Halirages helgae, Ringvold & Tandberg, 2014

Ringvold, Halldis & Tandberg, Anne Helene Solberg, 2014, A new deepwater species of Calliopiidae, Halirages helgae (Crustacea, Amphipoda), with a synoptic table to Halirages species from the northeast Atlantic, European Journal of Taxonomy 98, pp. 1-13 : 3-10

Halirages helgae sp. nov.

urn:lsid:zoobank.org:act:94170470-2502-4808-A77B-248EEACD8EF6

Figs 2–7

Diagnosis

Head with short rostrum, anteroventral corner with small projecting tooth. Eyes present, but very small, whitish in alcohol. Article 3 of mandible palp about half the length of article 2. Pereonite 7, and in large animals (> 11 mm) also pereonite 6 and pleonite 2, with weakly bilobed posterior margin. Length of dactylus on first and second gnathopod about half that of propodus palm. Carpus longer than propodus. Epimeral plate 2 with small tooth posteroventrally, and epimeral plate 3 with posterior corner rounded. Uropods 1 and 2 biramous, with strong setae. Telson entire, longer than wide, acute.

Etymology

The species is named in memory of Helga Ringvold, for encouraging her children in their future endeavours.

Material examined

Holotype

NORWAY: ♀, 10.5 mm long, R / V G.O. Sars, cruise 11408, st. 276-030A, Nordland, slope of Moskenesgrunnen, 68°28.86’ N, 10°55.81’ E, 1292 m, mud, –0,87 °C, salinity 34.92‰, RP sledge, leg. H. Ringvold ( ZMBN 90142 ).

Paratypes

NORWAY: 4 ♀♀, 9–13 mm long, R / V G.O. Sars, cruise 10408, st. 198-003A, Troms, slope of Mulegga, 70°14.67’ N, 16°44.52’ E, 1532 m, cobbles, –0.78°C, salinity 34.92‰ ( ZMBN 88021–88024). A total of 31 slides has been made of the holotype and paratypes.

Additional material

NORWAY: 1 ♀, 10 mm long, R / V G.O. Sars, cruise 11109, st. 487-157, Nordland, W of Lofoten, 69°04.13’ N, 12°26.91’ E, 2609 m, mud, clay and gravel, –0.82°C, salinity 34.89‰; 35 ♀♀ (6 with eggs; 3 juveniles), 3–13 mm long, R / V G.O. Sars, cruise 10408, st. 198-003A, Troms, slope of Mulegga, 70°14.67’ N, 16°44.52’ E, 1532 m, cobbles, –0.78°C, salinity 34.92‰; 6 ♀♀, 5–11 mm long, R / V G.O. Sars, cruise 11109, st. 444-148, Troms, slope of Eggagrunnen, 71°44.4’ N, 15°14.22’ E, 997 m, cobbles, –0.73°C, salinity 34.88‰; 3 ♀♀, 7–11 mm, R / V G.O. Sars, cruise 11010, st. 542-357, Troms, Vesthola, Egga, 70°23.69’ N, 16°58.86’ E, 1189 m, gravelly sand and sandy mud, –0.66°C, salinity 34.9‰.

Description

BODY. Up to 13 mm long. Pereonites 1-5 smooth, dorsal posterior margin of pereonite 7 slightly bilobed ( Fig. 2B ) (also on pereonite 6 and pleonite 2 on some large specimens greater than 11 mm long). Head ( Fig. 3A ). Rostrum short; corner of cephalic lobe with small projecting tooth; eye small (can be difficult to see in preserved specimens), reniform.

ANTENNA 1 ( Fig. 3B ). Flagellum broken in all examined specimens. Peduncle of article 1 longer than article 2, article 3 about ⅓ length of article 2, which has a posterodistal process. Eight articles remaining in flagellum, with one short seta on three of them.

ANTENNA 2 ( Fig. 3C ). Flagellum broken in all examined specimens. Article 5 longer than articles 3–4 combined, articles 4–5 with short spines, article 5 with a posterodistal process.

LABRUM ( Fig. 3D ). Rounded apically and acute dorsally.

LABIUM ( Fig. 3E ). With small inner lobes.

MANDIBLE ( Fig. 4D ). Incisor process with 4 blunt teeth; lacinia mobilis with 4 teeth on left molar; molar triturative, with ridged grinding surface and with row of lateral spines; palp 3-articulate, with elongate article 2, articles 2–3 with elongate setae on ventral margin. Article 3 short.

