Arvicolidae (Rodentia) from the Pliocene of Tollo de Chiclana (Granada, SE Spain)

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Arvicolidae (Rodentia) from the Pliocene of Tollo de Chiclana (Granada, SE Spain)

Arvicolidae (Rodentia) du Plioc&ne de Tollo de Chiclana (Grenade, SE de 1'Espagne)

Raef Minwer-Barakat, Antonio Garcia-Alix, Elvira Martin-SuArez *, Matthijs Freudenthal

Departamerzto de Estratigrafia y Paleontologia, Urziversidad de Granada, 18071, Granada, Spain

Received 23 December 2002; accepted 20 May 2004

Available online at www.sciencedirect.com

Geobios 37 (2004) 619-629

GEOBIOS

Arvicolidae (Rodentia) from the Pliocene of Tollo de Chiclana (Granada, SE Spain)

Arvicolidae (Rodentia) du PliocBne de Tollo de Chiclana (Grenade, SE de 1'Espagne)

Raef Minwer-Barakat, Antonio Garcia-Alix, Elvira Martin-Suiirez *, Matthijs Freudenthal

Departamento de Estratigrufla y Puleontologiu. Universidad de Granada, 18071, Grunudu, Spain

Received 23 December 2002; accepted 20 May 2004

Abstract

Several new fossiliferous Pliocene localities have been identified in the continental deposits of the area of Tollo de Chiclana (Guadix Basin, SE Spain), that have yielded a rich rodent and insectivore fauna. In this paper, we study the Arvicolidae from these localities. Remains adscribed to the genera Dolomys, Mimomys and Kislangia have been found, which are very interesting from a biostratigraphical point of view. O 2004 Elsevier SAS. All rights reserved.

Plusieurs gisements pliocbnes nouveaux ont CtC localisCs dans les dCp6ts continentaux de la region de Tollo de Chiclana (Bassin de Guadix-Baza, Espagne sud-orientale). Dans le present travail nous Ctudions les Arvicolidae de ces gisements, reprCsentCs par les genres Dolomys, Mimomys et Kislangia, qui sont trbs intkressants du point de vue biostratigraphique. O 2004 Elsevier SAS. All rights reserved.

Keycvords: Arvicolidae; Rodentia; Mammalia; Pliocene; Spain

Mots c1k.s : Arvicolidae ; Rodentia ; Mammalia ; Pliockne ; Espagne

1. Introduction

The Guadix Basin is situated in the Betic Cordillera (Spain), one of the mountain chains formed during the clos- ing of the Tethys (Sanz de Galdeano, 1990). It was estab- lished as a separate basin in the Late Miocene (Fernandez et al., 1996; Soria et al., 1998). Its marine infilling started in the Late Miocene, and the continental phase began in the Latest Tortonian, and continued throughout the Pliocene and Pleis- tocene (Viseras 199 1).

The area of Tollo de Chiclana is situated in the central part of the basin (Fig. l), where fine-grained detritic deposits

:Torresponding author. E-mail address: [email protected] (E. Martin-Suirez)

00 16-6995/$ - see front matter O 2004 Elsevier SAS. All rights reserved. doi: 10.1016/j.geobios.2004.05.001

corresponding to distal fluvial sedimentation alternate with lacustrine carbonates (Viseras, 1991 ; Fernandez et al., 1996). In this area several new Pliocene fossiliferous localities have been discovered, which have yielded rich micromammal faunas composed of various families of rodents and insecti- vores. All these sites are found in lutitic beds with perfect stratigraphic control; they are called, from the lower to the upper one, Tollo de Chiclana 1 (TCH-I), 1B, 3, 13, 10 and 10B; the two latter ones are stratigraphically equivalents (see Fig. I).

In this paper, a study of the Arvicolidae from these localities is made. Remains belonging to the genera Dolomys, Mimomys and Kislangia have been found, which have a great biostratigraphical interest.

620 R. Minwer-Barakat et al. / Geobios 37 (2004) 619-629

SOUTH NORTH CVEVA DE PLACIDO

930

BANIANCO DE LA CliLEHHA PAJAR DE

TCH-lR

I 810

TCH-1 800111.

Heig above sea level

Fig. 1. Location of the Guadix Basin and situation of the area of Tollo de Chiclana. Stratigraphic section with the position of the studied localities. Fig. 1. Situation du Basin de Guadix et de la zone de Tollo de Chiclana. Coupe stratigraphique avec la position des IocalitCs CtudiCes.

2. Systematics

The nomenclature used in the descriptions of the occlusal surface and the linea sinuosa, and the method of measuring the height of the hyposinulid are those defined by Rabeder (1981).

Family ARVICOLIDAE Gray, 182 1 Genus Dolomys Nehring, 1898 Type-species: Dolomys milleri Nehring, 1898 Dolomys adroveri Fejfar, Mein and Moissenet, 1990 Fig. 2 Original reference: Dolomys adroveri Fejfar, Mein and

Moissenet, 1990. Type-locality: Orrios 3 (Teruel, Spain). Holotype: M, dext, Orr 3-1, coll. University of Lyon,

Faculty of Geosciences. Localities in the studied area: TCH- 1. Description: MI: Large, relatively low-crowned teeth. No cement is

present in the re-entrant angles. The enamel is not differentiated. The closure of the inselfalte originates an enamel islet

in relatively early stages of wear; this islet may be round or oval-shaped, in the last case it is oblique to the longitudinal axis of the tooth; it persists even in very advanced stages of wear. The labial border of the t4 is never doubled, so there is no Mimomys-ridge, but the t4 is a simple, smaller than the rest, triangle. The LRA4 is deep and delimits a well-defined t5. The outer edges of t4 and t5 are rounded in every stage of abrasion; those of the t l , t2 and t3 are sharp in juvenile teeth, and rounded in adult and senile specimens. The difference of size between the labial and lingual triangles is not very accentuated. The tl and t2 are confluent; the rest of the triangles is isolated, or shows very narrow connections.

The linea sinuosa is very low: the anterosinuid is less than half of the crown height in the youngest specimens; the hyposinuid is even lower, and, on the lingual side, the hyposinulid is hardly a small elevation of the enamel crown base. Therefore, enamel interruptions in the occlusal surface are only present in very worn specimens; among the available teeth, very few show the enamel interruption in the anterolabial part of the anteroconid complex, corresponding to the anterosinuid, and in none of them the interruptions in the posterior lobe can be seen. There are two long and widely separated roots, the anterior is somewhat larger than the posterior one.

