New Karyotypic Data on 15 Genera of Lizards in the Family Iguanidae, With a Discussion of axonomic and Cytological Implications

Abstract

Karyotypic data are presented for 14 species of iguanid lizards assigned to 14 genera and for 9 species of iguanids in the genus Anolis. A basic chromosomal formula of six pairs of large metacentric chromosomes and 12 pairs of microchromosomes characterizes many of the representatives of the family: Oplurus sebae from Madagascar; eight species of Anolis; the anoline species Anisokpis grilli; the large iguanines Ctenosaura pectinata, Cyclura cornuta, Iguana iguana and Sauromalus obesus; the basiliscine Basiliscus vittatus; and two tropidurines, Tropidurus torquatus and L·eiocephalus schreibersi. Within the tropidurines there has been chromosome evolution. Liolaemus lutzae has only 11 pairs of microchromosomes, the largest of which is considerably larger than the others and probably represents centric fusion from the original 12 pairs. Plica plica differs from the other tropidurines and all other iguanids examined in having eight pairs of macrochromosomes – four metacentric pairs and four acrocentric pairs. Evidence is presented to show that this is a condition derived from six pairs of metacentrics. The sceloporine Uma notata is characterized by six pairs of metacentric macrochromosomes and 11 pairs of microchromosomes. A reduced number of microchromosomes from the presumably primitive number of 12 also characterizes all other sceloporines listed in the literature. Cupriguanus achalensis, a recently described genus and species, also has 12 macrochromosomes and 24 microchromosomes. The largest pair of microchromosomes appears heteromorphic in the male. Anolis auratus has seven pairs of macrochromosomes and eight pairs of microchromosomes; this is typical of the group within Anolis to which it belongs. This species is a beta Anolis, a group that was characterized in the literature as having seven pairs of metacentric macrochromosomes. The other major subgroup of Anolis has the more typical six pairs of macrochromosomes. One species of iguanid, Polychrus marmoratus has a karyotype so different from the remainder of the family that it is impossible to assess its relationship. There are 20 acrocentric chromosomes and ten microchromosomes in the female. In male meiosis there are 14 bodies, 13 bivalents and a presumed sex trivalent. The diploid number is 29;