Exceptionally preserved shark fossils from Mexico elucidate the long-standing enigma of the Cretaceous elasmobranch Ptychodus

• Verfasst von: Vullo, Romain [VerfasserIn]
• Verfasst von: Villalobos-Segura, Eduardo [VerfasserIn]
• Verfasst von: Amadori, Manuel [VerfasserIn]
• Verfasst von: Kriwet, Jürgen [VerfasserIn]
• Verfasst von: Frey, Eberhard [VerfasserIn]
• Verfasst von: González González, Margarito A. [VerfasserIn]
• Verfasst von: Padilla Gutiérrez, José M. [VerfasserIn]
• Verfasst von: Ifrim, Christina [VerfasserIn]
• Verfasst von: Stinnesbeck, Eva S. [VerfasserIn]
• Verfasst von: Stinnesbeck, Wolfgang [VerfasserIn]
• Titel: Exceptionally preserved shark fossils from Mexico elucidate the long-standing enigma of the Cretaceous elasmobranch Ptychodus
• Verf.angabe: Romain Vullo, Eduardo Villalobos-Segura, Manuel Amadori, Jürgen Kriwet, Eberhard Frey, Margarito A. González González, José M. Padilla Gutiérrez, Christina Ifrim, Eva S. Stinnesbeck, Wolfgang Stinnesbeck
• E-Jahr: 2024
• Jahr: 30 April 2024
• Umfang: 12 S.
• Illustrationen: Illustrationen
• Fussnoten: Online veröffentlicht: 24. April 2024 ; Gesehen am 24.09.2024
• Titel Quelle: Enthalten in: Royal Society (London)Proceedings of the Royal Society of London. Series B, Biological sciences
• Ort Quelle: London : The Royal Society, 1905
• Jahr Quelle: 2024
• Band/Heft Quelle: 291(2024), 2021 vom: Apr., Artikel-ID 20240262, Seite [1]-12
• ISSN Quelle: 1471-2954
• DOI: doi:10.1098/rspb.2024.0262
• Datenträger: Online-Ressource
• Sprache: eng
• Sach-SW: Chondrichthyes
• Sach-SW: ecomorphology
• Sach-SW: Lamniformes
• Sach-SW: Late Cretaceous
• Sach-SW: Ptychodontidae
• Sach-SW: Vallecillo fossil Lagerstätte
• K10plus-PPN: 1903404282

Abstract

The fossil fish Ptychodus Agassiz, 1834, characterized by a highly distinctive grinding dentition and an estimated gigantic body size (up to around 10 m), has remained one of the most enigmatic extinct elasmobranchs (i.e. sharks, skates and rays) for nearly two centuries. This widespread Cretaceous taxon is common in Albian to Campanian deposits from almost all continents. However, specimens mostly consist of isolated teeth or more or less complete dentitions, whereas cranial and post-cranial skeletal elements are very rare. Here we describe newly discovered material from the early Late Cretaceous of Mexico, including complete articulated specimens with preserved body outline, which reveals crucial information on the anatomy and systematic position of Ptychodus. Our phylogenetic and ecomorphological analyses indicate that ptychodontids were high-speed (tachypelagic) durophagous lamniforms (mackerel sharks), which occupied a specialized predatory niche previously unknown in fossil and extant elasmobranchs. Our results support the view that lamniforms were ecomorphologically highly diverse and represented the dominant group of sharks in Cretaceous marine ecosystems. Ptychodus may have fed predominantly on nektonic hard-shelled prey items such as ammonites and sea turtles rather than on benthic invertebrates, and its extinction during the Campanian, well before the end-Cretaceous crisis, might have been related to competition with emerging blunt-toothed globidensine and prognathodontine mosasaurs.