Halirages qvadridentatus G.O. Sars, 1877

D'Acoz, Cédric D'Udekem, 2012, On the genus Halirages (Crustacea, Amphipoda), with the description of two new species from Scandinavia and Arctic Europe, European Journal of Taxonomy 7, pp. 1-32 : 16-20

Halirages qvadridentatus G.O. Sars, 1877

Figs 8-9

Halirages qvadridentatus G.O. Sars, 1877: 257 .

Halirages elegans Norman, 1882: 688 .

Halirages qvadridentatus – G.O. Sars 1885: 172, pl. 14 fig. 4. — d'Udekem d'Acoz 2010: 146 (discussion on spelling).

Halirages quadrispinosus – G.O. Sars 1893: 436 (lapsus calami).

Acanthozone quadridentata – Della Valle 1893: 611 (pro parte), pl. 59 fig. 22.

Halirages quadridentatus – Stebbing 1906: 290, 292. — Stephensen 1931: 268-272, fig. 76; 1933: 32 (variations); 1938: 237, 240. — Gurjanova 1946: 288 (discussion); 1951: 606, 608, fig. 411 (after G.O. Sars 1885). — Yashnov 1948: 641, pl. 78 fig. 8 (after Stephensen 1931). — Kamenskaya 1980: 248 (discussion).

? Halirages spez. – Schellenberg 1925: 205.

Type material (syntypes) of Halirages elegans Norman, 1882

FAEROE ISLANDS: RV Knight Errant, stn 8, 60°04'N 007°37'W, 305 fathoms [= 558 metres], mud, 27 Jul.1880: 3 specimens (none with oostegites) (specimens of lengths 30, 25 and 19 mm), BM (NH) 17375- 377; RV Knight Errant, stn 8: 1 mandible, in very poor condition BM (NH), slide 1911.11.8.1268; Faeroe Islands, RV Knight Errant, stn 8: anterior part of head, right Gn1, right Gn2, left P7, left Ep3, left U3, 2 telsons, BM (NH), slide 1911.11.8.1269; RV Knight Errant, 1880, stn 8, label of slides indicating "main organs (mandible from three specimens)": 3 mandibles, 1 upper lip, 1 maxilliped, in poor condition, BM (NH), slide 1911.11.8.1270.

Description

HEAD. ( Fig. 8A ) Rostrum feeble; anterior lobe of head very bluntly subquadrate, posteriorly followed by distinct sinus; ventral lobe of head acute, pointing forward, not denticulate.

ANTENNAE. ( Fig. 8A ) Typical for the genus Halirages ; article 1 of peduncle with 2 normally developed ventrolateral distal teeth.

MOUTHPARTS. Typical for the genus but not described for the poor quality of the dissected material.

GNATHOPOD 1. ( Fig. 8 B-D) Coxa with anteroventral corner produced into a small tooth pointing forwards, with 18-20 small serrations along ventral margin; carpus 4.4 x as long as wide, as long as basis, anterior border not setose; propodus 2.4 x as long as wide, 0.66 x as long as carpus; palmar part of propodus 0.23 x as long as propodus.

GNATHOPOD 2. ( Fig. 8B, E ) Coxa rectangular, with about 16 crenulations along ventral margin; carpus 4.8 x as long as wide, as long as basis, with anterior border not setose; propodus 2.5 x as long as wide, 0.59 x as long as carpus; palmar part of propodus 0.23 x as long as propodus.

PEREIOPOD 3. Damaged, not suitable for description.

PEREIOPOD 4. ( Figs 8B , 9A ) Coxa broad and posteriorly produced, with about 15 crenulations along ventral margin; leg weakly spinose/setose; carpus 7.5 x as long as wide, 1.6 x as long as merus; propodus 11.4 x as long as wide, 1.6 x as long as merus.

PEREIOPOD 5. ( Fig. 8 A-B) Pereiopod 5 <pereiopod 6 <pereiopod 7; posterior lobe of coxa distinctly longer than anterior lobe; leg weakly spinose/setose; basis elliptic, anterior border distally without tooth, posterior border with about 17 low crenulations, posterodistal border rounded and smooth; ischium without anterodistal tooth.

PEREIOPOD 6. ( Figs 8 A-B, 9B) Posterior lobe of coxa considerably longer than anterior lobe; leg weakly spinose/setose; basis anteriorly convex and posteriorly straight, converging towards tip, 1.3 x as long as wide, anterior border distally without tooth, posterior border with more than 23 low crenulations, posterodistal border rounded and smooth; ischium without anterodistal tooth; carpus 9.5 x as long as wide, 1.4 x as long as merus; propodus 13 x as long as wide, 1.2 x as long as merus.

