Thursday, December 31, 2020

[Herpetology • 2020] Leptotyphlops sylvicolus Broadley & Wallach, 1997 One Species hides Many: Molecular and Morphological Evidence for Cryptic Speciation in A Thread Snake (Serpentes: Leptotyphlopidae)

 

 Leptotyphlops sylvicolus Broadley & Wallach, 1997

in Busschau, Conradie & Daniels. 2020. 


Abstract
We investigate the phylogeographic structure of a fossorial forest‐living snake species, the forest thread snake, Leptotyphlops sylvicolus Broadley & Wallach, 1997 by sampling specimens from the Eastern Cape and KwaZulu‐Natal provinces of South Africa. Phylogenetic results, using Bayesian inferences and maximum likelihood, from the combined mitochondrial sequence data (cyt b and ND4), along with population genetic analyses suggest the presence of phylogeographic breaks broadly congruent to those exhibited by other forest‐living taxa. Divergence‐time estimates indicate that cladogenesis within the study taxon occurred during the late Miocene climatic shifts, suggesting that cladogenesis was driven by habitat fragmentation. We further investigate the species‐level divergence within L. sylvicolus by including two partial nuclear loci (PRLR and RAG1). The three species delimitation methods (ABGD, bGMYC, and STACEY), retrieved 10–12 putative species nested within the L. sylvicolus species complex. These results were corroborated by iBPP implementing molecular and morphological data in an integrative Bayesian framework. The morphological analyses exhibit large overlap among putative species but indicate differences between grassland and forest species. Due to the narrow distributions of these putative species, the results of the present study have further implications for the conservation status of the L. sylvicolus species complex and suggest that forest and grassland habitats along the east coast of South Africa may harbor significantly higher levels of diversity than currently recognized.







Theo Busschau, Werner Conradie and Savel R. Daniels. 2020. One Species hides Many: Molecular and Morphological Evidence for Cryptic Speciation in A Thread Snake (Leptotyphlopidae: Leptotyphlops sylvicolus Broadley & Wallach, 1997).  Journal of Zoological Systematics and Evolutionary Research. DOI: 10.1111/jzs.12401

We investigated the phylogeographic structure of a fossorial forest‐living snake species, Leptotyphlops sylvicolus. Phylogenetic and population genetic analyses suggest the presence of phylogeographic breaks broadly congruent to those exhibited by other forest‐living taxa. Divergence‐time estimates suggest that cladogenesis was driven by habitat fragmentation during the late Miocene climatic shifts. The species delimitation methods retrieved 10–12 putative species nested within L. sylvicolus. Morphological analyses exhibit large overlap among putative species but indicate differences between grassland and forest species.