Dulichiella pacifica Lowry & Springthorpe, 2005

Published, First, 2007, A revision of the tropical / temperate amphipod genus Dulichiella Stout, 1912, and the description of a new Atlantic genus Verdeia gen. nov. (Crustacea: Amphipoda: Melitidae), Zootaxa 1424, pp. 1-62 : 40-43

Dulichiella pacifica Lowry & Springthorpe, 2005

( Figs 30–32)

Dulichiella appendiculata . – Ledoyer, 1986: 187, fig. 9 N Cal. – Berents, 1983: 111, fig. 9.

Dulichiella pacifica . – Lowry & Springthorpe, 2005: 292, figs 54–57.

Type material. Holotype male, 4.4 mm, AM P61112, between Tandai Point and Koilo Point, Guadalcanal, Solomon Islands (09º22.5'S 159º52.2'E), coral rubble, 10 m, R. T. Springthorpe , 24 September 1991, SI–3 . Paratypes: 1 female, 5.9 mm, AM P61113 , same as type locality; 9 specimens (1 male, 5 ovigerous females, 3 non-ovigerous females), AM P61117 , same as type locality; 1 male "b", 4.1 mm, AM P61114 ; 4 males, AM P61115 , Tandai Point , Guadalcanal, Solomon Islands, 9º23'S 159º52.5'E, sand with low algal turf, 20 m, hand dredge, R. T . Springthorpe , 11 October 2001, SI–36 ; 1 male, AM P61116 , same locality, black finger sponges from rubble bottom, 16 m, R. T . Springthorpe , 11 October 2001, SI–38 .

Type locality. Coral rubble between Tandai Point and Koilo Point, Guadalcanal, Solomon Islands (9°22.5'S 159° 52.2'E) .

Description. Based on holotype male "a", AM P61112, paratype female, AM P61113, and paratype male "b", AM P61114. Body small. Head eyes round; lateral cephalic lobe broad, truncated, anteroventral corner with slender seta. Antenna 1 peduncular article 1 shorter than article 2, with 3 robust setae along posterior margin. Antenna 2 peduncular article 2 cone gland reaching at least to end of peduncular article 3; article 4 subequal to article 5. Mandibular palp article 1 about as long as broad, inner margin produced distally; article 2 subequal to article 3.

Gnathopod 1 coxa anteroventral corner not produced, anterior margin straight, posteroventral corner notch present; carpus subequal in length to propodus; propodus small, linear, palm convex, without posterodistal corner, with posterodistal robust setae. Gnathopod 2 coxa posteroventral corner notch present; (larger) propodus distolateral crown with 4 rounded or subacute spines, fourth spine well developed, palm straight, posterodistal corner produced, upturned, dactylus fitting into corner; dactylus apically blunt; (smaller) merus with sharp posteroventral spine; palm convex, without robust setae, posterodistal corner with robust setae; dactylus with 1 or 2 setae on anterior margin. Pereopod 5 dactylar unguis anterior margin with accessory spine. Pereopods 6–7 carpus and propodus with bunches of long slender setae. Pereopod 6 basis posterior margin slightly concave; dactylar unguis anterior margin with one accessory spine. Pereopod 7 basis posterior margin straight.

Pleonite/urosomite dorsal spine formula (7-7-7-5-4/6-2). Pleonites 1–3 with sparse dorsal setae. Epimeron 1 posteroventral corner with small acute spine. Epimeron 2 posteroventral corner acute. Epimeron 3 posteroventral margin smooth. Urosomite 1 with 5 dorsal spines. Urosomite 2 with two groups of 1–3 small dorsolateral robust setae. Urosomite 3 without dorsal setae, with 2 dorsal spines. Uropod 3 outer ramus very long, about 2 x peduncle. Telson with dorsal robust setae.

Female (sexually dimorphic characters). Gnathopod 2 subequal in size, similar to smaller gnathopod 2 of male; palm concave; dactylus posterior margin smooth, with 5 setae on anterior margin. Pereopod 7 basis expanded, posterior margin convex and tapering distally.

Habitat. Marine epibenthic, living among coral rubble, sponges, sand and low algal turf in 10 to 20 m depth.

Remarks. Dulichiella pacifica has four spines on the distolateral crown of male gnathopod 2 and a 7-7-7- 5-4/6-2 pleonite/urosomite formula. Four other species share these characters: D. appendiculata ; D. fresnelii ; D. lecroyae ; and D. cuvettensis .

Dulichiella pacifica is most similar to D. cuvettensis and D. fresnelii . It differs from D. cuvettensis in having one accessory spine on the dactyli of pereopods 5 to 7 (two accessory spines in D. cuvettensis ) and in having bunches of long, slender setae on the carpus and propodus of male pereopods 6 and 7 which are absent in D. cuvettensis . The corner of male gnathopod 1 palm is rounded in D. pacifica and subquadrate in D. cuvettensis .

Dulichiella pacifica differs from D. fresnelii in the posterior margin of the basis of pereopod 6 which is concave in D. pacifica and straight in D. fresnelii and in the posterior margin of the basis of pereopod 7 which is straight in D. pacifica and tapering distally in D. fresnelii .

Dulichiella pacifica differs from D. appendiculata in the much less setose male pereopods 6 and 7 and in having a single accessory spine on the dactyli of the pereopods ( D. appendiculata has two spines). Dulichiella pacifica differs from D. lecroyae in the female gnathopod 2 which has a longer carpus and propodus and a smooth posterior margin on the dactylus (crenulate posterior margin in D. lecroyae ). In addition the posterior margin of the basis of pereopod 6 is concave in D. pacifica and straight in D. lecroyae .

Dulichiella pacifica is a common shallow-water species in Singapore, New Guinea, New Caledonia, the Solomon Islands and north-eastern Australia. J.L. Barnard (1965) did not report a species of Dulichiella from Micronesia and Myers (1985) did not report a Dulichiella from Fiji.

Distribution. Australia. Queensland: Yonge Reef; Lizard Island; Great Barrier Reef. Singapore. New Guinea. Madang Lagoon. Solomon Islands. Guadalcanal. New Caledonia: Poé Plage; Thio; South-east Lagoon (all Lowry & Springthorpe, 2005).