Review of New Zealand Coastal Talitroids with description of three new genera (Crustacea, Amphipoda, Senticaudata) Author Hughes, Lauren E. 0000-0002-5679-1732 l.hughes@nhm.ac.uk Author Lowry, James K. text Zootaxa 2023 2023-04-18 5268 1 1 81 http://dx.doi.org/10.11646/zootaxa.5268.1.1 journal article 250001 10.11646/zootaxa.5268.1.1 1f11027b-394e-4f01-8a2d-79d2c9bc1ecd 1175-5326 7840854 114B5413-5162-40A7-AAAE-E2E6371C3B6C Subantarctorchestia gen. nov. Type species. Orchestia aucklandiae Spence Bate, 1862 , original designation. Included species. Subantarctorchestia includes 2 species, S. aucklandiae ( Spence Bate, 1862 ) ; S. bollonsi ( Chilton, 1909 ) . Category. Mascupod. Habitat. Beach-hopper (habitat for S. bollonsi suspect according to Hurley (1957)) . Etymology. Named for the Subantarctic, the environment in which it lives plus the stem Orchestia . Diagnostic description. Eye medium (1/5–1/3 head length). Antenna 1 short, not reaching midpoint of peduncular article 5 of antenna 2. Antenna 2 peduncular articles slightly to strongly incrassate ; article 3 without plate or process ventrally. Maxilliped palp broad; article 2 with distomedial lobe ; article 4 reduced, button-shaped . Pereonites without transverse ridges, or with transverse ridges. Gnathopod 1 sexually dimorphic; subchelate; posterior margin of carpus and propodus each with lobe covered in palmate setae ; carpus longer than propodus; propodus anterior margin with 6 or 7 groups of robust setae, propodus ‘subtriangular’ with welldeveloped posterodistal lobe , palm transverse. Gnathopod 2 subchelate; posterior margin of merus, carpus and propodus each without lobe covered in palmate setae; propodus palm acute; without proximal sinus; with broad sinus near dactylar hinge; without proximal spine defining palm ; dactylus not modified distally, blunt, shorter than posterior margin of propodus. Oostegites setae with simple smooth tips. Pereopods 3–7 bicuspidactylate. Pereopod 6 not sexually dimorphic; basis expanded. Pereopod 7 not sexually dimorphic ; basis posterodistal lobe extending to merus ; basis, merus, and carpus 3-dimensional, not laminar, male basis not expanded into plate-like structure; basis expanded. Pleonites 1–3 without dorsal spines. Pleopods 1–3 all well-developed. Epimera 1–3 slits absent. Uropod 1 male exopod not sexually dimorphic, peduncle distolateral robust seta present, with simple tip. Uropods 1–2 rami without apical spear-shaped setae. Uropod 1 endopod with marginal robust setae in 2 rows; exopod with marginal robust setae in one row . Uropod 2 exopod with marginal robust setae in 1 row; endopod with marginal robust setae in 2 rows. Uropod 3 ramus linear (narrowing); longer than peduncle. Telson longer than broad, tapering distally, apically incised, apical dorsal groove, with apical and marginal robust setae, with 7–9 robust setae per lobe. Remarks. Subantarctorchestia shares a number of important generic-level characters with Orchestia including the slender antenna 2. They differ mainly in the structure of gnathopod 2 and pereopod 7. The gnathopod 2 is without proximal setae on the gnathopod 2 palm Orchestia , present in Subantarctorchestia ) and pereopod 7 (sexually dimorphic in Orchestia , not sexually dimorphic in Subantarctorchestia ). Distribution. New Zealand . Campbell Island, Auckland Islands, Stewart Island, South Island, ( Spence Bate 1862 ; Chilton 1909 ; Hurley 1957 ).