Lepidepecreum tourville, Lowry & Stoddart, 2002

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 : 360-363

Lepidepecreum tourville n.sp.

Figs. 23–25

Type material. HOLOTYPE, female, ovigerous (9 eggs), 5.8 mm, NMV J47730 ; 1 PARATYPE, male, 5.6 mm, NMV J17159 ; 3 PARATYPES, (2 ovigerous females, 1 immature), AM P57739 ; 48 km ENE Cape Tourville , Tasmania, Australia, 42°00.25'S 148°43.55'E to 41°57.77'S 148°42.08'E, 1264– 1130 m, gravel with lumps of sandy mud aggregate, WHOI epibenthic sled, G.C.B. Poore et al., 30 October 1988, RV Franklin stn SLOPE 81. —1 PARATYPE, immature, NMV J47731 , S of Point Hicks , Victoria, Australia, 38°25.90'S 148°58.60'E, 1850 m, muddy, sandstone, WHOI epibenthic sled, G.C.B. Poore et al., 22 July 1986, RV Franklin stn SLOPE 25. —1 PARATYPE, ovigerous female, NMV J47732 , S of Point Hicks , Victoria, Australia, 38°25.00'S 149°0.00'E, 1500 m, compacted clay, WHOI epibenthic sled, G.C.B. Poore et al., 22 July 1986, RV Franklin, stn SLOPE 27 .

1 PARATYPE, female, NMV J47733 , ESE of Nowra , NSW, Australia, 54 km 34°52.72'S 151°15.04'E, 996 m, mud, fine sand, fine shell, WHOI epibenthic sled, G.C.B. Poore et al., 22 October 1988, RV Franklin stn SLOPE 53 .

Type locality. 48 km ENE of Cape Tourville , Tasmania, Australia, 42°00.25'S 148°43.55'E to 41°57.77'S 148°42.08'E, 1264– 1130 m depth .

Description. Based on holotype female, 5.8 mm. Body expanded to form a lateral bulge. Head with lateral cephalic lobe semidome, apically subacute. Antenna 1 peduncular article 1 with well-developed anterodistally subacute lobe; article 2 without anterodistal lobe; accessory flagellum 2- articulate; flagellum with weak 1-field callynophore; robust setae absent from proximal articles; calceoli absent. Antenna 2 peduncular article 3 elongate; flagellum short, calceoli absent. Epistome/upper lip with epistome produced beyond upper lip, broadly rounded. Mandible molar columnar with oval, fully triturating surface; mandibular palp attached proximally, article 3 without proximal A3-setae. Maxilla 1 outer plate with left and right setal-tooth 7 asymmetrical, cuspidate distally; palp distal margin with apical robust setae. Maxilliped outer plate with 1 short, slender apical robust seta.

Gnathopod 1 subchelate; coxa large, about as long as coxa 2, subrectangular with straight anterior margin; basis moderately setose along anterior margin; ischium short; carpus long, subequal in length to propodus, without posterior lobe; propodus with margins subparallel, palm acute, entire, straight. Gnathopod 2 palm obtuse. Pereopod 4 coxa without distinct lateral ridge, with a well-developed posteroventral lobe. Pereonite 5 dorsally smooth. Pereopod 5 coxa without distinct lateral ridge, without umbo, basis about as long as broad. Pereopod 7 basis posterodistally produced less than halfway along merus.

Pleonite 1 with mid-dorsal carina, acutely produced posterodistally. Pleonite 2 with mid-dorsal carina, acutely produced posterodistally. Pleonite 3 with mid-dorsal carina, produced dorsodistally, apically acute, posterodorsal margin produced. Epimeron 3 posterior margin smooth, posteroventral corner subquadrate. Urosomite 1 projecting over urosomite 2, dorsodistally acute. Uropod 3 inner and outer rami well developed; outer ramus article 2 short; without plumose setae on rami. Telson moderately or slightly cleft, with dorsal robust setae, with 1 apical robust seta on each lobe.

Male (sexually dimorphic characters). Based on paratype male, 5.6 mm.Antenna 2 flagellum elongate, calceoli absent. Uropod 3 with plumose setae on each ramus.

The only male specimen available for this species is not fully mature; although antenna 2 is long, another moult can be seen inside. The final male stage may develop calceoli.

Etymology. Named for Cape Tourville, near the type locality.

Remarks. Lepidepecreum tourville is the only Australian species of Lepidepecreum without a greatly produced basis on pereopod 7. However it does have an anterodistal lobe on peduncular article 1, but not on article 2 and it has dorsodistally produced pleonites 1 to 3, a combination of characters which also occurs in the group of taxa with a large basis on pereopod 7. In fact L. tourville appears to be most similar to L. clypodentatum . They differ mainly in the dorsodistal lobe of antenna 1, which is more rounded in L. clypodentatum , and in the development of the basis of pereopod 7.

Distribution. Southeastern Australia, Tasman Sea; 996– 1850 m depth.

Figures

Figure 23. Lepidepecreum tourville n.sp. Holotype female,

Figure 24. Lepidepecreum tourville n.sp. Holotype female, 5.8 mm, NMV J47730; paratype male, 5.6 mm, NMV J17159; Cape Tourville, Australia. Scales represent 0.2 mm.

Figure 25. Lepidepecreum tourville n.sp. Holotype female, 5.8 mm, NMV J47730; paratype male, 5.6 mm, NMV J17159; Cape Tourville, Australia. Scales for U1–3 represent 0.1 mm, remainder represent 0.5 mm.