Paraleptostylis vityazi, Vassilenko, Stella & Tzareva, Ludmila, 2004

Vassilenko, Stella & Tzareva, Ludmila, 2004, New Cumacea species (Malacostraca, Peracarida) from the deepwater area of the Sea of Japan (Collections of the 52 Cruise by the R / V « Vityaz », 1972), Zootaxa 702, pp. 1-16 : 6-9

Paraleptostylis vityazi sp. nov.

( FIGS. 3–4 )

Material examined: Holotype is a female 5.5 mm length with rudimentary oostegites, kept

in the collection of Zoological Institute, ( ZIN ­ 1/88370), R/V “Vityaz”, 52nd cruise, sta. 6649; 7.06.1972, Sea of Japan, 42º37´8´´N, 134º18´5´´E, depth 1130 m, substrate: pelitic silt, “SIGSBY” trawl.

Paratypes: ( ZIN ­ 2/88371) 1 female 6.4 mm length with rudimentary oostegites, same locality; ( ZIN ­ 3/88372) 3 females 4.7–5.0 mm length with eggs, 3 females 4.3–5.1 mm length with rudimentary oostegites, 1 mature male with pleon torn away (peduncle of antenna I is reinforced, antenna II are elongated), 4 males of 4–4.5 mm length and 4 juveniles of 3.3–4.0 mm length – R/V “Vityaz”, 52nd cruise, sta. 6667; 21.06.1972, Sea of Japan, 37º43´7´´N, 136º20´2´´E, depth 209 m, substrate: watery silt of brown color.

Diagnosis: Carapace bulging widened in middle part, rather sharply narrowing anteriorly. Pseudorosrum long and sharp. Pereopod I very long, protruding beyond carapace edge by 2/3 of its length; basis of pereopod I comparatively short and curved, length equal to that of carpus; propodus longest, considerably exceeding carpus length, dactylus short, three times shorter than propodus. Pereopod II significantly shorter than pereopod I, carpus noticeably exceeding length of propodus, dactylus longest and slightly shorter than two preceding ones together. Uropodal peduncle 2.3 times longer than telson.

Description of the holotype: Female. Body ( Fig. 3 , A) weakly calciferous, tegument semitransparent. Carapace surface is smooth. Carapace bulging on each side, elongated, length slightly bigger than width, widened in middle, rather sharply narrowing anteriorly; pseudorostrum long and sharp. Antero­lateral angles not produced, lower edge of carapace dentate, denticles having a form of rectangular lugs with rounded corners.

Abdomen without telson slightly shorter than cephalothorax; postero­lateral angles of I–V abdominal segments well produced. Fifth abdominal segment longest; length slightly shorter than that of two preceding abdominal segments together.

Telson ( Fig. 3 , D) shorter than last abdominal segment; sharply narrowing in distal part, pre­anal and post­anal parts approximately similar in length. Telson bearing three spines on each lateral side of its narrowed part, and on the end – two long spines and a very little one.

Basis of maxilliped III ( Fig. 4 , E) slender, highly curved, length exceeding that of other five articles combined; outer distal edge of the basal article bearing three long plumose setae.

Pereopod I ( Fig. 4 , A) very long, protruding beyond carapace edge by 2/3 of its length, considerably longer than other pereopods; its carpus and propodus unusually thin and long. Basis of pereopod I comparatively short and curved, length equal to that of carpus, noticeably shorter than propodus; propodus longest, considerably exceeding carpus length, dactylus short, three times shorter than propodus, and slightly narrowing to the distal end.

Pereopod II ( Fig. 4 , C) significantly shorter than pereopod I, carpus noticeably exceeding length of propodus, and bearing one long stout setae and two thin setae on outer distal corner; dactylus longest and slightly shorter than two preceding ones together, bearing several thin long setae on each side, and two terminal setae, one of which is very long.

Pereopods III and IV ( Fig. 4 , D, B) shortened, baculiform, and similar in construction with small rudimentary double­articled exopodite.

Pereopods V without exopodite.

Uropods ( Fig. 3 , D) long, almost equal to length of last three abdominal segments and telson length combined; uropodal peduncle 2 times longer than VI abdominal segment, bearing 12–13 spines along inner edge; uropodal branches long, they longer than a half length of peduncle; outer branch slightly shorter than inner one, consisting of two articles: short basal and very long distal, which bears two long and two relatively short apical setae; inner branch consisting of three articles: basal article longer than articles 2 and 3 combined, terminal article bearing two long and one short setae.

Male. Males without pleopods. Mature male with flat carapace ( Fig. 3 , B) bearing one dentate lateral ridge on each side, denticles on ridges have form of small rectangular lugs, same ridges developed on carapace back: beginning from pseudorostrum and fringe lobe area, spreading backwards up to middle of carapace; antenna I ( Fig. 3 , C) biramous, with reinforced articles of the peduncle, with thick bunch of hairs on last article of peduncle, main flagellum consist of five articles, additional flagellum – of three articles with thin terminal setae; antenna II elongate, exceeding carapace length; exopodites normally developed on pereopods I–IV. In young males lateral and spinal ridges not developed; antenna I biramous, with reinforced peduncle articles, but without thick bunch of thin hairs on terminal article of peduncle, but with several thin hairs: main flagellum with five articles, and accessory flagella with three articles; telson length considerably greater than that of VI abdominal segment.

Remarks. This new species Paraleptostylis vityazi certainly belongs to the Paraleptostylis genus (Vassilenko, 1990). The new species is close to Paraleptostylis arctica (Vassilenko, 1990) , but differs from it by the larger sizes of females (up to 6.4 mm), by longer pereopods I and II, uropods, by a different ratios of articles length of pereopods I and II; and by a different ratios of the length of uropods and telson.

Figures

FIGURE 3. Paraleptostylis vityazi sp. nov. A — adult female, lateral view; B ­ carapace, adult male, dorsal view; C ­ antenna I, male; D — telson and uropods, dorsal view.

FIGURE 4. Paraleptostylis vityazi sp. nov. A — pereopod I; B — pereopod IV; C — pereopod II; D — pereopod III; E — maxilliped III.