A molecular phylogenetic hypothesis for the Asian agamid lizard genus Phrynocephalus reveals discrete biogeographic clades implicated by plate tectonics.

Abstract

Phylogenetic relationships of the agamid lizard genus Phrynocephalus are described in the context of plate tectonics. A near comprehensive taxon sampling reports three data sets: (1) mitochondrial DNA from ND1 to COI (3' end of ND1, tRNAGln, tRNAIle, tRNAMet, ND2, tRNATrp, tRNAAla, tRNAAsn, tRNACys, tRNATyr, and the 5' end of COI) with 1761 aligned positional sites (1595 included, 839 informative), (2) nuclear RAG-1 DNA with 2760 aligned positional sites (342 informative), and (3) 25 informative allozyme loci with 213 alleles (107 informative when coded as presence/absence). It is hypothesized that Phrynocephalus phyletic patterns and speciation reflect fault lines of ancient plates now in Asia rejuvenated by the more recent Indian and Arabian plate collisions. Molecular estimates of lineage splits are highly congruent with geologic dates from the literature.  A southern origin for the genus in Southwest Asia is resolved in phylogenetic estimates and a northern origin is statistically rejected. On the basis of monophyly and molecular evidence several taxa previously recognized as subspecies are recognized as species: P. hongyuanensis, P. sogdianus, and P. strauchi as "Current Status"; Phrynocephalus bannikovi, Phrynocephalus longicaudatus, Phrynocephalus turcomanus, and Phrynocephalus vindumi are formally "New Status". Phylogenetic evaluation indicates a soft substrate habitat of sand for the shared ancestor of modern Phrynocephalus. Size diversity maximally overlaps in the Caspian Basin and northwestern Iranian Plateau. The greatest species numbers of six in sympatry and regional allopatry are found in the southern Caspian Basin and southern Helmand Basin, both from numerous phylogenetic lineages in close proximity attributed to tectonic induced events.