Stylocheilus longicauda (Quoy & Gaimard, 1825)

Description

A pelagic aplysiid with a slender, elongate body and a remarkably long, pointed tail (the basis of the name). Body bright yellow to green, sprinkled with dark eye-like spots — circular bluish patches with reddish or orange centres — and scattered white tubercles. Quoy & Gaimard's original animal was bright green spotted with red dots ringed in sky blue, plus additional white and blue patches. Neck rather elongate; rhinophores acutely pointed; body ovate; gill aperture narrow. Strictly pelagic, drifting on floating macroalgae rather than on shore.

Distribution

Indo-Pacific. Holoplanktonic on drifting algal mats. The type locality is "under the equator, near New Guinea", on detached Fucus rafts.

Etymology

The specific epithet longicauda is a Latin compound of longus ("long") and cauda ("tail"), in reference to the very long pointed tail described by Quoy & Gaimard as "caudâ longissimâ, acutâ".

Remarks

Originally described as Aplysia longicauda by Quoy & Gaimard in their Zoologie for the Voyage autour du Monde sur les corvettes l'Uranie et la Physicienne (Pillet Aîné, Paris, p.421, pl. 66 fig. 8). The volume cover is 1824 but the mollusk fascicle was actually distributed in 1825, on which basis WoRMS attributes authorship to Quoy & Gaimard, 1825. Subsequently transferred to Stylocheilus Gould, 1852. The name was long applied to Stylocheilus striatus (Quoy & Gaimard, 1832); the species was separated by colour pattern (longitudinal lines vs spots) in modern revisions (Bazzicalupo et al., 2020).

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References

• Aplysia longicauda, Quoy J.R.C. & Gaimard J.P. (1824). Zoologie. In: Freycinet L. de (ed.). Voyage autour du Monde, entrepris par Ordre du Roi, sous le ministère de S. Exc. M. le Vicomte du Bouchage, exécuté sur les corvettes de S.M. l'Uranie et la Physicienne, pendant les années 1817, 1818, 1819 et 1820. Pillet Aîné, Paris. 712 pp., Atlas 96 pls.
• ヒメミドリアメフラシ, 鈴木敬宇. (2000). ウミウシガイドブック〈2〉. TBSブリタニカ.
• 高岡生物研究会. (2002). 日本海のウミウシ. 第2版.
• ヒメミドリアメフラシ, 殿塚孝昌. (2003). ウミウシガイドブック〈3〉. TBSブリタニカ.
• ヒメミドリアメフラシ, 小野篤司. (2004). 沖縄のウミウシ. ラトルズ.
• ヒメミドリアメフラシ, 中野理枝. (2004). 本州のウミウシ. ラトルズ.
• Stylocheilus longicauda, Terrence Gosliner, Ángel Valdés and David Behrens. (2015). Nudibranch and Sea Slug Identification Indo-Pacific. New World Pubns Inc.