Paracallisoma zivianii, 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 : 17-19

publication ID

https://dx.doi.org/10.3897/zse.91.8440

publication LSID

lsid:zoobank.org:pub:CAFFC884-904F-40C2-AACF-12BE3A2F3ECC

persistent identifier

https://treatment.plazi.org/id/2DA4860F-478E-4597-B2D6-9E68702B634A

taxon LSID

lsid:zoobank.org:act:2DA4860F-478E-4597-B2D6-9E68702B634A

treatment provided by

Zoosystematics and Evolution by Pensoft

scientific name

Paracallisoma zivianii
status

sp. n.

Paracallisoma zivianii sp. n. Figures 31, 32, 33, 34

Type material.

Holotype, male, 12.0 mm, AM P.69091, east of Flynn Reef, Queensland, Australia (16°37.82'S, 146°23.08'E), 1000 m, baited trap, 7-8 June 1993, coll. J.K. Lowry, P. Freewater & W. Vader, RV Sunbird [QLD-950/SEAS]. Paratype, 1 specimen, 0.8 mm, AM P.69092, east of Flynn Reef, Queensland, Australia (16°37.82'S, 146°23.08'E), 1000 m, baited trap, 6-7 June 1993, coll. J.K. Lowry, P. Freewater & W. Vader, RV Sunbird [QLD-931/SEAS].

Other Australian material examined.

New South Wales: 3 specimens, AM P.48103, [NSW-862]; 4 specimens, AM P.48127, [NSW-863] north-east of Coffs Harbour (30°10.93'S, 153°32.26'E), 963 m, baited trap, 11-12 August 1993, coll. P.B. Berents, R.T. Springthorpe & W. Vader, MV Cheryl Lee. 1 specimen, AM P.49817, [NSW-876]; 4 specimens, AM P.49831, north-east of Coffs Harbour (30°10.89'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].

Queensland: 6 specimens, AM P.50236, [QLD-931/SEAS]; 3 specimens, AM P.50245, [QLD-932/SEAS] east of Flynn Reef (16°37.82'S, 146°23.08'E), 1000 m, baited trap, 6-7 June 1993, coll. J.K. Lowry, P. Freewater & W. Vader, RV Sunbird.

Diagnosis.

Gnathopod 1 coxa margins subparallel. Gnathopod 2 propodus palm transverse, with slightly concave, minutely serrate margin; dactylus reaching corner of palm. Pereopod 5 basis much longer than broad; basis slightly to moderately expanded posteriorly, posterior margin straight. Epimeron 3 posteroventral corner produced into a weak spine. Telson deeply cleft.

Description.

Based on holotype, male, 12.0 mm, AM P.69091.

Lateral cephalic lobe large, down-turned, narrowly rounded apically. Rostrum absent. Eyes apparently absent. Antenna 1 short; accessory flagellum long, 3-articulate, forming cap covering callynophore; primary flagellum 7-articulate, with strong 2-field callynophore; calceoli present. Antenna 2 longer than antenna 1; peduncle with weak brush setae, article 1 greatly enlarged, not covering article 2; flagellum 19-articulate, calceoli present.

Labrum, epistome slightly produced, rounded; 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 palp 2-articulate. Maxilla 2 inner plate slightly 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 2.2 × width; carpus long, length × 2.0 width, shorter than 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 two cusps along posterior margin. Gnathopod 2 minutely subchelate; carpus long, length 3.4 × width; propodus long, length 2.5 × width, palm transverse, with slightly concave, 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 simple; coxa equilobate; basis much longer than broad; basis slightly to moderately expanded posteriorly, posterior margin straight, posteroventral lobe moderately broadened, extending beyond ischium, without row of long pappose setae medially; dactylus short, slender. Pereopod 6 simple; basis expanded posteroproximally, posterior margin tapering distally, with excavate posteroproximal margin, with rounded, moderately broadened posteroventral lobe, produced into merus; dactylus short, slender. Pereopod 7 simple; basis expanded posteriorly, slightly rounded proximally, minutely crenate, posteroventral corner excavate; propodus without anterodistal locking setae; dactylus short, slender.

Epimeron 1 anteroventral corner rounded. Epimeron 3 posteroventral corner produced into a weak spine. Urosomite 1 with dorsally smooth. Uropod 1 peduncle 1.2 × 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 1.5 × breadth, deeply cleft (to 75%).

Etymology.

The species is named for Bert Ziviani, skipper of the RV Sunbird.

Distribution.

Australia: east of Flynn Reef, Queensland, to north-east of Coffs Harbour, New South Wales.

Ecology.

A scavenger, taken in baited traps.

Discussion.

With its strongly developed pereopod 4 posteroventral lobe and relatively narrow and posterodistally lobate pereopod 5 basis, this species is most similar to Paracallisoma alberti , Paracallisoma platepistomum , and Paracallisoma coecum . It can be differentiated from the latter two species by the shape of the gnathopod 1 coxa, which is short with subparallel margins (longer than broad and tapering distally in Paracallisoma platepistomum and Paracallisoma coecum ) and the shape of the pereopod 7 basis (more distinctly excavate posteriorly in Paracallisoma zivianii sp. n.). It differs from Paracallisoma alberti in the shape of the gnathopod 2 palm, which is transverse, and the dactylus, which fits the palm (palm acute, dactylus distinctly shorter than the palm in Paracallisoma alberti ).