Hyatt and Smith (1905, p. 114-115) included the Gymnitidae in the suborder Ceratitoidea, which later became the superfamily Ceratitaceae and included in it genera more primitive than Gymnites as well as the more advanced Gymnites. Those being Xenaspis, Flemingites, and Ophiceras. Derivation as shown in Smith (1932 p. 30) is from Xenodiscus.
The more primitive Xenaspis, Flemingites, and Ophiceras, found in Lower Triassic beds in western America have ceratitic sutures. The more developed Gymnites has deeply digitate ammonitic sutures.
Arkell, et al., 1957, in the Treatise on Invertebrate Paleontology, on the other hand included the Gymnitidae in the Pinacocerataceae as the earlier and more primitive of its two families, combining Gymnites with coeval and more advanced forms. Genera included in the Gymnitidae sensu Arkell include Eogymnites, Buddhaites, Japanites, and of course, Gemnites. The genus Xiphogymnites was included by Tozer in 1981.
Whether to place the Gymnitidae in the Ceratitaceae, as in Hyatt and Smith, combining Gymnites with its more primitive relatives, or in the Pinacocerataceae, as in Arkell et al., combining Gymnites with its coeval or more advanced relatives is a matter of perspective which does little to change the overall phylogeny.
ReferencesEdit
Arkell, et al., 1957. Mesozoic Ammonidea. Treatise on Invertebrate Paleontology, Part L, Ammonoidea. Geol Soc of America and Univ. Kansas Press.
Alpheus Hyatt and James Perrin Smith, 1905. The Triassic Cephalopod Genera of America. U.S. Geological Survey Professional Paper no. 40. (p. 114-115)
James Perrin Smith, 1932. Lower Triassic Ammonoids of North America. U.S. Geological Survey Professional Paper no. 167 (p. 30)
gymnitidae, family, lower, middle, triassic, ammonite, cephalopods, with, evolute, discoidal, shells, temporal, range, early, triassic, middle, triassic, preꞒ, ngymnites, incultus, from, bosnia, display, galerie, paléontologie, anatomie, comparée, parisscienti. Gymnitidae is a family of Lower to Middle Triassic ammonite cephalopods with evolute discoidal shells GymnitidaeTemporal range Early Triassic Middle Triassic PreꞒ Ꞓ O S D C P T J K Pg NGymnites incultus from Bosnia on display at Galerie de paleontologie et d anatomie comparee in ParisScientific classificationDomain EukaryotaKingdom AnimaliaPhylum MolluscaClass CephalopodaSubclass AmmonoideaOrder CeratitidaSuperfamily PinacoceratoideaFamily GymnitidaeWaagen 1898GeneraSee textHyatt and Smith 1905 p 114 115 included the Gymnitidae in the suborder Ceratitoidea which later became the superfamily Ceratitaceae and included in it genera more primitive than Gymnites as well as the more advanced Gymnites Those being Xenaspis Flemingites and Ophiceras Derivation as shown in Smith 1932 p 30 is from Xenodiscus The more primitive Xenaspis Flemingites and Ophiceras found in Lower Triassic beds in western America have ceratitic sutures The more developed Gymnites has deeply digitate ammonitic sutures Arkell et al 1957 in the Treatise on Invertebrate Paleontology on the other hand included the Gymnitidae in the Pinacocerataceae as the earlier and more primitive of its two families combining Gymnites with coeval and more advanced forms Genera included in the Gymnitidae sensu Arkell include Eogymnites Buddhaites Japanites and of course Gemnites The genus Xiphogymnites was included by Tozer in 1981 Whether to place the Gymnitidae in the Ceratitaceae as in Hyatt and Smith combining Gymnites with its more primitive relatives or in the Pinacocerataceae as in Arkell et al combining Gymnites with its coeval or more advanced relatives is a matter of perspective which does little to change the overall phylogeny References EditArkell et al 1957 Mesozoic Ammonidea Treatise on Invertebrate Paleontology Part L Ammonoidea Geol Soc of America and Univ Kansas Press Alpheus Hyatt and James Perrin Smith 1905 The Triassic Cephalopod Genera of America U S Geological Survey Professional Paper no 40 p 114 115 James Perrin Smith 1932 Lower Triassic Ammonoids of North America U S Geological Survey Professional Paper no 167 p 30 nbsp Paleontology portal nbsp This Ceratitida related article is a stub You can help Wikipedia by expanding it vte Retrieved from https en wikipedia org w index php title Gymnitidae amp oldid 1165995867, wikipedia, wiki, book, books, library,
