Cymadusa cavimana ( Sivaprakasam, 1971 )

Hughes, L. E. & Lowry, J. K., 2009, Ampithoidae *, Zootaxa 2260 (1), pp. 153-219 : 174-178

Cymadusa cavimana ( Sivaprakasam, 1971)

( Figs 13 , 14 , Pl. 1E)

Ampithoe cavimana Sivaprakasam, 1971: 65 , fig. 1. — Appadoo & Steele, 1998: 639.

Ampithoe kergueleni . — Rabindranath, 1972: 166, figs 3, 4.

Amphithoe cavimana . —Ledoyer, 1978: 218, fig. 7. — Ledoyer, 1979a: 144, fig. 5. — Ledoyer, 1979b: 17, figs 4, 5. — Ledoyer, 1983: 116, fig. 37.

Cymadusa cavimana . — Appadoo & Myers, 2004: 343 (key).

Cymadusa jiigurru Peart, 2007a: 19 , figs 15–18 (key).

Material examined. 4 unsexed, AM P61919 ( QLD 1374 ) ; 2 unsexed, AM P61920 ( QLD 1376 ) ; 2 unsexed, AM P61921 ( QLD 1382 ) ; 1 male, 7.0 mm, AM P61916 ( QLD 1391 ) ; 1 male, AM P61916 ( QLD 1391 ) ; 1 female, AM P61917 ( QLD 1391 ) ; 1 dissected female, 7.0 mm, AM P61918 ( QLD 1391 ) ; 4 unsexed, P61918 ( QLD 1391 ); 6 unsexed, AM P61922 ( QLD 1396 ) ; 4 unsexed, AM P61923 ( QLD 1397 ) ; 1 juvenile male 7.5 mm, 4 slides, AM P76233 ( QLD 1637 ) ; 2 unsexed, AM P70861 ( QLD 1653 ) ; 2 unsexed, AM P70891 ( QLD 1653 ) ; 1 male, photo 3, AM P70795 ( QLD 1670 ) ; 1 unsexed, AM P70812 ( QLD 1670 ) ; 1 unsexed, AM P71056 ( QLD 1670 ) ; 1 unsexed, AM P76234 ( QLD 1670 ) ; 3 unsexed, AM P71203 ( QLD 1720 ) ; 2 unsexed, AM P71124 ( QLD 1730 ) ; 2 unsexed, AM P76236 ( QLD 1730 ) ; 8 unsexed, AM P71164 ( QLD 1751 ) ; many unsexed, AM P71177 ( QLD 1751 ) ; 1 unsexed, AM P76235 ( QLD 1757 ) ; 1 unsexed, AM P71261 ( QLD 1757 ) ; 4 unsexed, AM P75871 ( QLD 1856 ) ; 3 unsexed, AM P75873 ( QLD 1888 ) ; 1 unsexed, AM P75870 ( QLD 1914 ) ; 7 unsexed, AM P75872 ( QLD 1917 ) .

Type locality. Kilakkarai , Gulf of Mannar, India (~ 9.14°N 78.47°E) .

Description. Based on male, 7.0 mm, AM P61916.

Head. Head as long as deep. Antenna 1 longer than antenna 2; peduncular article 1 subequal to article 2; primary flagellum 21 articles; accessory flagellum scale-like with 1 article. Upper lip directed nearly straight down, lateral margins each with midlateral notch. Mandible molar well developed, triturating, accessory setal row with 5 serrate setae; palp 3–articulate, marginally setose; article 1 shorter than article 2; article 2 subequal 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, 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 smaller than gnathopod 2; coxa distinctly larger than coxa 2, produced, anterior margin straight, anteroventral corner rounded, with tuft of long slender setae in posteroventral corner; basis longer than coxa, anterodistal lobe rounded, with 1 slender seta; merus posterodistal lobe acute; carpus longer than propodus, anterior margin with slender setae, posterior margin straight; propodus subrectangular; palm acute, excavate, with posterodistal corner subquadrate, with 1 robust seta defining palm; dactylus overreaching palm, inner margin crenate. Gnathopod 2 coxa with tuft of long slender setae in posteroventral corner; basis with medial fringe of long, slender setae, anterodistal corner without setae; merus margin with short, acute anterodistal lobe; carpus much shorter than propodus, cupshaped; propodus subrectangular, greater than 1.5 x as long as broad; palm acute, excavate, 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 basis with medial slender setae; distal articles slender; propodus slightly expanded distally. Pereopod 6 basis posterior margin straight, with several marginal robust setae; distal articles slender; propodus not expanded distally, with 1 anterodistal striated robust seta; dactylus slightly curved. Pereopod 7 similar to pereopod 6.

