Cephalopyge trematoides (Chun, 1889)

Description

A small pelagic nudibranch reaching about 20 mm in body length. The body is transparent — with the visceral mass visible through it — elongate and leaf-shaped, with a laterally expanded tail resembling a fish's caudal fin. The foot is reduced and the animal swims freely in the open ocean. The rhinophores are slender and retractable into sheaths. The species preys on jellyfish (cnidarians).

Distribution

The original description (Chun, 1889) was based on specimens collected during a German expedition to the Canary Islands in 1887–88, studying the pelagic deep-water and surface fauna of the eastern Atlantic. Distributed broadly in the open oceans of the world, with records from the Western Pacific including Japan.

Etymology

The specific epithet trematoides is derived from Greek trēma ("hole") + -oides ("resembling"). The genus name Cephalopyge combines Greek kephalē ("head") and pȳgē ("rump"), referring to the elongate head-to-tail body shape.

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References

• Phylliroe trematoides n. sp., Chun C. (1889). Bericht über eine nach den Canarischen Inseln im Winter 1887-88 ausgeführte Reise. II. Beobachtungen über die pelagische Tiefen- und Oberflächenfauna des östlichen Atlantischen Oceans. Sitzungsberichte der Königlich Preussischen Akademie der Wissenschaften zu Berlin. pp. 519-553.