Cymadusa khbarnardi Hughes & Lowry

Hughes, L. E. & Lowry, J. K., 2009, Ampithoidae *, Zootaxa 2260 (1), pp. 153-219 : 188-191

Cymadusa khbarnardi Hughes & Lowry sp. nov.

( Figs 21 , 22 , Pl. 1G)

Type material. Holotype, male, 9.0 mm, 2 slides, AM P76756, Mermaid Cove , Lizard Island (14°38.91’S 145°27.26’E), mixed brown algae, sand with rubble bottom, 3.5 m, T. Krapp-Schickel, 28 February 2005 ( QLD 1732 ) . Paratypes: female, 11.0 mm, 3 slides, AM P76757 ( QLD 1732 ) ; 3 unsexed, AM P76758 ( QLD 1732 ) .

Additional material examined. 1 unsexed, AM P76760 ( JDT /LIZ-14); male, photo 6, AM P71123 ( QLD 1730); 1 unsexed, AM P71321 ( QLD 1787); 1 unsexed, AM 76759 ( QLD 1799).

Type locality. Mermaid Cove , Lizard Island (14°38.91’S 145°27.26’E), mixed brown algae, sand with rubble bottom, 3.5 m depth .

Etymology. Named for Keppel Harcourt Barnard, the first student of Great Barrier Reef amphipods.

Description. Based on holotype, male, 9.0 mm, AM P76756.

Head. Head slightly longer than deep. Antenna 1 longer than antenna 2; peduncular article 1 subequal to article 2; flagellum 30 articles; accessory flagellum with 1 article. Antenna 2 peduncle not densely setose on ventral margin; article 4 subequal in length to article 5; flagellum 26 articles. Mandible molar well developed, triturating; accessory setal row with 5 robust serrate setae; palp 3–articulate, article 3 apically setose; article 1 longer than article 2; article 2 shorter than article 3; article 3 longer than article 1. Lower lip outer plates notched, forming a slight medial excavation; mandibular lobe with curved margins, rounded apically. Maxilla 1 inner plate with 2 setae; palp article 2 broad. Maxilla 2 inner plate narrower than outer plate. Maxilliped outer plate with row of large robust setae along medial margin.

Pereon. Coxae 1–4 deeper than broad. Gnathopod 1 subequal in size to gnathopod 2; coxa subequal to coxa 2, slightly produced, anterior margin convex, anteroventral corner rounded, with a tuft of slender setae in the posteroventral corner; basis longer than coxa, anterodistal lobe absent; merus posterodistal lobe subacute; carpus about 3 x as long as broad, longer than propodus, anterior margin with slender setae distally, posterior margin straight; propodus broad, subtriangular; palm acute, straight, with posterodistal corner rounded, with 1 robust seta defining palm; dactylus subequal in length to palm, apically acute, inner margin crenate. Gnathopod 2, coxa with a tuft of slender setae in the posteroventral corner; basis with sparse slender setae, anterodistal corner with 1 slender seta; merus margin with long, rounded anterodistal lobe; carpus much shorter than propodus, subtriangular; propodus broad, less than 1.5 x as long as broad, subquadrate, not produced into an anterodistally setose lobe; palm acute, excavate, with posterodistal corner subquadrate, without palm defining robust setae; dactylus shorter than palm, tapering evenly, apically acute, inner margin crenate, with 3 groups of long slender setae on anterior margin. Pereopods 3–4 basis narrow; merus subequal in length to carpus. Pereopods 5–7 simple. Pereopod 5 without medial slender setae; distal articles slender; propodus not expanded distally, without anterodistal striated robust setae; dactylus slightly curved. Pereopod 6 basis posterior margin straight, with several marginal robust setae; distal articles slender; propodus not expanded distally, without anterodistal striated robust setae; dactylus slightly curved. Pereopod 7 similar to pereopod 6.

Pleon. Epimera 2–3 posteroventral corner broadly rounded. Uropod 1 peduncle with 7 robust setae, with short fringe of slender setae (less than 0.5 x length of peduncle), with large, acute distoventral spine; outer ramus length about 5–6 x as long as broad, with 9 lateral robust setae; inner ramus with 10 lateral robust setae. Uropod 2 peduncle with 3 robust setae; outer ramus with 7 lateral robust setae; inner ramus with 12 lateral robust setae. Uropod 3 peduncle longer than broad, less than 2 x length of rami, marginal slender setae present, with 5 distal and 2 lateral robust setae, with 2 distal slender setae; outer ramus with 2 large recurved distal robust setae, with 1 lateral robust seta and 4 lateral slender setae; inner ramus with 6 distal slender setae, with 2 lateral robust setae. Telson subtrapezoidal, apically truncated, with small apical cusp on each distolateral corner, with 4 pair of oblique medial slender setae, with 4 pair of lateral slender setae, and 1 pair of apical plumose setae.

Female (sexually dimorphic characters). Based on paratype, female, 11.0 mm, AM P76757. Gnathopod 1 subequal in size to gnathopod 2; coxa anteroventrally produced, anterior margin concave; basis shorter than coxa, anterodistal lobe rounded, without setae; merus anterodistal lobe acute; carpus about 2 x as long as broad, shorter than propodus. Gnathopod 2 basis without setae, anterodistal lobe without setae; carpus shorter than propodus; propodus subrectangular; palm straight; dactylus subequal in length to palm, inner margin crenate .

Colour. Body clear to white with small dark brown and white spots, eyes with red ommatidia in a white matrix.

Habitat. Brown algae.

Remarks. Cymadusa khbarnardi sp. nov. is similar to C. grossimana Ledoyer, 1984 from New Caledonia, in the propodus and palm shape of gnathopod 2. These species differ as follows: in C. khbarnardi the carpus of gnathopod 1 is extremely elongate (longer than the propodus) and rectolinear, while in C. grossimana it is subequal in length to the propodus.

Cymadusa khbarnardi sp. nov. forms a group with two other GBR species C. imbroglio Rabindranath, 1972 and C. smilodonta sp. nov. based on the large sized individuals with submassive, broadly rounded propodus of male gnathopod 2. These species may be distinguished from one another by the sculpting on the palm of gnathopod 2. In Cymadusa khbarnardi the palm of gnathopod 2 is excavate and smooth, while in C. imbroglio it has a midmedial projection and in C. smilodonta it has a proximal palmar projection.

Distribution. Australia. Queensland: Lizard Island (current study).

Figures

FIGURE 21. Cymadusa khbarnardi Hughes & Lowry sp. nov., holotype, male, 9.0 mm, AM P76756, Lizard Island, Great Barrier Reef.

FIGURE 22. Cymadusa khbarnardi Hughes & Lowry sp. nov., holotype, male, 9.0 mm, AM P76756, paratype, female, 11.0 mm, AM P76757, Lizard Island, Great Barrier Reef.