A new genus and species of sand-hopper, Mauritiorchestia fayetta gen. nov., sp. nov (Amphipoda, Talitridae) from Mauritius Author Green, M. A. A. 0000-0001-6970-3861 Department of Biosciences and Ocean Studies Faculty of Science, University of Mauritius, Reduit, Mauritius. & alison 0534 @ gmail. com; https: // orcid. org / 0000 - 0001 - 6970 - 3861 alison0534@gmail.com Author Appadoo, C. 0000-0002-4381-8238 Department of Biosciences and Ocean Studies Faculty of Science, University of Mauritius, Reduit, Mauritius. & chandani @ uom. ac. mu; https: // orcid. org / 0000 - 0002 - 4381 - 8238 chandani@uom.ac.mu Author Lowry, J. K. Australian Museum Research Institute, 1 William Street, Sydney, NSW 2010, Australia. Author Myers, A. A. School of Biological, Earth and Environmental Sciences, University College Cork, Cork Enterprise Centre, Distillery Fields, North Mall, Cork, Ireland. text Zootaxa 2021 2021-11-16 5068 2 295 300 journal article 3518 10.11646/zootaxa.5068.2.9 a94a502d-d301-4b1f-bc9e-4494405eaa96 1175-5326 5704439 5E7AC87E-8123-4C02-B4D6-7D33D220DFF8 Mauritiorchestia fayetta sp. nov. ( Figs 1 , 2 ) Platorchestia fayetta Beeltah & Appadoo, 2017: 44 ( nomen nudum ). Material Examined. HOLOTYPE , 1 male , 9.8 mm from Poste la Fayette ( 20°8.2’S , 57°44.5’E ), Mauritius , on coastal sandy substrate with huge amount of beach wrack algae, A. Green , ( 20 November 2014 ), NHM/ 2021/01/01 . PARATYPES : 1 female , 8.6 mm , NHM/ 2021/02/01 , other paratypes ; 3 males NHM/ 2021/03/01 , 5 females NNHM / 2021/04/01 , same data as holotype ; 6 females , 4 males , same data as holotype, author’s ( CA ) collection, Mauritius . Etymology. Named after the type locality Poste la Fayette. Description. Male holotype , length. 9.8 mm . Body laterally compressed. Head height equal to length. Eyes medium sized round. Antenna 1 shorter than peduncle of antenna 2; peduncular article 2 longer than peduncular article 1; not geniculate; flagellum with 5 articles and a small terminal article. Antenna 2 incrassate, longer than antenna 1; not geniculate; peduncular articles broad and long with sparse, small and robust setae; peduncular article 2 longer than peduncular article 1; flagellum longer than peduncle, 13 articles and a small terminal article. Mandible palp absent; left lacinia mobilis 5 cuspidate; incisor 5 dentate; setal row with 4 plumose setae. Maxilla 1 palp absent; inner plate with setae on margin and two strong apical plumose setae; outer plate with 7 strong medially serrate robust setae. Maxilla 2 inner plate with round distal margin with one strong, long plumose seta on lateral margin; outer plate with round distal margin with especially long setae on apex and fine setae on lateral margin. Maxilliped palp with 3 well developed articles, article 4 vestigial, visible only from ventral view. Lower lip with narrow lobes and wide shoulders; apical setal tuft present. Gnathopod 1 sexually dimorphic; subchelate; palmate lobe present on posterior margin of carpus and propodus; propodus subtriangular; palm transverse; dactylus as long as palm, triangular, thick. Gnathopod 2 sexually dimorphic; subchelate; larger and more robust than gnathopod 1; coxa as long as wide; basis broad; carpus triangular; propodus massive, with anterior margin convex, palm sinuous, notch in the middle of palm, row of marginal setae on palm; dactylus as long as palm, inner face with minute robust setae on margin; dactylus fitting into sulcus internally. Coxae 2–4 as long as broad. Pereopod 3 longer than pereopod 4; cuspidactylate. Pereopod 4 cuspidactylate with a thick dactylus compared to pereopod 3. Pereopod 5 shorter than pereopod 6; coxa bilobate with small robust setae on each lobe; propodus longer than carpus; cuspidactylate. Pereopod 6 not sexually dimorphic, coxa weakly serrate; merus, carpus and propodus all broadened, propodus longer than carpus, homosimplidctylate. Pereopod 7 posterior distal margin of basis serrate; merus and carpus subrectangular; homosimplidactylate. Uropod 1 biramous; 16 robust setae in two rows on peduncle; exopod 0.7 x as long as peduncle; endopod with 5 setae on inner margin; exopod without marginal robust setae. Uropod 2 biramous; inner margin of peduncle with 3 robust setae; exopod 0.8 x as long as peduncle; rami subequal in length, inner margin of endopod with 3 robust setae; exopod without marginal robust setae Uropod 3 uniramous; ramus 0.9 x as long as peduncle; peduncle with 4 robust setae; ramus narrowing distally, with 4 setae on inner margin and 4 apical setae. Telson entire; broader than long; apically incised; 6 robust setae per lobe; dorsal midline entire. Female (sexually dimorphic characters). 8.6 mm . Gnathopod 1 parachelate; propodus subrectangular; lobe absent at posterior margin of carpus and propodus; dactylus longer than palm. Gnathopod 2 mitten-shaped, smaller than gnathopod 2 in males; coxa with protuberance; basis enlarged and elliptical; dactylus shorter than of males and shorter than palm; palm with 3 small robust setae. Pereopod 6 coxa subquadrate with protuberance; basis posterior margin convoluted; basis narrower than in male; merus, carpus and propodus unexpanded. Pereopod 7 merus and carpus unexpanded. Distribution. Poste la Fayette, Mauritius .