Mexichromis trilineata (A. Adams & Reeve, 1850)
- Location
- Nakanosimachaneru, Miyakojima, Okinawa, Japan
- Date
- 2017/08/20
- Length
- 10mm
- Depth
- 7.0m
- Water temperature
- 29.2℃
Description
A small chromodorid reaching about 12 mm in body length. Ground colour is pale purple to violet, with a fine white line along the outermost mantle margin (occasionally yellow in some individuals).Three yellow longitudinal lines, each outlined in white, run along the dorsum — the source of the specific epithet trilineata. The central line forms a ring around the gill on the posterior dorsum, while the lateral lines run near the mantle margin. In some regional populations only the central line is present.
The rhinophores and gill plumes are a contrasting orange-yellow. The gill consists of 6-8 simply pinnate plumes.
Distribution
Western Pacific. Records come from Australia, Indonesia, Papua New Guinea, Palau, the Philippines and southern Japan. The species inhabits shallow to moderately deep coral and rocky reefs.Etymology
The specific epithet trilineata combines Latin tri- ("three") and lineatus ("lined"), meaning "three-lined", in reference to the three yellow dorsal stripes.Remarks
Originally described by A. Adams & Reeve 1850 in the H.M.S. Samarang report as Doris trilineata. Following Bertsch's 1977 supraspecific taxonomic revision of the Chromodoridinae, the species was transferred to Mexichromis Bertsch, 1977. The species is sponge-feeding.References
- Mexichromis trilineata (A. Adams & Reeve, 1850), Bertsch H. (1977). The Chromodoridinae nudibranchs from the Pacific coast of America. Part I. Investigative methods and supraspecific taxonomy. The Veliger. 20(2): 107-118.
- キイッポンウミウシ（仮称）, 小野篤司. (1999). ウミウシガイドブック. TBSブリタニカ.
- キイッポンウミウシ, 小野篤司. (2000). ウミウシガイドブック. 第2版. TBSブリタニカ.
- ペクテノドリス・トリリネアタ, 殿塚孝昌. (2003). ウミウシガイドブック〈3〉. TBSブリタニカ.
- Pectenodoris trilineata, 小野篤司. (2004). 沖縄のウミウシ. ラトルズ.
- Mexichromis trilineata, 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 trilineata
Tag:
Same Genus Nudibranchs
Similar Colors Nudibranchs
Academic Database
Sea slug observation data is available in international marine biodiversity databases.