Metaceratodus baibianorum, a new dipnoan species from the Upper Cretaceous of southern South America supported by traditional and geometric morphometric analyses

REVISITING THE CRETACEOUS LUNGFISH <em>ATLANTOCERATODUS IHERINGI</em> (AMEGHINO 1898) FROM THE MATA AMARILLA FORMATION (ARGENTINA) WITH COMMENTS ON TOOTH PLATES HISTOLOGY

“…Morphological descriptions were conducted using the set of terms implemented in Panzeri et al 2020, andoriginally defined by Kemp (1977), Churcher & De Iullis (2001), and Smith & Campbell (1987). Each tooth plate consists of a medial, lingual, and labial edge (Fig.…”

“…However, it is important to clarify that this tooth plate is detached from the bony base thus its identity as upper or lower was not clear. Nevertheless, it appears to represent a pterygopalatine tooth plate since among all tooth plates associated with basal bones collected from the Mesozoic of Argentina, only upper ones exhibit five denticulations (Panzeri et al 2020; Fig. S5).…”

“…Potamoceratodus guentheri (Marsh, 1878); Kirkland 1987, Pardo et al 2010Frederickson & Cifelli 2017;Harrel & Ehret 2019;Pawlak et al 2020), as well as in other species from Patagonia (e.g. Rinconodus salvadori; Apesteguía et al 2007;Panzeri et al 2020Panzeri et al , 2022a, Asia (e.g. Ferganoceratodus martini Cavin, Suteethorn Buffetaut & Tong 2007;Liu & Yeh 1960;Wang et al 2022), and Europe (e.g.…”

“…On the contrary, the majority of Cretaceous Patagonian species of Metaceratodus (M. baibianorum and M. wichmanni, Apesteguía et al 2007;Panzeri et al 2020) exhibit pterygopalatine tooth plates with a more pronounced development of the plateau area, denticulations directed towards the labial side, the inner angle positioned at the level of the second furrow, and a heterogeneous symphysis of the pterygopalatine bone (broader anteriorly). The prearticular tooth plates often display a sinuosity at the end of the first denticulation, the inner angle positioned at the level of the second denticulation (or slightly posterior to it), and curved mediolinguinal edges.…”

“…It follows the recent advancements in the study of the structural and anatomical variations in dipnoan morphology (e.g. Skrzycki 2015;Pawlak et al 2020;Panzeri et al 2020Panzeri et al , 2022a and histology (Denison 1974;Smith 1984;Campbell & Barwick 1998;Kemp 2001;Blaauwen et al 2006;Panzeri et al 2022b). Finally, the similarity with lungfish from other parts of the world and the taxonomic assignment of other species referred to this genus are discussed.…”