Cyerce nigra Bergh, 1870

Description

In life the body is 3.5 cm long, with a width across the back of 2.5 cm between the most projecting cerata of the two sides. The dorsal ground colour is black; the cerata are also black on the upper face, with a yellow border and yellow spots, and pale yellow on the lower face with numerous black transverse stripes.

In the spirit-preserved specimen the body length between the tips of the foremost and hindmost cerata is about 2.3 cm, the width between the ceratal tips about 2 cm, the height from foot to back 6 mm. The principal colour is black, with a single yellow spot in the middle of the back posteriorly. The rhinophores are rusty reddish-yellow on their front edges; the front of the head is strongly marked with rusty-yellow transverse bands. The cerata are uniformly black on the stalk and lower part of the plate. The upper face of the plate bears a narrow black marginal line and an inner rusty reddish-yellow band, with several rusty-red rounded knobs forming two irregular concentric rings (13-15 outer and 9-11 inner on the larger cerata). The cerata are arranged in three longitudinal rows on each side; the innermost row contains about 14 cerata, the largest reaching 10 mm long, 9 mm wide and 0.5-0.66 mm thick.

Distribution

Type locality: Aibukit, Palaos (Palau) Islands, Pacific Ocean. The species is recorded across the Indo-West Pacific in coral reef habitats.

Etymology

The Latin adjective niger (feminine nigra) means "black", referring to the almost entirely black body colour.

Remarks

The genus Cyerce was erected for sacoglossans distinguished by the dorsal position of the anal papilla, the transverse division of the foot in its anterior third, and the armature of the penis with a spine. The genus name Cyerce Latinises the Greek mythological sorceress Kirkē (Latin Circe).

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References

• Cyerce nigra (Semper) Bergh n. sp., Bergh L.S.R. (1871). Malacologische Untersuchungen. In: C. Semper (ed.), Reisen im Archipel der Philippinen, Wissenschaftliche Resultate. Theil 2, Band 2, Heft 2: 49-118, pls 9-16.
• Cyerce nigra var. ocellata Bergh, Allan J.K. (1947). Nudibranchia from the Clarence River Heads, north coast, New South Wales. Records of the Australian Museum, 21(8): 433-463, pls. xli-xliii and map. https://doi.org/10.3853/j.0067-1975.21.1947.561
• Cyerce nigra, Terrence Gosliner, Ángel Valdés and David Behrens. (2015). Nudibranch and Sea Slug Identification Indo-Pacific. New World Pubns Inc.
• クロスジウロコウミウシ（新称）, 中野理枝. (2018). 日本のウミウシ. 文一総合出版.