Vertebrate paleobiodiversity of the Early Cretaceous (Berriasian) Angeac-Charente Lagerstätte (southwestern France): implications for continental faunal turnover at the J / K boundary Author Allain, Ronan Author Vullo, Romain Author Rozada, Lee Author Anquetin, Jérémy Author Bourgeais, Renaud Author Goedert, Jean Author Lasseron, Maxime Author Martin, Jeremy E. Author Pérez-García, Adán Author Fabrègues, Claire Peyre De Author Royo-Torres, Rafael Author Augier, Dominique Author Bailly, Gilles text Geodiversitas 2022 2022-07-21 44 25 683 752 journal article 107849 10.5252/geodiversitas2022v44a25 d0184974-bea3-4f97-a2f8-98887ec4f87e 1638-9395 6902033 urn:lsid:zoobank.org:pub:EA12DCB7-A5BE-4763-B805-25087EBD726D Albanerpetontidae indet. ( Fig. 9 ) DESCRIPTION Albanerpetontids are represented in Angeac-Charente by numerous and diverse bones, including dentaries, premaxillae, maxillae, vertebrae and forelimb bones ( Fig. 9 A-K). All the material was recovered from screen washing residues. It is always disarticulated, and almost always fragmentary. Several diagnostic characters allow their assignment to the Albanerpetontidae , including: 1) intertonguing symphyseal joint between dentaries, in a mortise-and-tenon style ( Fox & Naylor 1982 ; Milner 1988 ; McGowan & Evans 1995 ; McGowan 1996 , 2002 ; Gardner 1999b , 2000 ; Gardner et al. 2003 ; Sweetman & Gardner 2013 ; Matsumoto & Evans 2018 ). In the Angeac-Charente specimens, there are two symphyseal prongs ( Fig. 9A, B ); 2) pleurodont, chisel-like and regularly arranged non-pedicellate teeth, labiolingually compressed and bearing three faint, mesiodistally aligned cuspules ( Fig. 9 A-G; Fox & Naylor 1982 ; Gardner 1999a , b, 2000 ; McGowan & Evans 1995 ; Sweetman & Gardner 2013 ; Matsumoto & Evans 2018 ); and 3) foramina arranged in line on external face of dentary ( Fig. 9F ; Fox & Naylor 1982 ; Gardner 2000 ). In Angeac-Charente albanerpetontids, the maxilla is unornamented labially, except for scattered external nutritive foramina that are characteristic of the group ( Fig.9D ; Fox & Naylor 1982 ; Gardner 2000 ). In this respect, they differ from Albanerpeton inexpectatum from the Miocene of France ( Gardner 1999a ). As in other albanerpetontid for which trunk vertebrae have been described ( Estes & Hoffstetter 1976 ; McGowan 1996 , 2002 ; McGowan & Ensom 1997 ; Sweetman & Gardner 2013 ; Matsumoto & Evans 2018 ), those from the Angeac-Charente material ( Fig. 9 I-K) are amphicoelous, hourglass-shaped and bear a short unicipital transverse process. The centrum is narrowly constricted at its center ( Fig. 9I, K ) and the cotyles are circular in outline and have thickened rims ( Fig. 9J ). As in other albanerpetontid trunk vertebrae described elsewhere, the notochordal canal is anteroposteriorly continuous ( Fig. 9J ; Sweetman & Gardner 2013 ) and thus the vertebrae are fully notochordal. Angeac-Charente specimens also show numerous features that have been described in other albanerpetontids and allow the distinction from other lissamphibians and lizards.The premaxilla ( Fig.9D, E ) and maxilla ( Fig.9C ) have a deep pars dentalis and the dentary ( Fig. 9A, B, F, G ) has a tall dental parapet, allowing the attachment of highly pleurodont teeth ( Gardner 2000 ). Upper jaws are also characterized by a prominent, shelf-like pars palatinum lingually ( Fig. 9E ; Gardner 2000 ). The maxilla has a low, posteriorly tapered pars facialis ( Fig. 9C ; Gardner 1999a , 2000 ). On the dentary, the Meckelian canal is closed anteriorly, and the subdental shelf is low, narrow and gutterlike anteriorly ( Fig. 9A ; Gardner 1999a , b, 2000 ). As in other known albanerpetontid species, the humeral condyle is spherical, fully ossified and larger than the adjacent radial epicondyle ( Fig. 9H ; Sweetman & Gardner 2013 ). Above this humeral ball is a triangular and well-defined cubital fossa, at the proximal extremity of which a small foramen can be seen ( Fig. 9H ), as also reported for Albanerpeton inexpectatum ( Estes & Hoffstetter 1976 ) and Wesserpeton evansae ( Sweetman & Gardner 2013 ) . The albanerpetontids from Angeac-Charente differ from Anoualerpeton and Albanerpeton nexuosum , but resemble other Albanerpeton species , Celtedens and Wesserpeton in having dentaries and maxillae with relatively straight occlusal margins, and teeth weakly heterodont in size ( Sweetman & Gardner 2013 ). Unfortunately, the diagnostic characters necessary for identification at the generic level are lacking. Neither the maxilla nor the dentary is diagnostic for Albanerpeton and Celtedens ( Gardner 2000 ) , as their diagnoses are based on frontal characters ( Gardner 1999a , b, 2000 ; McGowan & Evans 1995 ; McGowan 2002 ). We did not find any frontal bones in the Angeac-Charente material, and so we cannot attribute the albanerpetontid material to these genera with certainty. Within Albanerpeton , the premaxilla is the most taxonomically informative bone for species ( Gardner 1999b , 2000 ), but the specimens found to date at Angeac-Charente are too incomplete to be relevant. Thus, considering the characters mentioned above, we can attribute the Angeac-Charente specimens to the family Albanerpetontidae , but so far the material is too incomplete to allow a further attribution at the generic and specific level.