MAXILLA 1 ( Fig. 4A ). Inner plate with 9 plumose setae; outer plate with 11 spines of which 5–6 are bifurcate; palp 2-articulate and well developed, article 1 expanded distally, article 2 tapering and with 2 rows of 5–6 spines, one row apically and the other slightly lower. Left article 2 with long marginal

spines and margino-facial setae, right article 2 with a row of 6–7 stout, conical marginal spines with margino-facial row of setae.

MAXILLA 2 ( Fig. 4B ). Outer plate longer than inner plate, both plates with long setae apically. Upper and inner plate with posterior setae, on inner plate the setae also reach posterodistal area.

MAXILLIPED ( Fig. 4C ). Broad and covered with numerous setae; inner plate short with short setae apically and on inner margins, three apical teeth; outer plate slender with long setae apically and on inner margins; palp articles 2–3 elongate, article 2 longest; article 3 with long setae apically and on inner margins; dactylus stout, about half length of article 3.

GNATHOPODS 1 AND 2 ( Fig. 5A and 5B ). Quite similar in shape: both coxae sub-quadrate and smooth; bases rectangular with a few short setae; ischia narrow; meri longer than wide, with group of setae apically; propodi shorter than carpi, subovate, carpi subtriangular with rows of setae along posterior margin, propodi subtriangular. Gnathopod 1 carpus length / width ratio 3.0, of propodus 1.9. Gnathopod 2 carpus length / width ratio 2.7, of propodus 1.9; carpus setae along hind margins and palms, with

groups of setae along inner face, palm of gnathopods 1 and 2 similar and slightly excavate; dactyli on both gnathopods about half length of propodus palm, with dentate inner margin.

PEREOPODS 3–7 ( Fig. 6A–E ). Coxa 3 sub-quadrate and smooth, coxa 4 posteriorly excavate, coxae 5 and 6 longer than wide, coxa 7 elliptic and smallest of all coxae; bases of pereopods 5–7 broad and posteriorly smooth. Articles of pereopods 4–7 missing on all specimens except paratype 2, which has one pereopod 7 that includes carpus; ischium short and square-shaped, merus with setae along both margins and long setae apically, carpus with setae on both margins, 7 times as long as wide, and 1.5 times as long as merus.

UROPODS 1 AND 2 ( Fig. 7A and 7B ). With spines on both margins of peduncles and rami. Rami damaged on all specimens.

UROPOD 3. Missing on all specimens.

TELSON. Entire, longer than wide, triangular with blunt tip ( Fig. 7C ).

EPIMERAL PLATES. Epimeral plate 1 posteriorly rounded, posteroventral corner obtusely angular; epimeral plate 2 with small, posteroventral tooth; epimeral plate 3 with posteroventral corner rounded and with posterior border smooth and nearly straight ( Fig. 7D ).

COLOUR PATTERN. Colour of live specimens unrecorded.

Distribution

This species has only been found in the northeast Atlantic, off northern Norway. It has been recorded at some of MAREANO’s deepest stations, from 997 to 2,609 m, and only in cold water masses (NSAIW, Norwegian Sea Arctic Intermediate Water) ( Buhl-Mortensen et al. 2012), with mud as the dominant sediment.

Figures

Fig. 2. Halirages helgae sp. nov. A. Holotype, ♀, 10 mm long. B. Dorsal side, showing bilobed posterior margin of pereonite 7; paratype 1, ♀, 10 mm long.

Fig. 3. Halirages helgae sp. nov., holotype, ♀, 10 mm long. A. Head. B. Antenna 1. C. Antenna 2. D. Upper lip. E. Lower lip.

Fig. 4. Halirages helgae sp. nov., holotype, ♀, 10 mm long. A. Maxilliped. B. Maxilla 1. C. Maxilla 2. D. Mandible.

Fig. 5. Halirages helgae sp. nov., holotype, ♀, 10 mm long. A. Gnathopod 1. B. Gnathopod 2.

Fig. 6. Halirages helgae sp. nov. A–D. Holotype, ♀, 10 mm long. A. Pereiopod 3. B. Pereiopod 4. C. Pereiopod 5. D. Pereiopod 6. — E. Paratype 2, ♀, 9 mm long. Pereiopod 7.

Fig. 7. Halirages helgae sp. nov., holotype, ♀, 10 mm long. A. Uropod 1. B. Uropod 2. C. Telson. D. Epimeron 2–3.