South Africa is currently home to a highly diverse tortoise assemblage whose evolutionary history has been investigated mostly as a result of molecular studies. The fossil record is of little help because the remains of extant taxa are relatively recent, and only three extinct species, of uncertain relationships, have been described so far. An Early Pliocene extinct species of the currently monotypic genus Chersina, still inhabiting South Africa, was reported at the fossil-rich site of Langebaanweg more than 50 years ago but never formally described. Here we erect and describe the extinct species Chersina langebaanwegi sp. nov. on the basis of abundant material that provides information on its morphological variation. The referral of the new species to the genus Chersina is supported by phylogenetic analysis which includes the Malagasy ploughshare tortoise, sharing the presence of a single gular shield covering a very long gular protrusion with Chersina spp. and a domed shell with C. langebaanwegi sp. nov. The material from Langebaanweg represents the oldest fossil evidence of this genus. It significantly post-dates the branching of Chersina from its sister taxon Chersobius, but pre-dates the presumed split of the extant lineages of Chersina angulata as estimated on molecular basis.

中文翻译：

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南非陆龟的起源：来自上新世早期 Langebaanweg 化石遗址的一个新的 Chersina 物种


南非目前是高度多样化的陆龟群落的家园，其进化历史主要作为分子研究的结果进行研究。化石记录几乎没有帮助，因为现存分类群的遗骸相对较新，到目前为止，只有三个已灭绝的物种被描述，它们之间的关系不确定。50 多年前，在化石丰富的 Langebaanweg 遗址报道了目前单型属 Chersina 的一种早上新世灭绝物种，至今仍栖息在南非，但从未正式描述过。在这里，我们竖立并描述了已灭绝的物种 Chersina langebaanwegi sp. nov.基于提供有关其形态变化信息的丰富材料。将新物种归入 Chersina 属得到了系统发育分析的支持，其中包括马达加斯加犁铧龟，与 Chersina spp. 共享一个覆盖很长的沟突的单个沟盾，以及与 C. langebaanwegi sp. nov.来自 Langebaanweg 的材料代表了该属最古老的化石证据。它明显晚于切尔西纳从其姊妹分类群切尔索比乌斯（Chersobius）分支出来的时间，但早于根据分子基础估计的现存切尔西纳（Chersina angulata）谱系的假定分裂。