outward rotation.

Pes tracks are longer (30.0 cm mean length) than wide

(19.0 cm mean width) and have a subcircular to oval,

slightly elongated shape (Figure 6(C)).

Manus tracks are wider (19.1 cm mean width) than long

(9.6 cm mean length) and their shapes vary, due to different

degrees of overprinting by the subsequent pes and inclination

towards the anterior part of the tracks, from semicircular

to crescent shaped. Well-preserved and undeformed

manus tracks (e.g. LM4, Figure 6(B)) are semicircular

and lack evidence for digit and claw impressions.

Trackway CTD-SCR-1000-S10

This straight, 19 m long trackway (Figures 5(B) and 6(D))

was first described by Marty et al. (2003) and assigned to

the ichnotaxon Parabrontopodus. All tracks are rather

shallow and they are partially surrounded by small, and

narrow displacement rims.

This quadrupedal trackway is characterised by a

narrow gauge (Figure 6(D)) and a heteropody ratio of

about 1:3 for virtually undeformed manus tracks. The

centres of the manus tracks are placed about on the

prolongation of the pes’ long axis, and hence clearly

farther away from the trackway midline than the centres of

the pes tracks. Both pes and manus tracks are rotated

outwards with a higher outward rotation of the manus than

for the pes, and the trackway is slightly asymmetric such

as the right pes and manus tracks have a higher mean

outward rotation than the left ones.

The pes tracks have an oval shape and are longer

(46.9 cm mean length) than wide (35.8 cm mean width),

with the greatest width located in the anterior part of the

pes’ long axis but not so far away from its midpoint

(Figure 6(E) and (F)). Some of the pes tracks show up to

two very shallow and round digit impressions but without

evidence for claw impressions.

Virtually undeformed manus tracks (e.g. RM4) are

semicircular, convex forward, wider (23.3 cm mean width)

than long (12.3 cm mean length), and they exhibit neither

digit nor claw impressions (Figure 6(F)).

Trackway CTD-TCH-1055-S4

This straight, 14 m long trackway (Figures 5(C) and 6(G))

is one of the trackways with the best-preserved pes tracks

Historical Biology 115

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Table 1. Mean pes and manus track and trackway parameters and calculated gauge ratios for pes and manus tracks.

Country NW Switzerland Morocco

Tracksite CHE-CRO CTD-SCR CTD-TCH CTD-PMM Deio Deio Lav

Trackway number S10 S10 S4 S1 Deio-D Lav-A

Level 500 1000 1055 1505 3 2

Number of pes tracks 12 20 16 9 28 6Number of manus tracks 11 13 19 7 26 5Pattern (q, quadrupedal, p–d, pes dominated) p–d to q p–d to q q q q qTrackway length (m) 8.5 19 14 12 86 5Track orientation (8) 25 225 140 310 260 335

Track parametersPes tracksLength (PL) (cm) 30.0 46.9 36.0 108.7 110.7 54.0Width (cm) 19.0 35.8 27.1 92.1 88.5 40.5Index of track size (IPS)* (cm) 23.9 41.0 31.2 100.1 99.0 46.8Depth (cm) 4.3 3.3 2.6 3.0 13.0 9.2Left rotation (8) 8.8 21.4 30.3 30.0 23.0 20.3Right rotation (8) 30.5 31.0 19.0 47.3 34.0 18.7

Manus tracksLength (cm) 9.6 12.3 13.3 63.2 29.7 14.5Width (MW) (cm) 19.1 23.3 23.1 76.6 55.4 29.9Index of track size (IMS)* (cm) 13.5 16.9 17.5 69.6 40.6 20.8Depth (cm) 3.3 2.6 2.6 3.6 4.9 6.3Left rotation (8) 29.7 28.8 53.3 6.5 39.5 36.7Right rotation (8) 29.0 45.3 67.8 20.3 48.6 10.0

Trackway parametersPes tracksStride (cm) 137.0 159.2 117.0 284.3 350.5 203.8Width a. pattern (WAP) (cm) 68.9 37.1 33.3 137.9 104.8 56.3Left pace (cm) 98.0 90.2 68.0 201.8 207.8 109.2Right pace (cm) 91.7 90.2 68.4 191.8 195.3 120.5Pace angulation (8) 87.7 128.6 118.0 90.9 116.6 116.3

Manus tracksStride (cm) 141.3 144.7 121.7 287.0 354.9 202.0Width a. pattern (WAM) (cm) 76.2 74.1 49.8 142.6 148.1 61.3Left pace (cm) 107.0 105.8 75.4 201.0 233.8 108.6Right pace (cm) 112.0 80.3 80.3 182.0 231.7 123.9Pace angulation (8) 83.0 98.1 98.1 94.0 100.7 117.7Gleno-acetabular distance (cm) 98.3 104.0 104.0 261.3 216.0 126.7

Trackway gaugePes tracksPes trackway ratio (PTR) (%) 27.3 51.4 49.2 43.7 50.2 44.7[WAP/PL] ratio 2.3 0.8 0.9 1.3 0.9 1.0[WAP/IPS] ratio 2.9 0.9 1.1 1.4 1.1 1.2

Manus tracksManus trackway ratio (MTR) (%) 14.4 24.1 25.8 37.2 27.0 31.3[WAM/MW] ratio 4.0 3.2 2.2 1.9 2.7 2.1[WAM/IMS] ratio 5.6 4.4 4.8 2.0 3.7 2.9[PTR/MTR] ratio 1.9 2.1 1.9 1.2 1.9 1.4[WAP/WAM] ratio 0.90 0.50 0.67 0.97 0.71 0.92

[IPS/IMS] ratio (heteropody approximation) 1.8 2.4 1.8 1.4 2.4 2.2Pes trackway gauge Very wide Narrow Narrow Wide Narrow MediumLocomotion speed (km/h) 3.9 2.9 2.4 2.9 4.0 3.7

Notes: For details on the calculation of locomotion speed refer to text. The trackway pattern terminology follows Marty et al. (2006) and Marty (2008, p. 38, figure 2.16).Asterisks mark parameters, which were not measured in the field but calculated based on other parameters.

D. Marty et al.116

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(digit and claw impressions clearly discernible) of the

Ajoie ichnoassemblages. The tracks are rather shallow

with small displacement rims, and they were probably left

under ideal substrate conditions such as a thin layer of

plastic carbonate mud or microbial mats. After track

formation a network of mud cracks with a diameter of 10–

20 cm was formed.

This quadrupedal trackway has a very narrow gauge

and a regular configuration, with manus located almost as

close to the trackway midline as pes tracks (Figure 6(G)).

Both pes and manus tracks are rotated outwards and the

rotation is much higher for the manus than for the pes

tracks, reaching up to 1078 (LM12). In particular, some

manus tracks are located well in front of the pes tracks,

closer to the following opposite pes track than to the

preceding pes track from the same side (e.g. LM5 closer to

RP5 than to LP5; Figure 5(C)).

Pes tracks have a subcircular to oval shape and are

rounded posteriorly and longer (36.0 cm mean length) than

wide (27.1 cm mean width) with the greatest width located

in the anterior part of the pes’ long axis but not so far away

from its midpoint. The best-preserved tracks show three

digits (digits I–III; decreasing in size) and two claw

impressions (Figure 6(H)–(J)). The latter are triangular in

shape, laterally directed and located on the tip of the first

and second digit impressions (Figure 6(J)).

Manus tracks are never overprinted, semicircular to

crescent shaped and convex forward, wider (23.1 cm mean

width) than long (13.3 cm mean length) and have a track

bottom inclined towards the anterior part of the track

(Figure 6(H)–(J)). Well-preserved manus tracks (e.g.

LM5, Figure 6(H)) lack, in contrast to the pes tracks,

impressions of digits and claws.

Trackway CTD-PMM-1505-S1

This straight, 12 m long trackway (Figures 5(D) and 6(K))

is located on the level 1505, about 5 cm above the main

track level (level 1500) of the upper levels, and to date it is

the only trackway excavated at this site. The trackway was

most probably left in a thin layer of moist carbonate mud

or microbial mat, superimposed on a hardened layer

because the tracks are – despite their large size – not very

deep. The soft sediment was squeezed outwards into the

displacement rims and the foot was put on the hardened

layer explaining the lack of anatomical details. These

tracks are considered as underprints and this is also

confirmed by the absence of tracks on the overlying

(removed) levels. After track formation, a network of mud

cracks with a diameter of 10–20 cm was formed.

This quadrupedal trackway has a regular configuration

with manus tracks located as close, or exceptionally closer,

to the trackway midline than the pes tracks (Figure 5(D)).

It has a wide gauge and the mean widths of the pes and

manus angulation patterns are almost equal. Pes and

manus tracks are always rotated outwards, manus having a

smaller rotation than pes tracks, and the right pes and

manus tracks showing a higher rotation than the left ones.

Well-preserved pes tracks are longer (108.7 cm mean

length) than wide (92.1 cm mean width), with the greatest

width located in the anterior part of the pes’ long axis, and

they do not exhibit digit and claw impressions. They are

bell shaped or slightly triangular and pointed posteriorly

(Figure 6(L) and (M)).

Manus tracks are never overprinted, semicircular to

oval and convex forward, wider (76.6 cm mean width)

than long (63.2 cm mean length) and they exhibit neither

digit nor claw impressions (Figure 6(N)).

Morocco

Two trackways named ‘Deio Lav-A’ and ‘Deio-D’ by

Belvedere (2008) are described, where ‘Deio’ is the

abbreviation for Demnat Iouaridene and ‘Lav’ for lavatory,

because this tracksite is located close to a small runnel,

where local women wash their cloths (Belvedere 2008). Both

trackways are located on the northern side of the Iouaridene

valley close to the village of Taghbalout (Figure 1(A))

and are easily accessible in the field; however, they have

been subjected to erosion and disintegration for several

decades. Over the past few years the GeoParc M’Goun, the

Association pour la protection du PatrimoineGeologique du

Maroc, and another local association, the Association des

Enseignants des Sciences de la Vie et de la Terre (AESVT),

undertook efforts to protect the localities in situ.

Trackway Deio Lav-A

This trackway is located on top of level 2 (Belvedere

2008), and it corresponds to the leftmost trackway

illustrated in the outline drawing of Ishigaki (1986,

figure 4) and to the trackway ‘1Ta1’ of Nouri (2007,

figures 214 and 215, ‘premier gisement du Taghbalout’).

The tracks are most probably true tracks because they are

well defined, quite deep, surrounded by large and well-

defined displacement rims, and because of the absence of

undertracks in the cross section of the right pes track at the

end of the trackway (Figure 2(A)). The latter fact also

suggests that the layer, in which the trackway was made

was a moist to water-unsaturated mud superimposed on an

already hardened or even lithified layer. After track

formation, a network of mud cracks with a diameter of

10–20 cm was formed.

The trackway Deio Lav-A is about 5 m long and

straight (Figures 5(F) and 6(O)), and it is the best-

preserved and leftmost trackway of at least five parallel

trackways left by medium-sized sauropods (Belvedere

2008). It is a quadrupedal trackway composed of five pes-

manus couples and an incomplete right pes track at the end

of the trackway. Manus tracks are overprinted to different

Historical Biology 117

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LP2

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D. Marty et al.118

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Figure 6. Photographs of representative segments and tracks of the studied trackways from the Jura Mountains, NW Switzerland (A–N)and from the central High Atlas Mountains, Morocco (O–T). (A–C) CHE-CRO-500-S10. (D–F) CTD-SCR-1000-S10. (G–J) CTD-TCH-1055-S4. (K–N) CTD-PMM-1505-S10. (O–Q) Deio Lav-A. The arrow in Q points to the small lateral indentation at the interiorside in the middle of the manus track. (R–T) Deio-D (Breviparopus reference trackway).

