Skull of <I>Varanus monitor</i> (Linn.)

Jormungandr walhallaensis: A New Mosasaurine (Squamata: Mosasauroidea) from the Pierre Shale Formation (Pembina Member: Middle Campanian) of North Dakota

“…The sulci for the anterior process of the planum supraseptale (sensu Bahl, 1937; Oelrich, 1956; and Polcyn et al, 2022) are deep and sickle shaped, like in most mosasaurids (e.g., Tylosaurus proriger AMNH FARB 1585, Platecarpus tympaniticus AMNH FARB 1820/1821) (figs. 19, 20).…”

“…Of note, Konishi and Caldwell (2009: 420) interpret these structures as the “roofs of the cerebral hemispheres,” citing Russell (1967); however, Russell (1967: 21) describes the outlines of the cerebral hemispheres on the frontal ventral surface as “not clearly defined,” whereas these structures are very clearly defined, and match the shape of the sulci for the anterior process of the planum supraseptale figured by Oelrich (1956: 30) and Polcyn et al (2022: 132) perfectly. Konishi and Caldwell (2011) label these structures in Latoplatecarpus willistoni as the “orbitosphenoid articulation grooves,” which connect the orbitosphenoid to the ventral surface of the frontal via the “pila preoptica,” another name for the structures (in addition to planum supraseptale) given by Bahl (1937). Given that the sulci would have received the cartilaginous structures (the planum supraseptale) rather than the orbitosphenoid bones themselves, we elect to use the terminology of Oelrich (1956) and Polcyn et al (2022).…”

“…The cristae cranii (descensi processi frontalis sensu Konishi and Caldwell, 2009) begin as descending processes posterior to the internarial bar, flaring abruptly laterally before curving back medially, terminating just anterior to the sulci for the anterior process of the planum supraseptale and level to the posterior margin of the prefrontal facets. They lie lateral to a pair of deep fossae (parolfactory bulb recesses, sensu Konishi and Caldwell, 2009) that form the roof of the olfactory bulbs (Bahl, 1937; Bellairs, 1949). Posteriorly, the cristae cranii broaden and flatten, particularly lateral to the sulci for the planum supraseptale.…”

“…Abbreviations: ecp, ectopterygoid; f, frontal; j, jugal; mx, maxilla; pal, palatine; pmx, premaxilla; pof, postorbitofrontal; prf, prefrontal; pt, pterygoid; q, quadrate; sq, squamosal; vo, vomer. platecarpus willistoni as the "orbitosphenoid articulation grooves, " which connect the orbitosphenoid to the ventral surface of the frontal via the "pila preoptica, " another name for the structures (in addition to planum supraseptale) given by Bahl (1937). Given that the sulci would have received the cartilaginous structures (the planum supraseptale) rather than the orbitosphenoid bones themselves, we elect to use the terminology of Oelrich (1956) and Polcyn et al (2022).…”

Iguanian lizards (Acrodonta and Pleurodonta) from the earliest Eocene (MP 7) of Dormaal, Belgium: the first stages of these iconic reptiles in Europe

“…The anterior premaxillary foramina are absent, although the right side of the nasal process appears to bear a tiny elliptical depression. A posterior premaxillary foramen (sensu Bahl, 1937) pierces the posterior surface of the process on the right side, just medial to the lateral edge. An additional pair of foramina is present on each side, being located in a shallow depression.…”