July 22 , 2016

Late Cretaceous vertebrates are known from the Turonian Zhirkindek and Santonian Bostobe formations in the western Kazakhstan region northeast of the Aral Sea. The Zhirkindek vertebrate assemblage resembles that known from the Turonian Bissekty Formation of the Kyzylkum Desert, Uzbekistan, because of the presence of the rhinobatoid ray Myledaphus tritus that has unsculptured teeth and the prevalence of gars (Lepisosteidae). The latter apparently became locally extinct during the Coniacian. The Santonian Bostobe and Yalovach (Tajikistan) formations are similar in that they share the presence of the more derived rhinobatoid, Myledaphus glickmani, that has sculptured teeth. The Zhirkindek assemblage is also noteworthy for the presence of basal neoceratopsians, whereas the basal ceratopsid or stem-ceratopsid Turanoceratops tardabilis is present in the Bissekty Formation and possibly in the Santonian Bostobe and Syuk Syuk formations of southern Kazakhstan. The ornithopods from the Bostobe Formation, the basal hadrosauroid Batyrosaurus rozhdestvenskyi and the basal lambeosaurine Aralosaurus tuberiferus, are more derived than the basal hadrosauroid Levnesovia transoxiana known from the Bissekty Formation. The mammalian assemblage of the Bostobe Formation is dominated by zhelestid stemplacentals also similar to those from the Bissekty Formation.

Alexander O. Averianov, Igor G. Danilov, Pavel P. Skutschas, Ivan T. Kuzmin, Hans-Dieter Sues, and Gareth Dyke (2016)

The Late Cretaceous vertebrate assemblages of western Kazakhstan.

in Khosla, A. and Lucas, S.G., eds., 2016, Cretaceous Period: Biotic Diversity and Biogeography. New Mexico Museum of Natural History and Science Bulletin 71: 5-17.