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Senckenbergiana lethaea 87 (2) 157–170 4 text-fi gs, 2 pls Frankfurt am Main, 31.12. 2007

Note on Cyphaspis BURMEISTER 1843 (Trilobita, Aulacopleuridae), with a review of several species mainly from the Devonian of Belgium and Germany

With 4 Text-fi gures and 2 Plates

ALLART PHILIP VAN VIERSEN & HARALD PRESCHER

A b s t r a c t

Specimens of Cyphaspis BURMEISTER are recorded from Eifelian and Frasnian strata in Belgium as well as from Eifelian strata in Germany, and are assigned to six taxa. Scant information has hitherto been avail-able on Cyphaspis from the Ardennes. From this region Cyphaspis unguloides belgica n. ssp., Cyphaspis sp. B, Cyphaspis? sp. C, and Cyphaspis sp. D are recorded. Newly collected topotypical material of Cy-phaspis unguloides unguloides (ERBEN) from the Eifel is described which permits current assignment of this taxon to Cyphaspis. The holotype of Cyphaspis hoepfneri hoepfneri (KOWALSKI) from the Eifel, which was previously only known from poor illustrations, is refi gured. The diagnosis of Cyphaspis is emended to include several taxa that exhibit a relatively weakly vaulted glabella and occasionally shorter genal spines. Heliopyge HAAS & MENSINK (Acastidae), which is in need of revision, is briefl y discussed.

K e y w o r d s : Trilobita, systematics, Aulacopleuridae, Devonian, Belgium, Germany.

K u r z f a s s u n g

Funde zu sechs Taxa von Cyphaspis BURMEISTER aus dem Eifelium und Frasnium Belgiens sowie dem Eifelium der Eifel werden dargestellt. Aus den Ardennen lagen bislang kaum verwertbare Daten zu Cy-phaspis vor. Erläutert werden dazu Cyphaspis unguloides belgica n. ssp., Cyphaspis sp. B, Cyphaspis? sp. C und Cyphaspis sp. D. Neues topotypisches Material zu Cyphaspis unguloides unguloides (ERBEN) aus der Eifel gestattet gegenwärtig eine Zuordnung von unguloides zu Cyphaspis. Für den bislang nur unbefriedigend dokumentierten Holotypus von Cyphaspis hoepfneri hoepfneri (KOWALSKI) aus der Eifel werden brauchbare Abbildungen gegeben. Die Diagnose von Cyphaspis wird verändert, um einige Taxa integrieren zu können, die durch eine relativ schwach gewölbte Glabella und gelegentlich kurze Wangen-stacheln gekennzeichnet sind. Die Revisionsbedürftigkeit von Heliopyge HAAS & MENSINK (Acastidae) wird kurz dargestellt.

ALLART PHILIP VAN VIERSEN, c/o Natuurhistorisch Museum Maastricht, de Bosquetplein 6-7 NL-6211 KJ Maastricht, The Netherlands. E-mail: ap-vanviersen@gmail.com; HARALD PRESCHER, Hauptstraße 18; D-50169 Kerpen, Germany. E-mail: ceratarges@aol.com

© E. Schweizerbart’sche Verlagsbuchhandlung (Nägele u. Obermiller), 2006, ISSN 0037-2110

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The site was already discussed by VAN VIERSEN (2006b) who recorded a new species Dohmiella dewildei from it and pro-vided a preliminary list of trilobite taxa. The trilobite fauna of Nismes (Loc028) is similar to that of Üxheim (Üxheim01). Among genera that are represented at both localities are Asty-coryphe RICHTER & RICHTER 1919, Calycoscutellum ARCHINAL 1994, Ceratarges GÜRICH 1901, Cyphaspis BURMEISTER 1843, Dohmiella LÜTKE 1990, and Scabriscutellum RICHTER & RICH-TER 1956.

Embankment south of the railway station of Jemelle (Roche-fort area), southern border of Dinant Synclinorium, Ardennes, Belgium (Loc004). N50°09.420’, E5°15.880’.

Trilobites come from the middle Eifelian part of the upper Chavées Member of the Jemelle Formation. The rich trilobite fauna of this locality is very similar to that of the famous co-eval “Trilobitenfelder” of Gees (Flesten Member, Ahrdorf For-mation), Eifel. For further details on the Jemelle site see MA-GREAN & VAN VIERSEN (2005) and VAN VIERSEN (2006b, 2007a).

Embankment near the northern outskirts of Nismes, southern border of Dinant Synclinorium, Ardennes, Belgium (Loc018). N50°04.726’, E4°33.573’.

Subsequent to RICHTER & RICHTER (1926), MAILLIEUX (1927) provided an overview of Frasnian trilobite species in Belgium along with synonymies in earlier literature sources. The trilobites of site Loc018 comprise the same species that were cited by MAILLIEUX (1927: 83) for the “Assise de Frasnes, zone à Leiorhynchus formosus, F2e” on the southern border of the Dinant Synclinorium. This unit, which also outcrops at site Loc018, coincides with the middle part of the Moulin Liénaux Formation (middle Frasnian) according to BOULVAIN et al. (1999). Trilobites that were recovered from this local-ity include Bradocryphaeus cf. supradevonicus (FRECH 1888), Cyphaspis sp. D (see below), and the highly endemic species Bradocryphaeus maillieuxi (RICHTER & RICHTER 1926) and Heliopyge helios (RICHTER & RICHTER 1926). No Scutelluinae were found at site Loc018 but material of an unidentifi ed species of Calycoscutellum was recovered by W. van Herle (Halen) from coeval carbonate mounds near Frasnes that were recently described by BOULVAIN (2007). This material will be part of a future publication.

