Dulichiella beluu, Myers, A. A., 2016

Myers, A. A., 2016, Amphipoda (Crustacea) from Palau, Micronesia: Families Maeridae and Melitidae, Zootaxa 4170 (3), pp. 451-474 : 470-473

Family Melitidae Bousfield, 1973

Dulichiella beluu sp. nov. ( Figs. 18 , 19 )

Type material. Holotype male (OUMNH.ZC. 2002-24 -160), 4.0 mm, Beluu Lukes Reef, eastern side, from coralline algae encrusted with filamentous sponge, - 6 m depth; 07°17.530'N, 134°30.870'E; leg. S. De Grave & C. Burras, 20 May 2002. Paratypes. 9 males, 7 females ( OUMNH.ZC. 2002-24 -161), same data as holotype .

Additional material. 1 female 5.7 mm, Beluu Lukes Reef, eastern side, from Spondylus sp. (Mollusca: Spondylidae ), - 10 m depth; 07°17.530'N, 134°30.870'E; leg. S. De Grave & C. Burras, 20 May 2002; 9 male, 13 female, 1 juv. Siaes Corner, from Chondrilla sp. (Porifera: Chondrillidae ), - 30 m deep; 07°18.756'N, 134°13.515'E; leg. S. De Grave & C. Burras, 22 May 2002; 1 female, Beluu Lukes Reef, reef slope, from Pericharax heteroraphus Polejaéff, 1884 (Porifera: Leucettidae ), - 15m depth; 07°17.530'N, 134°30.870'E; leg. S. De Grave & C. Burras, 27 May 2002; 6 males, 5 females, Beluu Lukes Reef, reef slope, from Leucetta sp. 2 (Porifera: Leucettidae ), - 15m depth; 07°17.530'N, 134°30.870'E; leg. S. De Grave & C. Burras, 27 May 2002; 1 male, Siaes Tunnel, inside tunnel, from Leucetta sp. (Porifera: Leucettidae ), - 35m depth; 07°18.690'N, 134°13.605'E; leg. S. De Grave & P. Colin, 31 May 2002; 2 males, 1 female, Outside Malakal Harbour, light trap sample, 190 feet deep; 07°16.366'N, 134°27.906'E; leg. S. De Grave & C. Burras, night 1–2 June 2002.

Type locality. Beluu Lukes Reef , Palau, 07°17.530'N, 134°30.870'E.

Etymology. Named after the type locality.

Description. Based on male holotype, 4.0 mm.

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 almost reaching to end of peduncular article 3; article 4 subequal to article 5. Mandible article 2 subequal with article 3.

Pereon. Gnathopod 1 coxa anteroventral corner not produced, anterior margin straight, posteroventral corner notch present (minute); palm convex, weakly defined by posterodistal corner. Gnathopod 2 coxa posteroventral corner notch absent; left larger gnathopod propodus distolateral crown with 3 rounded spines, palm sinusoidal, posterodistal corner produced, rounded, dactylus fitting against corner; dactylus apically blunt; right smaller gnathopod merus with sharp posteroventral spine; palm straight, posterodistal corner with robust seta. Pereopods 3–7 dactylar unguis anterior margin with accessory spine. Pereopods 6–7 basis, merus, carpus and propodus without bunches of long slender setae. Pereopod 6 basis posterior margin substraight; dactylar unguis anterior margin with accessory spine. Pereopod 7 basis posterior margin sinuous.

Pleon. Pleonites/urosomites dorsal spine formula (7–7–7–5–6–2). Pleonites 1–3 with sparse dorsal setae. Epimera 1–2 posteroventral corner with acute spine. Epimeron 3 posteroventral margin smooth, corner produced with well developed spine. 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 substraight; dactylus posterior margin crenulate. Pereopod 7 basis expanded, posterior margin convex and tapering distally.

Habitat. Coralline algae and sponges.

Remarks. There are currently 18 species of Dulichiella described from world seas (see Lowry & Springthorpe 2007, Tomikawa & Komatsu 2012, Paz-Ríos & Ardisson 2014, Alves, Johnsson & Senna 2014 (with key to world species)). Only six species have male gnathopod 2 (left) with three spines on the propodus distolateral crown, D. anisochir ( Krøyer, 1845) , D. tulear Lowry & Springthorpe, 2007 , D. terminos Lowry & Springthorpe, 2007 , D. oahu Lowry & Springthorpe, 2007 , D. australis (Haswell, 1879) and D. spinosa Stout, 1912 , but the spines of D. terminos are acute. Of the remaining five species, D. anisochir and D. tulear have a serrate epimeron 3 posterior margin, D. oahu has two accessory spines on the anterior margins of the dactylar ungues of pereopods 3 to 7 and D.

australis has bunches of long setae on pereopods 6 to 7 merus to propodus. Dulichiella beluu sp. nov is most similar to D. spinosa from California but that species has a pleosome/urosome dorsal spine formulae of 9–9–7–5– 4–2, whereas in D. beluu sp. nov it is 7–7–7–5–6–2. It is also a much smaller species (4.0 mm in D. beluu sp. nov. whereas D. spinosa is 7.3–12.5 mm).

Distribution. Known only from Palau.

Figures

FIGURE 18. Dulichiella beluu sp. nov., male holotype and female paratype, Beluu Lukes Reef, Palau.

FIGURE 19. Dulichiella beluu sp. nov., male holotype and female paratype, Beluu Lukes Reef, Palau.