sign in sign up
<<
Home , Kotasaurus, Kota Formation

SHORT COMMUNICATIONS 575

FIRST RECORD OF ARMOURED FROM THE LOWER , PRANHITA-GODAVARI VALLEY, ANDHRA PRADESH

T.T. NATH,P. YADAGIRIand A.K. MOITRA Geological Survey of , Southern Region, Hyderabad - 500 068

For the first time, skeletal remains of an armoured Formation of the Pranhita-Godavari Valley is well known dinosaur (Ornithischia: Ankylosauria) were found in the through the occurrence of early sauropods, red clay bed of the Kota Formation, Pranhita-Godavari tagorei (Jain et al. 1975, 1979) and Valley, Andhra Pradesh. The bed occurs 2 m below the yamanpalliensis (Yadagiri, 1988,2001). During the present marker unit of the Kota Formation. The investigation, skeletal remains of ankylosaur were collected collection includes parts of skull, 30 specimens of body for the first time from red clay bed of Kota Formation. The armour, vertebrae and parts of girdle bones. The site is about one kilometer south of Bodepalli village and characteristics of armour plates, skull and teeth indicate about 30 km northeast of Bellampally, a coal-mining town that these fossils belong to ankylosauria. The (Fig.1). Whereas most of the fossils in the collection ankylosaurs are less known from the Lower Jurassic were found lying on the surface, a few including the parts period. The detailed studies of the present material are of skull and arrnour plates were recovered by shallow likely to throw light on the evolutionary history of these trenching. In addition, one complete turtle shell, fragments . of carapaces, and a skull were also collected from the red clay bed. The dinosaurian fauna from the Lower Jurassic Kota The Kota Formation comprises mainly pale brown

- 19'20'

DHARMARAM FORMATION

KOTA FORMATION

cu a 19O18'

Fig.1. Location map of fossil site.

JOUR.GEOL.SOC.INDIA,VOL.59, JUNE 2002 SHORT COMMUNICATIONS

Plate I. Skeletal parts of Ankylosaurian dinosaur. Parts of skull, maxilla in lateral (a) and ventral (b) views; mandibles in lateral (c) and dorsal (d) views; enlarged view of an anterior tooth showing the denticles (e); body armour (f-j); dorsal vertebra in lateral view (k), caudal vertebrae in lateral view 0) and scapula (m)with incomplete glenoid. The scale bar measures 1 mm in fig.e and 30 mm in all others.

