Abstract

Nessovophis tamdy, gen. et sp. nov. (Nigerophiidae, middle Eocene, Bartonian), Nessovophis zhylga, sp. nov. (early Eocene, Ypresian), Palaeophis ferganicus, sp. nov. (early Eocence, Ypresian), Palaeophis udovichenkoi, sp. nov. (middle -?late Eocene, Bartonian -?Priabonian), Palaeophis nessovi, sp. nov. (late Eocence, Priabonian), Palaeophis sp. (middle Eocence, Bartonian), and Pterosphenus muruntau, sp. nov. (middle Eocene, Bartonian) are described and Vialovophis zhylan Nessov, 1984 (?latest Paleocene) is redescribed on the basis of 45 isolated vertebrae from 8 localities in Kazakhstan, Tajikistan, Kirghizia, Uzbekistan, and Ukraine. Phylogenetic analysis of 8 Cretaceous-Paleogene taxa of sea snakes reveals two monophyletic groups: Palaeophiidae (Palaeophis and Pterosphenus) and Nigerophiidae (Nigerophis, Woutersophis, and Nessovophis)