Fossil marine vertebrates (Chondrichthyes, Actinopterygii, Reptilia) from the Upper Cretaceous of Akkermanovka (Orenburg Oblast, Southern Urals, Russia)

THE FIRST RECORD OF THE ORECTOLOBIFORM SHARK GENUS <em>CEDERSTROEMIA</em> (ELASMOBRANCHII, ORECTOLOBIDAE) IN ASIA (KASHIMA FORMATION, UPPER CRETACEOUS; OYUBARI AREA, HOKKAIDO, JAPAN)

“…Teeth of C. havreensis and C. nilsi closely resemble each other. Nevertheless, C. havreensis mainly differs from C. nilsi in exhibiting a labial, rarely also lingual, ornamentation on the tooth crown, whereas C. nilsi is lacking any ornamentation on the crown (Guinot et al 2013;Jambura et al 2024). Teeth of the C. triangulata and C. ziaensis have a basal face of the root that is subtriangular in outline with a straight labial bord, thereby differentiating this taxon from other species.…”

“…Fossils of these chondrichthyan taxa are to date only known from Europe. C. havreensis mainly differs from C. nilsi in exhibiting a labial, rarely also lingual, ornamentation on the tooth crown, whereas C. nilsi is lacking any ornamentation on the crown (Guinot et al 2013;Jambura et al 2024, see «Distinctive features of the teeth of valid Cederstroemia species», and Tab. 3).…”

“…In addition, some teeth of Cretorectorobus have lateral shoulders with cusplets. The cuspidate lateral shoulders are missing in Squatina and Cederstroemia teeth (Case 1978;Siveson 1996;Cappetta 2012;Guinot et al 2012;Guinot et al 2013;Siverson et al 2016;Hoganson et al 2019;Ebersole et al 2022;Jambura et al 2024). It should be underlined that a combination of a number of the characteristics listed above is required for reliable identification.…”

“…Later, Siverson (1995) established the genus Cederstroemia and included it along with Cretorectolobus in Orectolobiformes family incertae sedis (Siverson 1995;Guinot et al 2013). According to Cappetta (2012), Ebersole et al (2022), andJambura et al (2024), Cederstroemia belongs to the family Orectolobidae.…”

“…Currently, five valid species are believed to belong to Cederstroemia, namely Cederstroemia havreensis (Herman, 1977) The occurrence of the genus Cederstroemia is distributed in the Northern Hemisphere, including France (e.g., Landemain 1991;Biddle 1993;Guinot et al 2013), Ukraine (Sokolsky & Guinot 2021), the UK (Guinot et al 2013), European Russia (e.g., Ebersole et al 2022;Solonin et al 2023;Jambura et al 2024), Sweden (Siverson 1995Sørensen et al 2013), and the USA (e.g., Bourdon et al 2011). However, the occurrence of Cederstroemia has not been previously reported in the Asian Northwest Pacific.…”