Orchestia xylino Lowry & Fanini, 2013

Myers, Alan A. & Lowry, James K., 2020, A revision of the genus Orchestia Leach, 1814 with the reinstatement of O. inaequalipes (K. H. Barnard, 1951), the designation of a neotype for Orchestia gammarellus (Pallas 1776) and the description of three new species (Crustacea: Amphipoda: Talitridae Talitrinae), Zootaxa 4808 (2), pp. 201-250 : 221-224

Orchestia xylino Lowry & Fanini, 2013

( Figs. 15 , 16 )

Orchestia xylino Lowry & Fanini, 2013 , 208, figs 2–5.

Type locality. Gournes , Heraklion, Crete, Greece (35°20’1”N 25°16’82”E) .

Description of adult male (13.1 mm).

Head. Eyes unknown. Antenna 1 short, not reaching end of peduncular article 4 of antenna 2; accessory flagellum absent; primary flagellum with 6 articles. Antenna 2 peduncular article 5 1.4 × length of peduncular article 4, flagellum a little longer than combined length of peduncular articles 4 and 5, with 20 articles, final article cone shaped, with terminal cluster of imbricated setae. Labrum without epistome. Mandible left lacinia mobilis with 4 cusps. Maxilliped palp article 2 with distomedial lobe.

Pereon. Gnathopod 1 subchelate, coxa smaller than that of coxa 2; posterior margin of carpus and propodus each with lobe covered in palmate setae; propodus length to carpus length 1:2.4, propodus subrectangular; dac-

tylus only a little shorter than palm. Gnathopod 2 basis 2.5 × as long as broad; merus posterior margin without setae; propodus, markedly triangular, distal width 2.0 × proximal width. Pereopods 3–7 cuspidactylate. Pereopods 3–4 dactylus relatively slender, acute. Peropod 4 dactylus thickened proximally with a notch midway along posterior margin. Pereopod 5 basis subovoid. Pereopod 7 basis posterior margin weakly serrate; merus elongate and slender, weakly triangular, 2.0 × as wide distally as proximally; carpus subrectangular, elongate, weakly narrowing distally, about 1.7 × as long as broad; carpus and merus subequal in length; propodus and carpus subequal in length.

Pleon. Epimeron 3 posterior margin weakly crenulate. Uropod 1 peduncle longer than rami, with strong distolateral robust seta; rami subequal. Uropod 2 peduncle longer than rami, exopod shorter than endopod with 2 marginal robust setae; endopod with 3 marginal robust setae and 3 robust setae on inner face. Uropod 3 peduncle broader than long; ramus 3 × as long as broad, subequal in length with peduncle, outer margin with 2 robust setae. Telson with about 9 apical robust setae on each side.

Female (sexually dimorphic characters). Gnathopod 2 mitten-shaped; basis 1.5 × as long as broad, anterior margin convex proximally, strongly concave distally; carpus 1.6 × length of propodus.

Habitat. Marine, supralittoral, on mixed sand coarse gravel and bolder stone beaches.

Remarks. Orchestia xylino differs from all other species of Orchestia by the long carpus of the male gnathopod 1 that is much more than twice the length of the propodus (much less than twice length in other species) and in the exopod of uropod 2 being shorter than the endopod. It shares with O. montagui the presence of a distoventral robust seta on the peduncle of uropod 1.

Distribution. Gournes, Heraklion, Crete, Greece ( Lowry & Fanini 2013).

Figures

FIGURE 15. Orchestia xylino Lowry & Fanini, 2013, Gournes, Crete.

FIGURE 16. Orchestia xylino Lowry & Fanini, 2013, Gournes, Crete.