PHYLOGENETIC-RELATIONSHIPS AMONG AGAMID LIZARDS OF THE LAUDAKIA-CAUCASIA SPECIES GROUP - TESTING HYPOTHESES OF BIOGEOGRAPHIC FRAGMENTATION AND AN AREA CLADOGRAM FOR THE IRANIAN PLATEAU

Phylogenetic relationships within the Laudakia caucasia species group on the Iranian Plateau were investigated using 1708 aligned bases of m itochondrial DNA sequence from the genes encoding ND1 (subunit one of NADH dehydrogenase), tRNA(Gln), tRNA(IIe), tRNA(Met), ND2, tRNA(Trp), tRNA(Ala), tRNA(Asn), tRNA(Cys) tRNA(Tyr), and COI (subunit I of cytoc hrome c oxidase). The aligned sequences contain 207 phylogenetically i nformative characters. Three hypotheses for historical fragmentation o f Laudakia populations on the Iranian Plateau were tested. In two hypo theses, fragmentation of populations is suggested to have proceeded al ong continuous mountain belts that surround the Iranian Plateau, In an other hypothesis, fragmentation is suggested to have resulted from a n orth-south split caused by uplifting of the Zagros Mountains in the la te Miocene or early Pliocene [5-10 MYBP (million years before present) ]. The shortest tree suggests the latter hypothesis, and statistical t ests reject the other two hypotheses. The phylogenetic tree is excepti onal in that every branch is well supported. Geologic history provides dates for most branches of the tree. A plot of DNA substitutions agai nst dates from geologic history refines the date for the north-south s plit across the Iranian Plateau to 9 MYBP (late Miocene). The rate of evolution for this segment of mtDNA is 0.65% (0.61-0.70%) change per l ineage per million years. A hypothesis of area relationships for the b iota of the Iranian Plateau is generated from the phylogenetic tree. ( C) 1998 Academic Press.