Ptychoceratodus is an extinct genus of lungfish living from Early Triassic to Middle Jurassic. It was established by Otto Jaekel for one species (P. runcinatus), transferred from Ceratodus genus.[8] Type species is P. serratus from the Middle Triassic of Switzerland and Germany.[8][9]Ptychoceratodus had two pairs of massive dental plates, bearing 4-6 acute ridges. Its skull roof was composed from massive, plate-like bones. In the central part of skull roof was localized an unossified fenestra. Most of the Ptychoceratodus findings are isolated dental plates, some associated with jaws. Other parts of skull or postcranial skeleton are relatively rarely found as fossils. The anatomy of skull is the best recognized in P. serratus,[9] whereas less complete cranial material is available also for P. concinuus, P. phillipsi, and P. rectangulus.[10] Although Ptychoceratodus is known exclusively from the Triassic and Jurassic,[11] there were also Cretaceous specimens referred to this genus. However, they are more often regarded as representants of Metaceratodus.[12]Ptychoceratodus is the only member of the family Ptychoceratodontidae.[13][14] The first named species is P. phillipsi by Louis Agassiz in 1837 as a species of Ceratodus and later moved to the genus Ptychoceratodus.[6] Occurrences of Ptychoceratodus come mainly from Europe.[15][8] However, occurrences from other continents suggest it was dispersed globally during the Triassic.[15] After 2010, the new fossil material behind the Europe was reported from South America,[16] India,[5] and Greenland[10]
Fossil distribution
Fossils of Ptychoceratodus have been found in:[17]
^ abcdefghM. Martin. 1982. Nouvelles données sur la phylogénie et la systématique des dipneustes postpaléozoïques [New data on the phylogeny and systematics of post-Paleozoic dipnoans]. Comptes Rendues de l'Academie des Sciences, Paris, Série II 294:611-614
^ abcS. Apesteguia, F. L. Agnolin, and K. Claeson. 2007. Review of Cretaceous dipnoans from Argentina (Sarcopterygii: Dipnoi) with descriptions of new species. Revista del Museo Argentino de Ciencias Naturales nueva serie 9(1):27-40
^H. v. Meyer and T. Plieninger. 1844. Beiträge zur Paläontologie Württemberg’s, enthaltend die Fossilen Wirbelthierreste aus den Triasgebilden mit Besonderer Rücksicht auf die Labyrinthodonten des Keupers [Contributions to the Paleontology of Württemberg, Including the Fossil Vertebrate Remains from the Triassic Formations with Special Regard to the Labyrinthodonts of the Keupers] 1-132
^F. L. Agnolin, S. Bogan, F. Brissón Egli, F. E. Novas, M. P. Isasi, C. Marsicano, A. Zavattieri and A. Mancuso. 2017. A new lungfish (Dipnoi) from the Late Triassic of South America. Journal of Vertebrate Paleontology 37(1):e1245665
^ abcMohd Shafi Bhat; Sanghamitra Ray (2020). "A record of new lungfishes (Osteichthyes: Dipnoi) from the Carnian (Upper Triassic) of India". Historical Biology: An International Journal of Paleobiology. 32 (3): 428–437. Bibcode:2020HBio...32..428B. doi:10.1080/08912963.2018.1499020. S2CID92040062.
^ abcL. Agassiz. 1838. Recherches Sur Les Poissons Fossiles. Tome III (livr. 11). Imprimérie de Petitpierre, Neuchatel 73-140
^C.-C. Young. 1942. Fossil vertebrates from Kuangyuan, N. Szechuan, China. Bulletin of the Geological Society of China 22(-34):293-309
^ abcSchultze, Hans-Peter. "Das Schädeldach eines ceratodontiden Lungenfisches aus der Trias Süddeutschlands (Dipnoi, Pisces)". Stuttgarter Beiträge zur Naturkunde. Serie B (Geologie und Paläontologie). 70: 1–31.
^Skrzycki, Piotr (2015-09-03). "New species of lungfish (Sarcopterygii, Dipnoi) from the Late Triassic Krasiejów site in Poland, with remarks on the ontogeny of Triassic dipnoan tooth plates". Journal of Vertebrate Paleontology. 35 (5): e964357. Bibcode:2015JVPal..35E4357S. doi:10.1080/02724634.2015.964357. ISSN0272-4634. S2CID83615924.