P H Y T O S A U R R E M A I N S F R O M T H E C E N G E R F O R M A T I O N O F T H E

L Y C I A N T A U R U S ( W E S T E R N T U R K E Y ) : S T R A T I G R A P H I C A L I M P L I C A T I O N S

by

ERIC BUFFETAUT *, MICHEL MARTIN * & OLIVlER MONOD **

ABSTRACT RI~SUMI~

The red arkosic sandstones of the Cenger Forma- tion, in the allochthonous units of the Lycian Taurus (western Turkey), which had already yielded a small ichthyofauna, have yielded fragmentary remains (teeth, jaw fragments, vertebrae) of archosaurian rep- tiles. Among these, phytosaur remains can be recogni- sed ; they are too incomplete to warrant an accurate identification, but they do provide biostratigraphical data, since they indicate a Late Triassic age. The rep- tile remains from the Cenger Formation thus confirm the stratigraphical conclusions previously drawn from the study of lungfishes, and increase our knowledge of the geographical distribution of Gondwanan phytosaurs.

Les gr~s arkosiques rouges de la Formjtion Cenger, dans les unit6s allochtones du Taurus lycien (Turquie occidentale), qui avaient d6j~ livr6 une petite faune de poissons, ont fourni des restes fragmentaires de repti- les archosauriens (dents, d6bris de m~choires, vert~- bres). Parmi ceux-ci, on peut reeonna2tre des d6bris de phytosaures, non d6terminables avec pr6cision, mais qui ont un int6r~t biostratigraphique, puisqu'ils indiquent un ,~ge Trias sup6rieur. Les testes de reptiles de la Formation Cenger confirment donc les conclu- sions stratigraphiques tir6es auparavant de l'6tude des dipneutes, et accroissent notre connaissance de la dis- tribution g6ographique des phytosaures dans le Gond- wana.

KEY-WORDS : TRIASSIC, REPTILES, PHYTOSAURS, RED SANDSTONES, LYCIAN TAURUS, TURKEY, BIOSTRATIGRAPHY.

MOTS-CL~S : TRIAS, REPTILES, PHYTOSAURES, GRI~S ROUGES, TAURUS LYCIEN, TURQUIE, BIOSTRATIGRAPHIE.

INTRODUCTION

In 1983, Monod et alii reported the discovery of fos- sil vertebrates at the base of red arkosic sandstones (Cenger Formation) in allochtonous series of the Lycian Taurus (western Turkey) which had previously been described by de Graciansky (1972). A biometri-

cal study of lungfish toothplates from this formation suggested that these arkoses were Late Triassic in age. We now report the discovery in the Cenger Formation of fragmentary phytosaur remains which confirm this age assignment.

* UA 720 du CNRS, Laboratoire de Pal6ontologie des Vert6br6s, Universit6 Paris VI, 4 place Jussieu, 75252 Paris Cedex 05. ** Laboratoire de G6ologie historique, structurale et appliqu6e, Universit6 Paris-Sud, B,~t. 504, 91405 Orsay.

Geobios, n ° 21, fasc. 2 p. 237-243, 1 fig., 1 pl. Lyon, avri11988

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Fig. 1 - - Geological sketch map and section of the (~al Da~ in the Lycian Taurus. A. Situation of the ~al Da~ in the Lycian nappes. B. Geological map according to de Graciansky (1972), modified. C : Carboniferous shales ; P : Late Permian limestones ; TR : middle Triassic sandstones, limestones and shales ; L : Late Triassic to Liassic dolomites ; J-C : Jurassic to Cretaceous limestones ; V : peridotites. In black : Cenger Formation, red quartzites and shales (Late Triassic). C. Detailed section along the western ridge of the ~al Da~. 1 : white algal limestones (Late Permian) with karstic cavities filled with stratified red sandstones ; 2 : rusty quartzites ; 3 : red sandstones with dipnoan toothplates ; black dots indicate fossiliferous spots ; 4 : red quartzites and siltstones ;. 5 : coarse polygenetic conglomerates ; 6 : massive white dolomites (Late Triassic and Lias- sic).

