Raselimanana Achille P, Noonan Brice, Karanth K Praveen, Gauthier Jacques, Yoder Anne D
Département de Biologie Animale, Université d'Antananarivo, BP 906, Antananarivo (101), Madagascar.
Mol Phylogenet Evol. 2009 Feb;50(2):336-44. doi: 10.1016/j.ympev.2008.10.004. Epub 2008 Oct 14.
The endemic plated lizards (Gerrhosauridae) of Madagascar are one of the most diverse groups of lizards on the island (19 species) and are found in all ecoregions. On an island that presents so many interesting biological questions, plated lizards are an ideal group for examining patterns of diversification due to their high (but tractable) diversity and wide distribution. To resolve the taxonomy and evolutionary relationships of Malagasy plated lizards, and to explore their biogeographic history, we have generated a molecular phylogeny based on >2kb of both mitochondrial (cob, 1142 bp) and nuclear (NT-3, 419 bp; c-mos, 542 bp) DNA sequences. Phylogenetic relationships and divergence-time estimates indicate Zonosaurinae are monophyletic, arising from a single colonization event, likely from Africa to Madagascar in the Paleogene (Paleocene/early Eocene), with subsequent radiation. Furthermore, our results reveal widespread mischaracterization of species delimitation and assignment based on phenotypic characteristics. Paraphyly of a number of zonosaurine species was strongly supported by our dataset, revealing not only instances of likely cryptic species (phenotypic conservatism) but also phenotypic/genotypic discordance in the delimitation of species (phenotypic variability). These results clearly demonstrate the complex history of biotic diversification on Madagascar and provide novel insight into biogeographic patterns on the island.
马达加斯加的特产板蜥（环尾蜥科）是该岛最多样化的蜥蜴类群之一（有19个物种），分布于所有生态区域。在这个存在诸多有趣生物学问题的岛屿上，板蜥因其高度（但仍可处理）的多样性和广泛的分布，成为研究多样化模式的理想类群。为了解决马达加斯加板蜥的分类学和进化关系，并探索它们的生物地理历史，我们基于超过2kb的线粒体（细胞色素b，1142bp）和核DNA（神经营养因子-3，419bp；c-原癌基因mos，542bp）序列构建了分子系统发育树。系统发育关系和分歧时间估计表明，环尾蜥亚科是单系的，起源于一次单一的定殖事件，可能是在古近纪（古新世/始新世早期）从非洲到马达加斯加，随后发生了辐射分化。此外，我们的结果揭示了基于表型特征的物种界定和归属存在广泛的错误描述。我们的数据强烈支持了许多环尾蜥物种的并系性，这不仅揭示了可能存在隐存物种的情况（表型保守性），还揭示了物种界定中表型/基因型的不一致（表型变异性）。这些结果清楚地证明了马达加斯加生物多样化的复杂历史，并为该岛的生物地理模式提供了新的见解。