Historical Biology 119

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degrees, but one (LM2, Figure 6(Q)) is complete. The

heteropody ratio varies between 1:3 for the more

complete, semicircular manus tracks and 1:4 for the

incomplete, crescent-shaped manus tracks. The trackway

falls into the medium-gauge field and is clearly wider than

the trackway Deio-D. Pes and manus tracks are outward

rotated and manus tracks are generally located slightly to

the inside of the prolongation of the pes’ long axis. This is

also indicated by a similar width of the angulation pattern

for pes and manus tracks.

The pes tracks are sub-elliptical to bell shaped and are

less triangular in outline than those of the trackway Deio-

D. Pes tracks are longer (54.0 cm mean length) than wide

(40.5 cm mean width), with the greatest width located

between the middle and anterior part of the pes’ long axis

(Figure 6(P)). Notably the two left pes tracks LP1 and

LP2 exhibit several small depressions in their anterior

part, and these were interpreted as three to four digit

impressions separated by interdigital displacement rims

by Ishigaki (1986, figure 4) and Nouri (2007, figure 214).

Nonetheless, these impressions cannot clearly be ident-

ified as digit impressions because the track bottom is

generally very irregular. This can be explained, for

instance, by the adherence of the sediment to the foot

during withdrawal or due to a partial collapse of the track

interior. Displacement rims are large and well defined and

are best developed in the anterolateral exterior margin of

the tracks, where they cut across the displacement rims of

the manus tracks. Displacement rims are shallower at the

interior part and very shallow or absent in the rear part of

the pes tracks.

Manus tracks are crescent shaped to semicircular,

always wider (29.9 cm mean length) than long (14.5 cm

mean length), without digit and claw impressions (Figure

6(Q)). Manus tracks are generally placed on, inside and

outside the prolongation of the pes’ long axis and are

deformed by the subsequent pes track to different degrees

(Figure 6(P)). Contrary to the trackway Deio-D, manus

tracks of Lav-A are clearly deeper than the pes tracks and

are surrounded by well-defined, larger displacement rims

cut by those of the pes. The semicircular manus tracks are

suggested to have been left when the trackmaker did not

overprint it with the pes and when it put its manus in a less

digitigrade way resulting in a better impression of the shape

of the trackmaker’s manus. Such well-defined manus

tracks exhibit a small lateral indentation at the interior side

in the middle of the track (e.g. LM2, Figure 6(Q)), which is

probably a characteristic of the manus.

Trackway Deio-D

This trackway (trackway ‘4Am1’ of the ‘quatrieme

gisement d’Aıt Mimoun’ of Nouri 2007) is the reference

trackway of B. taghbaloutensis, first described by Dutuit

and Ouazzou (1980) and later illustrated by Ishigaki (1989,

figure 9.5). The trackway lies on the main track level

(named level 3), and all tracks of level 3 are interpreted as

true tracks. Undertracks are visible on a mud-cracked level

about 10 cm below level 3, where the true tracks of level 3

are already eroded. This suggests that the sediment was

moist and well laminated when the tracks were left,

possibly due to the former presence of microbial mats.

After track formation, a network of mud cracks with a

diameter of 5–10 cm was formed.

The trackway Deio-D (Figures 5(E) and 6(R)) is a

narrow-gauge, quadrupedal trackway composed of 33

tracks, and it is about 86 m long, even though there is a

22 m long gap between the tracks D/20 and D/21 due to the

erosion of the track level. After this gap the preservation is

poor, and one right pes–manus couple and a pes are

missing between the prints D/22 and D/23, while two other

pes–manus couples are missing between D/29 and D/30.

Trackway direction changes twice along the trackway

from 2628 to 2508 and then back to 2698, while the stride

length remains almost constant. The pes rotation is

outward and different between left and right tracks: the

average outward rotation for the left pes tracks is 158,

while for the right ones it is 308, without notable changes

in rotation close to the turns. The position of the manus is

almost always slightly more external with respect to the

prolongation of the pes’ long axis, also indicated by a

larger width of the angulation pattern of the manus. Manus

tracks also have an outward rotation, which is slightly

higher than for the pes tracks. Pes tracks are clearly deeper

(up to twice as deep) than the manus tracks, this was also

observed by Dutuit and Ouazzou (1980). Because all

manus tracks are at least partially overprinted, heteropody

varies from 1:3 to 1:4.5 depending on the degree of

overprinting. Dutuit and Ouazzou (1980) calculated a

heteropody ratio of 1:3.6, and Nouri (2007) of 1:4.5.

However, for undeformed manus tracks, heteropody is

suggested to be rather in the order of 1:3.

Pes tracks are longer (110.7 cm mean length) than wide

(88.5 cm mean width), the shape varies from elliptical to

bell shaped, but it is often slightly triangular (i.e. pointed

posteriorly). The maximum width of the track is generally

in the anterior part of the pes’ long axis, whereas in the bell

shaped to triangular tracks it is positioned more anteriorly.

Displacement rims are always present and are more

developed on the anterior and on the external sides of the

tracks, while they are smaller or sometimes even absent in

the posterior (rear) part of the pes tracks (Figure 6(S) and

(T)). Dutuit and Ouazzou (1980) stated that the pes tracks

have at least four digit impressions marked by three

interdigital displacement rims and accordingly to their

Figure 1, there are at least three claw impressions present.

Also, in the outline drawing of four pes–manus couples

illustrated in Ishigaki (1989, figure 9.5) (Figure 8(A)), up

to four digit impressions and up to three claw impressions

are drawn. On the other hand, Meyer and Monbaron

D. Marty et al.120

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(2002), who re-examined the trackway, stated that ‘neither

manus nor pes imprints show traces of claws’. However,

only the track Deio-D/28, also illustrated by Ishigaki

(1989, figure 9.5, second right), exhibits three faint

depressions in the anteriormost part of the track, which

could be interpreted as digit impressions, and the claw

impressions figured by Dutuit and Ouazzou (1980) and

Ishigaki (1989) are reinterpreted here as desiccation cracks

dissecting the footprint outline. Thus, in their present

preservation state (in May 2009), the evidence for digit or

claw impressions is weak, and it is suggested that this is

not an unequivocal characteristic of the trackway Deio-D.

None of the manus tracks is completely unaffected by

the subsequent pes, and their shape varies from

semicircular to crescent shaped depending on the degree

of overprinting by the subsequent pes track (Figure 6(T)).

In one case, the pes (D/16) almost completely overprints

the manus track. Manus tracks are always wider (55.4 cm

mean width) than long (29.7 cm mean length). No digit or

claw impressions are present on any of the manus tracks

and this is in accordance with the description of Dutuit and

Ouazzou (1980). Displacement rims are well developed all

around the tracks and are cut by the displacement rims of

the subsequent pes.

Comparison of studied trackways

Basically, the trackways from NW Switzerland and

Morocco are similar and with the exception of the

trackway CTD-TCH-1055-S4 (Figure 5(C)) they all lack

anatomical details such as digit and claw impressions.

Thus, the most important differences that can be observed

regarding track preservation are overall pes and manus

track outlines (from oval to bell shaped), trackway gauge

(from very narrow to very wide gauge), the position of pes

and manus tracks with respect to the trackway midline

(manus as close to midline as pes up to manus clearly

farther away from midline as pes tracks), the degree of pes

and manus outward rotation and heteropody.

Track preservation

Despite the different sedimentological settings of the

tracksites in Morocco (siliciclastic) and NW Switzerland

(carbonate), the studied trackways are similar from a

preservational point of view. All trackways have relatively

shallow tracks, which are generally surrounded by well-

defined displacement rims. This suggests that the substrate

in both paleoenvironments was well consolidated possibly

due to the presence of microbial mats (Marty et al. 2009), or

that it was rapidly consolidating due to early diagenetic

processes, which may have been induced by microbial mats

(e.g. Chafetz and Buczynski 1992 and Dupraz and Visscher

2005). Under such circumstances, even very large and

heavy trackmakers (e.g. sauropods with a pes length of

.1 m) are unlikely to leave tracks deeper than 0.2 m.

Some of the studied tracksites are characterised by the

presence of true tracks with underlying shallow under-

tracks, others by true tracks without undertracks and at

some by the presence of underprints. Shallow undertracks

indicate biolaminated and plastic sediment, strongly

suggesting the former presence of microbial mats.

Underprints and/or the absence of undertracks indicate a

moist layer, which was squeezed outwards on an already

consolidated layer by the pressure of the foot forming

displacement rims (Marty et al. 2009). This case is well

expressed in the cross section of a track of the Moroccan

Deio Lav-A trackway (Figure 2(A)), where the underlying

clays were clearly not affected by the impact of the foot,

and thus was already consolidated at the time of track

formation. Deio Lav-A has the deepest tracks with the

largest displacement rims of all trackways studied. When

the sediment was completely squeezed outwards, the

actual imprint of the foot may have also been left on a

level, which was situated within the sediment prior to track

formation. Such tracks are called underprints (sensuMarty

et al. 2009), and this scenario is expressed by the trackway

CTD-PMM-1505-S1 and explains why this trackway does

not show anatomical details of the feet of its trackmaker.

With the exception of some tracks of the trackway

CTD-TCH-1055-S4, none of the trackways has tracks with

substantial anatomical details of the foot. This is either

related to unsuitable substrate properties (e.g. compo-

sition, grain size, moisture content and the presence or

absence of microbial mats), covering of the foot with

adhering sediment, unsuitable behaviour of the trackmaker

(e.g. moving or dragging of feet during track formation), to

overgrowth and modification by microbial mats forming

overtracks and resulting in amalgamated track infills, or to

a combination of the above factors. In the case of the

Moroccan trackways, this may further be related to recent

weathering due to their long exposure, and this may

occasionally have modified the track outlines.

Because the preservational setting of all studied

trackways is similar in as far that the sediment was not

susceptible for deformation to greater depths (even though

it cannot be excluded that it was slippery in some cases),

differences in substrate properties are not very likely to be

the reason for the observed variations in trackway

configuration and gauge described below.

Pes and manus track morphology

The overall pes track outline varies from oval and rounded

posteriorly (CTD-SCR-1000-S10) to bell shaped and

pointed posteriorly (CTD-PMM-1505-S1, Deio-D). Pes

tracks are always longer than wide, and the maximum

width is located in the anterior half of the track with

respect to the midpoint of the pes’ long axis. The position

Historical Biology 121

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of its intersection with the pes’ long axis (i.e. the reference

point) is generally closer to the midpoint of the pes’ long

axis, even though in the two trackways with the largest

tracks (CTD-PMM-1505-S1 and Deio-D) it is closer to the

anterior end of the pes’ long axis. Some pes tracks of

the trackway CTD-TCH-1055-S4 have impressions of the

digits I–III and of two strongly outward rotated claws on

digits I and II.

Manus tracks are always wider than long, the overall

outline of undeformed and well-preserved manus tracks

varying from crescent shaped (CTD-SCR-1000-S10,

CTD-PMM-1505-S1) to semicircular (CHE-CRO-500-

S10, CTD-TCH-1055-S4, Deio Lav-A) and digit and

claw impressions are never discernible. Even along

single trackways, the shape of manus tracks is subjected

to strong variation, possibly related to a more or less

digitigrade posture of the manus depending on the

behaviour of the trackmaker. The best-defined manus

tracks are those of trackways CTD-TCH-1055-S4 and

Deio Lav-A, both being strongly inclined towards the

anterior part of the track and showing some evidence for

an anterior crescent-shaped groove. This possibly

indicates that digits II–IV were bound together in a

pad and that the manus was put in a pronounced

digitigrade way. The depth of pes and manus tracks is

always in the same order; only the trackway Deio-D has

slightly deeper pes than manus tracks.