It should be noted that Heliopyge HAAS & MENSINK 1970 is in need of revision. LIEBERMAN & KLOC (1997) excluded spe-cies from this genus that do not have the third pygidial pleural lappet projecting further posteriorly than the other lappets, a feature that they considered to be diagnostic of this genus. For example, according to these authors either Heliopyge troao-nensis MORZADEC 1983 is not a species of Heliopyge or the drawing by MORZADEC (1983: fi g. 23) is inaccurate because it shows the fourth pygidial pleural lappet projecting further pos-teriorly than the third. Heliopyge troaonensis was nonetheless treated as a valid species of Heliopyge (LIEBERMAN & KLOC 1997: 55, 56) even though it was simultaneously assigned to a new genus Hallandclarkeops in the same work (ibid.: 27). Furthermore, in discussing Heliopyge these authors over-looked that the type species of Heliopyge, H. helios, actually has the fourth pygidial pleural lappet projecting much further posteriorly than the other lappets (cf., e.g., RICHTER & RICHTER 1926: 224, pl. 12, fi g. 38a; MAILLIEUX 1927: pl. 4, fi g. 6; HAHN & HAHN 1975: pl. 1, fi g. 9). This also goes for another species that they included in Heliopyge, namely Heliopyge n. sp. aff.

Introduction

Cyphaspis is a common constituent of Middle Devonian tri-lobite faunas along the northern margin of the Rheic Ocean. According to BASSE (2002) the genus occurs in many strata of Early to Late Devonian age in the German part of the Rhe-nohercynian. Similar stratigraphic ranges may be expected for its occurrence in the Ardennes but the Devonian trilobites of this region are poorly documented and in need of revision (MAGREAN & VAN VIERSEN 2005). At present, many Cyphaspis species from the Devonian of the Eifel and Ardennes are in-adequately known while others remain to be described. The present paper is the fi rst part of a review of Cyphaspis that aims to enhance the knowledge about several poorly known species from these regions and to newly describe others.

Many concepts of Cyphaspis have been proposed by previ-ous workers (see, e.g., RICHTER & RICHTER 1926; THOMAS & OWENS 1978, and references therein; PŘIBYL & VANĚK 1981; ADRAIN & CHATTERTON 1994, 1996; BASSE 2002), and species have been variably assigned to Cyphaspis and Otarion ZENKER 1833. ADRAIN & CHATTERTON (1994, 1996) regarded Cyphaspis and Otarion as sister taxa and provided a differential diagnosis that was intended to distinguish between their less derived members. According to ADRAIN & CHATTERTON (1994: 312) their diagnosis “does not necessarily account for possible con-vergences in the Devonian”. Most species from the Devonian of the Rhenohercynian may be placed in either of these genera with little effort but some of the more derived members have proved to be particularly challenging. BASSE (2002) identifi ed several problematic cases and emended the generic diagnosis to include these in Cyphaspis. BASSE’s concept is partially adopted herein as it comprises species that are only tentatively assigned to Cyphaspis.

Locations and stratigraphy

The term ‘Couvinian’ is commonly used in old literature sources to designate an extensive range of Devonian strata in Belgium. In recent literature, this period is still occasionally roughly compared to the Eifelian and so its lower boundary is approximately correlated with that of the Middle Devonian. It should be noted that the lower boundary of the Couvinian pe-riod is situated considerably lower, in the basal part of the St. Joseph Formation (upper Emsian); its upper boundary is locat-ed in the upper part of the Hanonet Formation (lower Givetian) (see, e.g., BULTYNCK et al. 2000; BULTYNCK 2006).

Southern slope of Kirberg Hill near Üxheim, Eifel, Germany (Üxheim01).

Embankment 500 m north-northeast of the church of Üx-heim. Exposed is the Kirberg Member (lower Eifelian) of the Nohn Formation. This site is the same as the type locality of Cyphaspis unguloides unguloides (ERBEN 1953) and Dohmi-ella prescheri VAN VIERSEN 2006b. Coordinates are r 5433: h 7912, according to ERBEN (1953: 77).

Quarry near the western outskirts of Nismes (Couvin area), southern border of Dinant Synclinorium, Ardennes, Belgium (Loc028). N50°03.720’, E4°32.600’.

Trilobites were recovered from the middle part of the Foulerie Member of the Couvin Formation (lower Eifelian).

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axial rings and posterior pleural bands; primitively three or four axial rings; pygidial doublure broad for family.

D i s c u s s i o n : ADRAIN & CHATTERTON (1994: 312) pointed out that the type species of Cyphaspis, C. ceratophthalmus, is a derived member of the clade which, in some respects, is not representative of basal members. We have assigned our specimens to Cyphaspis mainly based on the presence of the following features that according to ADRAIN & CHATTERTON (1996: 101) distinguish members of this genus from Otarion: shorter preglabellar fi eld; short, more infl ated glabella; smaller L1; broader, shorter (exsag.) librigena with usually much longer genal spine; possession of 11 as apposed to 12 or more thoracic segments; relatively smaller, narrower pygidium, with more pronounced tubercle rows and broader doublure. In addi-tion, many Devonian species from the Rhenohercynian display an infl ated genal trunk. According to ADRAIN & CHATTERTON (1994, 1995, 1996) this morphology is also present in some other Aulacopleuridae but never in Otarion.

