Resolving the higher-order phylogenetic relationships of the circumtropical Mabuya group (Squamata: Scincidae): An out-of-Asia diversification

Abstract

Despite an abundance of phylogenetic studies focused on intrageneric relationships of members of the Mabuya group, the intergeneric relationships have remained difficult to resolve. The most-persistent unresolved regions of the phylogeny of the group include: (1) the placement of the Middle-Eastern Trachylepis with respect to the Afro-Malagasy Trachylepis and its taxonomic status; (2) the phylogenetic position of the Cape Verdean Chioninia within the larger Mabuya group; (3) support for the placement of Dasia with respect to the entire group; and (4) the phylogenetic placement of Eutropis novemcarinata with respect to other Eutropis and Dasia. In this study, we include representatives of all these taxa as well as African Eumecia and Neotropical Mabuya. We seek to address these phylogenetic and systematic issues by generating a well-resolved and supported phylogeny for the Mabuya group as a whole that can be used to develop a stable taxonomy and reconstruct the geographic patterns of diversification within the group. To meet these goals, we built a large multi-locus dataset of 11 markers (nine nuclear and two mitochondrial), and performed concatenated and species tree analyses to generate a well-supported phylogeny for the group. Statistical topology tests reject the monophyly of Middle-Eastern Trachylepis with Afro-Malagasy Trachylepis, and to reflect monophyly we place the Middle-Eastern species into a previously described genus, Heremites. Cape-Verdean Chioninia are resolved as the strongly supported sister-group to Afro-Malagasy Trachylepis. Monophyly of the Southeast-Asian genera, Eutropis and Dasia, is not supported, with a clade composed of Dasia+Eutropis novemcarinata more closely related to the rest of the Mabuya group than to the remaining Eutropis. The phylogenetic position of E. novemcarinata renders Eutropis polyphyletic, and we therefore describe and place E. novemcarinata into a new monotypic genus, Toenayar, to preserve monophyly among the genera. In light of these novel findings, we review and discuss the historical biogeography of the entire Mabuya group.

Keywords: Heremites; Mabuyidae; Mabuyinae; Novemcarinata; Species tree; Toenayar gen. nov.