Trackway configuration

The most obvious differences in trackway configuration

are the degree of overprinting of manus by the subsequent

pes tracks, the degree of outward rotation of pes and manus

tracks, heteropody, trackway gauge and the position of pes

and manus tracks with respect to each other and the

trackway midline.

Apart from CTD-TCH-1055-S4, where the manus

tracks are well in front of the pes tracks and closer to the

subsequent pes track of the opposite side, manus tracks are

located close to the subsequent pes tracks. Partial

overprinting of the manus by the subsequent pes occurs

(at least sometimes) in the trackways CHE-CRO-500-S10,

CTD-SCR-1000-S10, Deio-D and Deio Lav-A. However,

there is no evidence to suggest that this is related to

trackway gauge or locomotion speed, even though it is

generally assumed that overprinting in trackways of

quadrupedal tetrapods rather occurs at higher speeds (e.g.

Peabody 1959 and Haubold 1971). Nonetheless, Marty

(2008) observed on a trackway sample of the CHE-CRO

tracksite that overprinting tends to be associated with

lower locomotion speeds.

Pes and manus tracks are always rotated outward and

with the exception of CTD-PMM-1505-S1, manus tracks

generally have a higher outward rotation. Pes outward

rotation is in the order of 20–308 and manus outward

rotation in the order of 30–708, even though important

differences between left and right tracks are common (e.g.

CTD-PMM-1505-S1, Deio Lav-A). Manus outward

rotation may also be extremely pronounced with up to

1078 in CTD-TCH-1055-S4.

Heteropody, as expressed by the ratio between the

indices of pes and manus track size, is highest for CTD-

SCR-1000-S10 and Deio-D (2.4), followed by Deio Lav-A

(2.2). The trackways CHE-CRO-500-S10, CTD-TCH-

1055-S4 and notably CTD-PMM-1505-S1 (1.4) have

ratios smaller than 2.0.

Figure 7(A) shows that the [PTR] ratio and the

[WAP/PL] ratio give similar results for the gauge of the

trackways analysed, and this was also obtained by Marty

(2008, p. 163, figure 5.38) for other trackways from NW

Switzerland and selected ichnotaxa and other published

trackways. Gauge varies from narrow (CTD-SCR-1000-

S10, CTD-TCH-1055-S4, Deio-D) over medium (Deio

Lav-A) to wide (CTD-PMM-1505-S1) and very wide

(CHE-CRO-500-S10) (Figure 7(A) and (B), Table 1). The

trackway Deio Lav-A falls into the medium-gauge field

with a [WAP/PL] ratio slightly higher than 1.0 and a

PTR clearly smaller than 50%. The trackway CTD-SCR-

1000-S10 with a [WAP/PL] ratio of 0.8 and a PTR of 51.4

is the narrowest, and the trackway CHE-CRO-500-S10

with a [WAP/PL] ratio of 2.3 and a PTR of 27.3 is the

widest one. The [WAP/PL] ratio poorly correlates with

both mean pes length (Figure 7(C)) and locomotion speed

(Figure 7(D)) suggesting that trackmaker size and

differences in speed do not significantly contribute to the

observed differences in gauge. In Figure 7(B), the

[WAM/WM] ratio shows the variation in manus trackway

gauge. Manus trackway gauge is higher in the trackway

CHE-CRO-500-S10 because this trackway is much wider

than the other trackways, and it is comparatively high in

the narrow-gauge trackways CTD-SCR-1000-S10 and

Deio-D because of their pronounced exterior manus

position.

For all studied trackways, the ratio between the

widths of the pes and manus angulation pattern (i.e. the

[WAP/WAM] ratio) is smaller than 1.0 (Figure 7(B), (E)

and (F)) and thus manus tracks are located farther away

from the trackway midline than pes tracks. The trackway

outline drawings shown in Figure 5 and the distribution

of the trackways shown in Figure 7(E) and (F) further

suggest that the narrower trackways (CTD-SCR-S10,

CTD-TCH-1055-S4, Deio-D) tend to have manus tracks

located farther away from the trackway midline than the

wider trackways (Deio Lav-A, CTD-PMM-1505-S1,

CHE-CRO-500-S10), and that this configuration is

independent of trackmaker size because the mean pes

length correlates poorly with the [WAP/WAM] ratio

(Figure 7(E)). However, it has to be considered that the

good positive correlation in Figure 7(F) between the

[WAP/PL] ratio and the [WAP/WAM] ratio may be

D. Marty et al.122

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related to the fact that both ratios have WAP in the

numerator. The poor correlation in Figure 7(C)–(E), on

the other hand, may be related to the fact that the

trackways were left by different sauropod trackmaker

species. This is very likely the case for the trackways of

NW Switzerland when compared to those of Morocco,

and it is also possible that the trackways of NW

Switzerland were left by different sauropods.

Summary

The trackways from NW Switzerland and Morocco wereleft by sauropods ranging in size from small to very large.The pes and manus tracks of all studied trackways have asimilar morphology (overall track outline), notably alsothe narrow- and very wide-gauge trackways within theNW Switzerland trackway samples. Pes tracks are alwayslonger than wide, more or less oval to bell shaped and

A B

C D

E F

PBro

Bro

Bro

Bro

PBro

Bre

Deio-D

Deio Lav-A

Bro

PBro

Deio Lav-A

Deio Lav-A

CTD-PMM-1505-S1

PB

roDeio Lav-A

narrow medium wide

wid

em

ediu

mna

rrow

0.8

30

120

110

100

90

80

70

Mea

n pe

s le

ngth

[cm

]

Loco

mot

ion

spee

d [k

m/h

]60

50

40

30

1.2

1.1

1

0.9

0.8

0.7

0.6

0.5

40

50

1 1.2 1.4 1.6

[WAP/PL] ratio

[WAP/PL] ratio

[WA

P/W

AM

] rat

io

1.2

1.1

1

0.9

0.8

0.7

0.6

0.5

[WA

P/W

AM

] rat

io

Pes

trac

kway

rat

io [%

]

1.8 2 2.2 2.4

0.8

30 40 50 60 70 80Mean pes lenght [cm]

90 100 110 120

1 1.2 1.4 1.6 1.8 2 2.2 2.4

[WAP/PL] ratio

0.8 1 1.2 1.4 1.6 1.8 2 2.2 2.4

[WAP/PL] ratio0.8 1 1.2 1.4 1.6 1.8 2 2.2 2.4

very wide

CT

D-T

CH

-105

5-S

4CTD-PMM-1505-S1

CTD-PMM-1505-S1

CTD-PMM-1505-S1

Dei

o-D

& B

re

Dei

o-D

& B

reD

eio-

DB

reP

Bre

N = 9r = –0.97r = –0.92

N = 9r = –0.26r = –0.10

N = 9r = 0.56r = 0.78

N = 9r = –0.18r = –0.33

N = 9r = 0.16r = 0.07

CHE-CRO-500-S10

4CTD-S

CR-1000-S10

Parabrontopodus

Deio-DBrevip

aropus

CTD-TCH-1055-S

4

Deio Lav-A

CTD-PMM-1505-S

1

Brontopodus

CHE-CRO-500-S

10

3.5

3

2.5

Tra

ckw

ay g

auge

rat

ios

2

1.5

1

0.5

7

6

5

4

3

2

1

[WAP/PL] ratio [WAM/MW] ratio [WAP/WAW] ratio

Dei

o-D

CT

D-S

CR

-100

0-S

10

CT

D-T

CH

-105

5-S

4

CH

E-C

RO

-500

-S10

CT

D-S

CR

-100

0-S

10

CT

D-T

CH

-105

5-S

4

CHE-CRO-500-S10

CT

D-S

CR

-100

0-S

10

CT

D-T

CH

-105

5-S

4

Deio Lav-A

Bro

CTD-PMM-1505-S1

CHE-CRO-500-S10

CT

D-S

CR

-100

0-S

10

CHE-CRO-500-S10

CTD-TCH-1055-S4

CTD-SCR-1000-S10

man

us c

lose

rto

mid

line

pes

clos

er to

mid

line

Bre

Figure 7. Plots exhibiting the differences in trackway gauge and in the position of pes and manus tracks with respect to the trackwaymidline among the studied trackways and for the three sauropod ichnotaxa included in the discussion. For the data used, refer to Table 1(studied trackways) and Table 2 (sauropod ichnotaxa). (A) Plot of the [WAP/PL] ratio against the pes TR. (B) Variation of the [WAP/PL]ratio, the [WAM/MW] ratio and the [WAP/WAM] ratio. (C) Plot of the [WAP/PL] ratio against the mean pes length. (D) Plot of the[WAP/PL] ratio against locomotion speed. (E) Plot of the mean pes length against the [WAP/WAM] ratio. (F) Plot of the [WAP/PL] ratioagainst the [WAP/WAM] ratio. In (A) the boundaries between the different gauge types with respect to the PTR ratio follow Romano et al.(2007), and in (A), (C), (D) and (F) the gauge boundaries with respect to the [WAP/PL] ratio follow Marty (2008). Bro is Brontopodus;PBro, Parabrontopodus and Bre, Breviparopus.

Historical Biology 123

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occasionally slightly triangular (pointed posteriorly). The

latter pes tracks may be related to a slight sliding of the pes

on the surface while the track was left, or in the case of the

Moroccan trackway Deio-D also to recent weathering or to

a combination of both. A sliding or moving of the pes

during track formation may also explain the absence of pes

digit and claw impressions in some of the trackways.

Manus tracks, if undeformed by the subsequent pes, are

always wider than long, semicircular or slightly crescent

shaped, and without evidence for a claw impression on

digit I. This reflects the shape of the feet to a certain

degree, but the form of the tracks is also influenced to a

certain degree by the behaviour of the trackmaker and/or

the substrate properties (e.g. slippery, sediment backflow

into track). Manus tracks are often incomplete impressions

because the manus was put in a more pronounced

digitigrade way, resulting in the lack of the impression of

the rear part of the manus (e.g. Marty 2008). Such manus

tracks are inclined towards the anterior part of the track

(Figure 6(H)–(J)).

Apart from the wide range of trackway gauge, they are

also characterised by a similar general trackway configur-

ation with pes and manus tracks rotated outwards (where

manus tracks generally have a higher outward rotation than

pes tracks), more or less pronounced heteropody and

centres of manus being placed farther away from the

trackway midline than those of the pes tracks.

The trackways CTD-SCR-1000-S10 and Deio-D are

similar because they have a narrow gauge, manus tracks

located on the prolongation of the pes’ long axis and farther

away from the trackway midline than the pes and a

pronounced heteropody. CTD-TCH-1055-S4 is also

narrow gauge but it differs because of a smaller heteropody

coefficient, manus tracks located well in front of the pes

tracks and to the inside of the prolongation of the pes’ long

axis, a very high manus outward rotation and because of the

presence of digit and claw impressions in the pes track.

Deio Lav-A is different because it is a medium gauge, has

manus tracks located not much farther away from trackway

midline than pes tracks and relatively deep tracks.

CHE-CRO-500-S10 and CTD-PMM-1505-S1 are

similar because they have a wide gauge, a less

pronounced heteropody and semicircular manus tracks

located almost as close to trackway midline as pes

tracks. These characteristics are different from the other

trackways analysed. Nonetheless, regarding the overall

pes and manus track outline, even these two trackways

are similar to the other ones, notably the bell-shaped pes

tracks of CTD-PMM-1505-S1 are similar to the ones of

Deio-D.

Concluding this section, more trackways (including

wide-gauge ones) with digit and claw impressions need to

be examined for a more accurate distinction of the

trackways from NW Switzerland and Morocco, and also

for a distinction within the trackway samples of NW

Switzerland (notably between the narrow- and wide-gauge

trackways) and of Morocco.

