Proposal of new genus for Asterocheres mucronipes Stock, 1960 (Copepoda, Siphonostomatoida, Asterocheridae), an associate of the scleractinian coral Astroides calycularis (Pallas, 1766) in the Strait of Gibraltar

A new genus of Asterocheridae (Copepoda: Siphonostomatoida) Stockmyzon  gen. nov. is proposed for Asterocheres mucronipes Stock, 1960, and a new, previously misidentified, species Stockmyzon   crassus  sp. nov. from sponge washings in Mauritius. Stockmyzon gen. nov. can be differentiated from other asterocherid genera by the annulated mandibular stylet, the atrophied maxillulary palp with large modified lateral seta, the presence of beak‐shaped processes on the endopods of legs 1, and the transformation of the outer spine on the first exopodal segment of leg 4 into a seta. Stockmyzon mucronipes comb. nov. is the fourth copepod known to utilize the hermatypic coral Astroides calycularis (Pallas, 1766) as its host in the Strait of Gibraltar. A reinterpretation of the original description of Asterocheres stimulans Giesbrecht, 1897 from Naples revealed that it was based on an amalgam of two diffent species, the male being conspecific with S. mucronipes ; the illustrated female is formally designated here as the lectotype of A. stimulans . The current symbiotic relationship between S. mucronipes and the gorgonian Eunicella singularis (Esper, 1794) along the French mediterranean coast is reviewed in the light of potential host switching, following the extinction of A. calycularis in the north‐western Mediterranean, north of 40°N, during the late Sicilian regression (Rissian age), about 238 000–225 000 years ago. © 2008 The Linnean Society of London, Zoological Journal of the Linnean Society , 2008, 152 , 635–653.