Cymadusa wistari Peart, 2007

Hughes, L. E. & Lowry, J. K., 2009, Ampithoidae *, Zootaxa 2260 (1), pp. 153-219 : 204-207

Cymadusa wistari Peart, 2007

( Figs 31 , 32 )

Cymadusa wistari Peart, 2007a: 46 , figs 37–40.

Material examined. Holotype, male, AM P62534 ( QLD 1336 ); paratype, female, 8 mm, AM P62535 ( QLD 1371 ).

Type locality. Northern Reef Flat, Heron Island, Queensland, Australia (23º27’S 151º55’E), living on Dictyota sp. , Padina sp. and Sargassum sp. , 0.5 m.

Description. Based on holotype, male, 6 mm, AM P62534.

Head. Head as long as deep. Antenna 1 longer than antenna 2; peduncular article 1 subequal to article 2; flagellum 45 articles; accessory flagellum with 1 article. Antenna 2 peduncle not densely setose on ventral margin; article 4 subequal in length to article 5; flagellum 33 articles. Upper lip directed nearly straight down, lateral margins each with midlateral notch. Mandible molar well developed, triturating, accessory setal row with 7 serrate setae; palp 3–articulate, marginally setose; article 1 shorter than article 2; article 2 subequal in length to article 3, slender setae present. Lower lip outer plates notched, forming a medial excavation, lateral lobe distinctly longer than medial lobe; mandibular lobe with curved margins, subacute apically. Maxilla 1 inner plate with 4 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 smaller than gnathopod 2, with long, dense, setae on margins; coxa larger than coxa 2, produced, anterior margin concave, anteroventral corner rounded, with ventral row of slender setae of varying lengths; basis shorter than coxa, with small anterodistal lobe, anterodistal corner without setae; merus posterodistal lobe subacute; carpus about 1.75 x as long as broad, longer than propodus, anterior margin with slender setae, posterior margin subacute; propodus narrow, subovoid; palm acute, convex, with posterodistal corner rounded, with 1 robust seta defining palm; dactylus subequal in length to palm, tapering evenly, inner margin crenate. Gnathopod 2 with long, dense, setae on margins, coxa with long, plumose setal fringe on ventral margin, basis with medial fringe of long, slender setae, anterodistal lobe absent, anterodistal corner without setae; merus margin with short, subacute distal lobe, anterior margin with fringe of slender setae; carpus shorter than propodus, subtriangular; propodus broad, less than 1.5 x as long as broad, subovoid, not produced into an anterodistally setose lobe, anterior margin with fringe of slender setae; palm acute, entire, with short (length 1 x breadth) posterodistal tooth, apically subacute, with 1 robust seta defining palm; dactylus subequal in length to palm, tapering evenly, apically acute, inner margin crenate. Pereopods 3–4 basis slightly expanded; merus subequal in length to carpus. Pereopods 5–7 simple. Pereopod 5 without medial slender setae; distal articles slender; propodus not expanded distally, with 3 anterodistal striated robust setae; dactyl us slightly curved. Pereopod 6 basis posterior margin straight, with several marginal robust setae; distal articles slender; propodus slightly expanded distally, with 3 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 12 robust setae, with short fringe of slender setae (less than 0.5 x length of peduncle), with large, acute distoventral spine; outer ramus with 5 lateral robust setae; inner ramus with 9 lateral robust setae. Uropod 2 peduncle with 5 robust setae; outer ramus with 8 lateral robust setae; inner ramus with 9 lateral robust setae. Uropod 3 peduncle longer than broad, less than 2 x length of rami, without marginal slender setae, with 5 distal robust setae, with 3 distal slender setae; outer ramus with 2 large recurved distal robust setae, with 1 lateral robust seta, without lateral slender setae; inner ramus with 3 distal slender setae, with 2 lateral and 1 medial robust setae. Telson subrectangular, apically rounded, with small apical cusp on each distolateral corner, with 4 pairs of oblique medial slender setae, with 4 pair of lateral and 2 pair of apical slender setae.

Female (sexually dimorphic characters). Based on paratype, female, 8 mm, AM P62535. Gnathopod 1 subequal in size to gnathopod 2; coxa with a tuft of slender setae in the posteroventral corner; basis subequal in length to coxa; merus anterior margin without fringe of slender setae; carpus about 2 x as long as broad, subequal in length to propodus. Gnathopod 2 coxa with cluster of slender setae on posterodistal margin; basis with sparse slender setae, anterodistal lobe rounded, anterodistal corner with 1 slender seta; merus anterior margin without fringe of slender setae; carpus subequal to propodus; palm with posterodistal corner rounded.

Habitat. Brown algae Padina australis , Dictyota sp. and Sargassum sp.

Remarks. Cymadusa wistari is one of the densely setose group of Cymadusa species which includes: C. filosa Savigny, 1816 ; C. setosa ( Haswell, 1879) ; C. tattersalli Peart, 2004 and C. thagaay Peart, 2007a . Cymadusa wistari is most similar to C. tattersalli and C. thagaay which all have a rectolinear carpus on the male gnathopod 1 which is subequal in length to the propodus. In C. filosa and C. setosa the male carpus is extremely elongate and greater than 1.5 times the propodus.

Cymadusa wistari and C. tattersalli can be separated from C. thagaay , which has less setae along the medial margins of the basis of the male gnathopods 1 and 2. Cymadusa wistari differs from C. tattersalli by the ratio of antenna 1 to 2. Antenna 1 is longer than 2 in C. wistari and subequal in C. tattersalli . Also the straight palm on the propodus of the male gnathopod 2 in C. wistari is distinct from the acute palm with proximal subquadrate projection in C. tattersalli .

Distribution. Australia. Queensland: Heron Island ( Peart 2007a).

Figures

FIGURE 31. Cymadusa wistari Peart, 2007a, holotype, male, 8 mm, AM P62534, paratype female, 6 mm, AM P62535, Heron Island, Great Barrier Reef (based on Peart 2007a).

FIGURE 32. Cymadusa wistari Peart, 2007a, holotype, male, 6 mm, AM P62534, paratype female, 8 mm, AM P62535, Heron Island, Great Barrier Reef (based on Peart 2007a).