Abstract
Using 3226-bp-long mtDNA sequences and five nuclear loci (Cmos, ODC, R35, Rag1, Rag2, together 3409 bp), we examine genetic differentiation and relationships of Central American slider turtles (Trachemys grayi, T. venusta). Our investigation also included samples from taxa endemic to North America (T. gaigeae, T. scripta), the Antilles (T. decorata, T. decussata, T. stejnegeri, T. terrapen), and South America (T. dorbigni, T. medemi plus the two T. venusta subspecies endemic to northern South America). Our mitochondrial phylogeny retrieves all studied species as distinct, with three well-supported clades in a polytomy: (1) the Central and South American species (T. grayi + T. venusta) + (T. dorbigni + T. medemi), (2) the Antillean species, and (3) T. gaigeae + T. scripta. Our nuclear DNA analyses also suggest three distinct but conflicting clusters: (1) T. scripta plus the Antillean species, (2) T. gaigeae, and (3) the Central and South American species T. dorbigni, T. grayi, T. medemi, and T. venusta. However, in the mitochondrial phylogeny, T. gaigeae is the little divergent sister taxon of T. scripta. This conflicting placement of T. gaigeae suggests a distinct evolutionary trajectory and old hybridization with T. scripta and mitochondrial capture. Despite prominent color pattern differences, genetic divergences within T. grayi and T. venusta are shallow and the taxonomic diversity of each species with several currently recognized subspecies could be overestimated. Finally, we provide for the first time evidence for the occurrence of T. grayi along the Caribbean versant of Costa Rica.
Subject
Ecology, Evolution, Behavior and Systematics
Reference26 articles.
1. Balzverhalten und Systematik in der Subtribus Nectemydina. 1. Die Gattung Trachemys, besonders Trachemys scripta callirostris (Gray, 1855).;Fritz;Salamandra,1990
2. Balzverhalten und Systematik in der Subtribus Nectemydina. 2. Vergleich oberhalb des Artniveaus und Anmerkungen zur Evolution.;Fritz;Salamandra,1991
3. Molecular phylogeny of Central and South American slider turtles: implications for biogeography and systematics (Testudines: Emydidae:Trachemys)
4. Application of Phylogenetic Networks in Evolutionary Studies
5. adegenet: a R package for the multivariate analysis of genetic markers