Scavezzoni Isaure, Fischer Valentin
Evolution and Diversity Dynamics Lab, Université de Liège, Liège, Belgium.
PeerJ. 2018 Apr 10;6:e4594. doi: 10.7717/peerj.4594. eCollection 2018.
Modern marine turtles (chelonioids) are the remnants of an ancient radiation that roots in the Cretaceous. The oldest members of that radiation are first recorded from the Early Cretaceous and a series of species are known from the Albian-Cenomanian interval, many of which have been allocated to the widespread but poorly defined genus , possibly concealing the diversity and the evolution of early marine turtles. In order to better understand the radiation of chelonioids, we redescribe the holotype and assess the taxonomy of Moret (1935) (UJF-ID.11167) from the Late Albian ( Zone) of the Vallon de la Fauge (Isère, France). We also make preliminary assessments of the phylogenetic relationships of Chelonioidea using two updated datasets that widely sample Cretaceous taxa, especially . is a valid taxon that is supported by eight autapomorphies; an emended diagnosisis proposed. Our phylogenetic analyses suggest that could be polyphyletic, but constraining it as a monophyletic entity does not produce trees that are significantly less parsimonious. Moreover, support values and stratigraphic congruence indexes are fairly low for the recovered typologies, suggesting that missing data still strongly affect our understanding of the Cretaceous diversification of sea turtles.
现代海龟(海龟科)是白垩纪古老辐射演化的残余物种。该辐射演化的最古老成员最早记录于早白垩世,在阿尔比阶-森诺曼阶期间有一系列物种为人所知,其中许多被归入分布广泛但定义不明确的属,这可能掩盖了早期海龟的多样性和演化过程。为了更好地理解海龟科的辐射演化,我们重新描述了正模标本,并评估了来自法国伊泽尔省瓦隆德拉福热晚阿尔比阶(带)的莫雷海龟(1935年)(UJF-ID.11167)的分类学地位。我们还利用两个更新的数据集对海龟总科的系统发育关系进行了初步评估,这两个数据集广泛采样了白垩纪类群,尤其是。莫雷海龟是一个有效的分类单元,得到八个自近裔性状的支持;提出了修订后的诊断。我们的系统发育分析表明,莫雷海龟可能是多系的,但将其作为一个单系实体进行约束并不会产生显著不那么简约的树。此外,对于所恢复的分类类型,支持值和地层一致性指数相当低,这表明缺失的数据仍然强烈影响我们对海龟白垩纪多样化的理解。