Iphimedia garciensis, Myers, A. A., 2014

Myers, A. A., 2014, Amphipoda (Crustacea) from the Chagos Archipelago, Zootaxa 3754 (1), pp. 1-31 : 21-26

Iphimedia garciensis sp. nov.

( Figs 19 , 20 )

Type material. Holotype unsexed, 3.0 mm., Diego Garcia, outer reef, dead branching coral heads, 10 m. C. Head and H. Koldewey, 16.02.2012 ( OUMNH.ZC.2013.06.062).

Other material. 1 unsexed, Egmont, outer reef, dead branching coral heads, 10 m. C. Head and H. Koldewey, 0 1.03.2012 ( OUMNH.ZC.2013.06.063).

Etymology. Named after the type locality.

Description. Based on holotype, 3.0 mm.

Head. Head ocular and subocular lobes rounded; eye renifom. Antenna 1 about one third body length; peduncular article 1 with distal spines; peduncular articles 2 and 3 short; flagellum with 15 articles. Antenna 2 broken. Maxilla 1 palp uniarticulate (probably two fused articles), not reaching extremity of outer plate. Labium outer plate distal margins concave; inner plate rudimentary. Maxilliped palp with three articles; article 2 with a distal extension almost reaching end of article 3.

Pereon. Gnathopod 1 chelate; all articles slender. Gnathopod 2 similar to gnathopod 1 but subchelate. Pereopod 3 coxa scythiform; dactylus robust, two-thirds length of propodus. Pereopod 4 similar to pereopod 3 but coxa distal margin straight. Pereopod 5 coxa bilobed; basis posterior margin with proximal and mediodistal spines. Pereopod 6 coxa posterodistal margin weakly bifid; basis posterior margin with weak proximal spine and two mediodistal spines. Pereopod 7 coxa posterodistal margin with weak spine; basis posterior margin serrated with strong mediodistal spine.

Pleon. Segments 1–3 each with paired dorsal spines. Epimeron 1 with strong sub-distal spine and weak distal spine. Epimera 2–3 each with strong sub-distal and distal spines. Uropods 1–2 rami subequal in length. Uropod 3 peduncle inner distal margin produced into a broad-based spine; inner ramus twice length of peduncle with two pectinate setae; outer ramus shorter than inner ramus. Telson emarginate with well developed distal spines.

Remarks. Iphimedia garciensis sp. nov is very close to I. grossimana Ledoyer, 1972 from Madagascar but differs in a number of ways. The head subocular lobe is rounded in I. garciensis but acute in I. grossimana . Maxilla 1 palp is one-articulate and short in I. garciensis but two-articulate and equal in length to the outer plate in I. grossimana . The telson has well-developed distal spines in I. garciensis but these are scarcely apparent in I. grossimana . Coxa 7 has a posterodistal spine in I. garciensis but lacks a spine in I. grossimana . There are also subtle differences in the spination of the pereopod 5–7 bases. In pereopod 7, for example, the basis of I grossimana has spines distal to the large mediodistal spine, but these are absent in I. garciensis .

Habitat. Dead branching corals.

Distribution. Known only from Chagos archipelago.

Figures

FIGURE 19. Iphimedia garciensis sp. nov., holotype, unsexed, 3.0 mm, Diego Garcia.

FIGURE 20. Iphimedia garciensis sp. nov., paratype, unsexed, 3.0 mm, Egmont.