Discussion

The aim of this discussion is to briefly review important

Late Jurassic to Early Cretaceous sauropod ichnotaxa, to

provide a differential diagnosis (based on track mor-

phology and trackway configuration) for the studied

trackways from NW Switzerland and Morocco, and to

evaluate whether they can be assigned ichnotaxonomically

and whether possible trackmakers can be identified.

Review of Late Jurassic to Early Cretaceous sauropodichnotaxa

Sauropod ichnotaxa were reviewed by Farlow et al.

(1989), Farlow (1992), Lockley et al. (1994b), Meyer et al.

(1994), Dalla Vecchia and Tarlao (2000), Avanzini et al.

(2003), Dalla Vecchia (2005) and Wright (2005), and

Table 2. Data source of sauropod ichnotaxa used for the plots of Figure 7.

Ichnotaxon B. taghbaloutensis P. mcintoshi B. birdi

References (a) Ishigaki (1989),(b) Belvedere (2008)

(c) Lockley et al. (1994),(d) Lockley et al. (1986)

(e) Farlow et al. (1989),(f) Romano et al. (2007)

Outline drawing in Figure 8 after (a, figure 9.5) (c, figure 7b) (e, figure 42.3)PL (cm) 110.7 (b) 60 (d) 86.5 (e)PTR (%) 50.2 (b) 51.90 36.04 (f)[WAP/PL] ratio 0.90 0.87 1.46

Wap measured on outline drawingPL after (d, figure 9.5) (b) (d, figure 7b) (d) (f, figure 3a) (e)

[WAM/MW] ratio 2.20 2.03 2.32WAM measured on outline drawingMW after (a, figure 9.5) (b) (d, figure 7b) (d) (f, figure 3a) (e)

[WAP/WAM] ratio 0.66 0.81 1.13Trackway gauge Narrow Narrow WideLocomotion speed (km/h) 4.00 (b) 6.80 (d) 1.21 (this work)

D. Marty et al.124

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currently about a dozen of ichnotaxa are attributed to

sauropods. Of these, only a few are considered as valid by

the majority of the authors cited above, and in this

discussion, the ichnotaxa Breviparopus and Parabronto-

podus from the Late Jurassic and Brontopodus from the

Early Cretaceous are considered.

Breviparopus Dutuit and Ouazzou, 1980

The reference trackway of Breviparopus corresponds to

the trackway Deio-D of this study. According to the

detailed descriptions provided by Dutuit and Ouazzou

(1980), it is characterised by:

(1) A clearly narrow-gauge trackway with pes tracks

intersecting the trackway midline (l’axe de la piste

passe par la partie posterieure des empreintes des

pattes posterieures).

(2) Manus tracks located further away from the trackway

midline than pes tracks (l’empreinte du membre

anterieur est d’avantage ecartee de l’axe de la

marche que celle du membre posterieur).

(3) Manus tracks located in front of pes tracks and being

(slightly) overprinted by the pes tracks (l’empreinte

laissee par le membre posterieur suit immediatement

celle du membre anterieur, le bourrelet anterieur de

la premiere et le bourrelet posterieur de la seconde se

confondant).

(4) Manus tracks with a slightly semicircular shape

without evidence for digit impressions (l’empreinte

de patte anterieure est sensiblement en demi-cercle

. . . Aucun doigt n’est visible).

(5) Pes tracks with a slightly oval shape with at least four

digit impressions separated by three small interdigital

displacement rims, and evidence for claw marks

within the overall displacement rim (l’empreinte de

patte posterieure s’inscrit dans une figure geome-

trique intermediaire entre le triangle a sommet

posterieur et petit cote anterieur et l’oval deforme

s’effilant en arriere . . . on remarque aussi la presence

d’encoches sur le bourrelet anterieur de l’empreinte

posterieure, bourrelet qui temoigne ainsi de l’exist-

ence de griffes . . . au moins quatre doigts porteurs a

sa patte posterieure. On constate en effet la presence

de trois bourrelets interdigitaux).

(6) A pronounced heteropody in the order of 1:3.6

(La surface d’empreinte posterieure est donc 3.6

fois plus grande que celle de l’empreinte

anterieure).

We agree with this general description, but we could

not observe the described digit and claw impressions. The

trackway in the current preservation state – contra the

published outline drawings of Dutuit and Ouazzou (1980)

and Ishigaki (1989), illustrated in our Figure 8(A) – does

not show any evident digit and claw impressions, and this

was already noted by Meyer and Monbaron (2002). The

outline drawing in Ishigaki (1989) illustrates well the gross

outline of the Breviparopus pes tracks, but the illustration

of claws is misleading. In our opinion, digit and claw

impressions are also not clearly visible on the original

photos of the trackway published by Dutuit and Ouazzou

(1980). Furthermore, the Deio-D trackway is slightly

asymmetric with left manus tracks being located closer to

the trackway midline than the right ones and having a

smaller outward rotation than the right ones (Figures 5(E),

6(R) and 8(A)). At least, some of the left manus tracks are

located as close to the trackway midline as the

Figure 8. Outline drawings (drawn to scale) of Late Jurassic toEarly Cretaceous sauropod ichnotaxa as they were originallypublished. (A) Because Dutuit and Ouazzou (1980), whodescribed B. taghbaloutensis, only illustrated selected tracksbut not a trackway segment, here the outline drawing of Ishigaki(1989, figure 9.5, p. 85) is shown. These tracks correspond to thetracks D/25 to D/28 of Belvedere (2008). Compare the outlinedrawing of B. taghbaloutensis with our interpretation shown inFigure 5(E) and the photographs in Figure 6(R)–(T), even if theyare not the same tracks. (B) Outline drawing of the holotypetrackway CU-MWC 190.5, from Lockley et al. (1986; figure 7b,p. 1170). (C) Bird’s outline drawing (without the tridactyl tracks)of the slab excavated for the American Museum of NaturalHistory, from Farlow et al. (1989; figure 42.3, p. 374).

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corresponding subsequent pes tracks, contrary to Dutuit

and Ouazzou (1980), who stated that manus tracks are

located further away from the trackway midline than pes

(point 2 above).

A pes TR larger than 50% and a [WAP/PL] ratio

clearly smaller than 1.0 confirm that Breviparopus has,

despite a comparatively pronounced outward pes rotation,

a narrow gauge (Figure 7(A) and (B)), even if our PTR

(50.2%) is lower than that (51.48 and 53.54%) calculated

by Romano et al. (2007) based on the outline drawings of

Ishigaki (1989) and Thulborn (1990), respectively. This is

due to the fact that these published outline drawings refer

to the best-preserved and narrower trackway segment (i.e.

tracks Deio-D/25 to Deio-D/28), while our PTR is

calculated based on the whole trackway. Breviparopus is

further characterised by a low [WAP/WAM] ratio

indicating that the manus tracks are located clearly farther

away from the trackway midline than the pes tracks.

Dutuit and Ouazzou (1980) introduced the name

B. taghbaloutensis stating that they use it for description

only and without any taxonomical value. Nonetheless, this

ichnotaxon is generally considered as valid and was used

by Farlow (1992) as the ‘type’ example of a narrow-gauge

trackway. However, we suggest that Breviparopus needs to

be formally erected based on the reference trackway.

Because this trackway may have suffered from erosion

during the last 30 years, the description (notably the

presence and position of digit and/or claw impressions)

has to be verified and/or emended (cf. Sarjeant 1989;

Billon-Bruyat and Mazin 2003) based on new, better-

preserved tracks that could possibly be found by further

excavating at the beginning of the Deio-D trackway. The

type trackway should then be protected in situ and a cast of

at least one well-preserved pes–manus couple should be

made and housed in an official institute or museum.

Otherwise, the tracks risk rapid disintegration, continu-

ously lowering their ichnotaxonomic value.

Parabrontopodus Lockley, Farlow and Meyer 1994

This ichnotaxon is based on a trackway from the

Purgatoire Valley Dinosaur tracksite, USA (Unit B of

the Morrison Formation, Late Jurassic), described as:

Narrow sauropod trackway of medium to large size(footprint length about 50–90 cm), characterized by nospace between trackway midline and inside margin of pestracks. Pes footprint longer than wide with long axisrotated outward. Pes claw impressions, corresponding todigits I, II and III show strong outward rotation. Manustracks semicircular and small in comparison with pestracks (i.e. pronounced heteropody) (Lockley et al. 1994b)(Figure 8(B)).

Lockley et al. (1994b) further noted that Parabrontopodus

has a heteropody coefficient of about 1:4 or 1:5.

Even though Wright (2005) stated ‘Lockley et al.

(1994b) did not note how Parabrontopodus could be

differentiated from Breviparopus’ and that for this reason

‘Parabrontopodus may be a junior synonym of Brevipar-

opus’, Parabrontopodus is considered as valid here, also

because Breviparopus was never formally erected. A pes

TR larger than 50% and a [WAP/PL] ratio clearly smaller

than 1.0 confirm that Parabrontopodus is characterised by

a narrow gauge, in about the same order as Breviparopus

(Figure 7(A) and (B)).

The Parabrontopodus type tracks from the Purgatoire

Valley are found in high-energy oolitic shoreface

limestones with interbedded lacustrine shales (Lockley

et al. 1986; Prince and Lockley 1989), and judging from

illustrations in Lockley et al. (1986, 1994b), the holotype

tracks are relatively deep and do not have displacement

rims because they were left in a thick layer of water-

unsaturated carbonate mud with a high plasticity, and this

may be the reason why the claw impressions are quite well

defined.

Brontopodus Farlow, Pittman and Hawthorne 1989

This ichnotaxon was defined based on a trackway from the

Paluxy River Valley near Glen Rose, Texas (Trinity

Group, Aptian–Albian, Early Cretaceous), based on both

track morphology and trackway parameters (Figure 8(C)).

Farlow et al. (1989) stated that it is unknown

which features are diagnostic at the ichnogenus level

and provided the following detailed diagnosis for

Brontopodus:

Sauropod ichnites of small to large size, known pesfootprint length ranging 50 to over 100 cm. Manusfootprint length and width about the same in well-preserved tracks; manus tracks clawless, somewhat U-shaped, with digit impressions I and IV slightlyseparated from the impression of the conjoined digitsII–IV. Pes tracks longer than broad, with large, laterallydirected claw marks at digits I–III (diminishing in sizefrom I to III), a small claw, nail, or callosity mark atdigit IV, and a small callosity or pad mark at digit V;digit marks IV and V only seen in well-preservedfootprints. Manus tracks often (usually?) rotated outwardwith respect to direction of travel. Manus track medial toa line through pes track long axis, such that manus trackcentres are somewhat closer to the trackway midlinethan pes track centres. Trackway broad, with left andright manus and pes footprints often well away from thetrackway midline; trackway width roughly 1–1.5 timespes track length. Outer limits of trackway defined by pestracks. Manus-pes distance 0.5–1.2 times pes footprintlength. Stride length roughly 2–5 times pes track length.Step angle generally 1008–1208. Glenoacetabular lengthc. 3–4 times pes track length. Tail drag marks rare orabsent.

The B. birdi trackways of the Paluxy River are very well

preserved, and this has to be considered when comparing

these tracks with other less well-preserved tracks. Also, it

has to be born in mind that the Brontopodus tracks from

the Paluxy River Valley are very deep without displace-

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ment rims and with a well impressed foot morphology

including the claws because they were left in a nearshore

carbonate setting (e.g. Farlow 1987 and Pittman 1989,

1990, 1992) possibly in a thick layer of water-unsaturated

carbonate mud with a high plasticity (personal observation

DM). Walking in such deep sediment certainly had an

impact on the trackmaker’s behaviour, and the pronounced

claw impressions may also be related to a functional

reason, e.g. they may have improved the animal’s footing

providing a ‘snowshoe’ effect (Gallup 1989), or as

suggested by Pittman and Gillette (1989) that ‘ . . . on

firmer substrates the claws were “wrapped” around the

lateral margin of the foot, and on softer substrates the

claws were often extended forward, probably to provide

better traction’.

