Cymadusa smilodonta Hughes & Lowry, 2009

Hughes, L. E. & Lowry, J. K., 2009, Ampithoidae *, Zootaxa 2260 (1), pp. 153-219 : 194-198

Cymadusa smilodonta Hughes & Lowry sp. nov.

( Figs 25 , 26 )

Type material. Holotype, male, 7.9 mm, 4 slides, AM P76772, south end of Yonge Reef, Yonge Reef (14°36.954’S 145°37.184’E), filamentous red algae, back reef, 7 m, L. Hughes, 3 March 2005 ( QLD 1799 ) . Paratypes: female, 7.5 mm, 4 slides, AM P76773 ( QLD 1799 ) ; 8 unsexed, AM P71367 ( QLD 1799 ) .

Additional material examined. 1 unsexed, AM P76774 ( QLD 1916); many unsexed, AM P76775 ( QLD 1948).

Type locality. South end of Yonge Reef , Yonge Reef, near Lizard Island, Queensland, Australia (14°36.954’S 145°37.184’E), filamentous red algae, back reef, 7 m depth .

Etymology. Named derived from the sabre-toothed cat genus Smilodon – greek ‘knife tooth’, referring to the large “tooth” projecting from the male gnathopod two.

Description. Based on holotype, male, 7.9 mm, AM P76772.

Head. Head as long as deep. Antenna 1 slightly longer than antenna 2; peduncular article 1 subequal to article 2; primary flagellum 19 articles; accessory flagellum absent. Antenna 2 peduncle not densely setose on ventral margin; article 4 longer than article 5; flagellum 14 articles. Upper Lip lateral margins each with midlateral notch. Mandible molar well developed, triturating, accessory setal row with 10 serrate setae; palp 3–articulate, apically setose; article 1 shorter than article 2; article 2 shorter than article 3, slender setae present; article 3 longer than article 1. 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. Maxilliped outer plate with row of large robust setae along medial margin.

Pereon. Coxae 1–4 deeper than broad. Gnathopod 1 longer than gnathopod 2; coxa distinctly larger than coxa 2, anteriorly produced, anterior margin convex, anteroventral corner rounded, with a tuft of slender setae in the posteroventral corner; basis longer than coxa, anterodistal lobe rounded, without setae; merus posterodistal lobe acute; carpus about 2 x as long as broad, subequal in length to propodus, anterior margin with slender setae, posterior margin straight; propodus broad, subrectangular; palm acute, sinusoidal, with posterodistal corner subquadrate, with 1 robust seta defining palm; dactylus overreaching palm, inner margin crenate. Gnathopod 2 coxa with a tuft of slender setae in the posteroventral corner; basis with fringe of long, slender setae, with large rounded anterodistal lobe, without setae; merus margin without lobe; carpus much shorter than propodus, cup-shaped, anterior margin with 7 robust setae; propodus broad, less than 1.5 x as long as broad; palm acute, excavate, with proximal, columnar subquadrate projection near base of dactylus, with posterodistal corner, subquadrate, without palm defining robust setae; dactylus much shorter than palm, not tapering, apically blunt, unguis minute, inner margin crenate. 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 4 robust setae, without fringe of slender setae, with large, acute distoventral spine; outer ramus length about 5–6 x as long as broad, with 6 lateral robust setae; inner ramus with 6 lateral setae. Uropod 2 peduncle with 5 robust setae; outer ramus with 9 lateral robust setae; inner ramus with 11 lateral robust setae. Uropod 3 peduncle longer than broad, more than 2 x length of rami, without marginal slender setae, with 4 distal peduncular robust setae, with 1 distal slender seta; outer ramus with 2 large recurved distal robust setae, with 1 lateral robust seta and 2 lateral slender setae; inner ramus without distal slender setae, with 2 lateral robust setae. Telson subtrapezoidal, apically rounded, with small apical cusp on each distolateral corner, with 3 pair of apical slender setae, and with 2 pair of lateral and 1 pair of apical plumose setae.

Female (sexually dimorphic characters). Based on paratype, female, 7.5 mm, AM P76773. Gnathopod 1 subequal in size to gnathopod 2; coxa anterior margin concave; basis shorter than coxa; merus anterodistal lobe acute; merus anterodistal lobe truncate; carpus posterior margin convex; propodus palm convex, with rounded corner. Gnathopod 2 basis without anterodistal lobe; carpus shorter than propodus, subtriangular; propodus palm straight, posterodistal corner rounded, with 1 robust seta defining palm; dactylus subequal in length to palm, tapering evenly, apically acute .

Habitat. Filamentous red algae.

Remarks. Cymadusa smilodonta sp. nov. is similar to the Andaman Sea species, C. chalongana Peart 2002 . However C. smilodonta has no accessory flagellum (an unusual characteristic in Cymadusa ), a setose anterior margin on the carpus, and a better developed excavation in the palm of male gnathopod 2. The male gnathopod 2 palmar projection is in a similar proximal position in both species, but it is columnar and subquadrate in C. smilodonta and apically rounded and shorter in C. chalongana .

See remarks under C. khbarnardi for comparison of other GBR species.

Distribution. Australia. Queensland: Torres Strait (current study); Lizard Island (current study); One Tree Island (current study).

Figures

FIGURE 25. Cymadusa smilodonta Hughes & Lowry sp. nov., holotype, male, 7.9 mm, AM P76772, Yonge Reef, Great Barrier Reef.

FIGURE 26. Cymadusa smilodonta Hughes & Lowry sp. nov., holotype, male, 7.9 mm, AM P76772, paratype, female, 7.5 mm, AM P76773, Yonge Reef, Great Barrier Reef.