Amphipoda (Crustacea) from Palau, Micronesia: Families Maeridae and Melitidae Author Myers, A. A. text Zootaxa 2016 4170 3 451 474 journal article 10.11646/zootaxa.4170.3.2 bb281016-1373-441e-bc6d-db8fcb6bc890 1175-5326 272428 40798E20-A265-4950-B608-0E80043D8979 Linguimaera siaes sp. nov. ( Figs 8–11 ) Type material. Holotype male (OUMNH.ZC. 2002-24 -151), 2.6 mm , Siaes Corner, from Dysidea avara (Schmidt, 1862) (Porifera: Dysideidae ), - 25 m depth; 07°18.756'N, 134°13.515'E; leg. S. De Grave & C. Burras, 22 May 2002 . Paratypes, 2 females (OUMNH.ZC. 2002-24 -152), Lighthouse Reef, outer side, hand dredge of Halimeda sediment, - 25 m depth; 07°16.615' N, 134°27.606' E; leg. S. De Grave & C. Burras, 21 May 2002 . Type locality. Siaes corner, Palau , 07°18.756'N , 134°13.515'E . Etymology. Named after the type locality. Used as a noun in apposition. Description. Based on male holotype 2.6 mm . Head. Head with sub-ocular notch; eye consisting of a small number of isolated, divided ommatidea. Antenna 1 about two thirds body length; peduncular articles 1 and 2 subequal in length; article 3 less than one third length of article 2; accessory flagellum with two articles; primary flagellum subequal in length with peduncle, with 15 articles. Antenna 2 half length of antenna 1; peduncular article 4 longer than 5 flagellum longer than peduncular article 5, with 6 articles. Mandible palp article 3 shorter than article 2, rod-shaped with three long terminal setae. Pereon. Gnathopod 1 coxa anterodistal margin with acute spine, posterodistal margin with two spines; basis slender, carpus longer than propodus; propodus palm oblique; dactylus fitting palm. Gnathopod 2 coxa subquadrate, with posterodistal spines; basis stout, parallel-sided; merus with posterodistal spine; carpus short, cup-shaped; right gnathopod propodus elongate, almost parallel-sided; palm with two excavations; and with no defining spine at posterodistal corner; dactylus fitting palm; left gnathopod propodus much smaller than right gnathopod, propodus palm evenly convex, with very small defining spine. Pereopods 3–4 slender, coxa sub-round, with concave posterior margin; Pereopods 5–7 basis posterior margin serrate, that of pereopod 7 the strongest. Pleon. Epimera 1–2 with weak spine on posterodistal corner. Epimeron 3 posterodistal corner with 3 evenly spaced spines. Uropod 1 peduncle longer than rami, with long terminal robust setae; rami sub-equal in length, Uropod 2 peduncle a little shorter than inner ramus: inner ramus a little longer than outer ramus. Uropod 3 peduncle short with bunch of stout setae on outer margin; rami long, subequal, with numerous robust setae. Telson distal lobes blunt, each lobe with one long and one short robust seta. Female (sexually dimorphic characters). Based on female, 2.5 mm . Gnathopod 2 basis relatively slender; carpus long sub-triangular; propodus subequal in length with carpus, palm oblique, weakly convex: dactylus fitting palm. Habitat. In sponges and alga Halimeda sediment. Remarks. No previously described species of Linguimaera has the same structure to the palm of the male large gnathopod 2. The only other known Linguimaera species from Palau is L. bogombogo Krapp-Schickel, 2003 , from Eniwetok. That species is similar to L. siaes sp. nov. in many ways, but differs in the structure of the large male gnathopod 2. In L. siaes sp. nov. the palm has no delimiting spine, whereas in L. bogombogo , the palm is delimited by a strong, acute spine. Also in L. bogombogo , the pereopods 5 to 7 are much more stout than in L. siaes sp. nov. The mandible palp is similar in both species, but in L. bogombogo article 3 has several marginal setae that are absent in L. siaes sp. nov. Distribution. Known only from Palau .