title: Molecular evaluation of phylogenetic significances in the highly divergent karyotypes of the genus Gonocephalus (Reptilia: Agamidae) from tropical Asia.
abstract: The Oriental large-bodied crested dragons of the genus Gonocephalus are known to include two distinct karyomorphs. To evaluate their phylogenetic significances, we conducted phylogenetic analyses of the genus together with other agamid genera on the basis of 862 base positions of mitochondrial 12S and 16S rRNA genes. Results suggested the presence of two distinct lineages within Gonocephalus, of which one, represented by G. robinsonii that has a 2n = 32 karyotype, was closer to other Oriental agamid genera than to the other congeneric lineage. Monophyly of the latter, characterized by unique chromosomal arrangement among agamid genera (2n = 42 karyotype), was confirmed. It is thus likely that states of morphological characters shared between the two lineages are derived through convergence, or represent symplesiomorphy. Our results also suggest that the karyological similarity between G. robinsonii and several Australian agamids, pointed out in a previous study, is actually attributable to homoplasy rather than their recent common ancestry.
authors.affiliation: Tropical Biosphere Research Center, University of the Ryukyus, Nishihara, Okinawa, 903-0213 Japan. g019002@lab.u-ryukyu.ac.jp
authors.forename: Masanao
authors.initials: M
authors.lastname: Honda
authors.forename: Hidetoshi
authors.initials: H
authors.lastname: Ota
authors.forename: Showichi
authors.initials: S
authors.lastname: Sengoku
authors.forename: Hoi-Sen
authors.initials: HS
authors.lastname: Yong
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Hikida
mesh_terms: D000818:Animals; D001210:Asia, Southeastern; D004272:DNA, Mitochondrial / Q000235:genetics; D004275:DNA, Ribosomal / Q000235:genetics; D019143:Evolution, Molecular; D007621:Karyotyping; D008116:Lizards / Q000145:classification* / Q000235:genetics*; D008969:Molecular Sequence Data; D010802:Phylogeny; D012335:RNA, Ribosomal / Q000235:genetics; D012336:RNA, Ribosomal, 16S / Q000235:genetics
chemical_list: D004272:DNA, Mitochondrial; D004275:DNA, Ribosomal; D012335:RNA, Ribosomal; D012336:RNA, Ribosomal, 16S; C075526:RNA, ribosomal, 12S