tIn Becetèn, in southeast Niger, is one of the few mid-Upper Cretaceous (Coniacian-Santonian) fossil-iferous localities in Africa where multiple anuran taxa are known. Two of them, Pachycentrata taquetiand Inbecetenanura ragei, have been described from In Becetèn. Both are pipids, a clade composed ofexclusively aquatic anurans. Beside these two pipids, numerous isolated bones have also been referredto anurans within the site, but never referred to any known less inclusive taxa. Here we describe severalidentified cranial and postcranial bones referable to Pipidae or its stem-group, which together constitutePipimorpha. Among these elements, three cranial elements are referred to two unnamed pipimorphs.One of these has gondwanomorph affinities (pipids + South American and African extinct pipimorphs).These conclusions are supported by our phylogenetic analyses. Numerous postcranial elements are notreferable to any of the four pipimorph taxa identified at In Becetèn, although some ilia might be tenta-tively referred to ?Pachycentrata sp. The presence of at least four distinct anuran taxa makes In Becetènthe most diverse anuran site in Mesozoic Africa. It is also the first site in the Mesozoic where four pipi-morph taxa are identified. The dominance of pipimorphs in the anuran diversity of the site suggests thatIn Becetèn was likely more lacustrine than previously thought.
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RBINS Staff Publications 2025 OA
Thoracosaurs are a polyphyletic group of Cretaceous–Paleogene longisrostrine crocodylians from Europe and North America. Traditionally perceived as gavialoids, phylogenetically closer to Gavialinae than to Tomistominae, they play a key role in the gharial problem: their old age and seemingly close relationship to Gavialinae is inconsistent with molecular clock estimates indicating a far younger origin of Gavialoidea. Moreover, the phylogenetic position of thoracosaurs is debated, as recent studies suggested thoracosaurs are non-crocodylian eusuchians instead. Here we describe thoracosaur material from Mont-Aimé, France, rediscovered in the collections of the Musée d’Histoire Naturelle de Lille. The Mont-Aimé is famous for its richness in fossil vertebrates, among which the longirostrine species Thoracosaurus isorhynchus (formerly T. macrorhynchus). Confusion about the age of the vertebrate layers has recently been solved, indicating that they are Maastrichtian in age instead of Danian. The new material most likely belongs to T. isorhynchus based on a flexure in the ectopterygoid–pterygoid suture, a distinctive character found in adults of this taxon. Our study reveals new characters not visible on previously known material. An example is the short posterior non-dentigerous process of the maxilla, a character shared with early Paleogene longirostrines and tomistomines but not with gavialines. Furthermore, microCT data of the skull reveal for the first time endocranial characters of this taxon, such as the presence of an internal recess in the parietal. Together with redescribed T. isorhynchus material from the Muséum d’Histoire Naturelle, Paris, this leads to an updated phylogenetic position of this taxon.
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RBINS Staff Publications 2023
