Ceradocus cotonensis, Appadoo, Chandani & Myers, Alan A., 2006

Appadoo, Chandani & Myers, Alan A., 2006, Melitids (Crustacea: Amphipoda) of the genera Ceradocus and Mallacoota from Rodrigues Island (Indian Ocean), Zootaxa 1370, pp. 1-22 : 7-10

Ceradocus cotonensis sp. nov.

Figures 4 –6

Type material. HOLOTYPE. Male, 7.6 mm from Pointe Coton, 19 ° 40.996 ’ S 63 ° 29.883 ’ E, Rodrigues, base of limestone cliff, coral rock washings, N. Bruce, 17 September 2001, AM P 73600 .

PARATYPES. 1 male, 5.5 mm, AM P 73602 , 2 males, AM P 73601 , 3 males and 5 juveniles from Grande Pate, Mathurin Bay, 19 ° 39.307 ’S, 63 ° 24.950 ’E, 29 September 2001, loose coral rubble on hard bottom, 17 m, SCUBA, collectors N.L. Bruce & Jonathan Smith.

Description. Male length, 7.6 mm. Head, with subocular notch; eyes round with discrete ommatidia. Antenna 1, peduncle article 1 with few robust setae; article 2 slightly longer that article 1; article 3, 0.2 x article 1; accessory flagellum 5 -articulate. Antenna 2, peduncle 2.3 x length of flagellum; gland cone of article 2, 0.9 x article 1, article 5, 0.8 x article 4; flagellum 13 -articulate. Mandible palp 3 -articulate, article 1 distal corner produced; article 2 longest with slender setae on lateral margin; article 3, 0.3 x article 2, 0.8 x article 1, with long apical setae. Maxilla 2 outer plate with distal setae, inner plate with distal setae, inner marginal setae and an oblique row of setae.

Gnathopod 1 coxa 1.3 x as long as broad, antero-distal margin produced; basis 2.75 x as long as broad with one patch of long slender setae; carpus 2 x as long as broad, with groups of setae on medial and posterior margins, propodus 1.8 x as long as broad with one robust setae at postero-distal corner, palmar margin oblique, dactylus slender. Gnathopod 2 symmetrical; coxa as broad as long; basis 2.6 x as long as broad; carpus triangular, 1.1 x as broad as long; propodus 1.8 x as long as broad with few patches of setae on posterior margin; palmar margin oblique with a medial excavation, numerous robust setae, posterodistal corner slightly produced with one robust setae. Pereopod 3 coxa 1.2 x as broad as long, basis 3 x as long as broad, propodus subequal to carpus; dactylus margins smooth. Pereopod 4 similar to pereopod 3. Pereopod 5 coxa bilobed, basis 2.3 x as long as broad, posterior margin weakly serrated and lined with robust setae, postero-distal margin produced; propodus subequal to carpus; dactylus margins smooth. Pereopod 6 coxa 1.6 x as broad as long; basis 1.7 x as long as broad, posterior margin serrated, postero-distal corner produced, propodus subequal to carpus. Pereopod 7 similar to pereopod 6 except basis 1.8 x as long as broad, anterior margin of propodus with denser patches of setae. Pleonites 1–3 dorsal margin irregularly toothed. Epimeron 1-3 postero-distal margin with numerous teeth. Uropod 1 (from male, 5.5 mm), rami subequal, slender, 0.9 x length of peduncle, outer margins weakly serrated, with one robust setae between rami and three terminal robust setae. Uropod 2 rami subequal, outer ramus margin serrated, rami 1.4 x length of peduncle. Uropod 3 (from male, 5.5 mm) rami subequal, spatulate, 1.7 x length of peduncle, outer margins weakly serrated with several groups of robust setae. Telson cleft to about 60 % its length, anterior and posterior margin of telsonic lobes produced, each with a group of robust setae.

Female. Unknown

Remarks. C. cotonensis sp. nov. is characterised by symmetrical gnathopod 2. The other Ceradocus showing this feature is the species reported as Ceradocus rubromaculatus (Stimpson) by Ledoyer (1972: 213, figure 32). However, the palm in the current species is more oblique than transverse. Comparing with C. rubromaculatus described by Myers (1985: 102, fig. 79, 80) Ceradocus cotonensis sp. nov. differs by presenting numerous robust setae on the telson lobes as compared to only one in the former species.

Distribution. Rodrigues Island, Indian Ocean

Etymology. Named after the type locality Pointe Coton

Figures

FIGURE 4. Ceradocus cotonensis sp. nov., male holotype, 7.6 mm, Pointe Coton, AM P 73600. Scales: a = 1 mm (P 5, P 6, P 7), b = 0.5 mm (P 3, P 4, G 1, G 2).