This species has been observed on Reunion, Mauritius, Mayotte and Madagascar Islands

Order : Nudibranchia Suborder : Euctenidiacea Superfamily : Doridoidea Family : Chromodorididae Distribution : Japon, Indonesia, Red Sea and now Reunion Island. Maximal size : 30 mm Abundance : Seldom if ever on the fore reef zone Species characteristics : The body varying in ground colour from dirty yellow to dirty beige. It is covered with single and compound tipped tubercles, and these are creamy white; the terminal nipple of each is purple. The creamy marginal band contains smaller single purple-tipped tubercles and patches of burnt orange. The rhinophore club, distal quarter to half of the gills, tubercles, and the edge of the foot are a deep purple.
	Showing species characteristics...	Photo Philippe Cao Van Réunion, "la pierre au prefet" at Saint Gilles, 20 m, 12 November 2006, size 30-40 mm

See more about : Sightening and mating periods

Remarks :

Identification confirmed by Nathalie Yonow
    Synonymous (according worms) : No synonymous

Bibliographic data :

There is a disagreement between specialist about this species, for some people there are two species one with a yellow margin (M. katalexis) and one other with a purple one ( M. multituberculata). For other there is only one species with polymorphism and in that case the name is M. multituberculata.
    “Katalexis" is Greek for end or terminaison, referring to the tips of the tubercles, gills, and rhinophores which are coloured purple.
    The body is solid and domed, varying in ground colour from dirty yellow to dirty beige, but the beige mantle colour is absent at the bases of the tubercles and in a band around the margin.
    The rims of the rhinophore and gill sheaths and the rachis of the gills are creamy white. The rim of the gills has small single tubercles around the opening.
    The 9-11 gills are arranged in a ring and held upright in a tulip-shaped bell.
    These nudibranchs are feeding on a sponge, which Dr P.R. Bergquist has identified as a species of Euryspongia (Dysideidae).
    - M. mariei (Western Pacific and perhaps Indian Ocean) and M. cf mariei were very similar but is only slightly pustular (reddish purple-tipped rounded papillae on its back).
      - It is similar in colour to M. festiva ( Australia and Japan) but M. festiva have differences in the radula structure, and the purple spots are either flat or on a slightly rounded bump.
      - It is also similar in colour to M. macropus (Australia), with perpendicularly elongated patches of orange around the edge.

References :

Bill Rudman Sea slug site : Sea Slug Forum : Mexichromis multituberculata
   Nudipixel Mexichromis multituberculata

Publications :

Baba, K. (1953). Three new species and two new records of the genus Glossodoris from Japan . Publications of the Seto Marine Biological Laboratory, 3 : 205-211.
    Rudman, W.B., Darvell, B.W. (1990) Opisthobranch Molluscs of Hong Kong : Part 1. Nudibranch Families; Goniodorididae, Onchidorididae, Triophidae, Gymnodorididae, Chromodorididae. Asian Marine Biology, 7 : 31-79.
    Yonow, N. (2001) Results of the Rumphius Biohistorical Expedition to Ambon (1990). Part 11. Doridacea of the families Chromodorididae and Hexabranchidae (Mollusca, Gastropoda, Opisthobranchia, Nudibranchia), including additional Moluccan material. Zoologische Mededelingen uitgegeven Rijks Museum van Natuurlijke Historie te Leiden 75: 1-50.

Other photos of Mexichromis katalexis :

Philippe Cao Van Réunion, Saint Gilles, 20 m, 12 November 2006, size 30-40 mm “Katalexis" is Greek for end or terminaison, referring to the tips of the tubercles, gills, and rhinophores which are coloured purple.	The 9-11 gills are arranged in a ring and held upright in a tulip-shaped bell.

Emmanuelle Aigle Mayotte, bandrele, 6 December 2009, size : 30 mm Always a specimen with a yellow (a) incomplete margin... The gills are retracted (b) in this specimen

Fabrice Schubert Mayotte, 8 m, 4 February 2010 A specimen with a yellow (a) complete margin... The gills are retracted (b) in this specimen The edge of the foot (c) are a deep purple.

Pierre Peries Mauritius, 25 m, 28 Jully 2011, size : 35 mm Always a specimen with a yellow/orange incomplete margin...

Mayotte, Mexichromis katalexis (= multituberculata ?), at Dzaoudzi, by Philibert Bidgrain

Madagascar, Mexichromis katalesis, at Nosy Bé, by Alain-Benoît Rassat