Torquella elegans (Kudinova-Pasternak, 1978) Błażewicz-Paszkowycz, 2007

Błażewicz-Paszkowycz, Magdalena, 2007, Figure 6. Typhlotanais Compactus, Female A In Family Nototanaidae Sieg, 1976 And Typhlotanaidae Sieg, 1984, Zootaxa 1598, pp. 1-141 : 67-71

Torquella elegans (Kudinova-Pasternak, 1978) n. comb.

( Fig. 36–37 )

Typhlotanais elegans: Kudinova-Pasternak (1977 (1978)) 108: 127–130, 131.

Material examined: Holotype Mc- 986, Vitjaz Sta. 7391, 24°06.8'N, 143°47.1'E, depth 6330 m.

Diagnosis: Carapace 1.2 times as long as wide, 2.5 times as long as pereonite-1. Pereonite-2 over twice as long as pereonite-1; pereonite-3 over 1.3 times as long as wide. Antennule article-3 three times as long as article-2. Chela 2.8 times as long as wide. Pereopod-1 merus and carpus little shorter than basis, merus with short setae, propodus with three relatively long simple setae; pereopod-2 propodus with two long setae dorsally, merus with four long setae (just half of carpus), carpus with six long setae just reach half of propodus; pereopods 4–5 propodus with distal seta reaches end of dactylus; pereopods 4–6 with numerous spines around prickly tubercles; pereopod-6 propodus distal setae subequal. Uropod exopod reaching half of endopod distal article.

Complementary description: Female ( Fig. 36K ). Body length 2.2–5.4 mm (according to Kudinova-Pasternak, 1978), 7.4 times as long as wide; carapace little longer than wide, smooth, 15% of body length, narrowing rostrally, rounded laterally, rostrum acute; pereonite-1 twice as wide as long, latero-proximal corners expanded forward. Pereonites 2, 3 and 5 similar size, little longer than wide; pereonite-4 1.3 times as long as wide; pereonite-6 1.3 times as wide as long. Pleon 15% of body length, pleonites 1–5 similar in size; pleotelson rectangular.

Antennule ( Fig. 36A ): Article-1 slender, more than three times as long as wide, with simple and pinnate setae in two groups medially and distally on outer margin and simple proximal seta on inner margin; article-2 with two setae distally, article-3 just three times as long as article-2 with five setae distally.

Antenna ( Fig. 36B ): Article-2 long, three times as long as article-3, with one serrated seta; article-3 with one seta; article-4 is 2.5 times as long as article-5, with two long, one short simple and four pinnate setae distally; article-5 with one simple seta distally; article-6 very short, with four terminal setae.

Mouth parts: Labrum ( Fig. 36C ) hood-shaped with numerous setae. Mandible ( Figs 36D,E ) stout; molar process well-developed, edges supported with tubercle-like structures; lacinia mobilis well-developed, crenulated. Maxillule ( Fig. 36F ) endite with eight apical spiniform setae; palp lost during dissection. Maxilla ( Fig. 36G ) triangular. Labium ( Fig. 36H ) bilobed, outer lobe and outer corner of inner lobe setose. Maxilliped ( Fig. 36I ): bases fused, 2-lobed with simple setae reaching half of endites; endite armed with plumose seta in distolateral margin and two tubercles on distal margin; palp 4-articled: article-1 naked; article-2 wedge-shaped with three strong serrated setae on inner margin and one short seta on outer margin; article-3 with three strong serrated setae and one long simple setae on inner margin; article-4 with four strong serrated setae and two short setae. Epignath ( Fig. 36J ) tip rounded.

Cheliped ( Fig. 37A ): Basis 1.8 times as long as wide; merus wedge-shaped with one seta ventrally; carpus about 2.5 times as long as broad, with two dorsal setae and with two long setae ventrally; propodus and fixed finger little longer than carpus, about three times as long as wide, with one seta on inner side and one seta on outer side near insertion of dactylus; fixed finger with three setae on inner margin and with two setae on ventral margin.

