Lycenchelys aratrirostris

description

Description. Vertebrae 22 - 24 + 77 - 81 = 100 - 104; D 951 - 00; A 80 - 82; P 14 - 16; C 10 - 12; pelvics 3; branchiostegal rays 6; gill rakers 2 + 9 - 10; vomerine teeth 0 - 11; palatine teeth 0 - 11; pseudobranch filaments 0 - 7; pyloric caeca 2. Following proportions as percent SL (specimens 176 - 220 mm SL first followed by 264 mm SL male in parentheses): head length 16.4 - 17.2 (20.7); head width 7.5 - 8.2 (11.1); head depth 7.3 - 7.8 (9.8); predorsal length 18.2 - 20.0 (24.0); preanal length 34.5 - 36.7 (41.6); pectoral base depth 4.7 - 7.0 (4.2); pectoral-fin length 5.6 - 8.7 (10.5); body depth 7.8 - 8.6 (9.3); gill slit length 4.9 - 5.9 (4.6). Following proportions as percent HL, data presented as above: head width 44.2 - 47.8 (52.7); head depth 42.6 - 47.8 (47.3); mandibular symphysis length 15.4 - 20.7 (19.8); upper jaw length 39.5 - 43.2 (46.4); snout length 21.0 - 25.4 (26.8); eye diameter 18.1 - 25.6 (17.2); gill slit length 28.3 - 34.5 (22.1); pectoral-fin length 47.3 - 50.7 (50.7); interorbital width 6.7 - 8.4 (6.9); interpupillary width 26.4 - 27.8 (21.4); caudal-fin length 14.6 - 19.4 (12.7); pelvic-fin length 7.6 - 12.0 (6.7). Pectoral base / length ratio 39.2 -

Studies on the Zoarcidae of the southern hemisphere. X. New records from western Antarctica.

diagnosis

Diagnosis. Lycenchelys aratrirostris is distinguished from its congeners by the following combination of characters: fleshy mandibular symphysis deep, its length 18 - 20 % HL; suborbital pores 6 - 7; vertebrae 22 - 24 + 77 - 86 = 100 - 110.

Studies on the Zoarcidae of the southern hemisphere. X. New records from western Antarctica.

discussion

Remarks. This species was described from a single specimen taken off the South Shetland Islands, and I added data from three more from that area and the Weddell Sea (Anderson, 1988). The new material considerably increases knowledge of the species in characters, size (to 264 mm SL) and depth range (491 - 1120 m). Two gravid females are among the present sample, both in SAM 34534; one, at 180 mm SL had 35 ova 2.34.1 mm in diameter, the other, at 194 mm SL had ripening ova 0.9 - 2.0 mm in diameter. The smallest male, at 176 mm SL, had mature testes. The largest male, at 264 mm (RUSI 53455), exhibits secondary male characteristics found in a few Lycenchelys species (see above), such as a longer, deeper and wider head, longer upper jaw and pectoral fin, deeper body and smaller eye, caudal fin and gill slit compared to females or smaller males.

Studies on the Zoarcidae of the southern hemisphere. X. New records from western Antarctica.

materials_examined

Material examined. South Shetland Islands: SAM 34599 (1 specimen, 202 mm SL), off Elephant Island, 61 ° 12.6 ' S, 54 ° 32.3 ' W, 559 m, POLARSTERN sta. AGT 15, Agassiz trawl, 19 Nov. 1996, K. - H. Kock. SAM 34534 (5, 176 - 220 mm SL), off King George Island, 62 ° 18.9 ' S, 58 ° 41.7 ' W, 491 - 497 m, POLARSTERN sta. AGT 175, Agassiz trawl, 24 Dec. 1996, K. - H. Kock. SAIAB (RUSI) 53455 (4; 199 - 264 mm SL), off Smith Island, 700 m, POLAR DUKE, otter trawl, 5 July 1996, A. DeVries.

Studies on the Zoarcidae of the southern hemisphere. X. New records from western Antarctica.