M ~ : Moderately hypsodont teeth, without cement and with poorly differentiated enamel. The posterior border of the posterior lobe is undulated in young specimens, and some small short-lived enamel islets can develop close to it. The enamel islet of the posterior complex appears in somewhat worn specimens and persists even in very advanced stages of wear; it is oval-shaped, transversally elongated. The connections of the t2 with the anterior lobe and with the posterior complex are weak. BRA1 and LRA2 are deep; in a worn specimen the closure of the BRA1 produces another enamel islet, between the anterior lobe and the t2. t4 is small and sharp-pointed, and persists even in highly worn specimens. LRA3 and BRA3 are not much pronounced, so the posterior complex is wide. A weak LRA4 and a small t5 are present except for the most senile specimens. The end of the posterior complex is strongly shifted towards the labial side of the tooth.

The linea sinuosa is low; it reaches its maximum height at the distosinus. On the lingual side, the hyposinus is somewhat lower than the latter and slightly higher than the protosinus; on the labial face, the metasinus is lower than the distosinus, and parasinus and anterosinuid are similar in height and lower than the other ones. Enamel interruptions in the occlusal surface cannot be observed in any specimen. There are two roots, the posterior one with rounded section and the anterior one compressed. In addition, two specimens have another, minuscule, root on the lingual side, between the two main ones.

Measurements: See figure 3. Remarks: The mean length of the M, and M~ in the

population from TCH-1 is practically identical to that of D. adroveri from its type-locality (Orrios 3), very similar to

R. Minwer-Burukut et ul. / Geobios 37 (2004) 619-4529

Fig. 2. Dolonzys udroveri Fejfar, Mein and Moissenet. 1990, from TCH- 1. 1. TCH- 1 13 1 M I sin. 2. TCH- 1 135 M I sin. 3. TCH- 1 147 M~ sin. 4. TCH- 1 148 M" sin. Scale: 1 mm. Fig. 2. Dolonrys adr-owri Fejfar, Mein et Moissenet, 1990 de TCH- 1. 1. TCH- 1 13 1 M I gauche. 2. TCH- 1 135 MI gauche. 3. TCH- I 147 M' gauche. 4. TCH- 1 148 M' gauche. ~ c h e l l e : 1 mm.

that of the same species from Orrios 4 and 7, Villalba Alta 1965) and smaller than D. rnilleri Nehring, 1898. D. adroveri Corral and Escorihuela B (Fejfar et al., 1990), and somewhat from TCH- 1 is much larger than other Alfambrian arvicolids: larger than that of D. aff. adroveri from the locality of Asta Mirnonzys davakosi Van de Weerd (1 979) from Ptolemais Regia, in the Jerez basin (Castillo and Agusti, 1996). (type-locality), Villalba Alta and Arquillo 3 (Fejfar et al.. D. adroveri is bigger than the species D. occitan~rs (Thaler, 1990); M. vanderineuleni Fejfar, Mein and Moissenet 1990

Length n

Height of the hyposinulid

MI

Minzomys medasensis

n

6 7

4

21

14

Mimomys minor

min.

Mimomys medasensis

Mimonzys minor

Mimomysstehlini

Dolomys adroveri

TCH- 10 TCH-1OB

Mimoinys stehlini

Fig. 3. Length and hyposinulid height of the M,, and length of the M' of Doloinp admveri from TCH- 1. Minroinys stelzlini from TCH- 1 B, Min7onr~ls minor- from TCH-3 and 13 and Mimotn?:~ medusensis from TCH- 10 and 10B. Fig. 3. Longueur et hauteur du hyposinulide des MI. et longueur des M' de Doloinss ufr-over-i de TCH-I, Mimoinys stelrlini de TCH- 1 B, Minwi~r~~s iniiror- de TCH-3 et 13 et Min701n~s ilreduseirsis de TCH- I0 et 10B.

min.

2.93 3.19

2.63

2.92

3.09

TCH- 10 TCH-1OB

TCH- 13

TCH-1B

TCH- 1

. TCH- 13 TCH-3

Dolonzys adroveri

med.

4 13

TCH- 1B

max med.

3.39 3.51

2.8

3.23

3.52

5 1

TCH- 1

max

1.9 1.71

30

3.86 3.74

3.06

3.48

3.84

1.55

9

2.175 2.15

1.84

1 1

5

20

11

2.38 2.37

1.67 1.41

2.09

1.79

2.12

0.70

0.43

0.26

2.35

2.22 2.55

3.70 4.16

0.90

0.53

0.33

1.18

0.69

0.39


from La Gloria 2 (type-locality), Villalba Alta Rio 2a, 2bl and 2b2; and M. stehlini Kormos, 1934 in the numerous localities in which this species has been identified.

The most characteristic feature of this species is the absence of the Mimomys-ridge: in the various species within the genus Mimomys, and also in D. milleri, D. occitanus and D. nehringi Kretzoi, 1959 from Csarn6ta 2, the labial edge of the anterior loop is doubled, producing an additional buccal edge in the anterior part of the t4, a feature that cannot be observed in the specimens from TCH-1. It differs from other arvicolids of similar size, like D. milleri and K. cappetai in its lower linea sinuosa ("undat" type according to Rabeder, 1981).

The population from TCH-I differs from the type- population because in the latter the enamel islet of the M, appears only in very advanced stages of wear; at stratigraphically younger levels (Orrios 7 and Poblado IbCrico 1) this islet occurs in somewhat less-worn specimens, like in the case of the TCH- 1 population. The number of roots in the M~ (two main roots and occasionally a small third one on the lingual side of the tooth) is the same in TCH- 1 and in Omos 3, whereas in Orrios 7 and Poblado IbCrico 1 some specimens have three main roots. The rest of the morphological characters (moderate hypsodonty, rounded outer edges of the prisms in senile specimens, absence of cement, etc.) are alike in TCH- 1 and in all the populations of D. adroveri described in Fejfar et al. (1990), which those authors refer to the Upper Alfambrian (MN15).

