Mexichromis pusilla (Bergh, 1874)
- Location
- Sunabe Water Treatment Plants, Okinawa Island (Chatan and Southern area), Okinawa, Japan
- Date
- 2015/05/09
- Length
- 10mm
- Depth
- 5.0m
- Water temperature
- 23.0℃
Description
A small chromodorid reaching about 20 mm in body length. The dorsum is reddish-purple with a broad pale yellow band along the mantle margin. A large white blotch lies between the rhinophores and another in front of the gill, and the surrounding reddish-purple background extends outward toward the mantle margin in six places (flanking each white blotch and at the front and rear); the tips of these extensions become more violet. In the original 1874 description Bergh based the species on a single specimen collected by Andrew Garrett at Tahiti and provided only a coloured plate figure with no detailed text under the tentative name Chromodoris? pusilla.Distribution
Indo-West Pacific to central Pacific. Type locality: Tahiti (French Polynesia), based on material collected by Andrew Garrett. Subsequently recorded from South Africa, the Red Sea, the Maldives, Malaysia, Papua New Guinea, Indonesia, the Solomon Islands, the Philippines, Japan and the Marshall Islands.Etymology
The specific epithet pusilla is the feminine of Latin pusillus ("very small, tiny"), in reference to the small size of this species among the Chromodoris-like dorids. Bergh's original description does not give an explicit etymology.Remarks
Originally described by Bergh as Chromodoris? pusilla; the question mark indicates that he was uncertain about the generic placement. The species was subsequently moved through Noumea and is now placed in Mexichromis following Rudman's 1984 revision of the Indo-West Pacific Chromodorididae; this placement is supported by a molecular phylogeny of the Chromodorididae. The parentheses in the author citation reflect this generic transfer.References
- Chromodoris? pusilla Bgh. n. sp., Bergh R. (1874). Neue Nacktschnecken der Südsee. Malacologische Untersuchungen. Journal des Museum Godeffroy. 6: 65-96, Taf. I-VII.
- キベリアカイロウミウシ（新称）Noumea varians, 奥谷喬司. (1994). サンゴ礁の生きもの. 東海大学出版会.
- キベリフジイロウミウシ（新称）, 鈴木敬宇. (2000). ウミウシガイドブック〈2〉. TBSブリタニカ.
- キベリアカイロウミウシ, 小野篤司. (2004). 沖縄のウミウシ. ラトルズ.
- Mexichromis pusilla, Johnson R.F. & Gosliner T.M. (2012). Traditional taxonomic groupings mask evolutionary history: a molecular phylogeny and new classification of the chromodorid nudibranchs. PLoS ONE 7(4): e33479.
A Kindle field guide by the site author
Kimoto N. (2026). Sea Slugs of Japan & the Indo-Pacific, 2nd Edition.
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Photos of Mexichromis pusilla
Same Genus Nudibranchs
Similar Colors Nudibranchs
Academic Database
Sea slug observation data is available in international marine biodiversity databases.