ABSTRACT The anatomy of African lacertid lizards (Lacertidae: Eremiadini) is poorly known, which has hindered a better understanding of their evolutionary relationships. This applies especially to the East African clade, which includes the genera Nucras, Latastia, Philochortus, Pseuderemias and Heliobolus. We present a detailed description of the skull osteology of the genus Heliobolus using X-ray microcomputed tomography and compare its morphology to the above lacertid taxa. Because the genus Heliobolus includes species of doubtful validity and affinities (Heliobolus neumanni and Heliobolus nitidus), we also present a detailed intrageneric comparison and construct a morphological character matrix that we analyse against a phylogenetic backbone derived from previous molecular studies. Heliobolus lugubris and Heliobolus spekii can be well characterised as a monophyletic group on the basis of a short postorbital and a continuously broad posterior margin of the parietal, differing from H. nitidus and other members of the East African clade in an overall low degree of ossification and reduced ventral extension of the frontal bone. Our preliminary phylogenetic analysis suggests that the genus Heliobolus is currently polyphyletic. We propose that the name H. neumanni be officially retracted, because specimens assigned to this species show very different morphologies relative to each other and are placed in different parts of the tree in our analysis. Also, the type specimen is lost and no specimens were collected from the type locality. H. nitidus shows a signal towards the genus Latastia. A definitive, new generic assignment of H. nitidus must await further investigations based on molecular data.

中文翻译：

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比较头骨骨学和非洲蜥蜴属 Heliobolus（有鳞蜥蜴科）的初步系统修正

摘要 非洲蜘蛛蜥蜴（Lacertidae：Eremiadini）的解剖学知之甚少，这阻碍了对其进化关系的更好理解。这尤其适用于东非进化枝，包括 Nucras、Latastia、Philochortus、Pseuderemias 和 Heliobolus 属。我们使用 X 射线显微计算机断层扫描对 Heliobolus 属的颅骨骨学进行了详细描述，并将其形态与上述 lecertid 分类群进行了比较。由于 Heliobolus 属包括有效性和亲和力可疑的物种（Heliobolus neumanni 和 Heliobolus nitidus），我们还提供了详细的属内比较，并构建了一个形态特征矩阵，我们针对源自先前分子研究的系统发育骨架进行分析。Heliobolus lugubris 和 Heliobolus spekii 可以很好地表征为基于短的眶后和顶叶的连续宽阔的后缘的单系群，不同于 H. nitidus 和东非进化枝的其他成员，整体骨化程度较低和减少额骨的腹侧伸展。我们的初步系统发育分析表明 Heliobolus 属目前是多系的。我们建议正式撤回 H. neumanni 的名称，因为分配给该物种的标本相对于彼此显示出非常不同的形态，并且在我们的分析中被放置在树的不同部分。此外，模式标本丢失，没有从模式所在地采集标本。H. nitidus 向 Latastia 属发出信号。一个明确的、新的 H.