Mein et al. (1990) distinguish in the Teruel basin two subunits within MN15, the lower one being characterized by the presence of two archaic species of Mimomys, M. vandermeuleni and M. davakosi, and the upper one marked by the arrival of an arvicolid larger than the aforementioned, D. adroveri, a species which is characterized by a poorly developed linea sinuosa. Aguirre et al. (1995) and Castillo and Agusti (1996) report the presence of D. adroveri in the locality of Asta Regia-3 (Jerez basin), that they refer to the upper part of MN15 (Dolomys Zone of Mein et al., 1990). In the Guadix-Baza basin, Agusti et al. (1997) mention and figure the presence of D. adroveri in the locality of Galera- 1 C, also referred to the Upper Alfambrian. Therefore, the age equivalence of these populations with that the one from TCH- 1 seems to be clear, corresponding to the upper part of MN15 (Dolomys Zone).

Genus Mimomys Forsyth Major, 19 10 Type-species: Mimornys pliocaenicus Forsyth Major,

I889 Mimomys stehlini Kormos, 1934 Fig. 4 Original reference: Mimomys stehlini Kormos, 1934. Type-locality: San Giusto (Italy). Holotype: A mandible with M,. Localities in the studied area: TCH- 1B. Description: M,: Relatively low crowned teeth, without cement in the

re-entrant angles, with hardly differentiated enamel. The

enamel islet is isolated, large, oval-shaped, and oblique to the longitudinal axis of the molar; it disappears in considerably worn specimens, after the enamel has been interrupted in the anterolabial face of the anteroconid complex, but before the interruption in the labial side of the posterior lobe. The Mimomys-ridge persists even in highly worn specimens. There are no connections between the triangles, except for tl and t2, which are slightly confluent. The BRA2 is oriented markedly forwards, and the t4 is oriented backwards, with its extreme end placed very far from the t5. The LRA4 is deep in young specimens and weakens with wear. The inselfalte is not very deep, and the anterior complex is wide. The outer edges of the prisms are sharp in young specimens and become rounded through abrasion, except for t5, that is rounded practically along the entire height of the crown. The difference in size between the labial and lingual triangles is not very accentuated, so the teeth are rather symmetrical.

The height of the anterosinuid is variable: in the least worn specimens it may reach slightly beyond half the crown height; mimosinuid and hyposinuid are similar in height and notably lower than the anterosinuid. On the lingual side, the hyposinulid is much lower than all the former ones; it does not reach a quarter of the crown height in the youngest specimens, so the enamel interruption in the lingual side of the posterior lobe only occurs in very worn specimens. There are two roots, the anterior one larger than the posterior one, which are widely spaced.

M ~ : Moderately hypsodont teeth, without cement in the re-entrant angles, and with hardly differentiated enamel. There is only one enamel islet, in the posterior complex; in young specimens it is open towards the lingual side of the tooth; in more advanced stages of wear, it is irregular or oval-shaped and oblique to the longitudinal axis of the tooth; it persists even in senile specimens, in which it is small and circular. The t2 is small, so the anterior lobe and the t4 protrude more than it in the labial border; it may be isolated from the anterior lobe and from the posterior complex, or weakly communicated with both of them. BRA1 and LRA2 are deep. The lingual edge of the t3 is rounded. The t4 is small and sharp-pointed, persisting even in senile specimens. LRA3 is poorly marked, and placed somewhat forwards with respect to BRA3, which is even less pronounced. The posterior complex is very wide. LRA4 and BRA4, if present, are very slightly marked and delimit a small t5 and t6, respectively.

The linea sinuosa is low; it reaches its maximum height at the distosinus. Anterosinuid, protosinus and hyposinus are very low. The metasinus and the parasinus are even lower, and in many specimens they are not perceptible. There are two roots, the anterior one is wider than the posterior one, and the latter is longitudinally elongated. In one specimen there is also a third smaller root, situated between the two main ones on the lingual border.

Measurements: See figure 3 . Remarks: The differentiation between the species M. ste-

hlini and M. occitanus has not always been clear: the popu-

R. Minwer-Barakut et al. / Ceobios 37 (2004) 61 9-629

Fig. 4. 1-4. Miinomys ininor Fejfar, 1961 from TCH-13. 1. TCH-13 35 MI sin. 2. TCH-13 36 MI sin. 3. TCH-13 48 Mi sin. 4. TCH-13 50 M' dext. 5-8. Min~oiuys nleduseizsis Michaux, 197 1 from TCH- 10.5. TCH- 10 20 in. 6. TCH- 10 2 1 M' sin. 7. TCH- 10 12 MI sin. 8. TCH- 10 14 M, sin. 9-12. Minzomys srel~lir~i Kormos, 1934 from TCH- I B. 9. TCH- 1 B 508 MI sin. 10. TCH- 1 B 493 MI sin. 11. TCH- 1 B 528 M' sin. 12. TCH- I B 533 M' sin. Scale: 1 mm. Fig. 4. 1-4. Miiizonlys iniilor Fejfar, 196 1 de TCH- 13. 1. TCH- 13 35 MI gauche. 2. TCH- 13 36 MI gauche. 3. TCH- 13 48 M' gauche. 4. TCH- 13 50 M' droite. 5-8. Miilzoinys nmfuseirsis Michaux, 197 1 de TCH- 10.5. TCH- I0 20 M' gauche. 6. TCH- 10 2 1 M' gauche. 7. TCH- 10 12 M, gauche. 8. TCH- I0 14 M, gauche. 9-12. Minlonzj,~ rrehlini Kormos, 1934 de TCH- 1 B. 9. TCH- 1 B 508 M I gauche. 10. TCH- 1 B 493 MI gauche. 11. TCH-I B 528 Mi gauche. 12. TCH- 1 B 533 M' gauche. Scale : 1 mm.

624 R. Minwer-Burakut et al. / Geobios 37 (2004) 619429

lation from Sbte, type-locality of M. occitanus, was considered to belong to M. stehlini by various authors (Michaux, 1971; Chaline and Michaux, 1975). Other authors have considered that the species M. occitanus and M. stehlini are synonym (Ruiz Bustos and SesC, 1985), accepting the oldest denomination, i.e., M. stehlini. Posteriorly Chaline et al. (198 1) and Fejfar et al. (1990) recognized specific difference and included that population in the species M. occitanus. Recently Maul (1996) transfers the species occitanus to the genus Dolomys, an opinion that was accepted by other authors (Fejfar et al., 1998; Mein, pers. com.), that refers to the population from Sbte as belonging to the species Dolomys occitanus. We accept this consideration.