Of note is that some species exhibit features that are not common to Cyphaspis. These include: weakly infl ated glabella that does not overhang preglabellar fi eld when occipital ring is held in the vertical plane, short genal spines, small overall size, and comparatively large eyes. The presence of these char-acters, the fi rst two of which are widespread among members of Otarion, has occasionally led to tentative assignments of species to Cyphaspis in the past. Our examination of newly re-corded specimens has shown that Cyphaspis species can show a mixture of these features, and that at least shape of glabella and length of librigenal spine may even vary intraspecifi cally. For example, these last two characters vary between subspe-cies of Cyphaspis unguloides (ERBEN 1953), and librigenal spine length even varies among topotypical specimens of Cyphaspis unguloides unguloides (see below). We believe that both these characters are probably either plesiomorphies or homoplasies (i.e., convergences on Otarion) and that they should have no bearing on generic assignments. The other

helios of MORZADEC 1983. LIEBERMAN & KLOC (1997) also as-signed Asteropyge (Asteropyge) hispanica RICHTER & RICHTER 1926 to Heliopyge, even though it has the fourth pygidial pleural lappet projecting furthest posteriorly (this species was assigned to a new genus Quadratispina by GANDL 1972: 146). In view of the above, the diagnosis of Heliopyge proposed by LIEBERMAN & KLOC (1997) can no longer be maintained. According to MORZADEC (1983: 141, 2002: 416) Heliopyge is characterised by fi ve pairs of pygidial lateral spines and “in-terpleural perforations” of the pygidium. SMEENK (1983: 414, fi g. 5) reported “chink-shaped interpleural perforations” in a pygidium of Bradocryphaeus maillieuxi from its type locality. It is unclear whether the interpleural perforations of this spe-cies are homologous with those in Heliopyge and which impli-cations this would have. An analysis of these taxa, however, is beyond the scope of the present paper.

Acknowledgements

M. Basse (Bochum) and C. Brauckmann (Clausthal University of Technology) have reviewed the manuscript and made helpful suggestions for its improvement. C. Brauckmann also under-lined the validity of Otarion (Conoparia) hoepfneri KOWALSKI 1990 to us. N. Höller (Koblenz) has allowed us to examine and photograph the holotype of Cyphaspis hoepfneri hoepfneri. G. Daumeries (Gilly) has provided access to additional trilobite material from Belgium for comparison. We are indebted to these persons for their help.

Systematic palaeontology

Specimens described and fi gured are housed in Forschungsin-stitut und Naturmuseum Senckenberg, abbreviated as ‘SMF’, with the exception of one specimen in the private collection of N. Höller (Koblenz). All specimens were coated with am-monium chloride sublimate prior to photography. Terminology used follows WHITTINGTON & KELLY (1997), except for the term ‘infl ated genal trunk’ which is adopted from ADRAIN & CHAT-TERTON (1996: 101).

Family A u l a c o p l e u r i d a e ANGELIN 1854Subfamily O t a r i o n i n a e RICHTER & RICHTER 1926

Tribe O t a r i o n i n i RICHTER & RICHTER 1926

Genus Cyphaspis BURMEISTER 1843

Ty p e s p e c i e s : Phacops ceratophthalmus GOLDFUSS 1843, from the Ahrdorf Formation (Eifelian) of the Eifel region.

D i a g n o s i s (emend.): Adopted from ADRAIN & CHATTERTON (1996: 101) with some emendations to include taxa assigned to Cyphaspis here: Otarionini with glabella infl ated, usually overhanging preglabellar fi eld when occipital ring is held in vertical plane; preglabellar fi eld short; interocular fi xigenae narrow; L1 small; librigenal fi eld relatively broad and short (exsagittally); 11 thoracic segments, with long axial spine or occasionally a central tubercle on sixth; pygidium narrow and small even for subfamily, with transverse rows of tubercles on

Text-fi g. 1. Reconstructions of cephala (lateral view) of A. Cyphaspis? ranuncula (ERBEN 1953), middle Eifelian, Gees, Eifel (adopted from ERBEN 1953: fi g. 3c); B. Cyphaspis hamidi CHATTERTON et al. 2006, up-per Emsian, Morocco (after CHATTERTON et al. 2006: pl. 46, fi g. 14).

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Cyphaspis? sp. C in the present note. However, given the lack of data that is currently available on these Rhenohercynian species it is uncertain whether they constitute a clade. Another species, Cyphaspis? goerlichi (HAAS 1968) from the upper Emsian of Turkey (Text-fi g. 3), bears a general resemblance to these taxa. It too lacks a spine or tubercle centrally on the sixth thoracic segment. Even so, Cyphaspis? goerlichi shows a rather dissimilar glabellar infl ation and exceedingly long and robust genal spines, and it does not seem to be particularly closely related to either Cyphaspis hamidi or Cyphaspis? ra-nuncula and similar species.

Recently, one of us (H.P.) recovered material of an unde-scribed Cyphaspis species from the Emsian–Eifelian transi-tion in the Timrhanrhart Formation in Morocco, close to the type locality of Cyphaspis hamidi. This species is mor-phologically close to Cyphaspis hamidi yet distinct in sev-eral characters, including the consistent presence of a dorsal spine on the sixth thoracic segment and a well-developed occipital node, and will be described by us at a later time. Of note is that an enrolled paratype specimen of Cyphaspis hamidi that was illustrated by CHATTERTON et al. (2006: pl. 46, fi g. 8) appears to show the remains of a broken off dor-sal spine on the sixth thoracic segment. If this is indeed the case then it seems that the presence of this spine varies in Cyphaspis hamidi.

O c c u r r e n c e (only Belgium): Recent fi eldwork by the authors in the Ardennes has shown that Cyphaspis occurs here almost throughout the Eifelian, and in the Frasnian. This representation is biased in that most of our collections were conducted in strata of these ages.

Previous Cyphaspis records from Belgium mainly come from Eifelian strata along the southern border of the Dinant Synclinorium (e.g. MAILLIEUX 1919, 1933, 1938) and Frasnian strata in the Couvin area (e.g. MAILLIEUX 1909, 1912, 1927). MAILLIEUX’s Eifelian records from Belgium comprise only the Pragian Cyphaspis hydrocephala (ROEMER 1843) and we assume that none of the specimens were correctly identifi ed. Unfortunately, the lack of type numbers or whereabouts, which were never given, impedes a reassessment of the original mate-rial.

