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''Cricosaurus'' is an extinct genus of marine crocodyliform belonging to the family Metriorhynchidae. The genus was established by Johann Andreas Wagner in 1858 for three skulls from the Tithonian (Late Jurassic) of Germany.〔 The name ''Cricosaurus'' means "Ring lizard", and is derived from the Greek ''Cricos''- ("ring") and -''sauros'' ("lizard"). Fossil specimens referrable to ''Cricosaurus'' are known from Late Jurassic deposits in England, France, Switzerland, Germany,〔Steel R. 1973. Crocodylia. ''Handbuch der Paläoherpetologie, Teil 16''. Stuttgart: Gustav Fischer Verlag,116 pp.〕 Argentina (Vaca Muerta),〔Gasparini ZB, Dellapé D. 1976. Un nuevo cocodrilo marino (Thalattosuchia, Metriorhynchidae) de la Formación Vaca Muerta (Jurasico, Tithoniano) de la Provincia de Neuquén (República Argentina). ''Congreso Geológico Chileno'' 1: c1-c21.〕 Cuba,〔Gasparini ZB, Iturralde-Vinet M. 2001. Metriorhynchid crocodiles (Crocodyliformes) from the Oxfordian of Western cuba. ''Neues Jahrbuch für Geologie und Paläontologie, Monatshefte'' 9: 534–542.〕 and Mexico.〔Frey, E., Buchy, M.-C., Stinnesbeck, W. & López-Oliva, J.G. 2002. ''Geosaurus vignaudi'' n. sp. (Crocodylia, Thalattosuchia), first evidence of metriorhynchid crocodilians in the Late Jurassic (Tithonian) of central-east Mexico (State of Puebla). ''Canadian Journal of Earth Sciences'' 39: 1467–1483.〕 ==History and classification== ''Cricosaurus'' was first named by Wagner in 1858,〔Wagner A. 1858. Zur Kenntniss der Saurier aus den lithographischen Schiefern. ''Abhandlungen der Mathemat.-Physikalischen Classe der Königlich Bayerischen Akademie der Wissenschaften'' 8: 415-528.〕 as a re-classification of a specimen he had previously described in 1852.〔Wagner A. 1852. Neu-aufgefundene Saurier-Überreste aus dem lithographischen Schiefern und dem oberen Jurakalk. ''Abhandlungen der Mathemat.-Physikalischen Classe der Königlich Bayerischen Akademie der Wissenschaften'' 6: 661-710.〕 Several other species have since been named, including ''C. suevicus'' by Fraas in 1901 (originally as a species of ''Geosaurus''.〔Fraas E. 1901. Die Meerkrokodile (Thalattosuchia n. g.) eine neue Sauriergruppe der Juraformation. ''Jahreshefte des Vereins für vaterländische Naturkunde, Württemberg'' 57: 409-418.〕 One former species, ''C. medius'' (named by Wagner in 1858) has since been reclassified as a junior synonym of ''Rhacheosaurus gracilis''.〔 The original three skulls (all assigned to different species) were poorly known, and the genus had been considered a junior synonym of ''Metriorhynchus'', ''Geosaurus'' or ''Dakosaurus'' by different palaeontologists in the past.〔Steel R. 1973. ''Crocodylia. Handbuch der Paläoherpetologie, Teil 16''. Stuttgart: Gustav Fischer Verlag, 116 pp.〕 Some phylogenetic analysis did not support the monophyly of ''Cricosaurus'',〔Young MT. 2007. The evolution and interrelationships of Metriorhynchidae (Crocodyliformes, Thalattosuchia). ''Journal of Vertebrate Paleontology'' 27 (3): 170A.〕 However, a more comprehensive analysis in 2009 showed that the species contained in ''Cricosaurus'' were valid, and furthermore that several long-snouted species formerly classified in the related genera ''Geosaurus'', ''Enaliosuchus'' and ''Metriorhynchus'' were in fact more closely related to the original specimens of ''Cricosaurus'', and thus were re-classified into this genus.〔Young, M.T. and de Andrade, M.B. (2009). "What is ''Geosaurus''? Redescription of ''Geosaurus giganteus'' (Thalattosuchia: Metriorhynchidae) from the Upper Jurassic of Bayern, Germany." ''Zoological Journal of the Linnean Society'', 157: 551-585.〕 Cladogram after Cau & Fanti (2010). }} }} }} 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Cricosaurus」の詳細全文を読む スポンサード リンク
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