We have directly compared the specimens from TCH- 1B with several MI of the population from Skte, confirming that the linea sinuosa is more developed in those from TCH- IB, which have higher anterosinuid and hyposinuid and, in the lingual face, a small hyposinulid, that is almost imperceptible in the specimens from Sbte. The linea sinuosa is very similar to that of M. stehlini from its type-locality (San Giusto) and other sites, like Arondelli-Triversa (compared with specimens figured in Fejfar et al., 1998).

The linea sinuosa is higher in TCH- 1B than in the population from Escorihuela B (Fejfar et al., 1990) N.B.: The arvicolid from Escorihuela B, determined as M. occitanus, belongs to the species Mimomys (Cseria) gracilis (or an association of M. gracilis and D. adroveri) (Mein, pers. corn.).

Therefore, we have included the population from TCH- 1B in the species M. stehlini, to which it is similar in size, in the morphological characters that can be observed in the occlusal surface (like the shape, size and oblique position of the enamel islet, the extent of the anteroconid complex and the posterior orientation of the t4), and in the development of the linea sinuosa.

We have compared the length of the MI and M~ with those of other populations of the same species. The length of the M, from TCH- 1B is larger than those from Wkze (Michaux, 1971), Moreda 1-B and Rambla Seca-Ab (Castillo Ruiz, 1990), and very similar to that of the specimens from other sites of Guadix-Baza Basin, like HuCscar-3 and Barranco Cafiuelas-3 (SesC, 1989). The available data about the length of M~ are limited; we have compared with the measurements of M. stehlini from Moredal-B and 1L-4 and Rambla Seca- Ab; all these populations show smaller values than those of TCH-1B.

The length of the M, is much larger than those of M. davakosi from Villalba Alta and Arquillo 3 and M. vandermeuleni from La Gloria 2 and Villalba Alta Rio 2a, 2b 1 and 2b2, and smaller than that of Dolomys adroveri from Orrios 3,4 and 7, Villalba Alta Corral and TCH- 1. The measurements are similar to those of M. hajnackensis Fejfar, 1961 from the localities of Concud Pueblo 2 and 3, Concud Estaci6n 1 and 3 (Adrover et al., 1988) and Arcille (Maul et al., 1998), but this latter species shows some distinct morphological features, like the larger confluence between the triangles and the more

ephemeral enamel islet in the MI. The measurements are also similar to those of M. polonicus Kowalski, 1960 from several European localities (Rebielice, Magny-les-Auxonnes, Ces- sey, Arondelli), which, however, has a higher linea sinuosa, with a much more elevated hyposinuid, and presence of cement in the re-entrant angles. Mimomys stehlini from TCH- 1B is notably smaller than Kislangia cappetai from its type-locality, Balaruc I1 (Michaux, 1971), and from others like Moreda 1-B and Rambla Seca-Ab (Castillo Ruiz, 1990). The length of the M, is clearly larger than that of M. minor from the localities of Seynes, Balaruc I1 (Michaux, 1971) and Concud Estaci6n 1 (Adrover et al., 1988).

Mimomys minor Fejfar, 1961 Fig. 4 Original reference: Mimomys pliocaenicus minor Fej-

far, 1961. Type-locality: Hajnacka 1 (Slovakia). Holotype: M, dext., Fig. 4(b,d), Coll. UUG Prague,

No 65364, Coll. Fejfar. Localities in the studied area: TCH-3, TCH-13. Description of the material from TCH-13: MI: Small, moderately hypsodont molars, with scarce

cement in the re-entrant angles. The enamel is poorly differentiated. The anterior lobe is narrow. The enamel islet is small, rounded, and situated in the anteroconid complex near the labial border; it disappears in worn specimens. The Mimomys-ridge can be observed even in very advanced stages of wear. The inselfalte is slightly marked. The LRA4 is deep and delimits a well-developed t5, with a rounded outer vertex. The rest of the triangles has sharp outer edges. The BRA2 is transversally oriented. The labial triangles are notably smaller than the lingual ones. The t4 is small. The t l is separated from the posterior lobe, and confluent with the t2. The t2 may be isolated from the t3 or weakly connected to it, and this latter one is separated from the anteroconid complex.

In the linea sinuosa the anterosinuid is high, the hyposinuid is rather lower and, on the lingual side, the hyposinulid is much lower than both of them; it does not reach a third of the crown height in the youngest specimens. There are two roots, the anterior one larger than the posterior one.

M ~ : Small, moderately hypsodont teeth. There is no cement in the re-entrant angles. The enamel is poorly differentiated. There are two enamel islets, one of them situated between the anterior lobe and the t2, opposed to the LRA2, small, isolated and circular; the other one, situated in the posterior complex between the LRA3 and the BRAS, is somewhat larger than the former one and oval-shaped. In very young specimens none of these islets occur, in more advanced stages of wear the posterior one appears first; in more senile specimens the two islets are present and finally both of them disappear. In young specimens the BRA1 is very deep, and the connection between the anterior lobe and the t2 is narrow; somewhat later in abrasion, the anterior enamel islet begins to form, starting from the enamel of the BRA1, which results in a weakly pronounced angle, at the

R. Minwer-Barakat et al. / Geobios 37 (2004) 619-629 625

same time that the anterior lobe and the t2 become widely connected, with the islet between them. The LRA2 is very deep. t2 and t3 are separated. The posterior complex is narrow. BRA3 and LRA3 are opposed. The t4 is small and sharp-pointed, persisting even in senile teeth. In one specimen there are slightly marked LRA4 and BRA4, which delimit small t5 and t6, respectively.

The linea sinuosa is relatively low, the anterosinulus does not reach half the crown height in the youngest specimens. The distosinus is somewhat lower than the anterosinulus and slightly higher than the protosinus; the hyposinus is low, parasinus and metasinus even lower. There are two roots.