The pes TR in the type trackway (Farlow et al. 1989)

varies from c. 32.5% to nearly 38% and characterises

Brontopodus as medium gauge to wide gauge (Romano

et al. 2007, p. 261 and figure 15A), and the [WAP/PL] ratio

as wide gauge, respectively (Figure 7(A) and (B); Table 2).

Brontopodus is further characterised by a [WAP/WAM]

ratio higher than one indicating that the manus tracks are

located closer to the trackway midline than the pes tracks,

and this is also indicated by a comparatively small

[WAM/WM] ratio (Figure 7(B)). Brontopodus has a

heteropody of about 1:3 (Lockley et al. 1994b).

Differential diagnosis

Regarding Breviparopus

The Moroccan trackway Deio-D is the reference trackway

of Breviparopus, and it is similar to the Swiss trackway

CTD-SCR-1000-S10 because of its narrow gauge,

pronounced heteropody and outward rotated manus tracks

located on the prolongation of the pes’ long axis and

clearly farther away from the trackway midline than the

pes, expressed by the lowest [WAP/WAM] ratio of all

trackways (Figure 7(B)). Nonetheless, CTD-SCR-1000-

S10 has much smaller pes tracks with a more oval overall

track outline than Breviparopus (Deio-D), which has large

(.1.0m length) pes tracks with a bell-shaped, slightly

triangular outline. This particular pes track morphology,

on the other hand, is also characteristic for CTD-PMM-

1505-S1, with pes tracks equally longer than 1.0m.

However, the latter trackway has a wide gauge, a less

pronounced heteropody and manus tracks located

much closer to the trackway midline than in Breviparopus

(Deio-D). Breviparopus (Deio-D) differs from Parabron-

topodus and Brontopodus because of the bell-shaped pes

track outline, the absence of claw marks on the pes tracks,

a higher pes and manus outward rotation and manus tracks

located on the prolongation of the pes’ long axis and

farther away from the trackway midline. It further differs

from Brontopodus because of its narrower gauge, a

semicircular manus shape and a higher heteropody.

Regarding Parabrontopodus

Marty et al. (2003) assigned the narrow-gauge trackway

CTD-SCR-1000-S10 to the ichnotaxon Parabrontopodus,

mainly based on the typical trackway configuration

characterised by a pronounced narrow gauge and

heteropody. However, heteropody is less pronounced in

CTD-SCR-1000-S10, and the manus tracks are located

farther away from the trackway midline than in

Parabrontopodus. Belvedere et al. (2007) suggested that

the medium-gauge trackway Deio Lav-A from Morocco is

more similar to Parabrotopodus than Breviparopus,

because manus tracks are semicircular, pes and manus

tracks have a lower outward rotation and manus tracks are

located closer to the trackway midline than in Brevipar-

opus. The third narrow-gauge trackway CTD-TCH-1055-

S4 analysed here is also similar to Parabrontopodus,

notably because it has evident impressions of the first three

digits and the first two claws, the latter being strongly

rotated outwards as in Parabrontopodus. On the other

hand, heteropody is decidedly smaller in CTD-TCH-1055-

S4 and it further has an exceptional high manus outward

rotation and a particular manus position well in front of the

pes tracks and never deformed by the subsequent pes,

when compared with the holotype trackway of Para-

brontopodus. Parabrontopodus differs from Breviparopus

(Deio-D) because of the oval-shaped pes tracks with claw

impressions and manus tracks with a smaller outward

rotation and being located closer to the trackway midline.

It differs from Brontopodus because of its narrower gauge,

a semicircular manus shape and a higher heteropody.

Regarding Brontopodus

Marty (2008) tentatively assigned the very wide-gauge

trackway CHE-CRO-500-S10 to the ichnotaxon Bronto-

podus mainly because of its very wide gauge. This is

supported by manus tracks located almost as close to the

trackway midline as pes tracks. Nonetheless, the

assignation is tentative at best because CHE-CRO-500-

S10 does not exhibit digit and claw impressions due to the

poor preservation of the pes tracks, and Brontopodus is less

wide gauge and has manus tracks located closer to the

trackway midline than pes tracks. CTD-PMM-1505-S1 is

similar to Brontopodus because of a wide gauge, small

heteropody, semicircular to subcircular manus track

outline and manus tracks located almost as close to

trackway midline as pes tracks. This trackway compares

favourably with Brontopodus, but it cannot be assigned

with certainty because of the absence of digit and claw

impressions. Finally, the trackways CTD-SCR-1000-S10,

Deio-D and Deio Lav-A are different from Brontopodus

because of their narrow gauge and manus tracks located

farther away from trackway midline than pes tracks. CTD-

TCH-1055-S4 differs because of the absence of small digit

and clawmarks at digits IVand V, even though Farlow et al.

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(1989) noticed that in Brontopodus, these are only seen in

well-preserved footprints. Brontopodus differs from

Breviparopus (Deio-D) because of pes tracks with claw

impressions and manus tracks with a smaller outward

rotation. It differs from Breviparopus and Parabrontopo-

dus because of its wider gauge, U-shaped manus tracks, a

smaller heteropody and manus tracks located somewhat

closer to the trackway midline than pes tracks.

Summary

Wright (2005) recommended that sauropod trackways

should be classified primarily on pes and manus

morphology and only secondarily on trackway configur-

ation (trackway gauge). However, with the exception of

CTD-TCH-1055-S4, all studied trackways lack anatom-

ical details and for this reason an ichnotaxonomical

assignation based on footprint morphology is not

possible for these trackways. Based on trackway

configuration (notably gauge and for some of the

trackways heteropody and the position of pes and manus

tracks with respect to trackway midline), the studied

trackways could be assigned equally between the

narrow-gauge ichnotaxa Breviparopus (Deio-D, CTD-

SCR-1000-S10) and Parabrontopodus (CTD-TCH-1055-

S4, Deio Lav-A) and the wide-gauge ichnotaxon

Brontopodus (CHE-CRO-500-S10, CTD-PMM-1505-

S1). In trackway CTD-TCH-1055-S4, the number and

outward rotation of digits and claws is furthermore

similar to Parabrontopodus, even though trackway

configuration, heteropody and preservation (track

depth) are clearly different from the type specimen of

Parabrontopodus (CU-MWC 190.5; Lockley et al. 1986,

figure 7B; 1994b, figures 3 and 4). However, some

trackways from the Parabrontopodus-type locality (e.g.

CU MWC 190.3; Lockley et al. 1986, figures 7A and

9A) also show considerable changes in trackway

configuration (e.g. manus well in front of pes tracks,

high manus outward rotation) with regard to the

holotype. This can also be observed within the Swiss

narrow-gauge trackways CTD-SCR-1000-S10, CTD-

TCH-1055-S4 and CTD-SCR-1000-S4 [described by

Marty et al. (2003)] of the intermediate track-bearing

levels, which exhibit very different trackway configur-

ations, notably regarding the outward rotation and

position of pes and manus tracks. This evidence suggests

that this variability in trackway configuration may be

related to the behaviour of the trackmaker rather than to

different ichnotaxa.

Identification of possible trackmakers

A precise trackmaker identification is outside the scope of

this paper, because this is generally not possible unless the

animal is preserved at the end of its fossil trackway. The

purpose here is to provide a gross identification based on

track morphology, trackway configuration and on a short

review of skeletal material found in relative close

proximity to the tracksite localities, even though it has to

be considered that skeletal remains of the trackmakers may

not as yet have been found.

Based on track morphology

The typical pes and manus overall track morphology and

trackway configuration of all studied trackways readily

identify them as trackways left by sauropods. In the Late

Jurassic, the vast majority of quadrupedal dinosaur

trackways are attributed to sauropods, even though they

could have also been left by ornithischian dinosaurs such

as basal ceratopsians, ankylosaurs or most likely

stegosaurs as indicated by the skeletal record (Currie and

Padian 1997; Meyer and Hunt 1998; Weishampel et al.

2004). Thus, poorly preserved ornithischian trackways

could possibly be misinterpreted as the trackways of

smaller sauropods. Ankylosaur tracks are known from the

Cretaceous only (review in McCrea et al. 2001), even

though an ankylosaur trackway from Dorset (England)

may be of Late Jurassic age (Wright 1996; Ensom 2002).

Late Jurassic stegosaur tracks assigned to the ichnotaxon

Deltapodus are described from the Middle Jurassic of

England (Whyte and Romano 2001; Romano and Whyte

2003; Whyte et al. 2007), the Morrison Formation

(Lockley and Hunt 1998; Milan and Chiappe 2009),

from Spain (Cobos et al. 2008; Lockley et al. 2008), from

Portugal (Mateus and Milan, Forthcoming 2009), from

Poland (Gierlinski and Sabath 2002) and also from the

Iouaridene Formation, Morocco (Belvedere and Mietto

2010), and they all clearly differ from the herein described

sauropod tracks because of a particular pes morphology

characterised by a triangular outline with three short,

blunt, rounded and forward facing digit impressions and a

broad massive heel area.

When compared with predicted pes track mor-

phologies of Wright (2005) – which she based on pes

synapomorphies inferred from phylogenetic studies

(Upchurch 1998; Wilson and Sereno 1998) – the three

digits and laterally directed two claws in the pes tracks of

CTD-TCH-1055-S4 suggest a diplodocid sauropod as

possible trackmaker. On the other hand, CTD-TCH-1055-

S4 does not show any evidence for a claw impression on

digit I of the manus, which is in contradiction with the

predicted manus track morphology for diplodocid

sauropods of Wright (2005). However, this could also be

related to a functional reason (eventually related to

substrate properties) – even though the pollex claw may

have possessed a limited range of movement (e.g.

Upchurch 1994) – and/or because the rear part of the

manus tracks of CTD-TCH-1055-S4 was not impressed

due to a pronounced digitigrade posture of the manus.

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Based on trackway gauge

Lockley (1999) and Wilson and Carrano (1999) suggested

that more derived sauropods such as the titanosaurs were

the trackmakers of wide-gauge trackways while narrow-

gauge trackways were attributed to more ‘basal’ sauropods,

basal macronarians or diplodocoidea sensu Wilson and

Sereno (1998). Accordingly, and based on trackway gauge,

the studied trackways could, apart from the medium-gauge

trackwayDeioLav-A, easily be attributed tomore basal and

more derived sauropods, respectively. This would indicate

the presence of both groups of sauropods in very close

temporal relationship (and even on single paleosurfaces) on

the Jura carbonate platform, and of more ‘basal’ sauropods

only in the northeastern part of the Sahara Craton during the

Late Jurassic.

On the other hand, wide-gauge trackways could have

occurred more than once in sauropod evolution as the

result of the anteriorisation of the centre of mass

(Henderson 2006) and the overall morphology (Lockley

et al. 2002a), and trackway gauge could also be

influenced by the degree of lateral motion of the

trackmaker (Carpenter 2009). Lockley et al. (2002a),

based on trackway evidence from the Late Cretaceous of

Bolivia, suggested that titanosaurids may have shown

changes from narrow gauge to wide gauge during their

ontogenetic growth. Farlow (pers. comm. 2004 in Wright

2005) noticed that some Brontopodus trackways of the

Paluxy River have a narrow gauge along some trackway

segments, and a change from wide to narrow gauge

along a single trackway was also described by Leonardi

and Avanzini (1994) from the Early Jurassic of northern

Italy. Based on wide-gauge trackways (ichnotaxon

Polyonyx gomesi) from Portugal, which are characterised

by a small heteropody, pes tracks with four claw marks

(claws I–II anteriorly oriented), and notably manus

tracks with large digit I mark and a large triangular claw

mark I posteriorly oriented, dos Santos et al. (2009)

recently argued that at least one basal eusauropod was

able to produce wide-gauge trackways by the Middle

Jurassic. For this reason, they concluded that wide-gauge

trackways are not exclusive to titanosauriform

sauropods.

