Hyperoche capucinus Barnard, 1930

Zeidler, Wolfgang, 2015, A review of the hyperiidean amphipod genus Hyperoche Bovallius, 1887 (Crustacea: Amphipoda: Hyperiidea: Hyperiidae), with the description of a new genus to accommodate H. shihi Gasca, 2005, Zootaxa 3905 (2), pp. 151-192 : 177-180

Hyperoche capucinus Barnard, 1930

( Figs. 13–14 )

Hyperoche capucinus Barnard, 1930: 415 (key), 416–417, fig. 54.— Vinogradov et al. 1982: 282 (key), 288–289, fig. 147. Weigmann-Haass 1991: 173 –176, 178 (map), figs. 28–46. De Broyer & Jażdżewski 1993: 114. Vinogradov & Semenova 1996: 618. Browne et al. 2007: 819 (table), fig. 4 (phylogenetic tree). Zeidler 2004: 29. Zeidler & De Broyer 2009: 45 –46, fig. 13 (distribution), colour pls. 4a, 4b. Hurt et al. 2013: 31 (table), figs. 1–2 (phylogenetic trees). Zeidler & De Broyer 2014: 304, map 6.

non [mis-identification]— Lavaniegos & Hereu 2009: 151 (appendix).

Hyperoche luetkenides [mis-identification]— Monod 1926: 49 –50, figs. 47–48.

Type material. The unique holotype male (14 mm) of Hyperoche capucinus is in the NHM, London (1930.8.1.595); in spirit. The type locality is the Pacific Sector of the Southern Ocean, off Cape Adare [70°33’S 89°22’W], Terra Nova stn. 224, near-surface, 9 March 1912.

Diagnosis. Females: Sexually mature at about 14–17 mm. Antennae 1 relatively long, slightly longer than head and first pereonite combined, marginally longer than A2. Head length slightly more than first two pereonites combined. Pereon globular, length about 1.6 x pleon; first pleonite extended into short, dorsal rostrum, overlapping head; pereonites 5–7 (also sometimes pereonite 4) and pleonites with small, dorsal carinae. Gnathopod 1; basis relatively elongate, about 1.3 x length remaining articles combined, merus spoon-shaped, projecting under carpus, almost to base of propodus, with fringe of setae on distal margin; carpal process with sharp, dactyl-like tip, extending to distal margin of propodus, anterior margin denticulate; posterior and distal margin of propodus also denticulate; propodus with antero-distal corner produced into small tooth overlapping dactylus; dactylus slightly curved, length almost half of propodus. Gnathopod 2 slightly longer and more slender than G1 but similar in structure except that the merus is not produced as far under the carpus. Pereopoda all relatively slender. Pereopod 3 slightly longer than P4; basis length almost 3 x merus; postero-distal corner of merus slightly produced, with three, prominent denticles on distal margin; carpus with postero-distal corner also slightly produced, with several denticles and with denticulate posterior margin, twice as long as merus and almost as long as propodus; posterior margin of propodus denticulate; dactylus length 0.2–0.3 x propodus. Pereopod 4 slightly longer than P5–7; similar in structure to P3 except the basis is relatively shorter and the carpus is relatively longer. Pereopods 5–7 similar in structure, with P5 slightly longer than P6, and P7 slightly shorter than P6. Pereopod 5; basis length about 3 x merus; antero-distal corner of merus slightly produced, with a few denticles on distal margin; carpus length about twice merus, slightly longer than propodus; dactylus length about 0.3 x propodus. Pereopods 6 & 7; like P5 but basis relatively shorter, and P7 with coxa fused with pereonite. Epimeral plates with postero-distal corner produced into small point. Uropod 1; peduncle reaching almost to limit of peduncle of U2 and middle of peduncle of U3; inner ramus slightly longer than outer, about 0.7 x peduncle. Uropod 2; inner ramus slightly longer than outer, about 0.7 x peduncle. Uropod 3; inner ramus marginally shorter and wider than outer, length about half of peduncle. Telson triangular, marginally longer than wide, length about 0.4 x peduncle of U3.