Description of the material from TCH-3: This locality has yielded only one complete M ~ , one

fragment of this same dental element, and 7 incomplete M, (besides other dental elements not considered in the descriptions or determinations). Therefore, the only measured specimen is the complete M ~ , which is shorter than those from TCH-13; this is due to the fact that it is a very young specimen. Comparing directly the fragments found in TCH-3 with the specimens from TCH-13, it becomes clear, that the size of the teeth from both localities is very similar, and no morphological differences exist between them.

Measurements: See figure 3. Remarks: The size of the teeth of these populations is

very similar to that of M. minor from Seynes and Balaruc 11, populations that initially were assigned to the species M. sep- tiinanus Michaux, 1971; posteriorly, this same author recognized that these two species and a third one (M. baschkirica Suchov, 1970) are synonyms, and the older denomination, M. minor, was adopted (Michaux and Chaline, 1982). The measurements are also similar to those of M. minor from the locality of Concud Estacidn 1 (Adrover et al., 1988).

This species is larger than M. gracilis Kretzoi, 1959, and much smaller than M. medasensis, M. polonicus, M. pliocaenicus, Kislangia cappetai and K. ischus. It is also smaller than M. hajnackensis from Concud Pueblo 2 and Concud Estacidn 1 and 3 (Adrover et al., 1988), D. occitanus and M. stehlini from Skte, Wkze, Nimes, Escorihuela (Michaux, 1971), Rambla Seca-Ab and Moreda 1-B (Castillo Ruiz, 1990). Moreover, M. stehlini from HuCscar-3 and Barranco Caiiuelas-3 (SesC, 1989) is much larger than M. minor from TCH-13. It is slightly bigger than M. reidi Hinton, 1910 from the localities of Rebielice, Kadzielnia and Cessey-sur-Tille (Michaux, 197 I), Les Etouaires (Michaux, 197 I), and Tegelen (Tesakov, 1998). However, M. cf. reidi, found in the Guadix-Baza Basin in the localities of Alqueria (Martin Sufirez, 1988) and Cortijo de la Tapia (SesC, 1989), is clearly larger than M. minor from TCH- 13, and their size ranges do not overlap.

The specimens from TCH- 13 show the characteristic features of M. minor: small M,, with a small, rounded enamel islet, that disappears in senile specimens, well developed Mimomys-ridge, poorly differentiated enamel, scarce cement, t l and t2 more confluent than t2 and t3, and anterosinuid higher than hyposinuid; M~ with a narrow poste-

rior lobe and two enamel islets. We have directly compared with some specimens of the population from Seynes, confirming the morphological and biometrical resemblance with those from TCH-13.

The M, of M. minor can be distinguished from those of M. stehlini, besides their smaller size, by the following features: they are narrower and somewhat more hypsodont teeth, with a smaller and more rounded enamel islet that disappears in earlier stages of wear; the asymmetry between the labial and lingual triangles is more accentuated; the anterior lobe is narrower; the t4 and the BRA2 are transversal. This pattern can be observed in all the wear stages of the M,, and makes a clear difference between this population and that of M. stehlini from TCH-lB, in which the BRA2 is strongly oriented forwards and the labial end of the t4 is placed very much backwards. The inselfalte is deeper in the population from TCH-1B. The M~ of M. minor have a narrower posterior lobe, with LRA3 and BRA3 opposed and smaller than in M. stehlini. In the linea sinuosa, the anterosinulus is much higher and thinner in M. minor than in M. stehlini. In the population of the latter species .from TCH-1B no specimens with two enamel islets have been found.

M. minor differs from M. reidi in the following characters: in the M,, the linea sinuosa is lower and the enamel islet persists in more advanced stages of wear; the LRA4 is deeper; t2 and t3 are less confluent. The M~ of M. reidi is more elongated and has only one enamel islet.

This species has a large geographical range in Eurasia; in the Iberian Peninsula, it has been identified in various sites in the area of Teruel (Cerro de Los Espejos, Concud Estacidn 1); in France, in the localities of Seynes and Balaruc I1 besides others, and in Slovakia in the type-locality, Hajnacka I, all of them referred to MN 16 (Michaux and Chaline, 1982; Adrover et al., 1988).

According to Agusti (1986, 1990), M. minor, present in some MN16 localities in the Iberian Peninsula, but unknown until now in the Guadix-Baza Basin, may be the direct ances- tor of M. cf. reidi from the sites referred to MN17 in this basin (Alqueria, Cortijo de la Tapia-1, Cortes de Baza-6).

Mimomys medasensis Michaux, 197 1 Fig. 4. Original reference: Mimomys medasensis Michaux,

1971. Type-locality: Islas Medas (Gerona, Spain). Holotype: A right mandible with MI-M,, UM-016 Med,

kept in Montpellier. Localities in the studied area: TCH- 10, TCH-IOB. Description of the material from TCH-1OB: M,: Very hypsodont teeth with scarce cement. The enamel

islet, small and circular, can only be observed in the youngest specimens; on the contrary, the Mimomys-ridge persists along the entire height of the crown. The enamel is well differentiated. The LRA4 is very deep in young specimens, and becomes less pronounced with abrasion, but it delimits a

626 R. Minwer-Barakat et ul. / Geobios 37 (2004) 619629

well-differentiated t5 anyway. These teeth are rather asym- metrical, with the labial triangles much smaller than the lingual ones, and the labial re-entrant angles oriented forwards, while the lingual ones are transversal. The tl is isolated from the posterior lobe, and so is the t2 from the t3, and the latter one from the anterior complex. The tl and t2 are confluent in young specimens, and tend to become isolated in later stages of wear. The salient angles are "V"-shaped.

The linea sinuosa is very high; on the labial face, the anterosinuid is slightly higher than the hyposinuid, both of them almost reach the wear surface in the youngest specimens. There is a mimosinuid that surpasses half the crown height in unworn specimens. The hyposinulid is lower than the anterosinuid and the hyposinuid, and higher than the mimosinuid. Therefore, the enamel is interrupted on the anterolabial face of the anteroconid complex and on the labial face of the posterior lobe in early stages of wear, and on the lingual side of the posterior lobe in more advanced stages. There are two roots, the anterior one larger than the posterior one.

