Stuttgarter Beitrge zur NaturkundeSerie B (Geologie und Palontologie)

Herausgeber:

Staatliches Museum fr Naturkunde, Rosenstein 1, D-70191 Stuttgart

The neoselachian shark Sphenodus from the Late Kimmeridgian (Late Jurassic) of Nusplingenand Egesheim (Baden-Wrttemberg, Germany)

By Ronald Bttcher, Stuttgart, and Christopher J . Duffin, Sutton

With 2 Plates, 18 Textfigures and 1 Table

Abstract

A virtually complete articulated specimen of Sphenodus macer (QUENSTEDT) is describedfrom the Nusplingen Plattenkalk (Ulmense Subzone, Beckeri Zone, Late Kimmeridgian, LateJurassic) of Egesheim near Nusplingen in south-western Germany. The first reconstruction ofthe body outline and description of the complete dentition and the neurocranium of a speciesof Sphenodus can be made from the specimen. The presence of an eye tooth in the upperdentition of S. macer is a convergence with lamniform sharks. Teeth of Sphenodus nitidusWAGNER are also present in the Nusplingen Plattenkalk and comparisons between these twospecies and the type species Sphenodus longidens AGASSIZ, the most frequent Jurassic species,confirms the validity of the three species.

Rsum

Un spcimen articul pratiquement complet de Sphenodus macer (QUENSTEDT) est dcrit;il provient du calcaire lithographique de Nusplingen (sous-Zone Ulmense, zone Beckeri,Kimmridgien suprieur, Jurassique suprieur) dEgesheim prs de Nusplingen dans le Sud-Ouest de lAllemagne. Pour la premire fois sont prsents ici la reconstitution du contour ducorps ainsi que la description de la totalit de la dentition et du neurocrne dune espce deSphenodus. La prsence dune dent de l il dans la dentition suprieur de S. macer est uncaractre convergent avec les requins lamniformes. Des dent de Sphenodus nitidus WAGNERsont aussi prsentes dans le calcaire lithographique de Nusplingen: les diagnostics diffrentielsentre ces deux espces sont donns.

Zusammenfassung

Aus dem Nusplinger Plattenkalk (Ulmense Subzone, Beckeri Zone, Ober-Kimmeridgium)von Egesheim, Sdwestdeutschland, wird ein nahezu vollstndiges Exemplar des Hais Sphe-nodus macer (QUENSTEDT) beschrieben. Anhand dieses Fundes knnen erstmals Krperform,vollstndige Bezahnung und Neurocranium einer Art der Gattung Sphenodus beschriebenwerden. Die Prsenz eines Augenzahns in der Oberkieferbezahnung stellt eine Konvergenzmit lamniformen Haien dar. Auer dem Skelett wurden im Nusplinger Plattenkalk zahlreicheisolierte Zhne von Sphenodus nitidus WAGNER gefunden, die ebenfalls detailliert beschrieben

Stuttgarter Beitr. Naturk. Ser. B Nr. 283 31 pp.,2 pls, 18 figs, 1 tab. Stuttgart, 27. 6. 2000

werden. Aufgrund dieses Materials sowie durch Vergleiche mit der Typusart Sphenodus lon-gidens AGASSIZ, der hufigsten jurassischen Art, wird die Eigenstndigkeit aller drei jurassi-schen Taxa belegt.

1. Introduction

The Nusplingen Plattenkalk is one of the most famous fossiliferous horizons out-cropping in south-western Germany. It is a Late Jurassic limestone which is verysimilar to the lithographic limestone of Solnhofen in Bavaria. The sediments weredeposited in two basins (Westerberg Basin, Grosser Kirchbhl Basin) much smallerthan those in Bavaria; the outcrops are restricted to an area of 2 km2 (DIETL et al.1998). The deposits are located on a hill which lies between the villages of Nuspling-en and Egesheim, some 18 km east of Rottweil in the southwestern Swabian Alb(Fig. 1). They were discovered in 1839 and described four years later by QUENSTEDT(1843).

In the early 1850s the limestone was exploited for lithographic plates, but wasfound to be unsuitable. During this early phase of exploration many of the classicolder finds were made, largely by QUENSTEDT for the University of Tbingen(GPIT) and O. FRAAS for his private collection (later purchased by the Naturalien-kabinett, now the Staatliches Museum fr Naturkunde Stuttgart, SMNS). At the endof the nineteenth century a commercial collector actively worked the locality forfossils, selling his specimens to Tbingen, Stuttgart and other institutions. In morerecent times, the University of Tbingen has made three, and the University of Par-is a single excavation at the site (DIETL et al. 1995).

Currently, two small quarries some 250 m apart exist in the Westerberg Basin(DIETL et al. 1998). The older of the two lies within the borders of Nusplingen, whilethe other is part of Egesheim. The Nusplingen quarry is the property of the Gesell-schaft fr Naturkunde in Wrttemberg, and both quarries lie within the protectedexcavation area entitled Versteinerungen Nusplinger Plattenkalk. The SMNS hasbeen excavating the Egesheim quarry since the summer of 1993, and the Nusplingenquarry since 1994. A guide to the literature concerning geology and paleontology ofthe Nusplingen Plattenkalk is given in SCHWEIGERT (1997).

