Austrocallisoma jerryi, Kilgallen & Lowry, 2015

Kilgallen, Niamh M. & Lowry, James K., 2015, A review of the scopelocheirid amphipods (Crustacea, Amphipoda, Lysianassoidea), with the description of new taxa from Australian waters, Zoosystematics and Evolution 91 (1), pp. 1-43 : 8-9

Austrocallisoma jerryi sp. n. Figures 13, 14, 15, 16

Type material.

Holotype, female, 32.0 mm, AM P.69087, east of Sydney, New South Wales, Australia (33°44.5-08.9'S, 152°24.4-09.68'E), 0-1800 m over bottom depth 2994-3828 m, Isaacs-Kidd midwater trawl, 27-28 April 1989, coll. J.R. Paxton, HMAS Cook [JP 89-5]. Paratype, 1 immature female with non-setose oostegites, 26.0 mm, AM P.70171, east of Sydney, New South Wales, Australia (33°52.5-53.92'S, 152°39.0-05.9'E), 0-1800 m over bottom depth 1700-4856 m, Isaacs-Kidd midwater trawl, 27 April 1989, coll. J.R. Paxton, HMAS Cook [JP 89-3].

Diagnosis.

Mandible lacinia mobilis a stemmed distally expanded, irregularly cusped blade. Maxilla 1 palp 1-articulate. Maxilliped palp article 4 absent. Gnathopod 1 coxa reduced, slightly shorter than coxa 2; basis swollen, without glandular material.

Description.

Based on holotype female, 32.0 mm, AM P.69087.

Lateral cephalic lobe large, triangular, apically subacute. Rostrum absent. Eyes apparently absent. Antenna 1 short; accessory flagellum long, 2-articulate, forming cap partially covering callynophore; primary flagellum 7-articulate, with strong 2-field callynophore; calceoli absent. Antenna 2 longer than antenna 1; peduncle with strong brush setae, article 1 greatly enlarged, covering article 2; flagellum 30-articulate, calceoli absent.

Labrum, epistome produced, rounded distally; upper lip slightly produced, straight. Mandible incisor with slightly convex margins; lacinia mobilis a stemmed, distally expanded, irregularly cusped blade; molar flap-like; palp attached midway, article 2 slender. Maxilla 1 inner plate with pappose setae lining inner margin; palp 1-articulate. Maxilla 2 inner and outer plates subequal in length; outer plate without long distally barbed slender setae. Maxilliped outer plate small; palp large, 4-articulate; dactylus vestigial, represented by a short, narrow, curving robust seta.

Gnathopods 1-4 coxae without setal fringe along ventral margin. Gnathopod 1 coxa reduced, margins slightly tapering distally; basis broad; ischium long; carpus long, slightly longer than propodus; propodus margins tapering distally, anterodistal margin with row of long, slender setae, with 1 robust seta just above dactylus; dactylus small, simple, well developed, posterior margin without setae, without cusps along posterior margin. Gnathopod 2 minutely subchelate; propodus long, palm transverse; dactylus reaching corner of palm. Pereopod 3 simple; propodus with posterodistal locking setae; dactylus short, slender. Pereopod 4 simple; coxa wider than deep, with subacutely produced posteroventral lobe; dactylus short, slender. Pereopod 5 simple; coxa with posterior lobe slightly produced; basis much longer than broad, moderately expanded posteriorly, posterior margin straight, posteroventral lobe moderately broadened, not extending beyond ischium; without row of long slender pappose setae medially; dactylus short, slender. Pereopod 6 basis moderately expanded with straight posterior margin, with rounded, moderately broadened posteroventral lobe, produced into merus; dactylus short, slender. Pereopod 7 basis rounded, expanded posteroproximally, posterior margin almost straight, smooth, forming a posteroventral lobe produced along merus, posteroventral margin rounded; dactylus short, slender.

Epimeron 3 posteroventral corner subquadrate. Urosomite 1 dorsally smooth. Uropod 1 peduncle 2.2 × rami length; rami subequal in length. Uropod inner ramus slightly shorter than outer ramus. Uropod 3 peduncle short; rami lanceolate, subequal in length, outer ramus (?) 2-articulate, with plumose setae. Telson longer than broad, length 2 × breadth, moderately cleft (to 59%).

Etymology.

Named in honour of Jerry Barnard, in recognition of his enormous contribution to amphipod taxonomy.

Depth range.

0-1800 m over a bottom depth of 1700-4856 m.

Distribution.

Australia: east of Sydney, New South Wales.

Discussion.

The tip of the outer ramus on uropod 3 on both sides is damaged in both specimens available for study. Judging from where the damage occurs we suspect that the ramus is 2-articlulate, however this is uncertain.