Metacrangon jacqueti (A.Milne-Edwards, 1881)

Komai, Tomoyuki, 2012, 3468, Zootaxa 3468, pp. 1-77 : 11

Metacrangon jacqueti species group

Diagnosis. Carapace with two greatly unequal middorsal teeth; anterior tooth strong, styliform, obliquely erect, usually overlapping rostrum; posterior tooth usually hooked; branchial carina distinct. First and second abdominal pleura each with blunt to sharp ventral tooth. Third and fourth pleura each with blunt to sharp tooth at anteroventral angle (tooth on fourth somite sometimes obtuse). Fourth pereopods relatively slender for genus. Dactyli of fourth and fifth pereopods subspatulate, sometimes bearing stiff setae on margins.

Composition. Metacrangon agassizi , M. bahamondei , M. bythos n. sp., M. bellmarleyi , M. crosnieri , M. hauna , M. hikurangi , M. jacqueti , M. knoxi , M. ochotensis , M. procax , M. punctata n. sp., M. rau , M. similis , M. spinidorsalis , M. spinosissima and M. teina .

Remarks. This species group can be further divided in two subgroups on the basis of the structure of the orbit and the setation of the dactyli of the fourth and fifth pereopods. The following 11 species are characterized by the presence of orbital cleft and the presence of stiff marginal setae on the dactyli of the posterior two pereopods: M. agassizi , M. bahamondei , M. bellmerleyi , M. bythos , M. crosnieri , M. jacqueti , M. ochotensis , M. procax , M. punctata n. sp., M. similis , and M. spinidorsalis . On the other hand, M. hauna , M. hikurangi , M. knoxi , M. rau and M. teina , all known from waters around New Zealand, are characterized by the lack of an orbital cleft and the naked dactyli of the posterior two pereopods. In this study, M. spinosissima (the following material has been examined: Albatross, stn 4479, Santa Cruz Island, Monterey, California, 59 m, 16 May 1904, 1 female cl 9.5 mm, USNM 52514) is provisionally assigned to this group on the basis of the possession of ventral teeth on the first three abdominal pleura, though it is distinctive in having two ventral teeth on each of these abdominal pleura. In M. spinosissima , furthermore, the orbital margin has a distinct cleft; and the ambulatory dactyli are glabrous on their margins.