The stratigraphic position of the Nusplingen Plattenkalk is the Ulmense Subzoneof the Late Kimmeridgian, on the basis of the accompanying ammonite fauna(SCHWEIGERT 1998). This means that the deposit is somewhat older than the EarlyTithonian Solnhofen Plattenkalk (Fig. 2).

The Nusplingen Plattenkalk yields a flora and fauna similar to those of Solnhofen.The overall diversity known from the Nusplingen area is less than that from Soln-hofen, however, because of the limited geographical extent of the deposits and thecomparatively reduced level of exploitation. The fish fauna comprises sharks, rays,chimaeroids, actinopterygians and sarcopterygians (HEINEKE 1906; SCHWEIZER1964). Early on in the development of the site, several isolated teeth of Sphenoduswere found, described as Oxyrhina macer and Oxyrhina longidens (FRAAS1855: 98). No skeletal remains of Sphenodus were found at that time. By contrast, acomplete, articulated specimen of Sphenodus was one of the first discoveries duringthe preparatory work at the recent re-opening of the Egesheim quarry (Figs 3, 4). Itlies within a thin siliceous layer, whose matrix renders preparation very difficult.That specimen is the main subject of this paper.

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In addition to many other fossils (DIETL & SCHWEIGERT 1999), some 70 isolatedteeth of Sphenodus have been discovered throughout the succession during the re-cent excavation period in both quarries; they comprise 20 % of all fish remainsfound. Many of these teeth have been freed from the matrix by acetic acid treatment.

Sphenodus is a common genus in the European Jurassic with many nominal spe-cies (DE BEAUMONT 1960; DUFFIN & WARD 1993). Most of these species are found-ed on single teeth, some of them even being based upon cusps with the root missing.Since WAGNER (1862) described the cranial part of a skeleton of S. nitidus from Soln-hofen, no other skeletal remains of the genus have been found. The skeleton de-scribed here is the most complete specimen of one of these sharks.

Three species of Sphenodus have been described from the Late Jurassic of south-ern Germany: S. longidens AGASSIZ, S. macer (QUENSTEDT) (both represented byisolated teeth), and S. nitidus WAGNER (based upon a solitary partial skeleton fromSolnhofen). The holotype of S. nitidus and the older collections of Sphenodus teethfrom Nusplingen have been previously described by DE BEAUMONT (1960) andSCHWEIZER (1964). Both authors considered S. nitidus and S. macer to be synony-mous, whereas WOODWARD (1889) took the view that S. macer is a synonym of S.longidens. MUSPER (1920), on the other hand, treated all three names as valid. Re-ex-amination of older material in the light of the new specimens permits the develop-ment of differential diagnoses for S. macer and S. nitidus.

All the new material from the Nusplingen Plattenkalk is deposited in the Staat-liches Museum fr Naturkunde Stuttgart (SMNS). Some of the older material is held

bttcher & duffin, neoselachian shark SPHENODUS 3

Fig. 1. Sketch map of southern Germany to show the location of the Nusplingen Platten-kalk and the type localities of Sphenodus macer (QUENSTEDT) (Schnaitheim) andSphenodus nitidus WAGNER (Solnhofen).

in the Institut und Museum fr Geologie und Palontologie, Universitt Tbingen(GPIT), and the holotype of S. nitidus is in the Bayerische Staatssammlung frPalontologie und historische Geologie, Munich (BSPGM).

Acknowledgements

The authors would like to express their thanks to Drs G. Dietl, G. Schweigert (SMNS) andProf. D. Thies (Univ. Hannover) for helpful discussions. Prof D. Thies also provided the pho-tographs for Plate 2. Dr A. Liebau (GPIT, Tbingen) and Dr P. Wellnhofer (BSPGM, Munich)kindly loaned material from their respective institutions, Dr P. Wellnhofer also provided thephotograph of the holotype of Sphenodus nitidus. A. Leidner (Univ. Hannover) generouslyallowed us to use some of his SEM photographs of the scales of S. macer and gave us access tohis unpublished manuscript on synechodontiform scales. Our sincere thanks are also due toO. Maass, for undertaking the difficult and time-consuming task of preparing the S. macerskeleton, to Dr R. Wild for his attempts to take X-rays of the specimen and to R. Harling (allSMNS, Stuttgart), who took some of the photographs (Figs 3, 5, 7, Pl. 1). The manuscript wascritically appraised by David Ward (Orpington), and the French summary provided by Dr D.Delsate (Battincourt). Finally our thanks are due to Dr G. Bloos (SMNS, Stuttgart) for hiscareful proof-reading of the manuscript.

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Fig. 2. Stratigraphical position of the Solnhofen Plattenkalk (type horizon of S. nitidus),Nusplingen Plattenkalk, and Brenztal-Trmmerkalk (type horizon of S. macer). After SCHWEIGERT 1994, SCHWEIGERT & ZEISS 1994, and SCHWEIGERT (pers. comm.).

2. Systematic Palaeontology

Class Chondrichthyes HUXLEY, 1880Subclass Elasmob