Carte g~ologique sch~matique et coupe du (~al DaM dans le Taurus lycien. A. Situation du ~al Da~ dans les nappes lyciennes. B. Carte g6ologique, d'apr~s de Graciansky (1972), modifi6e. C : schistes carbonif6res ; P : calcalres du Permien sup6rieur ; TR : gr~s, calcaires et shales du Trias moyen. L : dolomies du Trias sup6rieur et du Lias ; J-C : calcaires jurassiques et cr6tac6s ; V : p6ridotites. En noir : quartzites et siltites rouges de la Formation Cenger (Trias sup6rieur). C. Coupe d6taill6e le long de l'ar~te occidentale du ~al DaM. 1 : calcaires algaires blancs (Permien sup6rieur) avec cavit6s karstiques emplies de gr6s rouges stratifi6s ; 2 : quartzites rouille ; 3 : gr~s rouges ~t dents de dipneustes ; les points noirs indiquent les gise- ments fossilif6res ; 4 : gr~s et siltites rouges ; 5 : conglom6rats grossiers polyg6niques ; 6 : dolomies blanches massives (Trias sup6- rieur et Lias).

G E O L O G I C A L S E T T I N G

T h e g e o l o g y o f t h e w e s t e r n r idge o f t h e ~ a l Da~ , w h e r e t he foss i l m a t e r i a l d e s c r i b e d b e l o w has b e e n co l l ec t ed , has b e e n d e s c r i b e d in de ta i l by M o n o d e t alii in 1983 a n d is s u m m a r i s e d in f ig. 1. W i t h i n t h e a l l o c h t h o n o u s un i t s o f t h e ~ a l D a ~ , t he C e n g e r

F o r m a t i o n i t se l f beg ins w i t h a r ed p o l y g e n e t i c sands- t o n e w i t h a c a l c a r e o u s m a t r i x , w h i c h h a s y i e l d e d the b o n e s a n d t ee th d e s c r i b e d h e r e a n d fills d e e p ka r s t i c p o c k e t s in a n u n d e r l y i n g l i m e s t o n e o f L a t e P e r m i a n age. T h i s r ed s a n d s t o n e is o v e r l a i n by d a r k s i l t s tones

239

and white quartzites, followed by red siltstones and coarse siliceous sandstones and conglomerates. The Cenger Formation is overlain by massive white

dolomites referred to the Late Triassic and the Liassic on the basis of calcareous algae.

DESCRIPTION

In 1983, additional fossiliferous matrix was collec- ted from the Cenger Formation by one of us (O.M.). Acid preparation has yielded a number of dipnoan toothplates, as well as reptile remains which include fragments of large bolaes and isolated small teeth and vertebrae. The available large bones are too incom- plete to be identified ; however, considering the age of the deposit, their large size suggests that they may have belonged to dinosaurs. The poorly preserved vertebrae are amphicoelous and can apparently be referred to archosaurs. A fairly well preserved very small caudal vertebra (plate 1, D) is reminiscent of phytosaur vertebrae.

Teeth, however, are more characteristic. Unfortu- nately, most of them are poorly preserved. Neverthe- less, three main types can be distinguished :

- long slender teeth with a circular cross-section ; they are recurved and bear unserrated carinae (pl. 1, H, I) ; the surface of the enamel is ornamented with well marked ridges.

- slender recurved teeth with well marked serrated carinae (pl. 1, E,F) ; they have a slightly compressed cross-section and bear enamel ridges.

- laterally compressed teeth with anterior and poste- rior serrated carinae and a fluted enamel (pl. 1, A,B,C,J,K,L).

These three types of teeth are known to occur in phytosaurs, as confirmed by comparison with speci- mens housed in the Staatliches Museum ftir Natur- kunde in Stuttgart. All three types can occur in the same species (Buffetaut & Wouters 1986) : in Rutio- don ruetimeyeri (HUENE, 1911), from the Upper Norian of Switzerland, Germany and France, for ins- tance, the anterior teeth are slender, circular in cross- section and unserrated, whereas the posterior teeth

are laterally compressed and serrated; teeth occupying an intermediate position are slender, slightly compressed and serrated (Huene 1922). It thus seems that most of the reptile teeth from the Cen- ger Formation may be referred to phytosaurs ; on the other hand, it is very difficult to identify the available poorly preserved material with any accuracy, even at the generic level, although enamel ornamentation on the teeth from the Cenger Formation is reminiscent of Rutiodon ruetimeyeri (cf. Buffetaut & Wouters 1986).

