Paracallisoma woolgoolga, 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 : 15-17

Paracallisoma woolgoolga sp. n. Figures 27, 28, 29, 30

Type material.

Holotype, female, 10.0 mm, AM P.69088, north-east of Coffs Harbour, New South Wales, Australia (30°10.88'S, 153°32.22'E), 1000 m, baited trap, 12-13 August 1993, coll. P.B. Berents, R.T. Springthorpe & W. Vader, MV Cheryl Lee [NSW-877]. Paratypes: 1 male, 7.5 mm, AM P.69089; many specimens, 7.0-9.3 mm, AM P.69090, with same collection details as holotype.

Other Australian material examined.

New South Wales: 564 specimens, AM P.48095, [NSW-862]; 175 specimens, AM P.48121, [NSW-863], north-east of Coffs Harbour (30°10.93'S, 153°32.26'E), 963 m, baited trap, 11-12 August 1994, coll. P.B. Berents, R.T. Springthorpe & W. Vader, MV Cheryl Lee. 6 specimens, AM P.50024, north-east of Coffs Harbour (30°10.93'S, 153°32.26'E), 1000 m, baited trap, 8-9 September 1994, coll. J.K. Lowry & K. Dempsey, MV Carrie Ann [NSW-999]. 26 specimens, AM P.50067, [NSW-1021]; 2 specimens, AM P.50082, [NSW-1022], north-east of Coffs Harbour (30°10.93'S, 153°32.26'E), 1000 m, baited trap, 9-10 September 1994, coll. J.K. Lowry & K. Dempsey, MV Carrie Ann. 1 specimen, AM P.51126, north-east of Coffs Harbour (30°14.83'S, 153°27.55'E), 200 m, baited trap, 11-12 August 1993, coll. P.B. Berents, R.T. Springthorpe & W. Vader, MV Cheryl Lee [NSW-869]. 480 specimens, AM P.49808; 237 specimens, AM P.49827; 17 specimens, AM P.52658, north-east of Coffs Harbour (30°10.88'S, 153°32.22'E), 1000 m, baited trap, 12-13 August 1993, coll. P.B. Berents, R.T. Springthorpe & W. Vader, MV Cheryl Lee [NSW-876].

Queensland: 3 specimens, AM P.47887, due east of Mooloolaba (26°36.23'S, 153°50.23'E), 1006 m, baited trap, 2-3 August 1994, coll. J.K. Lowry & K. Dempsey, MV Capricorn I [QLD-1140].

Tasmania: 20 specimens, AM P.73706, Main Pedra Hill, 76.8km south-south-east of South East Cape (44°15.6'S, 147°07.8'E), 1312 m, baited trap, 21-24 January 1997, coll. CSIRO party, FRV Southern Surveyor [SS01/97/08]. Many specimens, AM P.73707, Hill U, 82.8 km south-south-east of South East Cape (44°19.2'S, 147°07.2'E), 1083-1448 m, baited trap, 27-28 January 1997, coll. CSIRO party, FRV Southern Surveyor [SS01/97/41]. 132 specimens, AM P.73708, Hill D1, south-south-east of South East Cape (44°23.4'S, 147°16.2'E), 1942 m, baited trap, 31 January 1997, coll. CSIRO party, FRV Southern Surveyor [SS01/97/65].

Diagnosis.

Gnathopod 1 coxa margins subparallel. Gnathopod 2 propodus palm transverse, with straight, minutely serrate margin; dactylus reaching corner of palm. Pereopod 5 basis as long as broad, broadly expanded posteriorly, slightly excavate posterodistally. Epimeron 3 posteroventral corner narrowly rounded. Telson moderately cleft.

Description.

Based on holotype female, 10.0 mm, AM P.69088.

Lateral cephalic lobe large, triangular, apically subacute. Rostrum absent. Eyes apparently absent. Antenna 1 short; accessory flagellum long, 3-articulate, forming cap covering callynophore; primary flagellum 6-articulate, with strong 2-field callynophore; calceoli absent. Antenna 2 longer than antenna 1; peduncle without brush setae, article 1 greatly enlarged, not covering article 2; flagellum 26-articulate, calceoli absent.

Labrum, epistome slightly produced, rounded; upper lip slightly produced, straight. Mandible incisor with slightly convex margins; lacinia mobilis a stemmed, distally expanded, smooth blade; molar flap-like; palp attached midway, article 2 slender. Maxilla 1 palp 2-articulate. Maxilla 2 inner plate shorter than outer plate; outer plate without long, distally barbed slender setae. Maxilliped outer plate small; palp large, 4-articulate.

Gnathopods 1-4 coxae without setal fringe along ventral margin. Gnathopod 1 coxa large, about as long as coxa 2, margins subparallel; basis slender; ischium long, length 2.1 × width; carpus long, length × 2.9 width, subequal in length to propodus; propodus margins slightly tapering distally; anterodistal margin with row of long, slender setae, without robust setae just above dactylus; dactylus small, simple, well developed, posterior margin without setae, with one cusp along posterior margin. Gnathopod 2 minutely subchelate; carpus long, length 3.7 × width; propodus short, length 1.7 × width, palm transverse, with straight, minutely serrate margin; dactylus reaching corner of palm. Pereopod 3 weakly prehensile; propodus without posterodistal locking setae; dactylus short, slender. Pereopod 4 weakly prehensile; coxa wider than deep, with subacutely produced posteroventral lobe; propodus without posterodistal locking setae; dactylus short, slender. Pereopod 5 weakly prehensile; coxa equilobate; basis as long as broad, broadly expanded posteriorly, slightly excavate posterodistally, without row of long pappose setae medially; dactylus short, slender. Pereopod 6 weakly prehensile; basis expanded posteroproximally, posterior margin tapering distally, with very weakly excavate posterodistal margin; dactylus short, slender. Pereopod 7 weakly prehensile; basis expanded posteriorly, slightly rounded proximally, minutely crenate, posteroventral corner excavate; propodus without anterodistal locking setae; dactylus short, slender.

Epimeron 1 anteroventral corner narrowly rounded. Epimeron 3 posteroventral corner produced, narrowly rounded. Urosomite 1 with anterodorsal notch and rounded boss. Uropod 1 peduncle 1.5 × rami length; rami subequal in length. Uropod 2 rami 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 2.3 × breadth, moderately cleft (to 64%).

Sexually dimorphic characters.

Based on paratype male, 7.5 mm, AM P.69089. Antenna 1 flagellum 7-articulate, with strong 2-field callynophore (stronger than in female); calceoli present. Antenna 2 flagellum 35-articulate, calceoli present.

Etymology.

Named for Woolgoolga, a town west of the type locality on the coast of New South Wales; used as a noun in apposition.

Distribution.

Australia: east of Mooloolaba, Queensland, to south of Tasmania.

Ecology.

A scavenger taken in baited traps.

Discussion.

Paracallisoma woolgoolga sp. n. is morphologically very close to Paracallisoma spinipoda . It can be distinguished from that species by the gnathopod 2 palm (slightly concave in Paracallisoma spinipoda , straight in Paracallisoma woollgoolga ); the shape of the pereopod 5 basis (evenly rounded in Paracallisoma spinipoda , with a slight excavation along the posteroventral margin in Paracallisoma woolgoolga ); and the shape of the epimeron 2 posteroventral corner (producing a small spine in Paracallisoma spinipoda , subquadrate in Paracallisoma woolgoolga ). In addition the pereopod 6 basis is much less distinctly excavate posteriorly in Paracallisoma woolgoolga compared with that of Paracallisoma spinipoda .