Platorchestiinae subfam. nov. (Amphipoda, Senticaudata, Talitridae) with the description of three new genera and four new species Author Lowry, J. K. Author Myers, A. A. 0000-0003-3256-2123 School of Biological, Earth and Environmental Sciences, University College Cork, Cork Enterprise Centre, Distillery Fields, North Mall, Cork, Ireland. bavayia @ gmail. com; https: // orcid. org / 0000 - 0003 - 3256 - 2123 bavayia@gmail.com text Zootaxa 2022 2022-02-17 5100 1 1 53 journal article 20608 10.11646/zootaxa.5100.1.1 cabdbbb1-1226-4c2e-b90b-fae0742b5091 1175-5326 6127681 F42DAC62-0E30-442E-A375-87FC02B2CC99 Platorchestia Bousfield, 1982 Platorchestia Bousfield, 1982: 26 .— Jo, 1988: 160 .— Richardson, 1991: 186 .— Morino & Ortal, 1995: 825 .— Miyamoto & Morino, 2004: 68 . Type species. Orchestia platensis Krøyer, 1845 , original designation. Currently* included species : P. ano Lowry & Bopiah, 2013 ; P. crassicornis ( Costa, 1867 ) , not P. crassicornis ( Derzhavin, 1937 ) = Demaorchestia joi ( Stock & Biernbaum, 1994 ) com. nov. ; P. munmui Jo, 1988 ; P. pachypus ( Derzhavin, 1937 ) ; P. pacifica Miyamoto & Morino, 2004 ; P. paraplatensis Serejo & Lowry, 2008 ; P. platensis ( Krøyer, 1845 ) ; P. smithi Lowry, 2012 . Ecological type . Beach-hopper. Habitat. Among stranded algae and beach detritus on marine shores. Size. 8–15 mm , Remarks. Platorchestia is very similar to the north-western Pacific genus Sinorchestia . They differ mainly in the ventral plate on antenna 2 peduncular article 3 (absent in Platorchestia ); in the fourth article of the maxillipedal palp (reduced, button-shaped in Platorchestia , absent in Sinorchestia ); and in gnathopod 1 (subchelate in Platorchestia , parachelate in Sinorchestia ). Species inquirenda. Platorchestia chathamensis Bousfield, 1982 (based on a female). * A generic revision is currently in preparation by AAM and JKL