Based on the skeletal record

For the Late Jurassic, the presence of both groups of

sauropods on the Jura carbonate platform is also supported

by the skeletal record. Cetiosauriscus greppini from the

Kimmeridgian of Moutier, NW Switzerland (von Huene

1922, 1927; Meyer and Thuring 2003; Schwarz et al.

2007), currently considered a nomen dubium (Glut 1997),

is provisionally regarded as Diplodocoidea incertae sedis

(Upchurch et al. 2004), but its phylogeny is currently

under re-evaluation by one of the authors (Meyer).

Bothriospondylus madagascariensis from the Oxfordian

of Damparis, France (Buffetaut 1988), was re-examined

by Moine (1999) and assigned to Brachiosaurus byWilson

(2002, 2005).

From the northeastern part of the Sahara Craton, basal,

vulcanodontid sauropods (Tazoudasaurus naimi) are

known from the Early Jurassic (Allain et al. 2004) and

diplodocid sauropods (Rebbachisaurus garasbae) from the

Early Cretaceous (e.g. de Lapparent 1960 and Monbaron

1978). The presence of more derived sauropods is also

suggested by the Late Jurassic skeletal record of Africa,

notably the well-known Brachiosauridae remains from the

Late Jurassic of Tendaguru, Tanzania (e.g. Russell et al.

1980; Bonaparte et al. 2000 and Schwarz and Fritsch

2006) such as Brachiosaurus brancai recently identified as

Giraffatitan brancai (Taylor 2009). Furthermore, a

brachiosaurid-like sauropod (Atlasaurus imelakei) is

described from the central High Atlas Mountains

(Monbaron et al. 1999), and the bone-bearing layer –

initially thought to be Middle Jurassic in age (Monbaron

et al. 1999) – may actually be of Late Jurassic age (cf.

Charriere et al. 2005).

Concluding remarks and outlook

Sauropod trackways from the Late Jurassic of NW

Switzerland and the central High Atlas Mountains in

Morocco are similar from a preservational point of view

and with respect to the overall pes and manus track outline,

but they show a wide range of trackway configuration and

trackway gauge.

Based on trackway gauge solely, the studied trackways

can either be attributed to one of the narrow-gauge

ichnotaxa Breviparopus or Parabrontopodus, or to the

wide-gauge ichnotaxon Brontopodus. However, taking into

account the absence of digit and/or claw impressions in all

but one of the trackways, and the variable differences in

trackway configuration, an unambiguous ichnotaxonomi-

cal assignation of the trackways studied is not possible. The

Moroccan trackway Deio-D is the reference trackway of

Breviparopus, which we consider a valid ichnotaxon, but

which is in need of a formal and emended re-description

based on better preserved tracks with evident digit and/or

claw impressions. The latter condition is crucial for a clear

distinction between Breviparopus and Parabrontopodus.

The reference trackway (Deio-D) of Breviparopus is

characterised by more bell-shaped to triangular pes tracks

and by manus tracks located clearly farther away from the

trackway midline than in Parabrontopodus. The ichno-

taxon Parabrontopodus is also considered valid (and not a

junior synonym of Breviparopus) and it is characterised by

an oval pes track outline, pes claw impressions on digits I–

III and manus tracks located closer to the trackway midline

than in Breviparopus.

For the trackways and three ichnotaxa analysed, the

narrower trackways tend to have manus tracks located

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farther away from the trackway midline than the wider

ones. This evidence may indicate that the association of

narrow-gauge trackways with manus tracks located farther

away from the trackway midline and wide-gauge track-

ways with manus tracks located closer to the trackway

midline could be an expression of the general posture of

the trackmakers, and this could eventually be useful in the

classification of sauropod trackways.

No clear relationships between trackway gauge

(expressed by the [WAP/PL] ratio) and trackmaker size

(expressed by pes length), locomotion speed or substrate

properties were found for the trackways studied, but gauge

may be influenced by other factors than those analysed,

such as a particular individual behaviour (different degrees

of lateral bending) or sexual dimorphism.

The degree of pes and manus outward rotation, and of

manus overprinting and position in front of the pes is

interpreted as being related to the general locomotion

capabilities of the trackmakers (individual walking style,

locomotion speed, etc.), whereas heteropody is difficult to

calculate due to incomplete manus tracks.

The lack of digit and claw impressions in most of the

trackways studied makes it difficult to more closely

identify the sauropod trackmakers. At least, the three digits

and laterally directed two claws in the pes tracks of the

trackway CTD-TCH-1055-S4 suggest a diplodocid

sauropod as a possible trackmaker for this trackway.

In order to better understand the variability of sauropod

trackway configuration in general and within trackways left

by a specific group (e.g. diplodocids, brachiosaurids and

titanosauriforms) of sauropods, many more trackways need

to be analysed and compared in a similar way. This could be

helped by an online trackway database including pictures,

and if available three-dimensional pictures based on laser

scanning and/or photogrammetry. Then, trackway data

could also be analysed in a statistically more sophisticated

way than done in this work. This may help to better

understand the general locomotion capabilities of sauropods,

and to determine which parameters of trackway configur-

ation are to what degree useful in their classification because

they are an expression of the general posture of the

trackmakers rather than they are influenced by extrinsic

factors. However, even if trackway configuration may – to a

certain degree – be useful in the classification of sauropod

trackways, we agree that ichnotaxa should only be erected

based on well-preserved true tracks with impressions of

substantial anatomical details of the feet such as digit and/or

claw impressions.

Acknowledgements

A part of this research was carried out during the PhD theses ofDM and MB and therefore the Swiss National ScienceFoundation (grant no. 20-109214.05) and the Universita degliStudi di Padova, respectively, are acknowledged. We thank allthe authorities of the Demnat region, from the community chief

to the governor of the Azilal Province, for permissions for thefieldwork. We also warmly thank the AESVT of Demnat,especially M. Chaouki and M. Essoufi, and to SimohamedBenhimou from Taghbalout, for support with the logistics andcontact with the local authorities and people. N.-E. Jalil(University Cadi Ayyad, Marrakech) is thanked for theorganisation of the field trips, the relationships with theM’Goun Geopark direction and the invitation to contribute tothis special volume. S. Ishigaki (Hayashibara Museum of NaturalSciences, Okayama) is thanked for kindly sharing his hugeamount of unpublished sketches of the Iouaridene tracksites.G. Dyke and N.-E. Jalil are thanked for editorial work and foraccepting us to contribute to this special volume on north Africanvertebrate paleontology.

References

Alexander R McN. 1976. Estimates of speeds of dinosaurs. Nature.261:129–130.

Alexander R McN. 2006. Dinosaur biomechanics. Proc R Soc Lond, SerB. 273:1849–1855.

Allain R, Aquesbi N, Dejax J, Meyer CA, Monbaron M, Montenat C,Richir P, Rochdy M, Russell D, Taquet P. 2004. A basal sauropoddinosaur from the Early Jurassic of Morocco. C R Palevol.3:199–208.

Avanzini M, Leonardi G, Mietto P. 2003. Lavinipes cheminii ichnogen.,ichnosp. nov., a possible sauropodomorph track from the LowerJurassic of the Italian Alps. Ichnos. 10:179–193.

Belvedere M. 2008. Ichnological researches on the Upper Jurassicdinosaur tracks in the Iouaridene area (Demnat, central High-Atlas,Morocco) [dissertation]. [Padova (Italy)]: Universita degli Studi diPadova.

Belvedere M, Mietto P. 2010. First evidence of stegosaurian Deltapodusfootprints in North Africa (Iouaridene Formation, Upper Jurassic,Morocco). Palaeontology. 53:233–240.

Belvedere M, Mietto P, Mehdi M. 2007. Dinosaur tracks from the UpperJurassic Iouaridene Formation (Demnat, Morocco). Geoitalia 2007,Rimini, Italy. Epitome. 2:306.

Bertling M, Insalaco E. 1998. Late Jurassic coral/microbial reefs from thenorthern Paris Basin – Facies, palaeoecology and palaeobiogeo-graphy. Palaeogeogr Palaeoclimatol Palaeoecol. 139:139–175.

Billon-Bruyat J-P, Mazin J-M. 2003. The systematic problem of tetrapodichnotaxa: the case study of Pteraichnus Stokes, 1957 (Pterosauria,Pterodactyloidea). In: Buffetaut E, Mazin J-M, editors. Evolutionand palaeobiology of pterosaurs. London: Geol Soc of London SpecPubl. 217: 315–324.

Bonaparte JF, Heinrich WD, Wild R. 2000. Review of Janenschia Wildwith the description of a new sauropod from the Tendaguru beds ofTanzania and a discussion on the systematic value of procoelouscaudal vertebrae in the Sauropoda. Palaeontographica. 256:25–76.

Buffetaut E. 1988. Les restes de dinosauriens de l’Oxfordien superieur deDamparis (Jura): preuves d’emersion sur place. Rev Paleobiol.7:301–306.

Carpenter K. 2009. Role of lateral body bending in crocodylian trackmaking. Ichnos. 16:202–207.

Chafetz HS, Buczynski C. 1992. Bacterially induced lithification ofmicrobial mats. Palaios. 7:277–293.

Charriere A, Haddoumi H, Mojon P-O. 2005. Decouverte de Jurassiquesuperieur et d’un niveau marin du Barremien dans les «couchesrouges» continentales du Haut Atlas central marocain: implicationspaleogeographiques et structurales. C R Palevol. 4:385–394.

Cobos A, Royo-Torres R, Alcala L, Luque L, Aberasturi A. 2008. Nuevosdatos de las icnitas de dinosaurios en la Formacion Villard elArzobispo (Teurel). In: Ruiz-Omenaca JI, Pinuela L, Garcıa-RamosJC, editors. Colunga (Spain): Libro de resumenes. XXIV Jornadas dela Sociedad Espanola de Paleontologıa, Museo del Jurasico deAsturias (MUJA). p. 25–26.

Coombs WP Jr. 1978. Theoretical aspects of cursorial adaptions indinosaurs. Q Rev Bio. 53:393–418.

D. Marty et al.130

Downloaded By: [Belvedere, Matteo] At: 06:20 28 May 2010

Currie PJ, Padian K. 1997. Encyclopedia of dinosaurs. San Diego (CA):Academic Press.

Dalla Vecchia FM. 2005. Between Gondwana and Laurasia: Cretaceoussauropods in an intraoceanic carbonate platform. In: Tidwell V,Carpenter K, editors. Thunder-lizards. Bloomington (IN): IndianaUniversity Press. p. 395–429.

Dalla Vecchia FM, Tarlao A. 2000. New dinosaur track sites in the Albian(Early Cretaceous) of the Istrian peninsula (Croatia). Part II –Paleontology. In: Dalla Vecchia FM, Tarlao G, Tunis G, Venturini S,editors. New dinosaur track sites in the Albian (Early Cretaceous) ofthe Istrian peninsula (Croatia). Padova (Italy): Memorie di ScienzeGeologiche di Padova 52. p. 227–292.

Day JJ, Norman DB, Gale AS, Upchurch P, Powell HP. 2004. A MiddleJurassic dinosaur trackway site from Oxfordshire, UK. Palaeonto-logy. 47:319–348.

Day JJ, Norman DB, Upchurch P, Gale AS, Powell HP. 2002. Sauropodtrackways, evolution, and behavior. Science. 296:1659.

de Lapparent AF. 1960. Les dinosauriens du “Continental intercalaire” duSahara central. Mem Soc Geol France. p. 88A.

dos Santos VF, Moratalla JJ, Royo-Torres R. 2009. New sauropodtrackways from the Middle Jurassic of Portugal. Acta Palaeontol Pol.54:409–422.

