Elasmobranch fauna from the upper most part of the Cretaceous Bagh Group, Narmada valley, India

Abstract

AbstractIn India, Cretaceous elasmobranchs are known from the uppermost Cretaceous Deccan intertrappean sedimentary sequences of peninsular India and the lower Upper Cretaceous (Cenomanian) Karai Formation of the Cauvery basin, South India. The intertrappean elasmobranchs are represented mainly by rays and skates, whereas the Karai fauna is known by hexanchiform, squaliform, and lamniform sharks. The latter assemblage is dominated by cool temperate water forms in addition to some cosmopolitan forms. Here new shark teeth recovered from the upper part of the marine Cretaceous Bagh Group, in the lower Narmada valley, Western India are described. This is the first detailed description of sharks from the Bagh Group and the first record of sharks from the youngest horizons (Coniacian to Late Maastrichtian) of this marine sedimentary sequence. The fauna, recovered from an oyster shell‐rich green sandstone at the top of the youngest geological unit (the Coralline Limestone) of the Bagh Group, is assigned to Ptychodus sp., Scapanorhynchus sp. aff. S. raphiodon (Agassiz, 1844), Cretodus sp. aff. C. crassidens (Dixon, 1850), Cretalamna sp., Squalicorax sp. aff. S. falcatus Agassiz, 1843, and Elasmobranchii indet. This assemblage, previously widely documented from the Cretaceous deposits of North and South Americas, Europe, North and West Africa, Far East and Near East, demonstrates that there is a clear change in elasmobranch faunal composition of India from cool temperate water forms in the early Late Cretaceous to essentially cosmopolitan forms in the Late Cretaceous.