Robustochelia virilis, Wiak, Piotr Jó Ż & Błażewicz-Paszkowycz, Magdalena, 2007

Wiak, Piotr Jó Ż & Błażewicz-Paszkowycz, Magdalena, 2007, New records of two rare genera, Monstrotanais Kudinova-Pasternak, 1981 and Robustochelia Kudinova-Pasternak, 1983 (Tanaidacea: Crustacea), Zootaxa 1505, pp. 19-35 : 31-34

Robustochelia virilis n. sp.

( Figs 7–9 )

Diagnosis: Pereonites 2–6 wider than long. Pereopods 1–3 propodus setae almost reaching end of unguis. Pereopods 4–6 propodus elongated (over 4 times as long as wide).

Material examined: Holotype male (dissected on slides), USNM 1100228, Eltanin Sta 724, 54º05'– 54º04'S, 33º43'– 33º37'W, depth 2714–2727 m.

Etymology: virilis [Lat.] = male, masculine, manly.

Description: Male, body length 2.1 mm ( Fig. 7 A). Body: carapace almost twice as long as pereonite-1; pereonite-1 shortest, 0.7 times as long as pereonite-2; pereonites 3, 4 and 5 of equal length; pereonite-6 0.7 times as long as pereonite-5; pleonites equal, each pleonite half as long as pereonite-6; pleotelson as long as pereonite-5; length of pleon 0.3 times body length.

Antennule ( Fig. 8 A): 5-articled; article-1 massive, 1.5 times as long as wide, with three bipinnate setae subdistally and one simple and four bipinnate setae distally; article-2 wider than long, 0.5 times as long as article-1, with three bipinnate and one simple setae subdistally and one short, simple seta distally; article-3 0.75 times as long as article-2, with three bipinnate, one setulated and one simple setae distally; article-4 narrow, 1.7 times as long as article-3, with one simple seta and one aesthetasc distally; article-5 shortest, as long as wide, with four (three long and one short) simple setae terminally.

Antenna ( Fig. 8 B): Article-1 short; article-2 twice as long as article-3, with one simple seta distally; article-3 as long as wide, 0.4 times as long as article-4, with one short, simple seta distally; article-4 longest, 1.6 times as long as article-5, with three simple setae distally; article-5 with one simple seta distally; article-6 shortest, one third as long as article-5, with five (one short and four long) simple setae terminally.

Mouth parts: Labrum ( Fig. 8 C) hood-shaped, covered by numerous minute setae. Mandible ( Fig. 8 D) molar process poorly developed, pointed, bent downward, lacinia mobilis poorly developed. Maxillule ( Fig. 8 E) with seven spiniform setae and numerous short, simple setae terminally. Palp lost during dissection. Maxilla lost during dissection. Labium ( Fig. 8 F) 2-lobed; inner lobe with numerous, minute setae distally; outer lobe with minute teeth on outer margin. Maxilliped ( Fig. 8 G): bases fused, as long as wide, with one short, distal seta; endite with one short and one long, simple setae distally; palp article-1 naked, article-2 with three (one long and two short) setae distally and one on outer margin, article-3 with three long, simple setae on inner margin, article-4 slender, with one seta on inner margin and four seta terminally.

Cheliped ( Fig. 8 H): Basis 1.5 times as long as wide; merus 0.4 times as long as basis, with ventral seta; carpus 1.75 times as long as merus, with two ventral setae and one dorsal seta; propodus about as long as broad, propodus and fixed finger as long as basis, propodus ventral margin with well calcified carina and two long setae, inner side near the dactylus insertion with three simple setae, inner margin of fixed finger with bifurcated tooth directing frontally; dactylus 0.5 times as long as propodus.

Pereopod-1 ( Fig. 9 A): Of walking type; coxa with simple seta; basis subequal to carpus and propodus combined, almost four times as long as wide; ischium with simple seta ventrally; merus equal in length to carpus, with simple seta distally; carpus with four simple, distal setae; propodus about 1.7 times as long as carpus, with four setae distally, one reaching end of unguis; dactylus 0.3 times as long as propodus, shorter than unguis; unguis as long as merus.

Pereopod-2 ( Fig. 9 B): Of walking type; basis as long as merus, carpus and propodus combined, five times as long as wide; ischium with one simple seta; merus two thirds as long as carpus, with two setae distally; carpus about 0.6 times as long as propodus, with four simple, distal setae; propodus with four distal setae, one reaching end of unguis; dactylus 0.5 times as long as unguis.

Pereopod-3 ( Fig. 9 C): Similar to pereopod-2, but basis with one bipinnate seta subdistally.

Pereopod-4 ( Fig. 9 D): Of walking type; basis shorter than combined length of rest of articles, 3.3 times as long as wide, with one bipinnate seta on ventral margin and one bipinnate seta on dorsal margin; ischium with two simple setae; merus 0.25 times as long as basis, with two spiniform setae ventrally; carpus 1.5 times as long as merus, with four spiniform setae distally; propodus 1.6 times as long as carpus, with one bipinnate seta on dorsal margin and two simple setae on ventral margin, one simple seta distally, dorsal margin with small teeth directed distally; dactylus broken.

Pereopod-5 ( Fig. 9 E): Basis as long as ischium, merus and carpus combined, 2.7 times as long as wide, with two bipinnate setae dorsally; ischium with two simple setae; merus 0.35 times as long as basis, with two spiniform setae ventrally; carpus 1.4 times as long as merus, with four spiniform, distal setae; propodus twice as long as merus, with one bipinnate seta dorsally and two simple setae distally; dactylus 0.5 times as long as propodus, with microtrichia; unguis as long as dactylus.

Pereopod-6 ( Fig. 9 F): Coxa with simple seta; basis about as long as carpus and propodus combined, 2.8 times as long as wide; ischium with two simple setae; merus as long as carpus, with two spiniform seta ventrally; carpus 0.6 times as long as propodus, with four spiniform setae distally; propodus with two spiniform and three setulated setae distally; dactylus about 0.6 times as long as carpus, with microtrichia; unguis shorter than dactylus.

Pleopods 1–5 ( Fig. 9 G): Exopod with nine setulated setae on outer margin and one simple seta on inner margin. Endopod with twenty setulated setae.

Uropod ( Fig. 9 H): Endopod 2-articled; proximal article equal in length to exopod, with two bipinnate, distal setae, article-2 little as long as article-1, with one bipinnate and five long, simple setae terminally. Exopod

Figures

FIGURE 7. Robustochelia virilis n. sp. Holotype male. A) Body, lateral; B) Cephalothorax with appendages, ventral. Scale bars equal 0.1 mm.

FIGURE 8. Robustochelia virilis n. sp. Holotype male. A) Antennule; B) Antenna; C) Labrum; D) Left mandible; E) Maxillule; F) Labium; G) Maxilliped; H) Cheliped. Scale bars equal 0.1 mm.

FIGURE 9. Robustochelia virilis n. sp. Holotype, male. A) Pereopod- 1; B) Pereopod- 2; C) Pereopod- 3; D) Pereopod- 4; E) Pereopod- 5; F) Pereopod- 6; G) Pleopod; H) Uropod. Scale bar equals 0.1 mm.