Dupraz C, Visscher PT. 2005. Microbial lithification in marinestromatolites and hypersaline mats. Trends Microbiol. 13:429–438.

Dutuit JM, Ouazzou A. 1980. Decouverte d’une piste de dinosauresauropode sur le site d’empreintes de Demnat (Haut-Atlasmarocain). Mem Soc Geol France N S. 139:95–102.

Ensom PC. 2002. Vertebrate trace fossils in the Purbeck Limestone groupof Southern England. In: Milner AR, Batten DJ, editors. Life andenvironment in Purbeck times. Oxford (UK): The PalaeontologicalAssociation. Special Papers in Palaeontology 68. p. 203–220.

Farlow JO. 1987. A guide to Lower Cretaceous dinosaur footprints andtracksites of the Paluxy River Valley, Sommervell County, Texas.Geological Society of America, South-Central Section, 21st AnnualMeeting, Field Trip Guide-Book, Waco, Texas.

Farlow JO. 1992. Sauropod tracks and trackmakers: integrating theichnological and skeletal record. Zubia. 10:89–138.

Farlow JO, Pittman JG, Hawthorne JM. 1989. Brontopodus birdi, LowerCretaceous sauropod footprints from the US Gulf Coastal plain. In:Gillette DD, Lockley GM, editors. Dinosaur tracks and traces.Cambridge: Cambridge University Press. p. 371–394.

Frakes LA, Francis JE, Sykes RM. 1992. Climate modes of thePhanerozoic. Cambridge: Cambridge University Press.

Gallup MR. 1989. Functional morphology of the hindfoot of the Texassauropod Pleurocoelus sp. indet. In: Farlow JO, editor. Paleobiologyof the dinosaurs. Geol Soc Am Spec Pap. 238:71–74.

Gierlinski G, Sabath K. 2002. A probable stegosaurian track from theLate Jurassic of Poland. Acta Palaeontol Pol. 47:561–564.

Glut DF. 1997. Dinosaurs: the encyclopedia. Jefferson (NC): McFarland& Company Inc.

Gonzalez Riga BJ, Calvo JO. 2009. A new wide-gauge sauropod track sitefrom the Late Cretaceous of Mendoza, Neuquen Basin, Argentina.Palaeontology. 52:631–640.

Gygi RA. 2000. Annotated index of lithostratigraphic units currently usedin the Upper Jurassic of Northern Switzerland. Eclogae geol Helv.93:125–146.

Haddoumi H, Charriere A, Andreu B, Mojon P-O. 2009. Les depotscontinentaux du Jurassique moyen au Cretace inferieur dans le HautAtlas oriental (Maroc): paleoenvironnements successifs et significa-tion paleogeographique. Carnets de Geologie. CG2008-A06:1–29.

Hallam A. 1984. Continental humid and arid zones during theJurassic and Cretaceous. Palaeogeogr Palaeoclimatol Palaeoecol.47:195–223.

Hallam A. 1985. A review of mesozoic climates. J Geol Soc (London).142:433–445.

Haubold H. 1971. Ichnia Amphibiorum et Reptiliorum fossilium. In:Kuhn O, editor. Encyclopedia of paleoherpetology. Handbuch derPalaoherpetologie. Part 18. Stuttgart (Germany): Fischer Verlag.

Henderson DM. 2006. Burly gaits: centers of mass, stability and thetrackways of sauropod dinosaurs. J Vertebr Paleontol. 26:907–921.

Hutchinson JR, Anderson FC, Blemker SS, Delp SL. 2005. Analysis ofhindlimb muscle moment arms in Tyrannosaurus rex using a three-

dimensional musculoskeletal computer model: implications forstance, gait, and speed. Paleobiology. 31:676–701.

Ishigaki S. 1985a. Dinosaur footprints from Atlas Mountains. Nat Study.31(10):5–8 [In Japanese].

Ishigaki S. 1985b. Dinosaur footprints from Atlas Mountains. Nat Study.31(12):5–7 [In Japanese].

Ishigaki S. 1985c. Compte rendu d’activite 1984. Unpublished ReportRabat (Morocco): Ministere de l’Energie et des Mines.

Ishigaki S. 1986. Dinosaur footprints from Atlas Mountains. Nat Study.32(1):6–9 [In Japanese].

Ishigaki S. 1989. Footprints of swimming Sauropods from Morocco. In:Gillette DD, Lockley MG, editors. Dinosaur tracks and traces.Cambridge: Cambridge University Press. p. 83–86.

Jank M, Meyer CA, Wetzel A. 2006a. Late Oxfordian to LateKimmeridgian carbonate deposits of NW Switzerland (Swiss Jura):Stratigraphical and palaeogeographical implications in the transitionarea between the Paris Basin and the Tethys. Sediment Geol.138:237–263.

Jank M, Wetzel A, Meyer CA. 2006b. A calibrated composite section forthe Late Jurassic Reuchenette Formation in northwestern Switzer-land (?Oxfordian, Kimmeridgian sensu gallico, Ajoie-Region).Eclogae geol Helv. 99:175–191.

Jenny J. 1985. Carte geologique du Maroc a 1:100’000, feuille Azilal.Notes Mem Serv geol Maroc 399 p.

Jenny J, Jossen J-A. 1982. Decouverte d’empreintes de pas dedinosauriens dans le Jurassique inferieur (Pliensbachien) du Haut-Atlas central Maroc. C R Acad Sci (Paris). 294:223–226.

Jenny J, Le Marrec A, Monbaron M. 1981. Les couches rouges duJurassique moyen du Haut Atlas central (Maroc): correlationslithostratigraphiques, elements de datations et cadre tectono-sedimentaire. Bull Soc geol Fr (7). XXIII(6):627–639.

Leonardi G. 1987. Glossary and manual of tetrapod footprintpalaeoichnology. Brasılia (Brasil): Publicacao do DepartementoNacional da Producao Mineral Brasil.

Leonardi G, Avanzini M. 1994. Dinosauri in Italia. Le Scienze, Quaderni.76:69–81.

Lockley MG. 1991. Tracking dinosaurs: a new look at an ancient world.Cambridge: Cambridge University Press.

Lockley MG. 1999. The eternal trail: a tracker looks at evolution.Cambridge (MA): Perseus Books.

Lockley MG, Farlow JO, Meyer CA. 1994b. Brontopodus andParabrontopodus ichnogen. nov. and the significance of wide- andnarrow-gauge sauropod trackways. Gaia. 10:135–146.

Lockley MG, Garcia-Ramos JC, Pinuela L, Avanzini M. 2008. A reviewof vertebrate track assemblages from the Late Jurassic of Asturias,Spain with comparative notes on coeval ichnofaunas from thewestern USA: implications for faunal diversity in siliciclastic faciesassemblages. Oryctos. 8:53–70.

Lockley MG, Houck KJ, Prince NK. 1986. North America’s largesttrackway site: implications for Morrison Formation paleoecology.Bull Geol Soc Am. 97:1163–1176.

Lockley MG, Hunt AP. 1995. Dinosaur tracks and other fossil footprintsof the western United States. New York (NY): Columbia UniversityPress.

Lockley MG, Hunt AP. 1998. A probable stegosaur track from theMorrison Formation of Utah. In: Carpenter K, Chure D, Kirkland J,editors. The Upper Jurassic Morrison Formation: an interdisciplinarystudy. Modern Geology. 23:331–342.

Lockley MG, Hunt AP, Meyer CA. 1994c. Vertebrate tracks and theichnofacies: implications for paleoecology and palichnostratigraphy.In: Donovan SK, editor. The palaeobiology of trace fossils.Chichester: Wiley. p. 241–268.

Lockley MG, Meyer CA. 2000. Dinosaur tracks and other fossil footprintsof Europe. New York (NY): Columbia University Press.

Lockley MG, Santos VF dos, Meyer CA, Hunt A, editors. 1994a. Aspectsof sauropod paleobiology. Gaia 10.

Lockley MG, Schulp AS, Meyer CA, Leonardi G, Kerumba Mamami D.2002a. Titanosaurid trackways from the Upper Cretaceous ofBolivia: evidence for large manus, wide-gauge locomotion andgregarious behaviour. Cretaceous Res. 23:383–400.

Lockley MG, Wright JL, White D, Jianjun L, Lu F, Hong L, MatsukawaM. 2002b. The first sauropod trackways from China. Cretaceous Res.23:363–381.

Historical Biology 131

Downloaded By: [Belvedere, Matteo] At: 06:20 28 May 2010

Mannion PD. 2008. Environmental associations of sauropod dinosaursand their bearing on the early Late Cretaceous ‘sauropod hiatus’.J Vertebr Paleontol. 28 (Suppl. 3):111.

Marty D. 2008. Sedimentology, taphonomy, and ichnology of LateJurassic dinosaur tracks from the Jura carbonate platform(Chevenez–Combe Ronde tracksite, NW Switzerland): insightsinto the tidal-flat palaeoenvironment and dinosaur diversity,locomotion, and palaeoecology [dissertation]. [Fribourg (Switzer-land)]: University of Fribourg. GeoFocus 21.

Marty D, Ayer J, Becker D, Berger J-P, Billon-Bruyat J-P, Braillard L,Hug WA, Meyer CA. 2007. Late Jurassic dinosaur tracksites of theTransjurane highway (Canton Jura, NW Switzerland): overview andmeasures for their protection and valorization. Bull Appl Geol.12:75–89.

Marty D, Cavin L, Hug WA, Jordan P, Lockley MG, Meyer CA. 2004.The protection, conservation and sustainable use of the Courtedouxdinosaur tracksite, Canton Jura, Switzerland. Rev Paleobiol. VolSpec 9:39–49.

Marty D, Cavin L, Hug WA, Meyer CA, Lockley MG, Iberg A. 2003.Preliminary report on the Courtedoux dinosaur tracksite from theKimmeridgian of Switzerland. Ichnos. 10:209–219.

Marty D, Meyer CA, Billon-Bruyat J-P. 2006. Sauropod trackwaypatterns expression of special behaviour related to substrateconsistency? An example from the Late Jurassic of northwesternSwitzerland. Hantkeniana. 5:38–41.

Marty D, Pacton M. 2009. Formation and preservation of Late Jurassicdinosaur track-bearing tidal-flat laminites (Canton Jura, NWSwitzerland) through microbial mats. In: Billon-Bruyat J-P, MartyD, Costeur L, Meyer CA, Thuring B, editors. 5th InternationalSymposium on Lithographic Limestone and Plattenkalk, Abstractsand Field Guides. Societe jurassienne d’emulation, actes 2009 bis.p. 56–58.

Marty D, Strasser A, Meyer CA. 2009. Formation and taphonomy ofhuman footprints in microbial mats of present-day tidal-flatenvironments: implications for the study of fossil footprints. Ichnos.16:127–142.

Mateus O, Milan J. Forthcoming 2009. A diverse Upper Jurassic dinosaurichnofauna from central-west Portugal. Lethaia. 13 pp.

McCrea RT, Lockley MG, Meyer CA. 2001. Global distribution ofpurported ankylosaur track occurrence. In: Carpenter K, editor. Thearmored dinosaurs. Bloomington (IN): Indiana University Press.p. 413–454.

Meyer CA, Hunt AP. 1998. The first stegosaurian dinosaur (Ornithischia:Thyreophora) from the Late Jurassic of Switzerland. N Jb GeolPalaont. 1998(3):141–145.

Meyer CA, Lockley MG, Robinson JW, dos Santos VF. 1994.A comparison of well-preserved sauropod tracks from the LateJurassic of Portugal and the Western United States: evidence andimplications. Gaia. 10:57–64.

