On the Monophyly of the Agamid Genus Gonocephalus Kaup, 1825 (Reptilia: Squamata). A Chromosomal Perspective.

Molecular Evaluation of Phylogenetic Significances in the Highly Divergent Karyotypes of the Genus Gonocephalus (Reptilia: Agamidae) from Tropical Asia

“…Recent karyological studies further revealed prominent chromosomal variation within Gonocephalus sensu stricto: four of the five species examined shared a 2n = 42 karyotype including 22 biarmed macrochromosomes, whereas the remainder, G. robinsonii , had a 2n = 32 karyotype including no more than 12 macrochromosomes (Ota et al , 1992;Diong et al , 2000). Based on the fact that the former arrangement is exceptional as of the agamid karyotype, Diong et al (2000) interpreted it as a synapomorph of Gonocephalus exclusive of G. robinsonii , and went so far as to argue for the possible paraphyletic nature of the genus.…”

“…Based on the fact that the former arrangement is exceptional as of the agamid karyotype, Diong et al (2000) interpreted it as a synapomorph of Gonocephalus exclusive of G. robinsonii , and went so far as to argue for the possible paraphyletic nature of the genus. They, on the basis of similarities in the number of microchromosomes between G. robinsonii and a few Australian agamids, also noted that G. robinsonii may be an Asiatic representative of the Australian agamid radiation, like Physignathus cocincinus Macey et al , 2000).…”

“…Bar equals 0.1 unit of Kimura's two-parameter distance. Published data for the diploid chromosome numbers (2n) are given in parentheses (DeSmet, 1981;Witten, 1983;Solleder and Schmid, 1988;Ota et al , 1992;Ota and Hikida, 1989;Diong et al , 2000;Ota, unpubl data). Although Groups II-IV complex is mainly distributed in Australasia, Physignathus cocincinus is occurs in the continental part of Southeast Asia.…”

“…Our purposes are to examine consistency between patterns in chromosomal and phyletic diversification within the Gonocephalus , and to test the closer affinity of G. robinsonii to the Australian agamids as hypothesized by Diong et al (2000).…”

Karyological Analysis of the Indo-Chinese Water Dragon, <i>Physignathus cocincinus</i> (Squamata, Agamidae) from Thailand

“…One of these karyomorphs is considered to be derived from the other through a series of Robertsonian rearrangements (centric fusion) of macrochromosomes, sometimes accompanied with addition or deletion of one microchromosome pair (Bickham 1984, Diong et al 2000. The karyotypes of the sex chromosome of males and females are not different in contrast to the karyotypes of other agamid lizards (Diong et al 2000, Ota et al 2002, Srikulnath et al 2009). Morphologically differentiated sex chromosomes have been described in only two species of agamid lizards, Phrynocephalus vlangalii and Pogona vitticeps.…”