单词	orthocone
释义	orthocone /ˈɔːθəkəʊn / noun Palaeontology 1The straight shell typical of early nautiloid cephalopods.Long straight slender smooth orthocones, similar internally to the Ellesmeroceratidae, developing broader cross section and a thin marginal siphuncle which may be somewhat separated from the ventral wall.... An orthocone is a usually long straight shell of a nautiloid cephalopod. 1.1A fossil cephalopod with an orthocone shell.These latter orthocone ammonites do not modify the terminal body chamber, which cannot function as a floating egg-case.... The group continued right until the end of the Permian or - depending on the identification of the Triassic orthocones - the end of the Triassic. This single specimen is unlike all the other embryologic orthocones, but we do not believe at this time that this single individual is sufficient to erect a new species. Derivatives orthoconic adjective ... Cephalopod mollusks such as the orthoconic nautiloids patrolled the benthos, in a role as the main macrophagous predator. The apical end is missing, although the remainder of the conch suggests that its shape is orthoconic, and the apical angle may be inferred as being about 15 [degrees]. Riccardi & Sabattini described Sueroceras, an orthoconic form with reticulate ornament, from the Late Carboniferous of Patagonia.
随便看	parasol plant parasol skirt parasomnia parasorbic parasphenoid parasphenoidal paraspinal parastas parastatal parastate parasternal parasternal line parasternal region parastichy parastigmatic parasuicidal parasuicide parasymbiont parasymbiosis parasymbiotic parasympathetic parasympatheticomimetic parasympatholytic parasympathomimetic parasynapsis

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