JOUR.GEOL.SOC.INDIA, VOL.59, JUNE 2002 SHORT COMMUNICATIONS 577 sandstones and grits, red clays and a prominent limestone The centrum of dorsal vertebra (Plate I, fig.k) is unit. The red clay bed, which has yielded arrnoured dinosaur, platycoelous and elongated. The centrum measures 65 mm occurs 2 m below the marker limestone unit. The Kota in length, 55 mm in height and 60 mm in width. The centra vertebrates represented by semionotid fishes, flying of the caudal vertebrae (Plate 1, fig.1) are short and reptiles, sauropod dinosaurs, crocodiles turtles and early amphicoelous. They have a strong longitudinal keel in mammals, are indicative of aquatic, terrestrial and arboreal ventral part. habitat. The fauna indicates a Lower Jurassic age for the The total length of the scapula is 200 mm, width of Kota Formation (Jain, 1973; Yadagiri and Prasad, 1977). the shaft is 100 mm and width at glenoid is 120 mm Description: Both the lower and upper parts of the skull (Plate 1, fig.m). the shaft is plano-convex in shape and are filled up with hard matrix. The anterior part of the skull takes a gradual curvature. appears to be narrow and elongated. The teeth are small, Remarks: Ankylosaurs were short-limbed, four-legged crowns are leaf shaped and laterally compressed. The armoured dinosaurs. The most prominent armour of scutes, anterior and posterior edges of the teeth carry small denticles have keeled or unkeeled plates of bone embedded in the (Plate 1, fig.e), which are characteristic feature of the skin. The origin of ankylosaurs is not well understood, ankylosaurids. The skull does not show sutures and its because globally only a few specimens are known from the surface has pitted ornamentation. The symphsis of two Early and , during which period ankylosaurs mandibles is clearly seen. Both the mandibles are closely first appeared and diversified. They first appeared in the placed (Plate 1, figs.a-d) due to compression. (about 200 m.y.) as relatively smaller forms The body armour plates are flat and have varying heights not more than 2 m in length. It is known that Scutellosaurus, with broad bases. The anterior and posterior edges are from the Lower Jurassic Kayenta Formation of North smoothly curved to, a pointed summit. Based on the size America, shielded its dorsal body surface with rows of keeled and shape of the bases, they are classified into four types. In ossicles that were embedded in the skin (Colbert, 1981). type A (Plate 1, fig.f) the plate is flat and broad at the base. True ankylosaurs are known from the Middle Jurassic and The ventral keel is present anteriorly which runs diagonally include Sacrolestes from England and Tianchiasaurus from to the posterior edge. The plate measures 175 mm by height, China (Carpenter, 1997). These genera are represented by 130 mm by base length and 80 mm by base width. In type B fragmentary remains. The discovery of armoured dinosaur (Plate 1, fig.i) plates, the anterior edge is incurved with from the Lower Jurassic Kota Formation assumes broadly rounded posterior edge. The base has two distinct importance in this context. Detailed osteological studies are areas of dermal attachment, a prominent medial anterior envisaged for understanding the origin and evolution of process and lateral posterior process. A ridge separates both ankylosaurs. the areas. The overall height of the plate is 157 mm, of the base? the length is lo2 mm and width is l8 mm' In type Acknowledgement: We are thankful to Dr. N. Chattopadhyay, ('late , 'g-j) the base is narrow, gently arched with a Deputy Director General, Geological Survey of India, Southern depression in the central part. In type D (Plate 1, fig-g,h) Region, for extending facilities to carry out the field and laboratory the base is large in size compared to the height of the spine. studies. Thanks are due to Shri Robert Prasad for photographs.

References CARPENTER,K. (1997) Ankylosaurs. In: James 0. Farlow and M.K. sauropod dinosaur from the Lower Jurassic Deccan, Brett Surman (Eds.), The complete dinosaur. Indiana India. Proc. IV Internatl. Gondwana Symp., Kolkata, v.1, University Press, pp.307-3 16. pp.204-2 16. COLBERT,E.H. (198 1) A primitive ornithisehian dinosaur from the Y ADAGIRI,P. (1 988) A new sauropd Kofasaurusyarnaripalliensis Kayenta Formation of Arizona, Museum of Northern Arizona from Lower Jurassic Kota Formation of India. Rec. Geol. Surv. Press Bulletin, no.53, pp. 1-61. India, v.116, pts.3-8, pp.102-127. JAIN,S.L. (1973) New specimens of Lower Jurassic holostean YADAGIRI,P. (2001) The osteology of Kofasazcrr4syarnanpalliensis, fishes from India. Palaeontology, v.116, pp.149-177. a sauropod dinosaur from the Early Jurassic Kota Formation JAIN,S.L., KUTTY,T.S. and ROYCHOWDI:URY,T.K. (1975) The of India. Jour. Verteb. Palaeont., v.21(2), pp.242-252. sauropod dinosaur from the Lower Jurassic Kota Formation YADAGIRI,P. and PRASAD,K.N. (1977) On the discovery of new of India. Proc. Roy. Soc. London, A. 188, pp.22 1-228. Pholidophorous fishes from the Kota Formation, Adilabad JAIN,S.L., KUTTY,T.S., ROYCHOWDHURY,T.K. and CHA~ERJEE,S. district, AndhraPradesh. Jour. Geol. Soc. India, v. 18, pp.436- (1979) Some characteristics of Barapasaurus tagorei a 444.

(Received: 9 October 2001; Revised forrn accepted: 4 Janrtnry 2002)