Enterognathus inabai Ohtsuka, Shimomura & Kitazawa 2012

Enterognathus inabai — вид щелепоногих ракоподібних ряду Cyclopoida. Вид поширений у Японському морі. Паразитує на морських ліліях роду Lamprometra , відомі на глибині 40-50 м. Описані лише самиці, максимальна довжина тіла сягає 5,2 мм. Самці невідомі. Вид названий на честь професора Акіхіко Ініба (університет Хіросіми), який вивчав фауну Японського моря.

Female. Body (Fig. 1A) 5.17 mm long, from anterior tip of rostrum to caudal ramus excluding caudal setae, flattened dorso-ventrally, weakly sclerotized, elongate, but tagmosis clearly defined. Cephalosome ca. 1.2 times wider than long; rostrum (Fig. 1B) defined basally, slightly asymmetrical with 2 pairs of hair-sensilla. First to fifth pedigerous somites about 2.5, 1.6, 1.6, 1.2 and 1.7 times wider than long, respectively; fourth pedigerous somite (slightly twisted toward right side in Fig. 1A) exhibiting maximum width; genital double-somite protruded laterally into triangular process; each genital opening (Fig. 1C) covered with operculum representing leg 6 and armed with minute seta; single copulatory pore possibly located on posteroventral surface as in Enterognathus comatulae (see Fig. 4 in Giesbrecht 1900) and Parenterognathus troglodytes (see Fig. 2M in Ohtsuka et al. 2010), but not clearly seen due to damage. First post-genital somite expanded anterolaterally; second and third (anal) free abdominal somites nearly as long as wide. Caudal rami (Fig. 1A, D) symmetrical, slightly curved outward, about 3.7 times as long as wide; caudal setae I to III rudimentary, IV slender, V thick and VI positioned subterminally. Antennule (Fig. 1E) short, 3-segmented; first segment unarmed; second segment longest, with 10 short setae; third segment with 11 setae. Antenna (Fig. 1F) short, 2-segmented; basal segment long, unarmed; distal segment short, with 1 short seta and 1 rudimentary seta at tip. Mandible (Fig. 1G) with heavily sclerotized gnathobase; cutting edge with large and dorsal and ventral teeth and 2 smaller teeth; palp represented by simple seta. Labrum (Fig. 1H) with concave posterior margin. Paragnath (Fig. 1H) large, expanded distally, hirsute along inner margin. Maxillule (Fig. 1I) 2-segmented; proximal segment bearing praecoxal endite armed with 1 spiniform element and short seta distally; distal segment with 1 subterminal seta, 1 distal spine and row of spinules; other member of pair (Fig. 1J) abnormal, bilobed, with 2 spiniform elements and seta. Maxillae (Fig. 1K) connected by intercoxal sclerite; syncoxa with triangular process and single endite furnished with distal seta; basis with stout spine terminally; endopod represented by rudimentary seta. Maxilliped absent. Legs 1–4 biramous, with 2-segmented rami. Legs 1 and 2–4 ventrally and ventrolaterally positioned on pediger, respectively. Leg 1 (Fig. 2A, B) with minute outer setule on coxa; basis furnished with developed naked outer seta basally; first exopodal segment with 3 setules and longer distal setal element on outer margin, second segment sickle-shaped, abruptly curved outward, terminated at round tip, with naked seta at outer midlength; first endopodal segment broad, with 2 rounded projections, second segment bulbous, with minute seta terminally. Legs 2–4 (Fig. 2C–H) similar to each other, but gradually increasing in size; first exopodal segment bearing 3 or 2 setules/setal elements in legs 2 and 3–4, respectively; second exopodal segment curved outward, sharply pointed, with minute setule midway or subterminally; first endopodal segment produced outward into triangular process; second endopodal segment spatulate, unarmed. Leg 5 (Fig. 1A) 1-segmented, with 1 basal and 2 terminal, developed setae and 1 minute seta subterminally. Leg 6 (Fig. 1C) represented by genital operculum bearing minute seta. Male unknown.