Ampithoe hughesae, Myers, A. A., 2014

Myers, A. A., 2014, Amphipoda (Crustacea) from the Chagos Archipelago, Zootaxa 3754 (1), pp. 1-31 : 8-13

Ampithoe hughesae sp. nov.

( Figs 8 , 9 )

Type material. Holotype male, 4.8 mm, Peros Banhos, outer reef, dead branching coral heads, 10 m. C. Head and H. Koldewey, 23.02.2012 ( OUMNH.ZC.2013.06.015). Paratypes 1 male, 7 females same data as holotype ( OUMNH.ZC.2013.06.016).

Other material. 1 male, 8 females, Diego Garcia, outer reef, dead branching coral heads, 10 m. C. Head and H. Koldewey, 15.02.2012 ( OUMNH.ZC.2013.06.017); 5 females, Diego Garcia, outer reef, dead branching coral heads, 10 m. C. Head and H. Koldewey, 16.02.2012 ( OUMNH.ZC.2013.06.018); 3 females, Saloman Atoll, outer reef, dead branching coral heads, 10 m. C. Head and H. Koldewey, 18.02.2012 ( OUMNH.ZC.2013.06.019); 1 male, 6 females, Saloman Atoll, outer reef, dead branching coral heads, 10 m. C. Head and H. Koldewey, 19.02.2012 ( OUMNH.ZC.2013.06.020); 1 female, Saloman Atoll, outer reef, dead branching coral heads, 10 m. C. Head and H. Koldewey, 20.02.2012 ( OUMNH.ZC.2013.06.021); 1 male 6 females, Peros Banhos, outer reef, dead branching coral heads, 10 m. C. Head and H. Koldewey, 24.02.2012 ( OUMNH.ZC.2013.06.022); 4 males 14 females, Great Chagos Bank – Eagle Island, outer reef, dead branching coral heads, 10 m. C. Head and H. Koldewey, 27.02.2012 ( OUMNH.ZC.2013.06.023); 3 males, 14 females, Great Chagos Bank – Eagle Island, outer reef, dead branching coral heads, 10 m. C. Head and H. Koldewey, 28.02.2012 ( OUMNH.ZC.2013.06.024); 4 males, 7 females, Great Chagos Bank – Eagle Island, outer reef, dead branching coral heads, 10 m. C. Head and H. Koldewey, 29.02.2012 ( OUMNH.ZC.2013.06.025); 7 male, 24 females, Egmont, outer reef, dead branching coral heads, 10 m. C. Head and H. Koldewey, 0 1.03.2012 ( OUMNH.ZC.2013.06.026); 4 males, 7 females, Diego Garcia, outer reef, dead branching coral heads, 10 m. C. Head and H. Koldewey, 0 4.03.2012 ( OUMNH.ZC.2013.06.027); 1 male, 1 female, Diego Garcia, outer reef, dead branching coral heads, 10 m. C. Head and H. Koldewey, 0 5.03.2012 ( OUMNH.ZC.2013.06.028).

Etymology. Named for Lauren Hughes to recognise her work on this and other amphipod families. Description. Based on male holotype, 4.8 mm.

Head. Head eye lobes rounded; eye of moderate size, subround. Antenna 1 peduncular articles 1 and 2 subequal in length; article 1 posterior margin with three robust setae; peduncular article 3 short; flagellum more than 2 × length of peduncle with 26 articles. Antenna 2 shorter than antenna 1; peduncular article 4 a little longer than 5; flagellum equal in length to articles 4 and 5 combined, with 15 articles. Mandible palp three articulate; article 3 longer than 2, subovoid with two distal setae and 6 setae on the posterior margin. Maxilla 1 palp longer than outer plate; inner plate with 5 setae on posterior margin. Labium outer plate distally notched.

Pereon. Gnathopod 1 coxa produced forward, rounded; basis stout; ischium with anterior rounded flange; merus triangular; carpus longer than broad, anterior proximal margin with three robust setae, posterodistal margin with acute spine; propodus elongate, more than 2 × as long as broad, palm evenly rounded, defined by a robust seta; dactylus strongly overlapping palm. Gnathopod 2 coxa subround; basis stout with strong rounded anterodistal flange; merus with posterodistal spine; carpus short about as broad as long, posterior margin extended into lobe; propodus much longer than carpus, anterior margin swollen, posterior margin produced into a blunt spine, anterior and posterior margins densely setose; dactylus stout, opposable to spine. Pereopods 3–4 stout, dactylus shorter than propodus.

Pleon. Uropod 1 peduncle outer face with dense long fine setae; rami shorter than peduncle, subequal. Uropod 2 rami a little longer than peduncle, subequal. Uropod 3 rami shorter than peduncle; inner ramus with two very stout hooked robust setae.

Female (sexually dimorphic characters). Gnathopod 2 propodus much less enlarged than in male, lacking spine on posterior margin, palm substraight defined by a robust seta; dactylus fitting palm.

Remarks. Ampithoe hughesae resembles A. platycera Sivaprakasam (1970) but in that species the male gnathopod 1 palm is stepped whereas in A. hughesae it is evenly convex and male gnathopod 2 propodus posterior margin is truncate in A. platycera but produced forward into a strong "thumb" in A. hughesae . Other differences include the unflattened peduncular article 4 of antenna 2 in A. hughesae compared with the flatted peduncular article 4 in A, platycera (from which it derived its name). The male gnathopod 1 is also much more elongate in A. hughesae than it is in A. platycera .

Habitat. In dead branching coral.

Distribution. Known only from Chagos archipelago.

Figures

FIGURE 8. Ampithoe hughesae sp. nov., male, holotype, 4.8 mm, Peros Banhos.

FIGURE 9. Ampithoe hughesae sp. nov., male, holotype, 4.8 mm, female, paratype, 4.5 mm, Peros Banhos.