Procampodelphys gen. nov.

Diagnosis. Body caterpillar-like, consisting of cephalosome, cylindrical metasome, and small urosome. Cephalosome indistinctly defined from trunk. Metasome unsegmented or bearing constriction or wrinkle between first pedigerous somite and remaining part of metasome. Free urosome small, 3-segmented. Caudal rami small, armed with small caudal setae. Rostrum well-developed. Antennule short, 1- or 2-segmented.Antenna 3-segmented with unsegmented endopod bearing small terminal claw. Labrum simple. Mandible consisting of coxa with pectinate gnathobase and biramous palp, armed with 1 setaon basis, 4 setaeon exopod, 5 setaeon endopod. Maxillule consisting of precoxa and lobate palp; armed with 3 or 4 setae on precoxal arthrite and 5 or 6 setae on palp. Maxilla 2- or 3-segmented; armedwith 2 setaeon first segment and 4 setaeon distal segments. Maxilliped unsegmented with 5 to 7 setae. Leg 1 biramous with unsegmented protopod; rami fused with, or incompletely articulated from, protopod. Legs 2–4 present or absent; if present, legs 2 and 3 similarto leg 1, and leg 4 biramous or uniramous. Rami of these legs unarmed or armed with small setae. Leg 5 absent or represented by small seta. Leg 6 absent.

Type species. Procampodelphys bidentatus gen. et sp. nov. by original designation.

Other included species. Procampodelphys nodosus gen. etsp. nov., P. unipedatus gen. etsp. nov., P. diplosomae (Illg & Dudley, 1961) comb. nov. (originally Prophioseides diplosomae), and P. biramus (Stock, 1967) comb. nov. (originally Prophioseides biramus).

Etymology. The generic name Procampodelphys is a combination of the Greek prefix pro (=before) and Campodelphys,anewgenusestablishedbelowinthis work. It refers to the plesiomorphic condition of the cephalic appendages exhibited by species of Procampodelphys relative to those of Campodelphys gen. nov. Gender masculine.

Remarks. Procampodelphys gen. nov. resembles Pholeterides Illg, 1958 and Prophioseides. These three genera have in common a caterpillar-like body and rudimentary legs in the adult female. The genus Pholeterides currently consists of the type species, P. furtiva Illg, 1958 from the Northeastern Pacific (Illg,1958) and P. pilosa Kim & Moon, 2011 from the Northwestern Pacific (Kim & Moon, 2011). In both these species the mandible lacks a coxal gnathobase and is represented by a lobe bearing few setae or a spiniform process, the maxillule also is lobate and armed with 3 or 4 setae, and there are only three pairs of mouthparts, so that either the maxillae or maxillipeds are absent. Thus, by virtue of its more complex and relatively plesiomorphic mouthparts Procampodelphys gen. nov. is readily distinguishable from Pholeterides.

At present the genus Prophioseides comprises six nominal species, P. abdominalis (Chatton & Brément, 1911), P. delamarei Illg & Dudley, 1961, P. ampullacea Ooishi, 1972, P. biramus Stock, 1967, P. diplosomae Illg & Dudley, 1961, and P. brevis Stock, 1967. However, these six species do not exhibit a consistent evolutionary trend in terms of the morphology of the mandible. When it was originally established, Chatton & Brément (1911) illustrated the mandible of the type species P. abdominalis as having a denticulate medial margin of the coxal gnathobase, although the teeth are feeble. Prophioseides delamarei and P. ampullacea share a denticulate coxal gnathobase with the type species and are recognized here as members of Prophioseides. We note here that in the redescription of P. abdominalis by Illg & Dudley (1961) the mandible was depicted with a simple, styliform coxal gnathobase, butweconsiderthatthis apparentdifferencein the form of the mandible can be explained by a difference in viewing angle and we regard the original illustration (Chatton & Brément, 1911) as correct. Unlike the type speciesof Prophioseides, P. biramus and P. diplosomae both have a pectinate medial margin bearing numerous fine spinules on the coxal gnathobase of the mandible. In consideration of this major difference in morphology, these two species are placed in Procampodelphys gen. nov.

The remaining species, Prophioseides brevis, is treated as the type species of a new genus (Janius gen. nov.) proposed below.

Key to species of Procampodelphys gen. nov. based on adult females.

1. Palp (outer lobe) of maxillulearmed with 6 setae; maxilliped with 5 setae; legs 2–4 absent .............................................. ............................................ P. unipedatus gen. etsp. nov.

Palp of maxillule armed with 5 or 7 setae; maxilliped with 6 or 7 setae; at least legs 2 and 3 present.......................... 2

2. Palp of maxillule armed with 7 setae; maxilla with more than 6 setae; leg 4 absent .................................................... ............... P. diplosomae (Illg & Dudley, 1961) comb. nov.

Palp of maxillule armed with 5 setae; maxilla with 6 setae; leg 4 present...................................................................... 3

3. Arthrite (inner lobe) of maxillule armed with 3 setae; maxilliped with 7 setae............ P. nodosus gen. et sp. nov. Arthrite of maxillule armed with 4 setae; maxilliped with 6 setae .................................................................................. 4

4. First pedigerous somite with dorsal tubercle; antennule unsegmented; leg 4 biramous ............................................. ................................. P. biramus (Stock, 1967) comb. nov.

First pedigeroussomite without dorsal tubercle; antennule 2-segmented; leg 4 represented by a lobe........................... ............................................. P. bidentatus gen. etsp. nov.