Meyer CA, Monbaron M. 2002. Middle Jurassic dinosaur tracks fromMorocco – Facts and fiction. Paper presented at 7th EuropeanWorkshop on Vertebrate Palaeontology; 2002 Jul 2–7; Sibiu,Romania.

Meyer CA, Thuring B. 2003. Dinosaurs of Switzerland. C R Palevol.2:103–117.

Milan J, Chiappe LM. 2009. First American record of the Jurassicichnospecies Deltapodus brodricki and a review of the fossil recordof Stegosaurian footprints. J Geol. 117:343–348.

Moine O. 1999. Datation, condition de depot et position phylogenetiquede ‘Bothriospondylus madagascariensis’ (Damparis, Jura, France).[Master’s Thesis]. [Lyon (France)]: Ecole Normale Superieure 8:77–106.

Monbaron M. 1978. Nouveaux ossements de Dinosauriens de grandetaille dans le bassin jurassico-cretace de Taguelft (Atlas de Beni-Mellal, Maroc). C R Acad Sci Paris serie D. 287:1277–1279.

Monbaron M, Russell DA, Taquet P. 1999. Atlasaurus imelaki n.g., n. sp.,a brachiosaurid-like sauropod from the Middle Jurassic of Morocco.C R Acad Sci France. 329:519–526.

Moratalla JJ, Garcia-Mondejar J, dos Santos VF, Lockley MG, Sanz JL,Jimenez S. 1994. Sauropod trackways from the Lower Cretaceous ofSpain. Gaia. 10:75–84.

Moreno K, Benton MJ. 2005. Occurrence of sauropod dinosaur tracks inthe Upper Jurassic of Chile (redescription of Iguanodonichnusfrenki). J South Am Earth Sci. 20:253–257.

Nouri J. 2007. La paleoichnologie des empreintes de pas dinosauriens,imprimees dans les couches du Jurassique du Haut-Atlas Central duMaroc [dissertation]. [Rabat (Morocco)]: Universite Mohammed V,Faculte des Sciences, AGDAL.

Peabody FE. 1959. Trackways of living and fossil salamanders. UnivCalif Publ Zool. 63:1–72.

Pittman JG. 1989. Stratigraphy, lithology, depositional environment, andtrack type of dinosaur track-bearing beds of the Gulf Coastal Plain.In: Gillette DD, Lockley MG, editors. Dinosaur tracks and traces.Cambridge: Cambridge University Press. p. 135–153.

Pittman JG. 1990. Dinosaur tracks and trackbeds in the middle part of theGlen Rose Formation, Western Gulf Basin, USA. In: Bergman GR,Pittman JG, editors. Nearshore clastic-carbonate facies and dinosaurtrackways in the Glen Rose Formation (Lower Cretaceous) ofCentral Texas. Geological Society of America, 1990 AnnualMeeting, Field Trip Guidebook 8:47–83.

Pittman JG. 1992. Stratigraphy and vertebrate ichnology of the Glen RoseFormation, Western Gulf Basin, USA [dissertation]. [Austin (TX)]:University of Texas at Austin.

Pittman JG, Gillette DD. 1989. A new sauropod dinosaur tracksite inLower Cretaceous beds of Arkansas, USA. In: Gillette DD, LockleyMG, editors. Dinosaur tracks and traces. Cambridge: CambridgeUniversity Press. p. 313–332.

Plateau H, German G, Roch E. 1937. Sur la presence d’empreintes deDinosauriens dans la region de Demnat (Maroc). C R Somm Soc geolFrance. 16:241–242.

Prince NK, Lockley MG. 1989. The sedimentology of the Purgatoiretracksite region, Morrison Formation of southeastern Colorado. In:Gillette DD, Lockley GM, editors. Dinosaur tracks and traces.Cambridge: Cambridge University Press. p. 155–164.

Rainforth E, Manzella M. 2007. Estimating speeds of dinosaurs fromtrackways: a re-evaluation of assumptions. In: Rainforth E, editor.Contributions to the paleontology of New Jersey (II) – Field guideand proceedings. 2007 Oct 12–13; Geological Association of NewJersey XXIV Annual Conference and field trip, East StroudsburgUniversity; Pennsylvania, USA. p. 41–48.

Romano M, Whyte MA. 2003. Jurassic dinosaur tracks and trackways ofthe Cleveland Basin, Yorkshire: preservation, diversity anddistribution. P Yorks Geol Soc. 54:185–215.

Romano M, Whyte MA, Jackson SJ. 2007. Trackway ratio: a new look attrackway gauge in the analysis of quadrupedal dinosaur trackwaysand its implications for ichnotaxonomy. Ichnos. 14:257–270.

Ross CA, Moore GT, Hayashida DN. 1992. Late Jurassic paleoclimatesimulation–paleoecological implications for ammonoid provinci-ality. Palaios. 7:487–507.

Russell D, Beland P, McIntosh JS. 1980. Paleoecology of the dinosaurs ofTendaguru (Tanzania). Mem Soc Geol France NS. 139:169–175.

Salgado L, Coria RA, Calvo JO. 1997. Evolution of titanosauriddinosaurs, I: Phylogenetic analysis based on the postcranialevidence. Ameghiniana. 34:3–32.

Sarjeant WAS. 1989. ‘Ten paleoichnological commandments’: astandardized procedure for the description of fossil vertebratefootprints. In: Gillette DD, Lockley MG, editors. Dinosaur tracks andtraces. Cambridge: Cambridge University Press. p. 369–370.

Schwarz D, Fritsch G. 2006. Pneumatic structures in the cervicalvertebrae of the Late Jurassic Tendaguru sauropods Brachiosaurusbrancai and Dicraeosaurus. Eclogae geol Helv. 99:65–78.

Schwarz D, Wings O, Meyer CA. 2007. Super sizing the giants: firstcartilage preservation at a sauropod dinosaur limb joint. J Geol Soc(London). 164:61–65.

Stampfli GM, Borel GD. 2002. A plate tectonic model for the Palaeozoicand Mesozoic constrained by dynamic plate boundaries and restoredsynthetic oceanic isochrones. Earth Planet Sci Lett. 196:17–33.

Stampfli GM, Borel GD, Marchant R, Mosar J. 2002. Western Alpsgeological constraints on western Tethyan reconstructions. In:Rosenbaum G, Lister GS, editors. Reconstruction of the evolution ofthe Alpine–Himalayan Orogen. J Virtual Explorer 8:77–106.

Taylor MP. 2009. A re-evalutation of Brachiosaurus altithorax Riggs1903 (Dinosauria, Sauropoda) and its generic separation from

D. Marty et al.132

Downloaded By: [Belvedere, Matteo] At: 06:20 28 May 2010

Giraffatitan brancai (Janensch 1914). J Vertebr Paleontol.29:787–806.

Thalmann HK. 1966. Zur Stratigraphie des oberen Malm im sudlichenBerner und Solothurner Jura [dissertation]. [Bern (Switzerland)]:University of Bern.

Thierry J. 2000a. Early Kimmeridgian. In: Dercourt J, Gaetani M,Vrielvynck B, Barrier E, Biju-Duval B, Brunet MF, Cadet JP,Crasquin S, Sandulescu M, editors. Atlas Peri-Tethys Palaeogeo-graphical maps – Explanatory Notes. Paris: CCGM/CGMN(Commission for the Geological Map of the World). p. 85–97.

Thierry J. 2000b. Early Tithonian. In: Dercourt J, Gaetani M, VrielvynckB, Barrier E, Biju-Duval B, Brunet MF, Cadet JP, Crasquin S,Sandulescu M, editors. Atlas Peri-Tethys Palaeogeographical maps– Explanatory Notes. Paris. p. 99–110.

Thierry J, Abbate E, Alekseev AS, Ait-Ouali R, Ait-Salem H, Bouaziz S,Canerot J, Georgiev G, Guiraud R, Hirsch F, et al. 2000a. Map 10:Early Kimmeridgian (146–144 Ma). In: Dercourt J, Gaetani M,Vrielvynck B, Barrier E, Biju-Duval B, Brunet MF, Cadet JP,Crasquin S, Sandulescu M, editors. Paris (France): Atlas Peri-TethysPalaeogeographical maps.

Thierry J, Barrier E, Abbate E, Alekseev AS, Ait-Ouali R, Ait-Salem H,Bouaziz S, Canerot J, Georgiev G, Guiraud R, et al. 2000b. Map 11:Early Tithonian (141–139 Ma). In: Dercourt J, Gaetani M,Vrielvynck B, Barrier E, Biju-Duval B, Brunet MF, Cadet JP,Crasquin S, Sandulescu M, editors. Paris (France): Atlas Peri-TethysPalaeogeographical maps.

Thulborn T. 1990. Dinosaur tracks. London: Chapman & Hall.Upchurch P. 1994. Manus claw function in sauropod dinosaurs. Gaia.

10:161–172.Upchurch P. 1998. The phylogenetic relationships of sauropod dinosaurs.

Zool J Linn Soc. 124:43–103.Upchurch P, Barrett PM, Dodson P. 2004. Sauropoda. In: Weishampel

DB, Dodson P, Osmolska H, editors. The dinosauria. 2nd ed.Berkeley and Los Angeles (CA): University of California Press.p. 259–324.

von Huene F. 1922. Uber einen Sauropoden im oberen Malm des BernerJura. Eclogae geol Helv. 17:80–94.

von Huene F. 1927. Sichtung der Grundlagen der jetzigen Kenntnis derSauropoden. Eclogae geol Helv. 20:444–470.

Weishampel DB, Dodson P, Osmolska H. 2004. The dinosauria. 2nd ed.Berkeley and Los Angeles (CA): University of California Press.

Weissert H, Mohr H. 1996. Late Jurassic climate and its impact on carboncycling. Palaeogeogr Palaeoclimatol Palaeoecol. 122:27–43.

Whyte MA, Romano M. 2001. Probable stegosaurian dinosaur tracksfrom the Saltwick Formation (Middle Jurassic) of Yorkshire,England. P Geologist Assoc. 112:45–54.

Whyte MA, Romano M, Elvidge DJ. 2007. Reconstruction of MiddleJurassic dinosaur-dominated communities from the vertebrateichnofauna of the Cleveland Basin of Yorkshire, UK. Ichnos.14:117–129.

Wilson JA. 2002. Sauropod dinosaur phylogeny: critics and cladisticanalysis. Zool J Linn Soc. 136:217–276.

Wilson JA. 2005. Overview of sauropod phylogeny and evolution. In:Curry Rogers KA, Wilson JA, editors. The sauropods: evolution andpaleobiology. Berkeley and Los Angeles (CA): University ofCalifornia Press. p. 15–49.

Wilson JA, Carrano MT. 1999. Titanosaurs and the origin of ‘wide-gauge’ trackways: a biomechanical and systematic perspective onsauropod locomotion. Paleobiology. 25:252–267.

Wilson JA, Sereno PC. 1998. Early evolution and higher-level phylogenyof sauropod dinosaurs. J Vertebr Paleontol Mem. 5:198 p.

Wright JL. 1996. Fossil terrestrial trackways: function, taphonomy andpaleoecological significance [dissertation]. [Bristol]: University ofBristol.

Wright JL. 2005. Steps in understanding sauropod biology – Theimportance of sauropod tracks. In: Curry Rogers KA, Wilson JA,editors. The sauropods: evolution and paleobiology. Berkeley andLos Angeles (CA): University of California Press. p. 252–280.

Ziegler PA. 1988. Evolution of the Arctic – North Atlantic and theWestern Tethys. AAPG Memoir. 43:68 p.

Ziegler PA. 1990. Geological atlas of Western and Central Europe.2nd ed. London: Shell International Petroleum Mijnbouw andGeological Society.

Historical Biology 133

Downloaded By: [Belvedere, Matteo] At: 06:20 28 May 2010