Cyphaspis sp. A of MAILLIEUX (1909) was cited by RICHTER & RICHTER (1926) who mentioned that its occurrence in the lower Frasnian might suggest that it belongs to Cyphaspis el-

two characters, small overall size and comparatively large eyes, also occur in taxa that should obviously be assigned to Cyphaspis (e.g. Cyphaspis hoepfneri KOWALSKI (1990)) and so these alone do not provide convincing evidence for exclusion from this genus.

CHATTERTON et al. (2006: 52) suggested that a cladistic analysis of Cyphaspis may indicate that two of its species, Cy-phaspis? ranuncula (ERBEN 1953) from the middle Eifelian of the Eifel (Text-fi g. 1a) and Cyphaspis hamidi CHATTERTON et al. 2006 from the upper Emsian (Timrhanrhart Formation) of Mo-rocco (Text-fi g. 1b), should be assigned distinct generic rank. According to these last authors both these species are small, have comparatively short and straight genal spines, compara-tively large eyes, and the axial thoracic spine reduced to no more than a tubercle. A particularly close relationship of these two species, however, is not supported by the new data from our study. The fi rst three of these characters listed by CHAT-TERTON et al. (2006) have already been discussed above and are believed to be of limited value for generic assignment. The only remaining feature, the central tubercle on the sixth tho-racic segment, actually appears to be restricted to Cyphaspis hamidi. We were unable to identify it in any specimen of Cy-phaspis? ranuncula. Instead, arrangement of tubercles on the thoracic axis of Cyphaspis? ranuncula, including the holotype (SMF 58146), is more accurately defi ned as follows: “axial rings with few, moderately fi ne tubercles, none of which ever tending to settle in the center of the rings” (pers. comm. with M. Basse). Rather than being allied with Cyphaspis hamidi, Cyphaspis? ranuncula seems to stand closer to several other Rhenohercynian Eifelian species which show a similar ce-phalic and especially glabellar morphology. These taxa include a cephalon and an enrolled specimen from the Eifelian of the Eifel that were respectively assigned to Cyphaspis n. sp. 3 and Cyphaspis sp. 4 by BASSE (2002), and a cephalon designated

Text-fi g. 2. Reconstructions of cephala (lateral view) of A. Cyphaspis unguloides unguloides (ERBEN 1953), lower Eifelian, Üxheim, Eifel (adopted from ERBEN 1953: fi g. 2b); B. Cyphaspis unguloides belgica n. ssp., lower Eifelian, Nismes, Ardennes.

Text-fi g. 3. Reconstruction of cephalon (lateral view) of Cy-phaspis? goerlichi (HAAS 1968), upper Emsian, Turkey (adopt-ed from HAAS 1968: fi g. 12b).

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Cyphaspis unguloides unguloides (ERBEN 1953)Pl. 1 fi gs 1-4, 7, 8; Pl. 2 fi gs 3, 4; Text-fi g. 2a

* 1953 Otarion (Otarion) unguloides unguloides ERBEN: 77-78, fi gs 2a-c.e.p. 1982 Otarion (Otarion) unguloides – KOWALSKI: 116-120

[non fi gs 7-9 (= Cyphaspis hoepfneri hoepfneri)]. 2002 Cyphaspis unguloides (ERBEN 1953) – BASSE: pl. 29,

fi gs 583-585.partim 2006 Otarion unguloides – CHATTERTON et al.: 52 [reference to KOWALSKI (1982)].

H o l o t y p e : Cephalon, SMF 58137 (ERBEN 1953: fi g. 2; BASSE 2002: pl. 29, fi gs 583-585).Ty p e l o c a l i t y : Üxheim01. Southern slope of Kirberg Hill near Üxheim, Eifel.Ty p e h o r i z o n : Kirberg Member, Nohn Formation (lower Eife-lian).O t h e r m a t e r i a l : Three incomplete cephala, SMF 80592-80594; three cranidia, SMF 80595-80597; one librigena, SMF 80591; one pygidium, SMF 80590; from type locality and horizon.

D i f f e r e n t i a l d i a g n o s i s : Nominal subspecies of Cy-phaspis unguloides with the following characteristic features. Elongated (sag.) bulb-shaped, anteriorly weakly infl ated ante-rior glabellar lobe that is indented by deep S1. Long (exsag.), narrow (tr.) L1. Pygidial axis bearing numerous tubercles that are relatively small for this species, especially posteriorly. Tips of tubercles on posterior part of pygidial axis are acuminate and somewhat posteriorly directed.

D e s c r i p t i o n : See ERBEN (1953: 78). Also, see discussions below and under Cyphaspis unguloides belgica n. ssp.

D i s c u s s i o n : This subspecies was hitherto only known with certainty from the mostly exfoliated holotype cephalon. BASSE (2002: pl. 29, fi gs 589-594) recorded morphologically similar cephala of imprecise origin (some of these specimens come from ‘H 212’, which was later redefi ned as Ahrdorf For-mation, middle Eifelian, Üxheim, by BASSE & MÜLLER 2004: 17, whereas the provenance of others remains uncertain) that are different from Cyphaspis unguloides mainly in having a denser tuberculation, and so he assigned these to Cyphaspis cf. unguloides. According to BASSE (2002), specimens from Sau-erland consistently show this same denser tuberculation and these were also tentatively assigned to Cyphaspis unguloides. A detailed comparison of BASSE’s specimens from the Eifel and Sauerland with the present two subspecies from the Eifel and the Ardennes may warrant their descriptions as distinct subspecies.

