Elasmopus leveque, Hughes & Lowry, 2011

Hughes, L. E. & Lowry, J. K., 2011, The genus Elasmopus (Crustacea: Amphipoda: Maeridae) in Australian waters, Journal of Natural History 45 (9 - 10), pp. 579-628 : 598-602

Elasmopus leveque sp. nov.

( Figures 7–9 )

Type locality

Cygnet Bay, Cape Leveque, Buccaneer Archipelago, Western Australia (16 ◦ 28 ′ 39 ′′ S 123 ◦ 02 ′ 46 ′′ E).

Type material

Holotype dissected male 6.1 mm, WAM C45485 . Paratypes: 1 dissected female, 5.0 mm. WAM C45486; 10+ specimens, WAM C45487; 1 dissected male specimen, 3 slides, AM P.81005, Cygnet Bay, Cape Leveque, Buccaneer Archipelago , Western Australia (16 ◦ 28 ′ 39 ′′ S, 123 ◦ 02 ′ 46 ′′ E), collected by hand on snorkel, 10 April 2008, coll. J. Jelbart (MI WA 1069); 9 specimens, AM P.81006, Cygnet Bay , Cape Leveque , Buccaneer Archipelago , Western Australia (16 ◦ 28 ′ 39 ′′ S, 123 ◦ 02 ′ 46 ′′ E) 2 m, off floating rope line, by hand on snorkel, 10 April 2008, coll. J. Jelbart (MI WA 1068) .

Additional material examined

Western Australia. 3 specimens, AM P.80017, reef front south of Tantabiddy, Ningaloo Reef (21 ◦ 54 ′ 37 ′′ S, 113 ◦ 55 ′ 42 ′′ E), 9 m, coarse sediment, 12 June 2008, coll. N.L. Bruce and M. Blazewicz-Paszkowycz (MI WA 973) . Northern Territory. 6 specimens, AM P.81013, pontoon off Stokes Hill Wharf, Darwin Harbour (12 ◦ 28 ′ 12 ′′ S, 130 ◦ 50 ′ 54 ′′ E), 0.3 m at low tide, from algal scrapings, collected by hand, 22 November 2000, coll. R. A. Peart (NT 255) .

Etymology

Named from the type locality, Cape Leveque.

Description

Based on holotype male, 6.1 mm, WAM C45485 .

Head. Eyes subovate; lateral cephalic lobe broad, apically truncate, anteroventral margin with notch / slit. Antenna 1 longer than antenna 2; peduncular article 1 subequal in length to article 2, with one robust seta on posterodistal margin; article 2 longer than article 3; flagellum with 14 articles; accessory flagellum short, tri-articulate. Antenna 2 peduncular article 4 subequal to article 5; flagellum with nine articles. Mandible molar well developed, triturative; accessory setal row with three setae; palp tri-articulate;

article 1 twice as long as broad, shorter than article 2; article 2 slightly shorter than article 3; article 3 short (2.7 times as long as broad), strongly falcate, longer than article 1, with comb of short robust setae along anterodistal margin and three apical setae. Lower lip outer lobes with single pair of ducts; mandibular lobes apically rounded.

Pereon. Gnathopod 1 coxa anterior margin slightly concave, anteroventral corner produced, rounded; carpus about twice as long as broad, subequal in length to propodus, with rows of long slender setae; propodus anterior margin with rows of long slender setae, palm acute, straight, entire, defined by posterodistal corner, with posterodistal robust seta. Gnathopod 2 subchelate; basis slender; merus with rounded distoventral corner; carpus compressed, projecting between merus and propodus; propodus expanded, anterior margin with rows of short slender setae, posterior margin and medial surface with rows of short slender setae, palm about half length of propodus, acute, straight, smooth, subtriangular distomedial shelf with two robust setae on shelf, subpalmar surface with subacute seam, without posteroventral corner and posterodistal robust setae; dactylus closing along and reaching end of palm, apically subacute. Pereopod 4 coxa posteroventral lobe slightly developed, with rounded posteromedial corner. Pereopod 5 basis expanded; posterior margin slightly convex, without long slender setae, posteroventral corner subquadrate; carpus and propodus

without long, slender setae along anterior margin. Pereopod 6 basis posterior margin convex proximally, castelloserrate, excavate distally, without long slender setae, posteroventral corner produced distally, lobate; merus and carpus broadened; carpus and propodus without long, slender setae along margins. Pereopod 7 basis posterior margin convex, castelloserrate, without long slender setae, produced posterodistally, posteroventral corner subquadrate; merus and carpus not broadened; propodus slightly expanded.

Pleon. Epimera 1–3 posteroventral corner with small subacute tooth. Urosomites 1–3 dorsally smooth, without carina. Uropod 1 peduncle with two basofacial robust setae; rami subequal in length. Uropod 2 rami subequal in length to peduncle; outer ramus slightly shorter than inner ramus. Uropod 3 rami distally truncated, apical robust setae long and short; inner ramus short (length 1.9 × breadth), shorter than outer ramus; outer ramus, subequal in length to peduncle. Telson moderately cleft (30–65%), broader than long, truncated distally, apical margins concave, each lobe with two short and two long apical robust setae and pair of lateral plumose setae.

Remarks

Elasmopus leveque sp. nov., E. otus sp. nov. and E. pectenicrus (Bate, 1852) are similar in the form of the male gnathopod 2 propodus palm with dense setal brush and the pectinate margin of pereopod 6. The gnathopod 2 subpalmar seam is developed midway along the propodus and subacute in E. leveque sp. nov. and E. otus sp. nov., which separates them from E. pectenicrus where the seam is long and rectangular. In E. leveque sp. nov. the pereopod 6 basis posterior margin is straight with a subquadrate posterodistal corner. In E. otus sp. nov. pereopod 6 has an outstanding subjugate flap on the basis posterodistal corner, while in E. pectenicrus the basis posterior margin is convex with abruptly quadrate distoventral corner. Elasmopus leveque sp. nov. can be further separated from the latter species by the presence of two basofacial robust setae on uropod 1.

Distribution

Australia. Western Australia: Ningaloo Reef; Cape Leveque (current study) . Northern Territory: Darwin (current study).

Figures

Figure 7. Elasmopus leveque sp. nov., holotype male, 6.1 mm WAM C45485, Cygnet Bay, Cape Leveque, Western Australia.

Figure 8. Elasmopus leveque sp. nov., holotype male, 6.1 mm WAM C45485; paratype female 5.0 mm, WAM C45486, Cygnet Bay, Cape Leveque, Western Australia.

Figure 9. Elasmopus leveque sp. nov., holotype male, 6.1 mm WAM C45485, Cygnet Bay, Cape Leveque, Western Australia.