The Kem Kem Group is a lowermost lithostratigraphic unit from the Upper Cretaceous that extends along the border between Algeria and Morocco, in the northern region of Africa. This geological unit has yielded several tetrapod fossils, including a well-represented assemblage of theropod dinosaurs, after more than eight decades of research. Here, we report new occurrences of spinosaurid theropods from the spinosaurine clade in the Kem Kem Group by providing anatomical descriptions and taxonomic identifications of 11 new specimens derived from the Tafilalt region of Morocco. Among the findings, we describe a cervical vertebra of Sigilmassasaurus, in addition to several cranial, axial, and appendicular elements that can safely be attributed to Spinosaurinae. Moreover, based on a unique combination of characteristics, we also describe an isolated and partial ischium belonging to an indeterminate carcharodontosaurid. We also deliver a detailed redescription of one of the most complete snouts of a spinosaurine known to date. Therefore, the theropod dinosaurs of the Kem Kem Group show considerable diversity, but many questions, especially related to the diversity of spinosaurids and the general abundance of carnivorous dinosaurs in this region, remain unclear until new materials are discovered and complete descriptions are made.

中文翻译：

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来自 Kem Kem 群（摩洛哥东部）上白垩纪的新兽脚亚目恐龙遗骸阐明了棘龙的形态


Kem Kem 群是上白垩纪最底层的岩石学单元，沿着非洲北部地区阿尔及利亚和摩洛哥之间的边界延伸。经过八十多年的研究，这个地质单元已经产生了几块四足动物化石，包括一个具有代表性的兽脚亚目恐龙组合。在这里，我们通过提供来自摩洛哥 Tafilalt 地区的 11 个新标本的解剖学描述和分类学鉴定，报告了来自 Kem Kem 组棘龙分支的棘龙兽脚类恐龙的新发现。在这些发现中，我们描述了 Sigilmassasaurus 的颈椎，以及可以安全地归因于棘龙科的几个颅骨、轴向和附肢元素。此外，基于独特的特征组合，我们还描述了属于不确定的 carcharodontosaurid 的孤立和部分坐骨。我们还详细重新描述了迄今为止已知的棘龙最完整的鼻子之一。因此，Kem Kem 群的兽脚亚目恐龙表现出相当大的多样性，但许多问题，特别是与棘龙类的多样性和该地区食肉恐龙的普遍数量有关的问题，在发现新材料并做出完整描述之前仍不清楚。