Had we had fewer specimens of the nominal subspecies available for study and not discovered the material from Nis-mes then we might have been predisposed to treat smaller and larger specimens from Üxheim as distinct taxa. Smaller indi-viduals from this last locality tend to have short genal spines, groove-like anterior border furrow that is partially hidden by anterior border in frontal view, more weakly infl ated glabella that never overhangs preglabellar fi eld, and somewhat weakly infl ated genal trunks, whereas larger individuals commonly have longer genal spines (sometimes exceeding exsagittal length of librigena), more infl ated genal trunks, S1 partially obscured by anterior glabellar lobe in dorsal view, and rarely, glabella slightly overhanging preglabellar fi eld. Despite these

lipsocephala. This taxon was subsequently designated Otarion cf. ellipsocephala (sic) by MAILLIEUX (1927). We have not seen the original material nor illustrations of it. Its generic identity is unknown.

GODEFROID (1968: 14) reported Otarion (Otarion) cf. bala-nops ERBEN from ‘Co2a-b’ (probably lower Eifelian) near Wel-lin. No repository or type numbers were given for this record and we have not seen the original material. Fieldwork by one of us (A.V.V.) at the outcrop that this record came from has yielded several internal moulds of trilobite parts that could be identifi ed as Tropidocoryphe sp., Proetinae gen. & sp. indet., and Phacopinae gen. & sp. indet.

CRÔNIER & VAN VIERSEN (in press) cited the presence of Otarion ibergium in the Frasnian of the Couvin area, based on records by RICHTER & RICHTER (1926) and MAILLIEUX (1927), and a librigena collected by A.v.V. (see below). This species is considered to belong to Cyphaspis herein. Records of this spe-cies come from several different stratigraphic units and may not be conspecifi c with topotypical material.

VAN VIERSEN (2007b) mentioned the presence of Otarioni-nae gen. & sp. indet. in the basal part of the Hanonet Forma-tion (uppermost Eifelian) in the Resteigne quarry. Recent collections of this taxon suggest that it belongs to Cyphaspis but it is rare at Resteigne and there are only several fragments available of it at present.

Cyphaspis unguloides (ERBEN 1953)

A s s i g n e d t a x a : unguloides unguloides, lower Eifelian, Eifel; unguloides belgica n. ssp., lower Eifelian, Ardennes. Possibly also: n. sp. aff. unguloides of BASSE (1997), lower Eifelian, Sauerland; cf. unguloides of BASSE (2002), Eifelian, Eifel.

D i a g n o s i s : There are several taxa in the lower and mid-dle Eifelian of the Rhenohercynian that are morphologically similar to Cyphaspis unguloides and that show a potential of representing subspecies. Differential diagnoses are provided below for Cyphaspis unguloides unguloides and Cyphaspis unguloides belgica n. ssp., which are solely intended to dis-tinguish between these subspecies. We have not examined the original material of Cyphaspis n. sp. aff. unguloides of BASSE (1997) and Cyphaspis cf. unguloides of BASSE (2002), and their relationship with Cyphaspis unguloides is unknown. Therefore, a species diagnosis is postponed. Should BASSE’s two taxa be recognised as subspecies of Cyphaspis unguloides then the present differential diagnoses of the other two may require adjustment.

D i s c u s s i o n : This species has been tentatively included in Cyphaspis by some authors and it is absent from lists of valid species of Otarion (ADRAIN & CHATTERTON 1994) and Cy-phaspis (ADRAIN & CHATTERTON 1996). The nominal subspecies has a weakly infl ated glabella that usually does not overhang the preglabellar fi eld, which might suggest that it does not belong to Cyphaspis. Coeval Cyphaspis unguloides belgica n. ssp., however, is exceedingly similar to the nominal subspe-cies except mainly in having a strongly infl ated glabella that is typical of most Cyphaspis species. There is no doubt about the close alliance of these two taxa and so we are confi dent about our assignment of Cyphaspis unguloides unguloides to Cyphaspis.

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Pygidial contour rounded subtriangular. Axis comprised of six rings plus terminal axial piece; each ring bears a transverse row of about seven tubercles, the abaxial two of which are usually slightly closer spaced; tubercles in these rows are in-creasingly large and thimble-shaped on posterior rings; smaller tubercles are randomly positioned just anterior to these rows. Anterior four inter-ring furrows fi rmly impressed, the fi rst three of which are distally deep. Five pleurae are discernible. Posterior pleural bands more infl ated than associated anterior pleural bands. Pleural furrows proximally and distally shal-low, otherwise deep. Interpleural furrows shallow; anterior two relatively fi rmly impressed; third discernible mainly because of absence of prosopon; remainder vague. Coarse, large tubercles are present on pleural fi eld posterior to an imaginary straight line that runs from anteriormost pleural band just adaxial to border furrow, to abaxial margin of fi fth axial ring; anterior to this line only few, comparatively small tubercles are present. Tubercles on and just posterior to this line are large and thim-ble-shaped, especially on posterior pleural bands (commonly broken off). Border uniformly broad laterally and posterolater-ally; slightly broader (sag.) posteromedially; entirely covered with densely spaced tubercles that are clearly smaller than tubercles abaxially on pleural fi eld and that decrease in size towards pygidial margin.

M o r p h o l o g y : Cyphaspis unguloides belgica n. ssp. shows some variations that we regard as possible polymorphisms. Tubercles on glabella, preglabellar fi eld, and librigenal fi eld are usually large but may be signifi cantly smaller in some in-dividuals. Also, the anterior and lateral cephalic borders bear a mixture of smaller and larger tubercles or are entirely devoid of these. Two cranidia, one large (SMF 80577) and one small (SMF 80572), bear four coarse tubercles on anterior glabellar lobe, similarly positioned to those in the type species of Cy-phaspis, C. ceratophthalmus.

