Lepidepecreoides xenopus K.H. Barnard, 1931

Lowry, J. K. & Stoddart, H. E., 2002, The Lysianassoid Amphipod Genera Lepidepecreoides and Lepidepecreum in Southern Waters (Crustacea: Lysianassidae: Tryphosinae), Records of the Australian Museum 54 (3), pp. 335-364 : 344-347

Lepidepecreoides xenopus K.H. Barnard

Fig. 10

Lepidepecreoides xenopus K.H. Barnard, 1931: 426 .–K.H. Barnard, 1932: 62, fig. 24.–J.L. Barnard, 1958: 93.–Thurston & Allen, 1969: 360.–Lowry & Bullock, 1976: 93.–Barnard & Karaman, 1991: 496.–Ren & Huang, 1991: 247, fig. 37.–De Broyer & Jazdzewski, 1993: 15, 69.

Material examined. Three specimens, 4.0– 4.5 mm, and 1 partial specimen, USNM 306582, Weddell Sea, Antarctica, 74°07'S 39°38'W, 731 m, epibenthic sled, 6 February 1968, USCGC Glacier, IWSOE cruise 1, stn 0001. — 1 male, 9.5 mm, NMV J47714 , off Enderby Land, Antarctica, Southern Ocean, 65°50.10'S 50°34.30'E to 65°50.30'S 50°34.90'E, 540 m, rock with mud and clay patches, WHOI epibenthic sled, M. Norman, MS Nella Dan, stn HRD 011. — 1specimen, 6.0 mm, NMV J38225 , Amery Depression, Antarctica, 68°04.36'S 72°17.81'E to 68°04.44'S 72°18.11'E, 765 m, epibenthic sled, 17 February 1993, M. O’Loughlin on RSV Aurora Australis , stn AA93-151 .

Type locality. Schollaert Channel , Palmer Archipelago, Antarctica, [approx. 64°30'S 62°50'W], 160–335 m depth .

Description. Head with lateral cephalic lobe subtriangular,

apically subacute; eyes apparently absent. Antenna 1 peduncular articles 1 and 2 with weakly developed anterodistally rounded lobe; accessory flagellum 2- articulate, terminal article small, offset; flagellum with strong 2-field callynophore; robust setae present on proximal articles; calceoli absent.Antenna 2 flagellum short, calceoli absent. Epistome/upper lip with upper lip slightly produced, straight. Mandible molar columnar, with subcircular or oval, fully triturating surface; palp attached distally, article 3 with proximal A3-seta. Maxilla 1 outer plate with setal-tooth 7 cuspidate distally along inner margin; palp distal margin with apical robust setae. Maxilliped outer plate with 2, long, (one slender, one broad) apical robust setae.

Gnathopod 1 subchelate; coxa large, about as long as coxa 2, subrectangular with straight anterior margin; basis sparsely setose along anterior margin; ischium short; carpus long (2.4 × breadth), longer than propodus, without posterior lobe; propodus small, margins subparallel, palm acute. Gnathopod 2 palm slightly obtuse. Pereonite 3 with middorsal carina. Pereonite 4 with mid-dorsal carina. Pereopod 4 coxa with a weak posteroventral lobe (posterior margin concave). Pereonite 5 with mid-dorsal carina. Pereopod 5 coxa with distinct lateral ridge; basis about as long as broad, posterior margin with mid-central spine; with welldeveloped posteroventral lobe. Pereonite 6 with mid-dorsal carina. Pereonite 7 with mid-dorsal carina. Pereopod 7 basis posterodistally produced, not reaching merus, not posterodistally excavate.

Pleonite 1 with mid-dorsal carina. Pleonite 2 with middorsal carina. Pleonite 3 with mid-dorsal carina, dorsodistally produced, apically rounded, posterodorsal margin produced. Epimeron 3 posterior margin smooth, posteroventral corner broadly rounded. Urosomite 1 with a narrow vertically produced recurved acute spine. Uropod 3 outer ramus article 2 short, with plumose setae on each ramus. Telson deeply cleft, without dorsal robust setae, with 1 apical robust seta on each lobe.

Remarks. We have examined the type material of L. xenopus and, in all three specimens, the dorsal projection on pleonite 3 is more rounded than indicated in K.H. Barnard’s whole-animal figure of the male holotype. All six specimens recorded here have similar projections on pleonite 3 and urosomite 1, and a rounded posteroventral lobe on pereopod 5 basis. Five of the six specimens have a well-developed spine on the mid-posterior margin of pereonite 5 basis, as K.H. Barnard showed for his “juvenile” (an immature male). The 6 mm specimen from the Amery Depression has a rounded lobe on the posterior margin, similar to that of the holotype male and paratype female.

Distribution. Antarctic Peninsula, South Georgia, South Shetland Islands, Weddell Sea, Enderby Land and Amery Depression, Antarctica; 130–1080 m depth.

Figures

Figure 10. Lepidepecreoides xenopus K.H. Barnard. Whole figure: paratype