Parelasmopus sowpigensis Lowry & Springthorpe, 2005, n.sp.
Creators: name: Lowry, JK
name: Springthorpe, RT
Publisher: name: Zenodo
Year: 2005
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Amphipoda
Maeridae
Parelasmopus
Parelasmopus sowpigensis

description: Parelasmopus sowpigensis n.sp.
Figs. 37–40
Type material. HOLOTYPE, ♂, 8.9 mm, AM P60496; 1 PARATYPE, ♀, 7.1 mm, AM P60497; 16 PARATYPES, 3♂♂, 13♀♀, AM P60498; 21 PARATYPES, 13♂♂, 8♀♀, AM P60499, off Sow and Pigs reef, Port Jackson, New South Wales, Australia,33°50.3'S 151°16.2'E, shelley sand, 5 m, benthic grab, J.K. Lowry & A.R. Jones, 30 September 1976, stn NSW-184.
Type locality. Sow and Pigs Reef, Port Jackson, New South Wales, 33°50.3'S 151°16.2'E, shelley sand, 5 m.
Description. Based on holotype male, AM P60496 and paratype female, AM P60497.
Head. Lateral cephalic lobes broad, rounded, with anteroventral notch or slit, anteroventral corner with acute/ subacute spine. Antenna 1 longer than antenna 2; peduncular article 1 subequal in length to article 2, with 3 robust setae along posterior margin; flagellum with 22 articles; accessory flagellum with 4 articles. Antenna 2 peduncular article 2 cone gland reaching at least to end of peduncular article 3; article 4 longer than or subequal to article 5; flagellum with 6 articles. Mandible palp article 3 rectolinear, setose on distomedial margin, subequal to or shorter than article 1; article 2 shorter than article 3; article 1 curved, swollen distally, longer than article 2, at least 3× as long as broad. Maxilla 1 inner plate with 2 setae mainly terminal.
Pereon. Gnathopod 1 coxa anteroventral corner not produced, posteroventral corner notch absent; merus without posterodistal spine; propodus palm acute, convex, without posterodistal corner, defined by posterodistal robust setae. Gnathopod 2 sexually dimorphic; subchelate; coxa posteroventral corner notch absent; merus with sharp posteroventral spine; carpus short; propodus without medial depression, without strong concentration of setae, palm nearly transverse, straight, smooth, with group of anterodistal robust setae, defined by posterodistal robust setae, without posteroventral corner; dactylus apically blunt. Pereopod 5 basis posterior margin straight, posteroventral corner narrowly rounded or subquadrate. Pereopod 6 coxa anterior lobe ventral margin slightly produced, rounded; basis posterior margin slightly concave, posteroventral corner broadly rounded, narrowly rounded or subquadrate. Pereopod 7 basis posterior margin straight, with posterior margin smooth or minutely castelloserrate, posteroventral corner narrowly rounded or subquadrate.
Pleon. Epimeron 1 posteroventral corner narrowly rounded or subquadrate. Epimera 1–2 posteroventral margin without spines above posteroventral corner. Epimeron 3 posterior margin smooth, posteroventral corner with small acute spine. Urosomite 1 dorsally bicarinate. Uropod 3 inner ramus subequal in length to outer ramus; outer ramus longer (1.2 to 2× length) than peduncle, 1-articulate. Telson each lobe with 3 or more apical/subapical robust setae, apical conical extension reaching scarcely one third along longest seta.
Female (sexually dimorphic characters). Gnathopod 2 carpus long; propodus palm acute, convex, lined with robust setae, defined by posteroventral corner; dactylus apically acute/subacute.
Habitat. Marine; littoral; shelley sand, 5 m depth.
Etymology. Named for the Sow and Pigs Reef, the type locality.
Remarks. This species fits Parelasmopus because of the highly distinctive mandibular palp with its very long first article and very short second article, but it differs from the generic definition in not having a serrate posteroventral margin on epimeron 3, nor does it have dorsally bicarinate first and second pleonites. J.L. Barnard (1972a) established Ifalukia for one species of Parelasmopus that lacked dorsal carinae on the pleonites and urosomites, and lacked posteroventral serrations on epimeron 3. Parelasmopus sowpigensis is most similar to Ifalukia, but differs in having a dorsally bicarinate first urosomite. It therefore strictly fits neither genus. If the mandibular palp is the main synapomorphy defining Parelasmopus, then it appears that some species in the complex have either lost or never had dorsal carinae or serrate ventral margins. Until the phylogenetic implications of these questions can be analysed it is best to maintain a broad concept of the genus.
Parelasmopus sowpigensis is therefore a distinctive species differing from other Australian species in having dorsally smooth first and second pleonites and smooth ventral margins on epimeron 3.
Distribution. New South Wales: Sow and Pigs Reef, Port Jackson (AM).
Australian geographic areas. Southeastern Australia.
description: Published as part of Lowry, JK & Springthorpe, RT, 2005, New and Little-known Melitid Amphipods from Australian Waters (Crustacea: Amphipoda: Melitidae), pp. 237-302 in Records of the Australian Museum 57 on pages 276-277, DOI: 10.3853/j.0067-1975.57.2005.1463, http://zenodo.org/record/15323482