Pleon. Epimera 2–3 posteroventral corner broadly rounded. Uropod 1 peduncle with 9 robust setae, with long fringe of slender setae (greater than 0.5 x length of peduncle), with large, acute distoventral spine; outer ramus with 8 lateral robust setae; inner ramus with 8 lateral robust setae. Uropod 2 peduncle with 5 robust setae; outer ramus with 8 lateral robust setae; inner ramus with 10 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 and 4 lateral slender setae; inner ramus with 3 distal slender setae, 4 apical and 2 lateral robust setae. Telson subtrapezoidal, apically truncated, with small apical cusp on each distolateral corner, with 2 pair of lateral and 2 pair of apical slender setae, and with 2 pair of lateral and 1 pair of apical plumose setae.

Female (sexually dimorphic characters). Based on female, 7.0 mm, AM P61918. Gnathopod 1 subequal in size to gnathopod 2; basis shorter than coxa; merus anterodistal lobe subacute; carpus subequal in length to propodus, posterior margin truncated; propodus subovoid; palm convex, with rounded corner, with robust seta defining palm; dactylus subequal in length to palm. Gnathopod 2 basis with sparse slender setae, anterodistal corner with 1 slender seta; carpus subequal to propodus, subtriangular; propodus broad, less than 1.5 x as long as broad; palm entire, corner rounded, with 2 robust setae defining palm; dactylus subequal in length to palm, tapering evenly, apically acute.

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

Habitat. Red and green algae, including the brown alga Turbinaria sp.

Remarks. Peart (2007a) apparently overlooked Cymadusa cavimana when she described C. jiigurru . We can find no morphological differences between these species and place C. jiigurru in synonymy with C. cavimana .

Until Appadoo & Myers (2004) C. cavimana was referred to the genus Ampithoe , but it confounds the generic diagnoses. Apparently the Indian Ocean population has no accessory flagellum ( Appadoo & Myers 2004), a character of Ampithoe , but it has a well developed distoventral spine on the peduncle of uropod 1, a character of Cymadusa . Gnathopods 1 and 2 are well-developed and enlarged, also a Cymadusa character. The material of C. cavimana from the Great Barrier Reef has a minute 1–articulate accessory flagellum, possibly overlooked in the Indian Ocean population.

Until now C. cavimana has been recorded from places in the Indian Ocean and Indonesia. This is the first record from Australian waters. It is possible that the record of Ren (2001) of C. brevidactyla ( Chevreux, 1907) might be C. cavimana .

Cymadusa cavimana is most similar to C. brevidactyla and the GBR species C. smilodonta . In Cymadusa cavimana and C. brevidactyla the male gnathopod 2 palm is defined by a right angle excavation. In C. smilodonta the excavation is rounded. Cymadusa cavimana and C. brevidactyla can also be distinguished from each other by the palm shape of male gnathopod 1, concave in C. cavimanus and convex in C. brevidactyla .

Distribution. India. Gulf of Mannar, Madras Coast ( Sivaprakasam 1971). Australia. Queensland: Torres Strait (current study), Lizard Island ( Peart 2007a; current study). Indonesia. Misool Island, Banda Sea ( Ledoyer 1979a). Madagascar. Tulear ( Ledoyer 1979b). Mauritius (Ledoyer 1978, Appadoo & Myers 2004).

Figures

FIGURE 13. Cymadusa cavimana (Sivaprakasam, 1971), male, 7.0 mm, AM P61916, paratype, female, 7.0 mm, AM P61917, Lizard Island, Great Barrier Reef (based on Peart 2007a).

FIGURE 14. Cymadusa cavimana (Sivaprakasam, 1971), male, 7.0 mm, AM P61916, juvenile male ‘a’, 7.5 mm, AM P76233, paratype female, 7.0 mm, AM P61917, juvenile, AM P76233 (QLD 1637), Lizard Island, Great Barrier Reef (based, in part, on Peart 2007a).