PEREIOPOD 7. ( Figs 8 A-B, 9C-D) Coxa small and elliptic; leg weakly spinose/setose; basis with anterior and posterior border straight and converging towards tip, 1.3 x as long as wide, anterior border with 6 slender spines and no setae, distally without tooth, posterior border with 22-37 serrations, posterodistal border with 3-5 serrations; junction between posterior and posterodistal border sharply angular; ischium without anterodistal tooth; carpus 8.8 x as long as wide, 1.4 x as long as merus; propodus 13 x as long as wide, 1.6 x as long as merus.

DORSAL ORNAMENTATION. ( Fig. 8A ) Pereionite 7 (2 smaller syntypes) or pereionites 6-7 (largest syntype), and pleonites 1-2 with strong posterodorsal tooth.

EPIMERON 1. ( Fig. 8A ) With 5 isolate margino-facial spines, with well-developed posteroventral tooth, with posterior border rounded and smooth.

EPIMERON 2. ( Fig. 8A ) With 5 isolate margino-facial spines, with weak but acute posteroventral tooth, with posterior border sigmoid and smooth.

EPIMERON 3. ( Fig. 8A, F ) With a few isolate margino-facial spines, with weak but acute posteroventral tooth, with posterior border weakly rounded and weakly serrate.

UROPODS 1-2. Adequate description impossible without destructive dissection.

UROPOD 3. ( Figs 8A , 9E ) Peduncle with 4 distal dorsal spines, with dorsomedial border spinose; rami with irregularly sized (mostly slender and small) spines; outer ramus 0.88 x as long as inner ramus; inner ramus 1.8 x as long as peduncle, without medio-proximal bulging.

TELSON. ( Fig. 9 F-G) Triangular, with border convex, distally produced into 3 teeth of which the median one is by far the longest, without setules.

BODY LENGTH. The largest syntype of H. elegans is 30 mm long.

Distribution

Baffin Bay, Eastern Iceland, Southeast of Faeroe Islands, Southeast of Jan Mayen ( Stephensen 1938), Western Greenland ( Stephensen 1933), Northwestern Greenland ( Just 1980), Northeastern Greenland ( Piepenburg 1988; Brandt 1997), Eastern Greenland ( Stephensen 1913; Brandt 1997), Håkon Mosby mud volcano, Norwegian Sea, c. 1250 m ( Gebruk et al. 2003), Northern and Western Svalbard ( Gulliksen et al. 1999); 640-1435 m ( Stephensen 1938), off Eastern Greenland at less than 425 m ( Brandt 1997); Kara Sea ( Gurjanova 1936: 152), Barents, Kara and Laptev Seas, Central polar Basin ( Sirenko 2001). The much deeper records (2700 and 3200 m) from 'Svenska Djupet' by Oldevig (1959) require confirmation and the specimens of that author could actually be H. cainae sp. nov. Similarly, the very shallow records (8 to 500 m) in the Barents Sea by Bryazgin (1997) are considered as suspect. Weisshappel (2001) found H. qvadridentatus in Iceland in the Arctic Bottom Water Mass between -0.5°C and -0.6°C and Stephensen (1931) found it at temperatures between +0.8°C and -1.0°C.

Remarks

The original description of H. elegans , based on specimens from the Faeroe Islands, was meager and devoid of illustrations ( Norman 1882), so that it was impossible to figure out exactly what the species looked like and how it differed from congeners. Stappers (1911), reluctantly followed by Stephensen (1931), applied the name H. elegans to a species very distinct from H. qvadridentatus and in many respects closer to H. fulvocinctus . Examination of the type material of H. elegans demonstrated that it consisted of specimens of H. qvadridentatus , confirming the assumptions of Della Valle (1893) and Stebbing (1906). A description and figures of these type specimens are given herein to demonstrate their synonymy and a new name is proposed for the species described in Stappers (1911) and Stephensen (1931) in the next section.

Norman (1882: 688) indicated that his specimens came from station 8 of the Knight Errant Expedition, 540 fathoms [= 988 metres]. The real depth of station 8 was 305 fathoms [= 558 metres] ( Norman 1882: 650), and it is station 6, which was 540 fathoms [= 988 metres] deep.

Figures

Fig. 8. Halirages qvadridentatus G.O. Sars, 1877 (syntypes of Halirages elegans Norman, 1882), Faeroe Islands, RV Knight Errant, stn 8. A-B. largest syntype, ♂ (30 mm); C-F. microscopical preparations by Norman. A. habitus. B. ventral part of pereion with coxal plates and proximal part of posterior pereiopods. C. right Gn1 (coxa broken in two parts on slide and reassembled on drawing). D. ventral margin of right coxa 1. E. right Gn2 (anteroventral corner of coxa indistinct, hidden by varnish on border of microscopical preparation). F. posterior border of Ep3.

Fig. 9. Halirages qvadridentatus G.O. Sars, 1877 (syntypes of Halirages elegans Norman, 1882), Faeroe Islands, RV Knight Errant, stn 8, microscopical preparations by Norman. A. left P4. B. right P6. C. left P7. D. basis and ischium of left P7 (proximal part of posterior border eroded). E. left U3. F-G. telson.