Normanion whoi, Stoddart & Lowry, 2010

Stoddart, H. E. & Lowry, J. K., 2010, The family Opisidae (Crustacea: Amphipoda: Lysianassoidea) in Australasian waters, Zootaxa 2479 (1), pp. 22-38 : 27-28

Normanion whoi sp. nov.

( Figs 3 , 4 )

Type material. HOLOTYPE, female, 3.2 mm, MV J61508 , south of Point Hicks , Victoria, Australia, 38°17.70'S 149°11.30'E, 400 m, coarse sand, gravel and mud with many sponges, WHOI epibenthic sled, 24 July 1986, M.F. Gomon et al., RV Franklin, stn SLOPE 40 . PARATYPES: 1 female, MV J14615 and 2 females, AM P.81162, same data as holotype ; 1 female, MV J61509 , off Freycinet Peninsula , Tasmania, Australia, 41°58.60'S 148°38.80'E, 500 m, coarse shell, WHOI epibenthic sled, 27 July 1986, M.F. Gomon et al., RV Franklin, stn SLOPE 47 .

Type locality. South of Point Hicks , Victoria, Australia, 38°17.70'S 149°11.30'E, 400 m depth .

Etymology. The species is named for the epibenthic sled, WHOI, developed at the Woods Hole Oceanographic Institute, Massachusetts, USA.

Diagnostic description. Antenna 1 callynophore present. Eyes present. Mouthpart bundle subconical. Mandible left incisor with strongly convex margin, smooth, right with slightly convex margin, smooth; lacinia mobilis absent; molar present, setose; palp attached midway, article 2 longer than article 3. Maxilla 1 outer plate with 11 setal teeth in an 8/3 crown arrangement, outer row with cusps in 1 row; palp apical margin serrate, with apical robust setae. Maxilliped palp 4-articulate, article 4 vestigial. Gnathopod 1 weakly chelate; ischium long; carpus posterior margin not produced, curved; propodus subovate, proximal margin produced into strong posteroproximal lobe, palm serrate, posterodistal corner produced into a short acute spine with 3 robust setae. Gnathopod 2 minutely chelate; carpus longer than propodus (about 1.5x); palm obtuse. Pereopod 4 coxa posteroproximal excavation large. Pereopods 5–7 basis with smooth posterior margin; [dactylus not known]. Epimeron 3 posterior margin smooth, posteroventral corner broadly rounded. [Uropod 3 unknown.] Telson about as long as broad, entire, distally emarginate, without dorsal robust setae.

Male not known.

Remarks. Unfortunately all specimens lack the distal articles of pereopods 5–7 and uropod 3. Normanion whoi is similar to N. amblyops , N. abyssi and N. hipposideros in having a vestigial article 4 on the maxillipedal palp. It differs from N. amblyops and N. abyssi in its strongly serrate gnathopod 1 palm and from N. hipposideros in having 11 setal teeth on maxilla 1 outer plate, each with only one set of cusps, and a weakly chelate gnathopod 1.

It is interesting to note that the female MV J14615 has the right gnathopod 1 extended and rotated between merus and carpus so that the propodus is inverted as in species of Trischizostoma which are parasitic on fishes. The left gnathopod 1 is tucked in under the coxae and is not inverted.

Distribution. South-eastern Australia; 400–500 m depth.

Figures

FIGURE 3. Normanion whoi sp. nov. Holotype female, MV J61508. *A1, A2 paratype female, AM P.81162. Scales represent 0.1 mm.

FIGURE 4. Normanion whoi sp. nov. Holotype female, MV 61508. Scales represent 0.1 mm.