Akanthophoreus

Akanthophoreus sp.KK#1

Figure 11–12

Material. 1 non-ovigerous female, station TD-4, 39°27.08’– 39°29.15’N 143°37.79’– 143°38.52’E, 3272– 3146 metres, 26 September 2001.

emarks. A long (4.6 mm) and very slender species of Akanthophoreus (even allowing for the relaxedextended condition of the single specimen), as the pereonites 2–5 are all as long as, or almost as long as, broad (Fig. 11 A). Other potentially diagnostic characters (in combination) are the long antennules (Fig. 11 C), slight crenulation on anterior-lateral margins of the carapace and pereonites (Fig. 11 A), strong pleonal ventral processes (Fig. 11 B), crenulate dorsal margin of distal cheliped propodus and dactylus and slight crenulation of carpus near ventral setal insertion (Fig. 11 D). The cheliped carpal shield is moderately developed.

The affinities of this species are uncertain, but it approaches Akanthophoreus multiserratus in general morphology but lacks the crenulate/ribbed basis of pereopods 4–6 (cf. undulatus) that are present in that species and the more extensive cheliped crenulation/nodules. The Antarctic species Paraleptognathia multiserratoides Guerrero-Kommritz, 2004 is also very similar, but the ventral margin of the cheliped propodus and disto-ventral margin of the carpus are also crenulate. A possible species-group is evident here.

Distribution. Japan Trench, 3146–3272 metres.