C o m p a r i s o n s : The nominal subspecies differs from the new subspecies as follows: Smaller individuals may have a groove-like anterior border furrow that is partially obscured by anterior border in frontal view. Highest point of glabella positioned far posteriorly, between eyes and occipital ring. Anterior glabellar lobe elongated (sag.) bulb-shaped, later-ally weakly curved or straightened (exsag.) anterior to S1, anteriorly weakly infl ated, indented by deep S1, always lacking four larger tubercles anteriorly, and usually not over-hanging preglabellar fi eld. In larger individuals, S1 may be partially obscured by anterior glabellar lobe in dorsal view.

tendencies, there appears to be a considerable overlap of these characters between smaller and larger individuals so that none of them would render further subdivision of this taxon feasible.

Cyphaspis unguloides belgica n. ssp.Pl. 1 fi gs 5, 6, 9; Pl. 2 fi gs 1, 2, 6, 7; Text-fi gs 2b, 4

v 2006b Cyphaspis sp. – VAN VIERSEN: 231.

E t y m o l o g y : Gallia Belgica, disambiguated Belgica, a Roman province in northern Gaul.

H o l o t y p e : Disarticulated cephalon, SMF 80571 (pl. 1 fi g. 6).

Ty p e l o c a l i t y : Loc028. Quarry of Nismes, Belgium.

Ty p e h o r i z o n : Foulerie Member, Couvin Formation (lower Eife-lian).

P a r a t y p e s : Cranidium, SMF 80572; librigena, SMF 80573; pygid-ium, SMF 80574.

O t h e r m a t e r i a l : Incomplete cephalon, SMF 80575; two incom-plete cranidia, SMF 80577, 80578; three incomplete librigenae, SMF 80579-80581; two librigenae on a single rock slab, SMF 80582; one partial librigena, SMF 80583; incomplete thorax with pygidium of Dohmiella dewildei, SMF 80576; two pygidia, SMF 80584, 80585; from type locality and horizon.

D i f f e r e n t i a l d i a g n o s i s : A subspecies of Cyphaspis unguloides with the following characteristic features. Trun-cated (sag.) bulb-shaped, anteriorly strongly infl ated anterior glabellar lobe. Short (exsag.), subovoid L1. Large, thimble-shaped tubercles present posteriorly on pygidial axis and abaxially on pygidial pleural fi eld.

D e s c r i p t i o n : Cephalon with convex (sag., exsag.) contour. Anterior border weakly vaulted with smooth surface or bearing few tubercles. Anterior border furrow shallow; completely vis-ible in frontal view. Preglabellar fi eld steep, medially about as high as anterior border (sag.); bearing tubercles smaller than on anterior glabellar lobe. Highest point of glabella is just posterior to halfway along cephalon (sag.). Anterior glabellar lobe partially overhanging anterior border when S0 is held in the vertical plane; bearing alternation of smaller and larger cone-shaped tubercles; not indented by lateral glabellar furrow S1. In some specimens, four large tubercles are discernible an-teriorly on anterior glabellar lobe; their position is the same as these large tubercles in Cyphaspis ceratophthalmus (cf. BASSE 2002: pl. 30, fi g. 608). Lateral glabellar lobe L1 bearing dense-ly spaced tubercles. Fixigenal fi eld bearing tubercles similar to those on L1. S0 relatively broad (sag., exsag.), shallow. Oc-cipital ring about as long (sag.) as anterior border (sag.); bear-ing few tubercles. Steep librigenal fi eld that is much longer (exsag.) than wide (tr.); bearing alternation of large and small, cone-shaped tubercles. In some specimens tubercles on librige-nal fi eld are abaxially interchanged by transversally elongated pits (pl. 2, fi g. 2). Lateral border uniformly vaulted; bearing small tubercles on inner half and alternation of small and large tubercles on outer half, or completely devoid of tubercles. Lateral border furrow shallow, broad (tr.). Genal spine slightly divergent; proximally straight, as thick as lateral border; at least as long as librigena (exsag.); distally somewhat inward curving. Eye subhemispherical; taller than wide.

Thorax is only known from seven articulated segments. One axial ring is well-developed and shows the robust subtri-angular base of a dorsal spine (pl. 2, fi g. 7).

Text-fi g. 4. Reconstruction of pygidium (dorsal view) of Cyphaspis unguloides belgica n. ssp., lower Eifelian, Nismes, Ardennes.

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specimens from Üxheim at a subspecifi c level. Later, KOW-ALSKI (1990) recorded another incomplete trilobite specimen (Höller Coll.) from Gees and assigned this to a new species. BASSE (1997), in regarding KOWALSKI’s (1990) “Otarion (Con-oparia) hoepfneri n. sp.” as a nomen nudum, subsequently se-lected this last specimen as the holotype of his new subspecies Cyphaspis hoepfneri hoepfneri. However, KOWALSKI (1990: 34, 35) had provided a brief description that includes features characteristic of this species (e.g. sub-exsagittally running ge-nal spines) and only one specimen from the Höller Collection was illustrated (ibid.: fi gs 19, 20) which he obviously intended as the holotype. In the captions of these illustrations the type locality and horizon (see above) were defi ned. Therefore, Ota-rion (Conoparia) hoepfneri KOWALSKI 1990 is, in fact, a valid taxon. Conoparia HAWLE & CORDA 1847, to which this species was originally assigned, was considered a junior subjective synonym of Otarion by ADRAIN & CHATTERTON (1994). A re-vised concept of Conoparia that was proposed by PŘIBYL & VANĚK (1981) is clearly polyphyletic and, therefore, is not sup-ported by us. Instead, Otarion (Conoparia) hoepfneri displays a number of apomorphies of Cyphaspis and we follow BASSE (1997) in assigning it to this genus.