Pereopod-1 ( Fig. 37B ): Of walking type; coxa with one seta; basis shorter than ischium, merus and carpus combined, with three simple setae dorsally and one seta ventrally; ischium short with one seta; merus little shorter than carpus, with two setae distally; carpus with four setae distally and one subdistal short seta ventrally; propodus 1.3 times as long as carpus with one seta ventrally and three setae dorsally; dactylus with long seta; unguis 1.5 times as long as dactylus.

Pereopod-2 ( Fig. 37C ): Of walking type; coxa with one seta; basis with one ventral and one simple, dorsal setae, as long as merus, carpus and propodus combined; ischium with one seta; merus almost as long as carpus, with four long simple setae distally; carpus with six simple and one spiniform setae distally; propodus a little shorter than merus and carpus combined, with spiniform seta ventrally and two setae dorsally reaching half length of unguis; dactylus with one seta, little shorter than unguis.

Pereopod-3 ( Fig. 37D ): Similar to pereopod-2, but merus with two setae only.

Pereopod-4 ( Fig. 37E ): Basis with one seta ventrally and one seta dorsally; ischium with two seta ventrally; merus with two spiniform setae and microtrichae on ventral margin; carpus with hooks distally and prickly tubercles surrounded by dense spines; propodus over seven times as long as wide with two spiniform ventro-distal setae and with distal setae just reaching end of dactylus; propodus twice as long as dactylus and unguis combined; unguis distally simple, with row spines on ventral margin.

Pereopod-5 ( Fig. 37F ): Similar to pereopod-4.

Pereopod-6: Similar to pereopod-4, but propodus with three setae distally (according to Kudinova-Pasternak, 1978, Fig 8 , page 129).

Pleopods missing from specimen.

Uropod (according to Kudinova-Pasternak, 1978, Fig. 8 , page 129): Endopod with two articles, proximal and distal article subequal; proximal with two pinnate setae distally; distal article with five terminal setae. Exopod with two articles, reaching half of endopod distal article.

Distribution: The species is known from two locations in the North Pacific: 24°06.8'N 143°47.l'E, at a depth of 6330m and 29°18.3'N, 143°15.2'E, at the depth range from 6770 to 6850m (Kudinova-Pasternak, 1978).

Remarks: Kudinova-Pasternak (1978) measured 19 females of lengths between 2.2 and 5.4 mm and four mancae of lengths 1.8–2.9 mm. From that collection only the holotype was available for study. The holotype ( Fig. 36K ) differs from the specimen illustrated by Kudinova-Pasternak (1977 (1978)) in the proportion of pereonites. For example, the holotype’s pereonite-2 is twice as long as pereonite-1 and pereonite-4 is the longest, but in figure 7 by Kudinova-Pasternak (page: 127–130) pereonite-2 is 1.5 times as long as pereonite-1 while pereonite-3 is the longest. The holotype also has a shorter antennule, longer setae on the carpus of pereopod-1, no setae on the merus of pereopod-2 and a generally more compact pereopod-2. It is also interesting that the nineteen females and four mancae measured by Kudinova-Pasternak have overlapping body length ranges. It may be that the material studied by Kudinova-Pasternak embraced two sympatric hadal species of Torquella , but because the material was lost it is impossible to resolve this problem.

Figures

FIGURE 8. Paratyphlotanais alveolus n. sp., holotype, adult female. A) dorsal view; B) lateral view. Scale = 0.1 mm.

FIGURE 36. Torquella elegans, female holotype. A) Antennule; B) Antenna; C) Labrum; D) Left mandible; E) Right mandible; F) Maxillule; G) Maxilla; H) Labium; I) Maxilliped; J) Epignath; K) Female dorsal view. Scale: K = 1 mm, A, B, H-J = 0.1 mm, C-G = 0.01 mm.

FIGURE 37. Torquella elegans, female holotype. A) Cheliped, B) Pereopod-1; C) Pereopod-2; D) Pereopod-3; E) Pereopod-4; F) Pereopod-5. Scale = 0.1 mm.