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Jovellania
''Jovellania'' is an extinct prehistoric nautiloid genus from the order Oncocerida known from the Lower Devonian of Europe (France, Germany).〔Sweet, W.C. 1964. Nautiloidea -Oncocerida. Treatise on Invertebrate Paleontology Part K Nautiloidea, Teichert & Moore (eds)〕 Nautiloids form a broad group of shelled cephalopods that were once diverse and numerous but are now represented by only a handful of species in two genera.
''Jovellania'' was named by Bayle (1879) and is type genus for the Jovellaniidae, a family assigned to the Oncocerida by Flower (1950)〔Flower, R.H & Kummel, B 1950, A Classification of the Nautiloidea, Journal of Paleontology 24(3) Sept 1950〕
==Morphology==
''Jovellania'' can be described as having a slowly widening, straight or slightly cytoconic shell with faint undulations and nearly circular or slightly depressed cross-section 〔Kroger, B. 2008. Nautiloids Before and During the Origin of Ammonoids ...Special Papers in Palaontology no.79, The Palaentological Association, London, March 2008.〕
The ventrolateral sides are flattend causing the prosiphuncular (ventral) side to be slightly angular. Septa are closely speced and sutures are transverse. The siphuncle is positioned between the center and the ventral margin and closer to the margin;〔 segments are expanded into the chambers; actinosiphonate deposits consist of longitudinal lamellae 〔
抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』
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