Since there was much room for improvement of the original illustrations, the holotype was whitened and new photographs are provided in the present paper (pl. 2, fi g. 10). Another topotypical incomplete specimen and a cephalon were recently illustrated by RÜCKERT & KLEVER (2007: 42, 43, un-numbered fi gs). Unfortunately, like in KOWALSKI’s (1982, 1990) illustrations, these trilobite specimens were not whitened prior to photography. The poor quality of the photographs impedes a detailed comparison with the holotype at present but we assume that the specimens were correctly identifi ed. A topo-typical cephalon that was previously questionably assigned to this subspecies by BASSE (2002: pl. 28, fi gs 579, 580) is very similar and probably conspecifi c.

Cyphaspis sp. BPl. 2 fi g. 9

M a t e r i a l : One external mould of a cranidium plus silicone cast, SMF 80587; one internal mould of a cranidium, SMF 80588. From site Loc004, Jemelle, Belgium; Chavées Member of Jemelle Forma-tion (middle Eifelian).

D i s c u s s i o n : Cyphaspis cranidia are relatively abundant in Jemelle although rarely well-preserved. As far as specimens can be classifi ed, the majority probably belongs to Cyphaspis sp. B. The cranidium illustrated herein shows some resem-blance to coeval Cyphaspis ceratophthalmus from the Eifel but its limited preservation impedes any further comparison.

Cyphaspis? sp. CPl. 2 fi g. 5

M a t e r i a l : One external mould of a cephalon plus silicone cast, SMF 80586. From site Loc004, Jemelle, Belgium; Chavées Member of Jemelle Formation (middle Eifelian).

D i s c u s s i o n : This cephalon is morphologically similar to that of Cyphaspis? ranuncula from the middle Eifelian of the Rhenish Massif. It also bears a resemblance to Cyphaspis n.

S0 relatively narrow (sag., exsag.). Long, tongue-shaped L1. Tubercles on librigenal fi eld reaching abaxially until border furrow, more rarely interchanged by pits here. Lateral bor-der bearing granules on inner half or entirely covered with tubercles slightly smaller than on librigenal fi eld. Thorax is not known. Each pygidial axial ring bears a more or less transverse row of at least ten tubercles occasionally with iso-lated granules just anterior or posterior to these. Tubercles on rings four to six somewhat acuminate and pointed posteriorly. Anterior two inter-ring furrows fi rmly impressed, abaxially with broad (exsag.), elongated (tr.) depressions. Third inter-ring furrow weakly impressed. Remaining inter-ring furrows very faint and recognisable by absence of tubercles. Anterior and posterior pleural bands of fi rst pleura equally infl ated. Tubercle pattern on pleural fi eld similar to that of Cyphaspis unguloides belgica n. ssp. but tubercles are generally smaller, and there is no distinct difference in size between tubercles on anterior and posterior pleural bands. Relatively steep and narrow, more vaulted pygidial border, bearing weak tubercles that disappear towards margin.

VAN VIERSEN (2006a) recorded coeval Cyphaspis n. sp. A from the basal part of the Jemelle Formation (Vieux Moulin Member, according to DUMOULIN & BLOCKMANS 2008) near the village of Vireux-Molhain (northern France), just 15 km east of Nismes. The French taxon seems to come close to our new subspecies and especially its glabella is similarly shaped. Un-fortunately, among numerous articulated specimens that were examined by this author, none are adequately preserved for further comparison.

Cyphaspis hoepfneri (KOWALSKI 1990)

A s s i g n e d t a x a : hoepfneri hoepfneri, middle Eifelian, Eifel, Sau-erland; hoepfneri pumilio BASSE 1997, upper Eifelian, Sauerland.

Cyphaspis hoepfneri hoepfneri (KOWALSKI 1990)Pl. 2 fi g. 10

v e.p. 1982 Otarion (Otarion) unguloides – KOWALSKI: 116-120, fi gs 7-9 [only material from Gees].

* 1990 Otarion (Conoparia) hoepfneri KOWALSKI: 34, 35, fi gs 19, 20.

1997 Cyphaspis hoepfneri hoepfneri n. sp. – BASSE: 124, pl. 10, fi gs 10, 11.

2002 Cyphaspis hoepfneri BASSE 1997? – BASSE: pl. 28, fi gs 579, 580.

partim 2006 Otarion unguloides – CHATTERTON et al.: 52 [reference to KOWALSKI (1982)].

2007 Cyphaspis hoepfneri BASSE – RÜCKERT & KLEVER: 42, 43 [unnumbered fi gs].

H o l o t y p e : Articulated specimen, priv. coll. of N. Höller, Koblenz (pl. 2, fi g. 10).Ty p e l o c a l i t y : ‘Trilobitenfelder’ near Gees/Gerolstein, Eifel.Ty p e h o r i z o n : Upper part of Gees Subformation, Flesten Mem-ber, Ahrdorf Formation, (middle Eifelian).

