Dulichiella cuvettensis, Appadoo & Myers, 2005

Appadoo, C & Myers, AA, 2005, Amphipods of the Genera Ceradocus, Dulichiella, Melita and Nuuanu (Crustacea: Melitidae) from Mauritius, Indian Ocean, Records of the Australian Museum 57, pp. 221-236 : 225-227

Dulichiella cuvettensis n.sp.

Fig. 4

Melita appendiculata .– Ledoyer, 1978:282;Appadoo & Steele, 1998: 639. (Not Gammarus appendiculatus Say, 1818: 377–379 ).

Type material. HOLOTYPE 3, 3.3 mm, AM P67233, from Sargassum sp. at depth less than 1 m, La Cuvette (20°00'S 57°34.2'E), Mauritius, C. Appadoo, 12 October 1999. PARATYPES: 13, 1♀, from Sargassum sp. , La Cuvette (20°00'S 57°34.2'E), 14 May 1998. 1♀ from Turbinaria sp. , Bain Boeuf (19°59'S 57°36'E), 15 May 1998; 13, 3♀♀ from Acanthophora spicifera, Anse la Raie (19°59.5'S 57°37.5'E), 15 May 1998; 533, 3♀♀ and 4 juv. from Sargassum binderi, Bain Boeuf , 16 June 1998; 13, 2♀♀ from Sargassum sp. and Padina sp. , Ile D’Ambre (20°02'S 57°40'E), 12 November 1998; 13 from Sargassum sp. and Ulva reticulata, La Cuvette , 5 May 1999; 13 from Padina sp. and Halimeda sp. , Grand Baie (20°0.5'S 57°34'E), 5 May 1999; 13, 1♀, from mixture of Padina sp. , Pocockiella variegata and Sargassum sp. , Bain Boeuf; 233 and 1♀, AM P67234, from Sargassum sp. and Pocockiella variegata, Bain Boeuf , 12 October 1999.

Description. Male length, 4 mm. Head without subocular notch; eyes round with well-developed ommatidia. Antenna 1 poorly setiferous, peduncle article 1 with 3 stout robust setae on ventral margin; article 2 longest, 1.5× article 1; article 3, 0.3× the length of article 1; accessory flagellum 4-articulate, primary flagellum 35-articulate. Antenna 2 weakly setiferous, peduncular article 4 subequal to 5, flagellum 14-articulate. Mandible palp slender, article 1 with a small tooth; article 3 slightly longer than article 2. Maxilla 1 palp, article 1 with long setae on distal margin; inner plate with 2 apical plumose setae. Gnathopod 1 coxa 1.6× as long as broad, posterodistal margin with a notch; basis slender, 4× as long as broad; propodus slightly 0.7× length of carpus, palmar margin with short and long setae; dactylus normal. Gnathopods 2 dissimilar (left and right). Larger gnathopod 2 basis without setae, and 2.3× as long as broad; carpus reduced, 3.3× as long as broad; propodus robust, distally expanded, palmar margin transverse, with 3 well-developed medial protuberances; dactylus broad throughout its length. Small gnathopod 2, coxa slightly less than 2× as long as broad, distal margin with short setae; basis slender, 3.5× as long as broad, with setae on anterior and posterior margins; merus posterodistal margin acute; propodus slightly shorter than carpus, subrectangular, palm oblique, dactylus fitting palm. Pereopod 3 coxa subrectangular with a small notch on posterodistal margin; basis anterior margin with stout short setae; propodus 1.5× length of carpus; dactylus with bifid tip. Pereopod 4 similar to pereopod 3, but coxa without posterodistal notch and weakly excavate posteriorly. Pereopod 5 basis subrectangular, slightly more than 2× as long as broad, anterior and posterior margins parallel, anterior margin with numerous robust setae, posterior margin weakly serrated with short setae; dactylus bifid. Pereopod 6 similar to pereopod 5 but basis more slender; merus and propodus with strong groups of setae on anterior and posterior margins. Pereopod 7 basis anterior margin straight, posterior margin slightly convex; other features similar to pereopod 6. Pleonites 1 and 2 with 7 teeth, median tooth and the last tooth on either side shorter than others. Pleonite 3 with 7 teeth, median tooth small, other teeth on either side of this median tooth are successively longer than one another. The concavities of the teeth of pleonites have small setae. Urosomite 1 produced into acute teeth on dorsal surface. Urosomite 2 with a small robust seta and small tooth on dorsal surface. Urosomite 3 with a small dorsal tooth. Epimeron 1 with one robust seta on distal margin, posterodistal margin rounded. Epimeron 2 posterodistal margin slightly produced, posterior margin smooth, distal margin bears 3 robust setae. Epimeron 3 posterodistal margin produced into an acute tooth, posterior margin with a very small tooth, distal margin with three robust setae. Uropod 1 slender, with robust setae, rami subequal to each other and slightly longer than peduncle; inner margin of inner ramus with very fine short setae. Uropod 2 outer ramus slightly shorter than inner ramus; peduncle 0.75× inner ramus; inner margin of inner ramus similar to that of uropod 1. Uropod 3 outer ramus 1.8× peduncle, 2-articulate, article 1 truncate, article 2 pointed; inner ramus vestigial consisting of a small oval lobe with one robust seta. Telson cleft to about three-quarter its length, telsonic lobes produced at apex. Telson with three groups of robust setae, located subapically and medially on inner and outer margins.

Female: length, 4.8 mm (mature, with eggs). Gnathopod 1 coxa 0.75× as long as broad, posterodistal margin with notch and setae; basis with setae on anterior and posterior margins; merus with a triangular process at anterodistal margin; propodus palm oblique, palm with long setae. Gnathopod 2 coxa subrectangular about as long as broad; basis anterior and posterior margins setose; ischium anterior margin sinuous; propodus slightly longer than carpus, palm oblique with setae on margins.

Remarks. Dulichiella cuvettensis n.sp. differs from D. appendiculata ( Say, 1818) in having epimeron 1 with a smoothly rounded posteroventral margin (rather than with a small acute spine) and the propodus disto-lateral margin with three (as apposed to two) subacute teeth. Dulichiella cuvettensis n.sp. is most similar to D. australis ( Haswell, 1879) but differs from that species in the strongly setose uropod 3 outer ramus as well as in the rounded posteroventral corner of epimeron 1.

Habitat. This species was collected in depths of less than 1 m. It occurs mostly on brown algae especially Sargassum sp. and was collected from sites on the north coast of the island.

Type locality. La Cuvette, Mauritius .

Distribution. Mauritius.

Etymology. Named after the type locality.