Mexichromis antonii
(Bertsch, 1976)

Order: NUDIBRANCHIA
Suborder: DORIDINA
Superfamily: EUDORIDOIDEA
Family: Chromodorididae

DISTRIBUTION

Pacific Coast of central America [Sonora, Mexico to Panama].

PHOTO

Careyeros, north of Punta Mita, Nayarit. [Pacific coast of Mexico]. Depth: 13 feet, Length: 12 mm. Photo: Alicia Hermosillo

The background colour of the mantle would appear to be a translucent with pinkish - purplish tinge, but this is obscured by a series of concentric colour bands starting at the mantle edge and extending in to the level of the rhinophore and gill pockets. Right at the edge there is a bright orange band, followed by one of  purplish black. Inside that is a double band of milky bluish white, the two bands being separated by a thin shadowy purplish band which is most obvious laong each side of the mantle. The whitish bands are almost lumpy in appearance, and around the anterior end of the mantle they almost merge into one band.  In the pinkish median region there is a broken white band running from in front of the rhinophores back to the gill pocket. The rhinophore club is deep purple, while the stalk is translucent pink. The gills are translucent clear with deep purple tips.

The body and foot is an opaque milky blue with a deep purplish black border to the foot.  It grows to at least 12 mm in length.

Although not immediately obvious, this species has many colour similarities to Mexichromis antonii, which has the same 5-banded mantle margin, with the inner 'milky' coloured almost merging anteriorly and the colourless gills with purple tips.

• Bertsch,H (1976) A new species of Chromodoris (Opisthobranchia: Nudibranchia) from tropical west America. The Veliger, 19(2): 156-158.
• Bertsch, H. (1977) The Chromodoridinae nudibranchs from the Pacific coast of America. Part I. Investigative methods and supra-specific taxomony. The Veliger, 20(2): 107-118.
• Bertsch, H. (1978) The Chromodoridinae nudibranchs from the Pacific coast of America. Part III. The Genera Chromolaichma and Mexichromis. The Veliger, 21(1): 70-86.
• Camacho-Garcia, Y., Gosliner, T. M., and Valdés, A. (2005)  Field Guide to the Sea Slugs of tropical Eastern Pacific. San Francisco, California Academy of Sciences.  1-129.
• Marcus, Er. & Marcus, Ev (1967) American opisthobranch mollusks. Part 1, Tropical American opisthobranchs. Studies Tropical Oceanography, Miami 6(1-2): 1-137. (Figs 1-150, Pl.1, figs 1-9)
• Rudman, W.B. (1984) The Chromodorididae (Opisthobranchia: Mollusca) of the Indo-West Pacific: a review of the genera. Zoological Journal of the Linnean Society, 81: 115-273.

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