D i s c u s s i o n : An incomplete specimen (Höpfner Coll.) of this subspecies was recorded by KOWALSKI (1982) from the middle Eifelian of Gees, Eifel, who assigned it to Otarion (Otarion) unguloides while making note that certain small dif-ferences might permit distinction from similar early Eifelian

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References

phologies and provenances of specimens included in it vary signifi cantly. The librigena from Loc018 is possibly the fi rst specimen from Belgium to reveal the full length of the genal spine, which greatly exceeds that of some “Cyphaspis iber-gia” from Germany (RICHTER & RICHTER 1926: pl. 7, fi g. 9): about 2,5 times that of length (exsag.) of librigena in the fi rst; about as long as librigena in the last. The internal mould of a cephalon with broken off genal spines from Bousse-en-Fagne (Couvin area) that RICHTER & RICHTER (1926: pl. 7, fi g. 10) designated as Cyphaspis ibergia is too poorly preserved for a detailed comparison with topotypical specimens. MAILLIEUX (1927) reported the presence of Otarion ibergia (sic) in the Frasnian (F2e, F2g, F2j) of Boussu-en-Fagne (two distinct lo-calities), Nismes, and Roly. His material from F2e comes from Nismes (Les Abannets: type locality and horizon of Heliopyge helios and Bradocryphaeus maillieuxi) and is possibly conspe-cifi c with our librigena. The other specimens from Belgium recorded by MAILLIEUX (1927), including the internal mould of a cephalon from Boussu-en-Fagne illustrated by RICHTER & RICHTER (1926), are provenant from stratigraphically younger units (F2g, F2j). They may or may not be conspecifi c with the specimens from F2e and topotypical material.

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Manuscript submitted: 2007-07-11; accepted 2007-08-24

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VAN VIERSEN & PRESCHER: Note on Cyphaspis BURMEISTER 1843 (Trilobita, Aulacopleuridae), with a review of several species ...166

Plate 1

Figs 1-4, 7, 8. Cyphaspis unguloides unguloides (ERBEN 1953) Nohn Formation (lower Eifelian), site Üxheim01, Üxheim, Germany. 1. Incomplete cephalon, SMF 80592. – a) Dorsal view, x 8; b) anterior view, x 10; c)

oblique lateral view, x 8. 2. Incomplete cephalon, SMF 80593. – a) Dorsal view, x 6; b) anterior view, x 6; c)

oblique lateral view, x 6. 3. Cranidium, SMF 80595. – a) Dorsal view, x 5; b) anterior view, x 6. 4. Cranidium, SMF 80596. – a) Dorsal view, x 6; b) anterior view, x 5. 7. Large incomplete cephalon, SMF 80594. – a) Dorsal view, x 5; b) anterior view, x

5; c) lateral view, x 5. 8. Large cranidium, SMF 80597. – a) Dorsal view, x 5; b) anterior view, x 5; c) lateral

view, x 5.

Figs 5, 6, 9. Cyphaspis unguloides belgica n. ssp. Couvin Formation (lower Eifelian), site Loc028, Nismes, Belgium. 5. Incomplete cranidium, SMF 80577. – Lateral view, x 7. 6. Holotype, disarticulated cephalon, SMF 80571. – a) Lateral view, x 10; b) dorsal

view, x 12; c) anterior view, x 10. 9. Paratype, cranidium, SMF 80572. – a) Lateral view, x 13; b) anterior view, x 13.

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Senckenbergiana lethaea, 87 (2); 2007 Plate 1

A. P. VAN VIERSEN & H. PRESCHER Note on Cyphaspis BURMEISTER 1843 (Trilobita, Aulacopleuridae), with a review of several species mainly from the Devonian of Belgium and Germany.

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VAN VIERSEN & PRESCHER: Note on Cyphaspis BURMEISTER 1843 (Trilobita, Aulacopleuridae), with a review of several species ...168

Plate 2

Figs 1, 2, 6, 7. Cyphaspis unguloides belgica n. ssp. Couvin Formation (lower Eifelian), site Loc028, Nismes, Belgium. 1. Paratype, partially exfoliated pygidium, SMF 0000. – a) Dorsal view, x 11; b)

posterior view, x 11; c) lateral view, x 18. 2. Paratype, librigena (genal spine broken off), SMF 0000. – Lateral view, x 8. 6. Incomplete cephalon (tectonically deformed), SMF 0000. – Dorsal view, x 8. 7. Incomplete thorax, SMF 0000. – Dorsal view, x 5.

Figs 3, 4. Cyphaspis unguloides unguloides (ERBEN 1953) Nohn Formation (lower Eifelian), site Üxheim01, Üxheim, Germany. 3. Pygidium, SMF 0000. – a) Dorsal view, x 8; b) posterior view, x 8; c) oblique lateral

view, x 12. 4. Librigena, SMF 0000. – Lateral view, x 6.

Fig. 5. Cyphaspis (s.l.) sp. C Jemelle Formation (middle Eifelian), site Loc004, Jemelle, Belgium. Silicone cast of cephalon, SMF 0000. – a) Lateral view, x 8; b) dorsal view, x 7; c) ante-

rior view, x 8.

Fig. 8. Cyphaspis cf. ibergia RICHTER & RICHTER 1926 Moulin Li_naux Formation (middle Frasnian), site Loc018, Nismes, Belgium. Mostly exfoliated librigena, SMF 0000. – Lateral view, x 12.

Fig. 9. Cyphaspis sp. B Jemelle Formation (middle Eifelian), site Loc004, Jemelle, Belgium. Silicone cast of cephalon, SMF 0000. – Dorsal view, x 6.

Fig. 10. Cyphaspis hoepfneri hoepfneri BASSE 1997 Ahrdorf Formation (middle Eifelian), ‘Trilobitenfelder’, Gees, Germany.

H o l o t y p e , articulated specimen, SMF 0000. – a) Dorsal view, x 10; b) lateral view, x 11; c) anterior view, x 10.

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Senckenbergiana lethaea, 87 (2); 2007 Plate 2

A. P. VAN VIERSEN & H. PRESCHER Note on Cyphaspis BURMEISTER 1843 (Trilobita, Aulacopleuridae), with a review of several species mainly from the Devonian of Belgium and Germany.

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