The presence of phytosaurs seems to be confirmed by a small and poorly preserved jaw fragment which is apparently the anterior end of a left premaxilla, showing the remains of two large alveoli followed by two much smaller ones. The shape of the anterior tip of the bone, to the extent that it can be reconstructed, is hook-shaped as in all phytosaurs, and there is nc indication of a nasal opening (which excludes a croco- dilian but is in good agreement with the posteriorly displaced position of the nostrils in phytosaurs).

In addition, it should be mentioned that a single iso- lated tooth (pl. 1, G) appears to be noticeably diffe- rent from the phytosaur teeth described above. It is strongly compressed laterally, and its carinaeobear very distinct, relatively large serrafions ; otherwise, the enamel is completely smooth. Although the paex is broken, it seems that this tooth was rather strongly recurved, which is not the case of the posterior teeth of phytosaurs. This tooth cannot be precisely identi- fied ; it is reminiscent of the teeth of both carnivorous dinosaurs (theropods) and rauisuchid pseudosuchians (similar compressed, recurved and serrated teeth occur in both groups, and the status of forms with such teeth has been disputed, as in the case of Terato- saurus : see Benton 1986). All that can be said is that this tooth from the Cenger Formation strongly sug- gests that phytosaurs are not the only archosaurs to be represented in this formation.

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CONCLUSIONS

The available phytosaur remains from the Cenger Formation are too incomplete to provide accurate palaeobiogeographical evidence. However, they increase the number of known phytosaur localities south of the Tethys : phytosaurs were hitherto known from only a few Late Triassic Gondwanan localities, in southern Morocco, central India and Madagascar (see map in Buffetaut & Martin 1984). The remains from the Upper Triassic of the Lycian Taurus (then a part of northern Gondwana) thus bridge a gap in the distribution of phytosaurs on the southern supercon- tinent.

In addition, the phytosaur remains from the Cenger Formation give some indications about the depositio- nal environment of the formation. Phytosaurs were crocodile-like reptiles which usually occur in freshwa- ter deposits (the very few instances of phytosaur remains in marine sediments can be explained by transportation into a marine environment, presu- mably after death: see Buffetaut & Martin 1984). Their occurrence in the Cenger Formation therefore suggests that the <~ red arkoses >> were deposited in a freshwater environment, an interpretation which is good agreement with that based on the presence of arganodontids (a family of freshwater lungfishes • see Monod et alii 1983 ; Martin 1984). The presence of possibly marine fishes (Monod et alii 1983) is a pro- blem, but it remains that both the phytosaurs and the

arganodontids provide strong evidence in favour of a freshwater environment. The hypothesis of lacustrine deposits filling an older karst and gradually changing to a deltaic environment, as put forward by Monod et alii (1983) is thus strengthened.

However, the most important implications of the discovery of phytosaurs in the red arkoses of the Cen- ger Formation are of a biostratigraphical nature. It is generally accepted that phytosanrs are restricted to the Late Triassic (Gregory 1969 ; Westphal 1976), and the early Jurassic ages recently proposed for forma- tions previously held to be Late Triassic (see the review by Olsen & Sues 1986) have not modified this view : there is no really conclusive evidence of post- Triassic phytosaurs. The phytosaur fragments from the Cenger Formation thus lead to the conclusion that this formation is Late Triassic in age. The Permian age suggested by Argyriadis et alii (1976) can no lon- ger be accepted. This is in agreement with the conclu- sion drawn by Monod et alii (1983) from the study of the lungfish material, which indicated an age poste- rior to the middle Triassic, and probably Late Trias- sic. The stratigraphic and tectonic conclusions (Monod & Akay 1985) concerning the red detritic for- mations in the Taurides (and probably Chios) are thus in good agreement with the discovery of phytosaurs in the Cenger Formation.

Acknowledgements

We thank Dr Rupert Wild (Staatliches Museum filr Natur- kunde, Stuttgart) for permission to study the phytosaur

material in his care. We also thank Turkish Petroleum Orga- nization (TPAO) for providing facilities for field work.

REFERENCES

ARGYRIADIS I., GRACIANSKY P.C. de & LYS M. (1976) Datation de niveaux rouges dans le Permien marin p6ri- 6g6en. Bull. Soc. gdoL France, Paris, 28, 2 : 513-519.

