Paranarthrura vitjazi Kudinova-Pasternak 1970

Paranarthrura vitjazi Kudinova-Pasternak, 1970

Figures 10–13

Material examined. Neotype, non-ovigerous female ((KMNH IvR 500.167), station XR12, 41°37.67’– 41°37.08’N, 146°54.19’– 146°52.72’E. 5473–5484 metres, 22–23 September 2001. 1 non-ovigerous female (dissected; KMNH IvR 500.168), 1 male (dissected; KMNH IvR 500.169), 3 females, 3 males, 4 mancae (KMNH IvR 500.170), same locality. 3 non-ovigerous females, 1 male (KMNH IvR 500.171), station TD-8, 39°15.54’– 39°17.01’N, 144°45.37’– 144°42.46’E. 5762–5733 metres, 29 September 2002. 1 non-ovigerous female (KMNH IvR 500.172), station XR-7, 42°12.87’– 42°12.10’N 145°33.93’– 145°32.05’E, 3853–3858 metres, 17 September 2001.

Diagnosis (modified from Kudinova-Pasternak 1970), female. Carapace in dorsal view with smooth lateral edges; longer than wide; longer than pereonites 1 and 2 combined. Pereonite 1 wider than long. Pleonites combined length, only marginally longer than pleotelson. Antennular article 1 as long as rest of antennule. Cheliped propodus with inferior margin 1.4 times as long as carpus; fixed finger and apex of dactylus not thickened. Pereopods 1–3 with unguis without dorsal process but with sharp reduction in width at midlength. Pereopod 4–6 dactyli with one or no setae. Pleon narrower than pereon. Uropods about the length of pleotelson, endopod longer than basal article; endopod uniarticulated; exopod process tiny and barely visible.

Description. Adult female.

Body (Fig. 10 A) nine times as long as wide. Lateral shoulders weakly defined.

Cephalothorax. With smooth lateral edges in dorsal view. Longer than wide. Longer than pereonites 1 and 2 combined.

Pereonites. Pereonite 1 wider than long. Pereonites 2 and 6 square. Pereonites 3–5 longer than wide. Pleon. Short (including pleotelson only 0.15 times as long as total body length). All pleonites subequal. Pleotelson almost as long as all pleonites combined, acorn-shaped, apex rounded and covered by dorsal plate.

Antennule (Fig. 10 B). Shorter than carapace, with four articles. Article 1 as long as rest of antennule combined, with three distal setae. Article 2 less than twice as long as article 3, with two distal setae. Article 3 shorter than other articles, with two distal setae. Article 4 shorter than article 2, with four simple distal setae and one aesthetasc.

Antenna (Fig. 10 C). With five articles, 0.8 times as long as antennule. Article 1 longer than article 2, naked. Article 2 shorter than article 4, with one dorsodistal seta. Article 3 longer than other articles, with two distal setae. Article 4 shorter than article 1, naked. Article 5 minute, with two long setae and one aesthetasc.

Mouthparts. Labrum (Fig. 10 D) setose. Mandibular molar indistinct and membranous. Left mandible (Fig. 10 E) lacinia mobilis shorter than incisor; incisor broad with three denticles. Right mandible (Fig. 10 F) incisor blunt. Labium (Fig. 10 G) lobes rounded and setose. Maxillule (Fig. 10 H) endite with nine spiniform distal setae; palp longer than endite, with two long terminal setae. Maxilla (Fig. 10 I) small, tip pointed. Maxilliped (Fig. 10 J) endites with medial process and one seta. Palp (twisted during dissection) article 1 naked, article 2 and 3 with three setae on inner margin, article 4 only 0.5 times as wide as article 3, with five setae. Epignath (Fig. 10 K) naked, widest at basis.

Cheliped (Fig. 10 L). Pseudocoxa wider than and more than two times as long as basis. Basis naked. Merus prominent, with one medial seta. Carpus shorter than propodus including fixed finger, with two dorsal and two ventral setae. Propodus as long as pseudocoxa. Fixed finger with one ventral seta and three setae on inner margin. Dactylus as long as fixed finger.

Pereopod 1 (Fig. 11 A). Coxa rounded and naked. Basis as long as the three succeeding articles combined, naked. Ischium with one simple seta. Merus more than half as long as carpus, widening distally, with two simple setae. Carpus half as long as basis, with three distal setae. Propodus marginally longer than carpus, with two simple and one spiniform distal setae. Dactylus and unguis combined shorter than propodus and not fused.

Pereopods 2–3 (Fig. 11 B,C). As pereopod 1 except: propodus with only one spiniform seta.

Pereopod 4 (Fig. 11 D) Basis longer than the three succeeding articles combined, naked. Ischium with one seta. Merus more than half as long as carpus, widening distally, and with two spiniform setae. Carpus shorter than half as long as basis, with one simple and two spiniform setae. Propodus longer than carpus, with three spiniform setae and dorsal. Dactylus and unguis combined longer than propodus, not fused, and unguis without decline in width at midlength.

Pereopod 5 (Fig. 11 E). As pereopod 4 except: basis with two setulate setae. Ischium with two setae.

Pereopod 6 (Fig. 11 F). As pereopod 4 except: ischium with two setae. Carpus with one simple and three spiniform setae. Propodus with four distal spiniform setae.

Pleopods not present in females.

Families Anarthruridae Lang, 1971, Colletteidae Larsen & Wilson, 2002, and Leptognathiidae Sieg, 1976

Uropod (Fig. 10 M). Marginally shorter than pleotelson. Basal article naked, about one third as long as endopod. Exopodal spur reduced and little more than a blunt process with two setae. Endopod uniarticulated, with one subdistal and two–four distal setae.

Description of adult male (where different from female).

Body (Fig. 12 A). Pleon as wide as pereon and pleotelson.

Antennule (Fig. 12 B). Thicker than that of female. Article 1 shorter than rest of antennule. Article 4 longer than in female.

Cheliped (Fig. 12 L). With pseudocoxa even more prominent than in female.

Pereopods (Fig. 13 A–F). Identical to those of the female except for the odd setae.

Pleopods (Fig. 13 G). All pairs subequal, not coalesced, with simple setae only.

Uropod (Fig. 13 H). Apparently more setose than in female.

Remarks. This species was originally very poorly described; only the antennae, molar, cheliped and uropods were described/illustrated (Kudinova-Pasternak 1970). To make things worse, the type material is reported lost (pers. comm. M. Błażewicz-Paszkowycz). The new material from the type locality has made a full redescription possible, for both male and female genders. Paranarthrura vitjazi is fairly easily diagnosed by the short pleonites, the uniarticulated uropodal endopod and tiny blunt exopod process.