M ~ : Very hypsodont teeth, with some cement in the re- entrant angles. The enamel is well differentiated. There is only one enamel islet, in the posterior complex, open towards the lingual side of the tooth in the youngest specimens and isolated in later stages of wear; it disappears in somewhat worn specimens. Very deep LRA2. The anterior lobe is isolated from the t2 in the young specimens, and a weak connection between them appears with wear. The t2 is isolated from the t3. The BRA1 is deep in young specimens, and become weaker with abrasion.The t4 well delimited with a sharp outer edge, persisting even in senile teeth. In the posterior complex, LRA3 and BRA3 are deep and opposed, so the space between them is narrow. There is a small, but well differentiated t5, with a very sharp vertex. In some specimens there exists a tiny BRA4 which delimits an incipient t6. The end of the posterior complex is sharp-pointed.

The linea sinuosa is high; the anterosinulus and the protosinus are very high and reach the occlusal surface in early stages of wear, the distosinus is notably lower. The hyposinus is even lower than the former ones and somewhat higher than the metasinus, and the parasinus is very low. There are two roots, the anterior transversally compressed, and the posterior one more elongated.

Description of the material from TCH-10: The length of the M, found in this locality exceeds the size

range of the same dental element from TCH- 10B, despite this latter has yielded a larger number of specimens. This difference is due to the fact that two specimens from TCH-10 correspond to very young individuals with very short wear surfaces, and a third one to a very worn individual, with an occlusal length larger than that of all the specimens of the population from TCH-1OB. The real length of this dental element is very similar in both localities, like in the case of the M ~ . The morphology is also very alike, and no differences between these two populations have been found.

Measurements: See figure 3 .

Remarks: The length of the M, of Mirnomys medasensis from these localities is slightly larger than that of the same species in its type-locality (Islas Medas). This parameter is similar to that of the same species from Casablanca I: the maximum values are slightly larger than those found by Gil and SesC (1984) and Agusti (1990); however, both the maximum and the minimum values in the localities studied in this paper fit into the size range of level B from Casablanca I, which has yielded the bigger population (37 MI) (Esteban Aenlle and L6pez Martinez, 1987). The size range is greater than that of M. medasensis from Galera 2 (Martin Sufirez, 1988) and M. cf. medasensis from El Rinc6n-1 (Alberdi et al., 1997), as may be expected since the populations from the Tollo de Chiclana consist of a larger number of specimens.

There are no available data about the length of the M~ in the type-locality; this parameter is somewhat larger in the populations from TCH-10 and 10B than in Galera 2, and similar to its values in various levels of Casablanca I.

The morphology of the MI agrees with that described by Michaux (1971) in the definition of this species: very hypsodont teeth, with ephemeral enamel islet, well-defined Mimomys-ridge even in senile specimens, marked asymmetry between the labial and lingual triangles, which are isolated except for t l and t2, and enamel interruptions in early stages of wear, both in the posterior lobe and in the anteroconid complex.

Mimomys medasensis is similar in size to Kislangia cappetai, but is more hyspsodont and has a higher linea sinuosa. Is clearly smaller than K. gusii Galobart and Martin SuBrez, 1993 and than K. ischus, and larger than M. reidi and M. stehlini; moreover, all these species differ from M. medasensis in their morphology. The length of the MI is somewhat larger than that of M. polonicus, species that has also less hypsodont teeth, with a less-developed linea sinuosa and the enamel islet present until more advanced stages of wear.

This species is, according to the opinion of several authors (Esteban Aenlle and L6pez Martinez, 1987; Martin SuBrez, 1988; Agusti, 1990; Alberdi et al., 1997), an Iberian endemic parallel of the European species M. pliocaenicus, from which it differs in some features like the disappearance of the enamel islet, that happens in earlier stages of wear in M. medasensis, and the number of roots in the M': M. pliocaenicus has three isolated roots, and M. medasensis only two, al- though the anterior one is bilobed. However, this latter char- acter often shows intrapopulational variability, and cannot be a diagnostic criterion (Esteban Aenlle and L6pez Martinez, 1987; Alberdi et al., 1997).

Genus Kislungia Kretzoi, 1954. Type-species: Kislangia ondatrina Kretzoi, 1954. Kislangia ischus (Esteban and Martinez-Salanova, 1987). Original reference: Mimomys ischus Esteban and

Martinez-Salanova, 1987. Type-locality: La Marmota 2 (Albacete, Spain). Holotype: M,, MAR.2-RAl, kept in the Universidad

Complutense, Madrid.

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Localities in the studied area: TCH-3. Description: No complete M, or M~ has been found, so measurements

of the length of these dental elements are not available. The fragments of M, correspond to large hypsodont molars, with the enamel islet present even in very worn specimens. The Mimomys-ridge reaches the base of the crown, the prismen- falte is very wide and the inselfalte very deep. The posterior lobe is wide and separated from the tl . The t l and t2 are slightly confluent. There is cement in the re-entrant angles.

In some fragments part of the linea sinuosa can be observed: the hyposinuid and the hyposinulid are low, and a poorly developed mimosinuid exists. None of the specimens conserves the anterior root; the posterior one is broad.

A single fragment of M~ has been found, that preserves the posterior complex and part of the t2, and has lost the anterior lobe. It corresponds to a very young, big and hypsodont, specimen, which is practically unworn, so the enamel islet cannot be observed. It doesn't preserve the roots either.

Remarks: The morphological features observed in the fragments of M, from TCH-3 resemble those of K. ischus from the localities of La Marmota 1 and 2, El Carrasco, El Rinc6n 2 (Esteban and Martinez-Salanova, 1987), Moreda 1-B and 1-L4 and Rambla Seca-Ab (Castillo Ruiz, 1990).

The size of K. ischus is only comparable to that of K. rex (Kormos, 1934) and K. gusii, but it differs from those in its lower crown-height and less developed linea sinuosa. By direct comparison with teeth of K. gusii from Galera 2, we

TCH-IOB

TCH- I0

TCH- 13

TCH-3

TCH- 1 B

TCH-I

have checked that the M, of this latter species has a notably higher hyposinuid, mimosinuid and hyposinulid than the specimens from TCH-3. The size of K. ischus is much larger than that of K. cappetai, as has been observed by direct comparison with specimens of this latter species from Bal- aruc 11.

