Microlysias soela Lowry & Kilgallen, 2014, sp. nov.
Creators: name: Lowry, J. K.
name: Kilgallen, N. M.
Publisher: name: Zenodo
Year: 2014
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Amphipoda
Tryphosidae
Microlysias
Microlysias soela

description: Microlysias soela sp. nov.
(Figs 13–15)
Microlysias xenokeras.— Azman & Othman, 2013: 14, fig. 9.
Types. Holotype female 5.5 mm, AM P.68958, North West Shelf, Western Australia, (19°58.4’S 117°49.2’E), 43 m, sled, 26 June 1983, CSIRO Division of Fisheries, FRV Soela stn 03-D4-S. Paratypes: 33 specimens, 3.2–5.6 mm, AM P.68959, with same collection details as holotype; 2 specimens, AM P.68960, North West Shelf, Western Australia, Australia (19°59.2’S 117°48.6’E), 41 m, sled, 26 June 1983, CSIRO Division of Fisheries, FRV Soela stn 03-D8-S; 1 male, 6.0 mm, NMV J67527, North-West Shelf between Port Hedland and Dampier, Western Australia, Australia (20°01.00’S 117°11.00’E – 20°01.00’S 117°12.00’E), 48 m, WHOI epibenthic sled, 11 June 1983, G.C.B. Poore & H.M. Lew Ton, FRV Soela [stn NWA-48].
Additional material examined. 1 male, NMV J67528 North-West Shelf between Port Hedland and Dampier, Western Australia, Australia (20°01.00’S 117°11.00’E –20°01.00’S 117°12.00’E), 48 m, WHOI epibenthic sled, 11 June 1983, G.C.B. Poore & H.M. Lew Ton, FRV Soela [stn NWA-48]; 23 specimens, NMV J67529, North-West Shelf between Port Hedland and Dampier, Western Australia, Australia (20°01.00’S 117°11.00’E –20°01.00’S 117°12.00’E), 48 m, WHOI epibenthic sled, 11 June 1983, G.C.B. Poore & H.M. Lew Ton, FRV Soela [stn NWA-48]; 1 female, NMV J67530, North-West Shelf between Port Hedland and Dampier, Western Australia, Australia (20°01.00’S 117°11.00’E –20°01.00’S 117°12.00’E), 48 m, WHOI epibenthic sled, 11 June 1983, G.C.B. Poore & H.M. Lew Ton, FRV Soela [stn NWA-48]; 1 specimen, NMV J67531, North-West Shelf between Port Hedland and Dampier, Western Australia, Australia (19°38’S 118°06’E –19°37’S 118°05’E), 49 m, crinoids, WHOI epibenthic sled, 13 June 1983, G.C.B. Poore & H.M. Lew Ton, FRV Soela [stn NWA-56]; 1 specimen, NMV J67532, North-West Shelf between Port Hedland and Dampier, Western Australia, Australia (19°00.5’S 117°26.0’E –19°00.5’S 117°46.23’E), 120 m, WHOI epibenthic sled, 12 June 1983, G.C.B. Poore & H.M. Lew Ton, FRV Soela [NWA-52]; 1 specimen, NMV J67533, North-West Shelf between Port Hedland and Dampier, Western Australia, Australia (20°01.00’S 117°17.00’E –20°00.00’S 117°18.00’E), 46 m, WHOI epibenthic sled, 2 June 1983, G.C.B. Poore & H.M. Lew Ton, FRV Soela [NWA-5].
Type locality. North West Shelf, Western Australia, Australia (19°58.4’S 117°49.2’E); 43 m depth.
Etymology. Named for the FRV Soela; used as a noun in apposition.
Description. Based on holotype female, 5.5 mm, AM P.68958. Head lateral cephalic lobe subtriangular, apically subacute; eyes irregularly subrectangular, covering most of head. Antenna 1 accessory flagellum forming a partial operculum, 3-articulate; primary flagellum with strong 2-field callynophore, robust setae absent from proximal articles; calceoli absent. Antenna 2 peduncular article 3 short; articles 3 to 5 not enlarged; flagellum short, calceoli absent. Labrum, epistome and upper lip fused, broadly rounded, concave. Mandible molar ridge-like, narrow, setose with narrow distal triturating surface; palp attached about midway, article 3 with 1 proximal A3-setae. Maxilla 1 inner plate apically produced into a slender spine; outer plate setal-tooth 7 present, left and right symmetrical, cuspidate distally; palp distal margin with apical robust setae. Maxilliped outer plate with 1 short apical robust seta.
Pereonites 1–7 dorsally smooth. Gnathopod 1 subchelate; coxa large, about as long as coxa 2, subrectangular, with concave anterior margin, distally straight; basis moderately setose along anterior margin; ischium short; carpus compressed, shorter than propodus, with narrow posterior lobe; propodus small, margins subparallel, sparsely setose along posterior margin, palm transverse, entire, straight. Gnathopod 2 minutely chelate; propodus palm moderately obtuse. Pereopod 4 coxa with a well-developed posteroventral lobe. Pereopod 5 basis slightly broader than long, not posteroproximally excavate, posterior margin weakly serrate. Pereopod 7 basis posterodistally produced less than halfway along merus.
Pleonite 3 without mid-dorsal carina, not produced dorsodistally, posterodorsal margin not produced. Epimeron 3 posterior margin smooth, posteroventral corner broadly rounded. Urosomite 1 with anterodorsal notch and slightly rounded boss. Uropod 2 inner ramus without constriction. Uropod 3 inner and outer rami well developed, outer ramus article 2 short, with plumose setae on both rami. Telson deeply cleft, longer than wide, with 2–3 dorsal robust setae per lobe and 1 apical robust setae on each lobe.
Sexually dimorphic characters. Based on male, 6.0 mm, NMV J67527. Antenna 1 primary flagellum with strong 2-field callynophore (stronger than female); calceoli present, small. Antenna 2 peduncular article 3 short; article 5 greatly enlarged; flagellum long, calceoli present.
Remarks. The only other recognised species of Microlysias, M. xenokeras Stebbing, 1918, is known from south-western South Africa. A second species, M. indica K.H. Barnard, 1937, from the south Arabian coast is considered by Griffiths (1975) to be a synonym of M. xenokeras.
Microlysias soela sp. nov. is very similar to M. xenokeras. The gnathopod 2 palm in M. xenokeras is extremely obtuse (almost at a right angle), but only moderately obtuse in M. soela and the antenna 2 peduncle article 3 is longer in the female of M. xenokeras. Microlysias soela also has a distinct spine-like projection from the apical margin of the maxilla 1 inner plate that is absent in M. xenokeras.
Based on the less obtuse palm of gnathopod 2 the record of M. xenokeras from Pulau Tioman (Azman & Othman 2013) appears to be M. soela.
Depth range. 41–120 m (this study).
Distribution. Australia. North West Shelf, Western Australia (this study). Malaysia. Pulau Tioman (Azman & Othman 2013).
description: Published as part of Lowry, J. K. & Kilgallen, N. M., 2014, New tryphosine amphipods from Australian waters (Crustacea, Amphipoda, Lysianassoidea, Lysianassidae, Tryphosinae), pp. 1-64 in Zootaxa 3844 (1) on pages 19-22, DOI: 10.11646/zootaxa.3844.1.1, http://zenodo.org/record/5116622