BENTON M.J. (1986) - The Late Triassic reptile Terato- saurus - a rauisuchian, not a dinosaur. Palaeontology, London, 29, 2 : 293-301.

BUFFETAUT E. & MARTIN M. (1984) - Continental verte- brate distribution, faunal zonation and climate in the Late Triassic. In Third Symposium on Mesozoic Terres- trial Ecosystems, Short Papers, W.E. REIF & F. WEST- PHAL eds, Attempto Verlag, Tiibingen : 25-29.

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BUFFETAUT E. & WOUTERS G. (1986) - Amphibian and reptile remains from the Upper Triassic of Saint-Nicolas- de-Port (eastern France) and their biostratigraphic signi- ficance. Modern Geology, London, 10 : 133-145.

GRACIANSKY P.C. de (1972) - Recherches g6ologiques dans le Taurus Lycien. Th~se de Doctorat, Universit6 Paris- Sud, Orsay, n ° 896 (in6dit).

GREGORY J.T. (1969) - Evolution und interkontinentale Beziehungen der Phytosauria (Reptilia). Pal¢iont. Z., Stuttgart, 43, 1/2 : 37-51.

HUENE F. yon (1911) - Beitr~ige zur Kenntnis und Beurtei- lung der Parasuchier. GeoL Palaont. Abh., Jena, N.F. , 1 0 , 1 : 65-122.

HUENE F. yon (1922) - Neue Beitrage zur Kenntnis der Parasuchier. Jb. preuss, geoL Landesanst., Berlin, 42 : 59-160.

MARTIN M. (1984) - R6vision des Arganodontid6s et des N6oc6ratodontid6s (Dipnoi, Ceratodontiformes) du

Cr6tac6 africain. N. Jb. GeoL Palt~ont., Stuttgart, 169, 2 : 225-260.

MONOD O. & AKAY E. (1985) - Evidence for a Late Triassic Early Jurassic orogenic event in the Taurides. In The geological evolution of the Eastern Mediterranean, J.E. DIXON & A.H.F. ROBERTSON, eds., Spec. PubL Geol, Soc. London, n ° 17 : 113-122.

MONOD O., MESHUR M., MARTIN M. & LYS M. (1983) D~couverte de dipneustes triasiques (Ceratodontiforrnes, Dipnoi) dans la Formation de Cenger (¢~ Arkoses rou- ges ))) du Taurus lycien (Turquie occidentale). Geobios, Lyon, 16, 2 : 161-168.

OLSEN P.E. & SUES H.D. (1986) - Correlation of conti- nental Late Triassic and Early Jurassic sediments, and patterns of the Triassic-Jurassic tetrapod transition. In The beginning of the age of dinosaurs, K. PADIAN ed., Cambridge University Press : 321-351.

WESTPHAL F. (1976) - Phytosauria. In Handbuch der Pal~ioherpetologie, 13 (Thecodontia), Gustav Fischer Verlag, Stuttgart, 99-120.

M a n u s e r i t d6pos6 le 14.12. t987

Manuse r i t d6f in i t i f re~u le 18.02.1988

P L A T E 1

Reptile remains from the Late Triassic Cenger Formation, (~al Da~, Lycian Taurus, Turkey. Specimens kept in the Laboratoirc de Paldontologie des Vertdbrds, Universitd Paris, VI, under collective number IF-94.

Restes de reptiles de la Formation Cenger (Trias sup6rieur), (~al DaM, Taurus Lyeien, Turquie. Spdcimens ddposds au Labora- toire dc Paldontologie des Vertdbrds, Univcrsitd Paris VI, sous le numdro collcctif IF-94.

A,B,C : posterior tooth of phytosaur. Dent postdrieure de phytosaure.

D : caudal vertebra, presumably of phytosaur. VertSbre caudale, probablement de phytosaure.

E,F (1 of fig. 2) : phytosaur tooth from the middle part of the tooth row. Dent de phytosaure provenant de la partie moyenne de la ran#e dentaire.

G : tooth of indeterminable archosaur (theropod or pseudosuchian ?). Dent d'archosaure inddtermin6 (thdropode ou pseudosu- chien 2).

H,I : anterior tooth of phytosaur. Dent antdrieure de phytosaure.

J,K,L : posterior tooth of phytosaur. Dent post6rieure de phytosaure.

Scale bars (dchelles) : 2 mm.

G e o b i o s

n ° 21, fasc . 2

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