Paradoris tsurugensis Baba, 1986

Description

Live length 30-50 mm. The body is rather broad, elliptical, depressed and leathery in consistency. The back is covered with granular tubercles of various sizes; spicules in the integument tend to stand together to support the larger tubercles. The underside of the animal is smooth. The margin of the rhinophoral opening is entire. The gills consist of 6 tri- or quadripinnate plumes; the margin of the branchial opening is also entire. The oral tentacles are digitate when alive (or triangular when preserved) and grooved ventrally. The upper lip of the anterior foot margin is notched medially. Ground colour grayish yellow to grayish brown with scattered blackish-brown flecks. A narrow line of chocolate-brown dots surrounds the base of the larger tubercles. The upper half of the rhinophore is chocolate brown. The branchial plumes are grayish yellow to grayish brown. The underside of the mantle and the sole are white, closely covered with chocolate spots.

Distribution

Type locality: Okazaki, Tsuruga Bay (Fukui Prefecture, Japan). Additional original material from Ogi, Toyama Bay, and Tomioka, Amakusa.

Etymology

The specific epithet tsurugensis is a toponymic adjective ("of Tsuruga"), referring to the type locality at Tsuruga Bay. The Japanese vernacular name Tsuruga-umiushi derives from the same place name.

Remarks

Most closely allied to the Mediterranean P. granulata in external morphology and internal anatomy. The two are separated by the genital accessories: P. granulata has 3 stylet sacs and 4-5 vestibular glands, whereas P. tsurugensis has only 2 stylet sacs and 2 vestibular glands. Originally placed in Dorididae; currently assigned to Discodorididae.

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References

• Paradoris tsurugensis Baba n . sp . ツルガウミウシ(新種 ・新称), 馬場菊太郎. (1989). 日本産新種ツルガウミウシの記載. 貝類学雑誌. 48(2): 73-78. https://doi.org/10.18941/venusjjm.48.2_73
• 高岡生物研究会. (2002). 日本海のウミウシ. 第2版.
• ツルガウミウシ, 中野理枝. (2004). 本州のウミウシ. ラトルズ.
• Paradoris tsurugensis (compared), Hermosillo A. & Valdés Á. (2004). Two new species of dorid nudibranchs (Mollusca, Opisthobranchia) from Bahía de Banderas and La Paz, Mexico. Proceedings of the California Academy of Sciences, Series 4. 55(28): 550-560.
• Paradoris tsurugensis (Baba, 1986), Padula V. & Valdés Á. (2012). Phylogeny and Biogeography of Paradoris (Nudibranchia, Discodorididae), with the Description of a New Species from the Caribbean Sea. The Veliger. 51(3): 165-176.