Micromelo undata (Bruguière, 1792) [Bulla]

Click the thumbnail photos to enhance!

Micromelo undata is characterized by a thinly calcified shell with wavy red/brown lines (as the specific name undata suggest, it is a Latin word meaning wavy) and large colourful body. It feeds on cirratulinid Polychaeta worms.
There is still some discussion on the correct name:
Micromelo undata, Micromelo undatus or Micromelo undatum
Dr. Richard Willan writes at the  Sea Slug Forum 
"The name Micromelo is feminine and, because the specific name is an adjective meaning wavy, it must agree with the gender of the genus. So the correct name is Micromelo undata (Bruguiere, 1792)."
according to WoRMS - World Register of Marine Species
is the accepted name Micromelo undatus (Bruguière, 1792)
IPN uses the name Micromelo undatum (Bruguière, 1792) at page 19:
Gosliner, Terrence M., David W. Behrens & Ángel Valdés. 2008. Indo-Pacific Nudibranchs and Sea Slugs. Sea Challengers Natural History Books.
Gig Harbor, Washington. 426pp.
NUDIPIXEL uses the name Micromelo undata (Bruguière, 1792).
This species is in older publications placed in the Order Cephalaspidea, according to Bouchet & Rocroi (2005) are
the superfamilies: Acteonoidea and Ringiculoidea no more in the Order Cephalaspidea in the Subclass: OPISTHOBRANCHIA, but
in the new informal group Lower Heterobranchia (= Allogastropoda) Haszprunar, 1985.
Bouchet P., Rocroi J.-P., Frýda J., Hausdorf B., Ponder W., Valdés Á. & Warén A. (2005). "Classification and nomenclator of gastropod families".
Malacologia: International Journal of Malacology (Hackenheim, Germany: ConchBooks) 47 (1-2): 1-397.
ISBN 3925919724. ISSN 0076-2997.
More informations on Micromelo undata are at Bill Rudman's Sea Slug Forum!
How to cite:
Köhler, E. (2016), published 27 July 2016, Micromelo undata (Bruguière, 1792)
available from http://www.Philippine-Sea-Slugs.com/Heterobranchia/Micromelo_undata.htm