The coexistence of this species with M. stehlini and K. cappetai in some localities suggest that the localities where K. ischus is present must be referred to the Lower Villafranchian (MN16) (Esteban and Martinez-Salanova, 1987).

3. Age of the localities

On the basis of the vertical distribution of the rodent species, the age of the localities can be determined. Figure 5 shows the distribution of the several taxa identified in these sites, and the age assigned to each locality.

The faunal association of TCH-1 is characteristic of the Upper Alfambrian. In a more detailed way, the species D. adroveri is found in the Teruel basin in several localities (Orrios 3, 4 and 7, Villalba Alta Rio 3, Escorihuela B) belonging to the upper part of the Upper Alfambrian. These sites are younger than those containing the more primitive Mimomys (M. vandermeuleni and M. davakosi) characteristic of the lower part of the Upper Alfambrian. The occurrence of D. adroveri in TCH-1 allow us to assign this locality to the

Fig. 5. Vertical distribution of the several taxa identified in the sites of Tollo de Chiclana-I, lB, 3, 13, 10 and IOB, and the age assigned to each locality. Fig. 5. Distribution verticale des diffirents taxons reconnus dans les localitis de Tollo de Chiclana-I, lB, 3, 13, 10 et 10B, et 1'Lge attribuC ?I chaque gisement.


upper part of the Upper Alfambrian (MN15), corresponding to the Dolomys-zone in the Teruel basin (Mein et al., 1989- 1990).

The locality of TCH-1B has yielded a fauna that is characteristic of the uppermost Alfambrian. The biostratigraphical position of the species M. stehlini is not clear: several authors (Michaux, 197 1; Ruiz Bustos and Ses6, 1985; Ruiz Bustos, 1995; Ses6 et al., 2001) consider it to be exclusive of the Upper Alfambrian; others (Agusti, 1986, 1990; Fejfar et al., 1998) think that it is typical of the lower part of the Lower Villafranchian. Van de Weerd (1976) defines in the Teruel- Alfambra basin the biozone of M. stehlini, which includes the uppermost part of the Upper Alfambrian and the lower- most part of the Lower Villafranchian. Other species of the association like Occitanomys brailloni, Trilophomys vandeweerdi and Blancomys meini are typical of the Upper Alfambrian, though they have also been identified in the lower part of the Villafranchian in the Teruel basin (Mein et al., 1989-1990); however, Agusti (1986, 1990) and Agusti et al. (1999) consider that Occitanomys disappears from the Guadix-Baza basin at the end of Alfambrian time. Anyway, Pliopetaurista pliocaenica has its last occurrence in the Upper Alfambrian (Mein et al., 1989-1990), as well as Stephanomys donnezani (Castillo Ruiz, 1990; Ruiz Bustos, 1995; Ses6 et al., 2000). Those considerations allow us to assign the level of TCH-1B to the uppermost part of the Upper Alfambrian (MN15).

The fauna of TCH-3 and TCH- 13, with M. minor, and the murids Stephanomys minor and S. thaleri can be assigned without doubts to the Lower Villafranchian (MN16). The presence of K. ischus in TCH-3 indicates the same age, and the rest of the faunal association is in agreement with this interpretation.

The localities of TCH-10 and 10B are assigned to the upper part of the Upper Pliocene (MN17). M. medasensis has been found in many iberian localities belonging to MN17, like Islas Medas (type-locality), Galera-2 and Casablanca I (Almenara I). The presence of the murids Castillomys rivas, whose first appearance is recorded in the Upper Pliocene (MN17) (Martin Suhrez and Mein, 199 l), and Stephanomys balcellsi confirms this age.

Acknowledgements

This study was carried out within the framework of the Project BOS 2001-1044 of the DGI: "Dinimica de ecosiste- mas terrestres en el Ne6geno de las cuencas del levante espafiol".

References

Adrover, R., Mein, P., Moissenet, E., 1988. Contribuci6n a1 conocimiento de la fauna de Roedores del Plioceno de la regidn de Ternel. Ternel 79, 191-151.

Aguirre, J., Castillo, V., Ferriz, F.J., Agusti, J., Oms, O., 1995. Marine- continental magnetobiostratigraphic correlation of the Dolomys subzone (Middle or Late Ruscinian): implications for the Late Ruscinian age. Palaeogeography, Palaeoclimatology, Palaeoecology 1 17, 139-1 52.

Agusti, J., 1986. Continental mammal units of the Plio-Pleistocene from Spain. Memorie de la Societa Geologica Italiana 3, 167-173.

Agusti, J., 1990. The Plio-Pleistocene arvicolid succession in southern and eastern Spain. International Symposium on the Evolution. Phylogeny and Biostratigraphy of Arvicolids, Praha 1990 pp. 21-32.

Agusti, J., Garcks, M., Parks, J.M., 1999. Pliocene correlation between climatic change and mammalian succession in the Western Mediterra- nean. In: Wrenn, J.H., Suc, J.-P., Leroy, S.A.G. (Eds.), The Pliocene : Time of Change. American Association of Stratigraphic Palynologists Foundation pp. 121-129.

Agusti, J., Oms, O., Garcks, M., Parks, J.M., 1997. Calibration of the late Pliocene-early Pleistocene transition in the continental beds of the Guadix-Baza Basin (South-Eastern Spain). Quaternary International 40, 93-100.

Alberdi, M.T., Cerdefio, E., L6pez-Martinez, N., Morales, J., Soria, D., 1997. La fauna Villafranquiense de El Rinc6n-1 (Albacete, Castilla-La Mancha). Estudios Geol6gicos 53,69-93.

Castillo Ruiz, C., 1990. Paleocomunidades de micromamiferos de 10s yacimientos kirsticos del Ne6geno Superior de Andalucia Oriental. Thesis, University of Granada.

Castillo, C., Agusti, J., 1996. Early Pliocene rodents (Mammalia) from Asta Regia (lerez basin, Southwestern Spain). Proceedings Koninklijke Ned- erlandse Akademie van Wetenschappen 99,25-43.

Chaline, J., Mein, P., Adrover, R., 1981. Mimomys occitarzus de Villalba Alta et Arquillo 3 (Espagne). Geobios 14,821-826.

