Phylogenetic relationships of mesozoic turtles
Phylogenetic relationships of mesozoic turtles
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DOI：
10.3374/0079-032x(2007)48
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发表时间：
2007-04-01
影响因子：
1.3
通讯作者：
Joyce, Walter G.
中科院分区：
文献类型：
--
作者：
Joyce, Walter G.
本文首次对海龟亲缘关系进行了形态分析，以考察多个海龟种群的单系性，仅以单一物种为末端，并整合了大量原始化石类群。数据矩阵包括136个骨学简约信息特征和169个派生特征状态，分别代表45个化石和22个活着的TESTUDINATA分支物种。这些结果证实了大量先前假设的分支的单调性，但驳斥了关于活着的海龟基本分裂的公认假设。特别是，原始海龟Proterochersis robusta、Kayentcheys aprix、Mortolochelys efemovi、Meiolania Plyceps和Kallokibotion bajazidi被从目前的冠龟位置上移除，并沿着该支系的系统发育茎放置。因此，龟冠的年龄被调整为从晚三叠世到晚侏罗世，这与验证分子钟假说有关。这一修改后的拓扑结构对几个字符复合体的进化具有重要意义，因为它意味着所有活着的海龟的共同祖先一定有一个部分支撑的脑壳和原始的滑车机制。其他值得注意的结论包括将原生硬柄动物暂时排除在贝类总科之外，将巨头扁藻放在海龟总科之外，以及将哈里桑多尼亚初步解释为基础真核生物。
Presented herein is the first morphological analysis Of turtle relationships to examine the monophyly of many turtle groups by using only single species as terminals and by integrating a large number of primitive fossil taxa. The data matrix consists of 136 osteological parsimony informative characters with 169 derived character states for 45 fossil and 22 living species of the clade TESTUDINATA. The results corroborate the monophyly of a large number of previously hypothesized clades, but refute the accepted hypothesis regarding the basal split of living turtles. In Particular, the primitive turtles Proterochersis robusta, Kayentachelys aprix, Mortgolochelys efremovi, Meiolania platyceps, and Kallokibotion bajazidi are removed from their current position as crown turtles and placed along the phylogenetic stem of this clade. The age of the turtle crown is thereby adjusted from the Late Triassic to the Late Jurassic, which is relevant to testing molecular clock hypotheses. This revised topology has important implications for the evolution of several character complexes, because it implies that the common ancestor of all living turtles must have had a partially braced brain case and a primitive trochlear mechanism. Other noteworthy conclusions include the tentative exclusion of protostegids from CHELONIOIDEA, the placement of Platysternon megacephalum outside of CHELYDRIDAE, and the tentative interpretation of Sandownia harrisi as a basal eucryptodire.