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 Transorchestia Bousfield, 1982 Transorchestia Bousfield, 1982: 19 .— Serejo & Lowry, 2008: 164 , table 1. Type species. Orchestia chiliensis Milne Edwards, 1840 . Included species. Transorchestia includes four species: Trans. chiliensis ( Milne Edwards, 1840 ) ; Trans. marlo Serejo & Lowry, 2008 ; Trans. miranda ( Chilton, 1916 ) ; Trans. serrulata ( Dana, 1852a ) . Diagnostic description (male). Expanded from Bousfield (1982) ; Varela (1983). Head . Eye medium (1/5–1/3 head length). Antenna 1 short, rarely longer than peduncular article 4 of antenna 2 . Antenna 2 peduncular articles incrassate (expanded); article 3 without plate or process ventrally. Upper lip epistome without robust setae. Mandible left lacinia mobilis 4-cuspidate. Maxilliped outer margin of precoxa not stepped; palp article 2 with distomedial lobe; article 4 reduced, button-shaped. Pereon . Gnathopod 1 sexually dimorphic; subchelate; posterior margin of merus, carpus and propodus each with lobe covered in palmate setae ; palm acute or transverse. Gnathopod 2 subchelate; propodus palm acute; posterior margin of merus, carpus and propodus each without lobe covered in palmate setae; dactylus not modified distally, blunt; shorter than propodus. Pereopods 3–7 bi-cuspidactylate. Pereopod 4 dactylus thickened proximally with notch midway along posterior margin. Pereopod 5 dactylus long, slender, not inflated. Pereopod 6 sexually dimorphic (merus and carpus expanded) ; shorter than pereopod 7 (slightly). Pereopod 7 sexually dimorphic. Pereopod 7 sexually dimorphic, merus broad, carpus expanded, subrectangular. Pleon. Pleonites 1–3 without dorsal spines. Oostegites setae with curled tips. Pleopods 1–3 all well-developed. Epimera 1–3 slits absent. Uropod 1 peduncle distolateral robust seta absent; rami without apical spear-shaped setae; exopod with marginal robust setae in one row ; endopod with marginal robust setae in 1 row. Uropod 2 rami without apical spear-shaped setae; exopod with marginal robust setae in 1 row; endopod with marginal robust setae in 2 rows. Uropod 3 ramus shorter than peduncle. Telson longer than broad, tapering distally, apically incised, with marginal and apical robust setae, with 7 to 9 robust setae per lobe. Remarks. Transorchestia is a distinctive genus based on the incrassate antenna 2, palmate lobes on the merus, carpus and propodus of gnathopod 1 and 7–9 robust setae per lobe on the telson. The sexually dimorphic pereopods 6 and 7 are defining characters for Transorchestia , distinguishing it from Orchestia which has only pereopod 7 as sexually dimorphic. Distribution . South America . Cape Horn district ( Milne Edwards 1840 ). Australia ( Serejo & Lowry 2008 ). New Zealand ( Chilton 1916 ; Dana 1852a ).