A non-adaptive radiation of viviparous skinks from the seasonal tropics of India: Systematics of Subdoluseps (Squamata: Scincidae), with description of a new genus and five cryptic new species

Abstract

Subdoluseps is a recently described genus of Lygosomine skinks distributed in peninsular India and Southeast Asia. We conduct the first revision of Indian Subdoluseps based on range-wide sampling including 89 specimens from 33 localities. We use two mitochondrial and three nuclear markers, 58 morphological characters, and ecological data to reconstruct the evolutionary history of Indian Subdoluseps and assess their diversity and distribution, providing insights into lygosominin biogeography. We formally describe the Indian clade as a new genus, Dravidosepsgen. nov. and name five new species from Tamil Nadu, India in an integrative taxonomic framework – D. gingeeensissp. nov., D. jawadhuensissp. nov., D. kalakadensissp. nov., D. srivilliputhurensissp. nov., and D. tamilnaduensissp. nov.. We transfer Riopa goaensis, Subdoluseps pruthi and S. nilgiriensis to the new genus and designate neotypes for the former two. Members of Dravidosepsgen. nov. are the first known viviparous skinks from peninsular India and the only known viviparous lygosominins apart from a few species of east African Mochlus. The Lygosomini have a Southeast Asian origin and began diversifying in the Eocene with three dispersals between India and Southeast Asia. Species level diversification in Dravidosepsgen. nov. was likely driven by a combination of niche conservatism, paleoclimate and past forest distribution. The discovery of a new genus and five new species reiterates the high levels of diversity and endemism present in peninsular India and how much more remains to be discovered.