Unraveling evolutionary lineages in the limbless fossorial skink genus Acontias (Sauria: Scincidae): are subspecies equivalent systematic units?
Subspecies in the limbless, endemic African fossorial skink genus Acontias constitute ill-defined operational taxonomic units, consequently considerable systematic debate has lingered on the systematic diversity within Acontias. In the present study, the systematic affinities among acontine taxa are explored with the utility of partial sequence data from two mitochondrial gene loci (16S rRNA and cytochrome oxidase subunit 1 (COI)) for all taxa, while two additional loci (12S rRNA, cytochrome b) were used to investigate relationships within the Acontias meleagris complex. Phylogenetic results, derived from the combined analysis, revealed two monophyletic clades. Clade 1 is comprised of small-bodied skinks while clade 2 comprised the medium bodied skinks. Within clade 2 none of the traditionally recognized subspecies formed reciprocally monophyletic groups. Furthermore, constraining the topology and enforcing sister taxa relationships between the assumed subspecies, consistently recovered a topology that was statistically significant worse, indicating that the traditionally designated subspecies groupings probably represent invalid taxonomic units, thus clearly reflecting considerable discord with current taxonomy. The burrowing life style of these lizards has probably led to marked convergent evolution and constrained the development of diagnostic morphological characters among these species. Morphological similarities in color as well as scale architecture within Acontias are labile and highly homoplaseous and do not reflect the evolutionary history of the group. Taxonomic implications of these results are discussed.
Daniels
Savel R
SR
Evolutionary Genomics Group, Department of Botany and Zoology, University of Stellenbosch, Private Bag X1, Matieland 7602, South Africa. sdaniel3@email.byu.edu
Heideman
Neil J L
NJ
Hendricks
Martin G J
MG
Mokone
Mphalile E
ME
Crandall
Keith A
KA
D000818:Animals; D005075:Biological Evolution; D045303:Cytochromes b / Q000235:genetics; D003576:Electron Transport Complex IV / Q000235:genetics; D008116:Lizards / Q000145:classification* / Q000235:genetics*; D008928:Mitochondria / Q000235:genetics; D010802:Phylogeny; D012335:RNA, Ribosomal; D012336:RNA, Ribosomal, 16S
D012335:RNA, Ribosomal; D012336:RNA, Ribosomal, 16S; C075526:RNA, ribosomal, 12S; D045303:Cytochromes b; D003576:Electron Transport Complex IV