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''Protatlanta souleyeti'' is a species of sea snail, a holoplanktonic marine gastropod mollusk in the family Atlantidae. ''Protatlanta souleyeti'' is the type species on the genus ''Protatlanta''.〔 It is considered to be the only Recent species on the genus.〔 The specific name ''souleyeti'' is in honor of French malacologist Louis François Auguste Souleyet. ==Description== The maximum recorded shell length is 2 mm.〔Welch J. J. (2010). "The "Island Rule" and Deep-Sea Gastropods: Re-Examining the Evidence". ''PLoS ONE'' 5(1): e8776. .〕 Some of the fossil specimens preserve a pinkish colour of the larval shells.〔 The protoconch is naticoid in shape and has approximately 3¼ whorls.〔 Most specimens have two thin spirals above the periphery, visible in apical view, and a third such spiral below the periphery, which separates the base of the protoconch and becomes covered by subsequent whorls.〔 The described ornament can be fairly constant, but some specimens were found in which these three spirals are lacking.〔 Richter (1968, p. 17, fig. 6c) described Recent larval shells from the Gulf of Naples as smooth.〔 For Recent material from near Hawaii, Seapy (1990, p. 114, fig. 4A-D) also stated that the first whorls are smooth.〔 But Batten & Dumont (1976, figs. 39-41) and Richter & Seapy (1999, p. 633, fig. 5A) and Janssen (2007)〔 have described two protoconch morphologies.〔 On the teleoconch whorls, the peripheral belt on which the conchiolin keel was attached is very clear.〔 Growth lines are strongly bent backward on this belt, indicating the presence of a deep sinus on the apertural margin.〔 A very faint spiral striation is visible all over the adult shell surface.〔 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「Protatlanta souleyeti」の詳細全文を読む スポンサード リンク
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