Males: Sexually mature at about 13–17 mm. Antennae almost as long as entire animal. Head length equal to first three pereonites combined. Pereon slender, only slightly longer than pleon, otherwise like female. Appendages similar to females in structure and relative lengths of articles, except for the following minor variations. Gnathopoda with merus not projected as far under the carpus. Pereopoda with distal corners of merus and carpus not as produced and less denticulate, and pereopods 5–7 with marginally thicker articles and relatively shorter carpus (slightly shorter than propodus). Epimeral plates relatively much longer and deeper. Urosome relatively less slender and larger. Uropod 1; peduncle not quite reaching limit of peduncle of U2; rami of similar length, inner margins with characteristic proximal excavation, length almost 0.7 x peduncle. Uropod 2; inner ramus slightly wider and longer than outer. Uropod 3; length of inner rami about half of peduncle.

Material examined. The unique type of Hyperoche capucinus as detailed above and the following additional material.

Antarctic, Atlantic Sector: Female, 4 males ( USNM 1090280), Scotia Sea, west of South Sandwich Islands [60°34’S 31°11’W], R/V Eltanin ( USARP) Cruise 12, stn. 1051, 1867– 2013 m, University of Southern California, 2 April 1964. Female ( USNM 1196380), Weddell Sea [60°34’S 52°49’W], 0–328 m, K. Osborn. Antarctic, Indian Sector: Seventeen females, 2 males (17 lots, SAMA C7947–7963), Prydz Bay [range 66°58’– 68°59’S 68°50’– 78°31’E], WZ on Aurora Australis ( ANARE), 0–530 m, January/ February 1991. Antarctic, Pacific Sector: 117 females, 7 males (23 lots, NIWA 48153, 48155, 48157–61, 48171–3, 48187–92, 48194, 48211, 48214, 48235, 48238–41), Ross Sea region (range, 66°25’– 72°35’S 159°40’– 165°27’E), Voyage TAN0602 (“ Antarctic Geophysical & Scientific Studies”), Ministry of Sea Fisheries, NIWA, 0–520 m (most 0–200 m), February/ March 2006.

Remarks. This is one of the largest species of Hyperoche , like H. luetkenides , reaching sexual maturity at about 13–17 mm. This species has a number of distinctive characters that readily distinguish it from all its congeners; the most distinctive being the structure of the gnathopoda, with the propodus projected anteriorly over the dacylus and gnathopod 1 being more sub-chelate than chelate. Additional distinguishing characters are as follows: the first pereonite is produced into a small, pointed rostrum, dorsally over the head; pereonites 5–7, and sometimes the pleonites, are produced into small dorsal carinae; the postero-distal corners of the merus and carpus of pereopods 3 & 4, and the antero-distal corner of the merus of peropods 5–7, are generally more produced than in other species and armed with conspicuous spines and setae, especially in females.

A gelatinous plankton associate has not been recorded for this species.

Distribution. Restricted to the region between the Antarctic Polar Front and the Antarctic Continent. A relatively uncommon species found mainly near the Antarctic Continent with reliable records from the Weddell and Scotia Sea, the Ross Sea region and Prydz Bay. Most records are from near-surface waters down to about 500 m.

Figures

FIGURE 13. Hyperoche capucinus Barnard, 1930. Female (13.3 mm), SAMA C 7954; Prydz Bay, Antarctica [67 ° 29.3 ’ S 68 ° 50.5 ’ E – 67 ° 30.5 ’ S 68 ° 51.7 ’ E], Aurora Australis stn. 37 B, 88 – 67 m, 12 Feb. 1991. Scale bars = 0.5 mm (Us); 1.0 mm (remainder).

FIGURE 14. Hyperoche capucinus Barnard, 1930. Male (12.9 mm), SAMA C 7957; Prydz Bay, Antarctica [67 ° 53.9 ’ S 71 ° 04.1 ’ E – 67 ° 55.52 ’ S 71 ° 06.5 ’ E], Aurora Australis stn. 28 A, 211 – 249 m, 7 Feb. 1991. Scale bars = 0.5 mm (Us); 1.0 mm (remainder).