Chaline, J., Michaux, J., 1975. Microkvolution chez les campagnols (Arvi- colidae, Rodentia). La cladogenkse Mimomys stehlini-Dolomys Izun- guricus. Colloque Intemational CNRS 218,749-758.

Esteban Aenlle, J., L6pez Martinez, N., 1987. Les Arvicolidks (Rodentia, Mammalia) du Villanien rkcent de Casablanca I (Castellon, Espagne). Geobios 20,59 1424.

Esteban, F.J., Martinez-Salanova, J., 1987. Mimomys ischus n. sp y M. reulerzsis n. sp.: Dos nuevos Arvic6lidos (Rodentia, Mammalia) del Plioceno de la Cuenca del Jlicar (Albacete). Estudios Geologicos 43, 299-308.

Fejfar, O., Heinrich, W.D., Lindsay, E.H., 1998. Updating the Neogene Rodent biochronology in Europe. Mededelingen Nederlands lnstituut voor Toegepaste Geowetenschappen TNO 60,533-554.

Fejfar, O., Mein, P., Moissenet, E., 1990. Early arvicolids from the Ruscin- ian (Early Pliocene) of the Teruel Basin, Spain. In: Fejfar, O., Heinrich, W.D. (Eds.), International Symposium-Evolution, Phylogeny, and Bios- tratigraphy of Arvicolids (Rodentia, Mammalia) Rohanov (Czechoslovakia), May 1987, Geological Survey Praha pp. 133-164.

Femindez, J., Viseras, C., Soria, J., 1996. Pliocene-Pleistocene continental infilling of the Granada and Guadix basins (Betic Cordillera, Spain): the influence of allocyclic and autocyclic processes on the resultant stratigraphic organization. In: Friend, P.F., Dabrio, C.J. (Eds.), Tertiary Basins of Spain: the stratigraphic record of crustal kinematics. Cambridge University Press, Cambridge, pp. 353-365.

Gil, E., Sese, C., 1984. Micromamiferos del nuevo yacimiento villafranquiense de Casablanca I (Almenara, prov. de Castell6n). Estudios Geol6gicos 40,243-249.

Martin SuArez, E., 1988. Sucesiones de micromamiferos en la depresi6n Guadix-Baza. Thesis, University of Granada.

Martin Suarez, E., Mein, P., 1991. Revision of the genus Castillomys (Muridae, Rodentia). Scripta Geologica pp. 47-81.

Maul, L., 1996. Biochronological implications of the arvicolids (Mammalia, Rodentia) from the Plio- and Pleistocene faunas of Neuleiningen (Rheinland-Pfalz, SW-Germany). Acta Zoologica Cracoviensa 39, 349- 356.

Maul, L., Masini, F., Abbazzi, L., Turner, A,, 1998. The use of different morphometric data for absolute age calibration of some South- and Middle European arvicolid populations. Paleontographica Italica 85, 111-151.

R. Minwer-Barakar e f al. / Geobios 37 (2004) 619-629 629

Mein, P., Moissenet, E., Adrover, R., 1990. Biostratigraphie du Neogkne Supdrieur du bassin de Teruel. Paleontologia i Evoluci6 23, 121-139.

Michaux, J., 1971. Arvicolidae (Rodentia) du Pliockne terminal et du Qua- ternaire ancien de France et d'Espagne. Palaeovertebrata 4, 137-214.

Michaux, J.J., Chaline, J., 1982. Remarques i propos de Mimomys septi- m n u s Michaux, 1971 (Rodentia, Mammalia). Geobios 15,95-96.

Rabeder, G., 198 1. Die Arvicoliden (Rodentia, Mammalia) aus dem Plioz2n und dem alteren Pleistodn von Niederosterreich. BeiWge zur Palaon- tologie ~sterreichs 8, 1-373.

Ruiz Bustos, A., 1995. Biostratigraphy of the Continental Deposits in the Granada, Guadix and Baza Basins (Betic Cordillera). In: Gibert, J., Sinchez, F., Gibert, L., Ribot, F. (Eds.), The Hominids and Their Envi- ronment During the Lower and Middle Pleistocene of Eurasia. Proceed- ings of the International Conference of Human Paleontology, Orce pp. 153-174.

Ruiz Bustos, A., SesB, C., 1985. Evolucidn de 10s gdneros Mimomys, Arvi- cola y Allophaiomys (Arvicolidae, Rodentia, Mammalia) en el Plioceno y Pleistoceno de la Peninsula Iberica. Estudios Geologicos 41,99-104.

Sanz de Galdeano, C., 1990. Geologic evolution of the Betic Cordilleras in Western Mediterranean, Miocene to the present. Tectonophysics 172, 107-1 19.

Sed, C., 1989. Micromamiferos del Mioceno, Plioceno y Pleistoceno de la cuenca de Guadix-Baza (Granada). In: Alberdi, M.T., Bonadonna, F.P. (Eds.), Geologia y Paleontologia de la cuenca de Guadix-Baza. Trabajos Neogeno-Quaternario pp. 185-214.

SesB, C., Alberdi, M.T., Mazo, A., Morales, J., 2001. Mamiferos del Mio- ceno, Plioceno y Pleistoceno de la Cuenca Guadix-Baza (Granada, Espaiia): revision de las asociaciones faunisticas mas caracteristicas. Paleontologia i Evoluci6 32-33.31-36.

Soria, J.M., Viseras, C., Fernandez, J., 1998. Late Miocene-Pleistocene tectono-sedimentary evolution and subsidence history of the central Betic Cordillera (Spain): a case study in the Guadix intramontane basin. Geological Magazine 135,565-574.

Tesakov, AS., 1998. Voles of the Tegelen fauna. The dawn of the quaternary. Mededelingen Nederlands Instituut Toegepaste Geowetenschappen TNO 60,71-134.

Van de Weerd, A., 1976. Rodent faunas of the Mio-Pliocene continental sediments of the Teruel-Alfarnbra region, Spain. Micropaleontological Bulletin 2, 1-217.

Viseras Alarcon, C., 199 1. Estratigrafia y sedimentologia del relleno aluvial de la cuenca de Guadix (Cordilleras Beticas). Thesis, University of Granada.

Arvicolidae (Rodentia) from the Pliocene of Tollo de Chiclana (Granada, SE Spain)

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