Leaché Adam D, McGuire Jimmy A
Museum of Vertebrate Zoology, Department of Integrative Biology, University of California, Berkeley, CA 94720-3160, USA.
Mol Phylogenet Evol. 2006 Jun;39(3):628-44. doi: 10.1016/j.ympev.2005.12.016. Epub 2006 Feb 20.
It has proven remarkably difficult to obtain a well-resolved and strongly supported phylogeny for horned lizards (Phrynosoma) because of incongruence between morphological and mitochondrial DNA sequence data. We infer the phylogenetic relationships among all 17 extant Phrynosoma species using >5.1 kb of mtDNA (12S rRNA, 16S rRNA, ND1, ND2, ND4, Cyt b, and associated tRNA genes), and >2.2kb from three nuclear genes (RAG-1, BDNF, and GAPD) for most taxa. We conduct separate and combined phylogenetic analyses of these data using maximum parsimony, maximum likelihood, and Bayesian methods. The phylogenetic relationships inferred from the mtDNA data are congruent with previous mtDNA analyses based on fewer characters and provide strong support for most branches. However, we detected strong incongruence between the mtDNA and nuclear data using comparisons of branch support and Shimodaira-Hasegawa tests, with the (P. platyrhinos+P. goodei) clade identified as the primary source of this conflict. Our analysis of a P. mcalliixP. goodei hybrid suggests that this incongruence is caused by reticulation via introgressive hybridization. Our preferred phylogeny based on an analysis of the combined data (excluding the introgressed mtDNA data) provides a new framework for interpreting character evolution and biogeography within Phrynosoma. In the context of this improved phylogeny we propose a phylogenetic taxonomy highlighting four clades: (1) Tapaja, containing the viviparous short-horned lizards P. ditmarsi, P. hernandesi, P. douglasii, and P. orbiculare; (2) Anota, containing species with prominent cranial horns (P. solare, P. mcallii, and the P. coronatum group); (3) Doliosaurus, containing three species lacking antipredator blood-squirting (P. modestum, P. platyrhinos, and P. goodei); and (4) Brevicauda, containing two viviparous species with extremely short tails that lack blood-squirting (P. braconnieri and P. taurus).
由于形态学数据和线粒体DNA序列数据之间存在不一致性，事实证明，要获得角蜥（角蜥属）的一个解析良好且有有力支持的系统发育树是非常困难的。我们使用超过5.1 kb的线粒体DNA（12S rRNA、16S rRNA、ND1、ND2、ND4、细胞色素b以及相关的tRNA基因），以及针对大多数分类单元的来自三个核基因（RAG-1、BDNF和GAPD）的超过2.2 kb的序列，推断了所有17种现存角蜥属物种之间的系统发育关系。我们使用最大简约法、最大似然法和贝叶斯方法对这些数据进行了单独和联合的系统发育分析。从线粒体DNA数据推断出的系统发育关系与之前基于较少特征的线粒体DNA分析结果一致，并为大多数分支提供了有力支持。然而，通过比较分支支持度和Shimodaira-Hasegawa检验，我们检测到线粒体DNA数据和核数据之间存在强烈的不一致性，其中（宽鼻角蜥+古氏角蜥）分支被确定为这种冲突的主要来源。我们对麦氏角蜥×古氏角蜥杂交种的分析表明，这种不一致性是由渐渗杂交导致的网状进化引起的。我们基于联合数据（不包括渐渗的线粒体DNA数据）分析得出的首选系统发育树为解释角蜥属内的性状进化和生物地理学提供了一个新的框架。在这个改进的系统发育背景下，我们提出了一种系统发育分类法，突出了四个分支：（1）塔帕亚分支，包含胎生的短角蜥，即迪氏角蜥、赫氏角蜥、道格拉斯角蜥和圆鼻角蜥；（2）阿诺塔分支，包含具有突出颅角的物种（太阳角蜥、麦氏角蜥和冕角蜥组）；（3）多利奥龙分支，包含三种不具备反捕食者喷血能力的物种（温和角蜥、宽鼻角蜥和古氏角蜥）；（4）短尾分支，包含两种胎生的、尾巴极短且不具备喷血能力的物种（布拉孔尼尔角蜥和金牛座角蜥）。
