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 Miyamotoia Morino, 2020 Miyamotoia Morino, 2020: 2 . Type species. Miyamotoia spinolabrum Morino, 2020 , original designation. Included species. Miyamotoia contains 2 species: M. daitoensis Morino, 2020 ; M. spinolabrum Morino, 2020 . Category. Mascupod. Ecological type . Forest-hopper. Habitat. Humid forests. Diagnostic description ( male ). Based on Morino (2020) . Head. Antenna 2 peduncular articles slender . Mandible left lacinia mobilis 5-cuspidate. Labium without inner lobes. Maxilliped palp article 2 with distomedial lobe; article 4 reduced, button-shaped. Pereon. Gnathopod 1 sexually dimorphic; subchelate; coxa slightly smaller than coxa 2; posterior margin of carpus and propodus each with lobe covered in palmate setae; propodus anterior margin with 3 or with 4 groups of robust setae, ‘subtriangular’ with well-developed posterodistal lobe, palm transverse; dactylus simplidactylate . Gnathopod 2 subchelate; propodus palm acute; propodus palm evenly rounded, without palmar sinuses; without proximal spine or thumb defining palm, without large projection near dactylar hinge; dactylus short, recurved distally or attenuated distally (short) . Pereopods 3–7 dactyli bicuspidactylate. Pereopod 4 subequal or slightly shorter than pereopod 3; carpus significantly shorter than that of pereopod 3; dactylus amplidactylate, thickened proximally with notch midway along posterior margin or short with mini-wavy posterior margin . Pereopod 6 subequal in length to pereopod 7, not incrassate; basis moderately expanded; male merus and carpus not expanded. Pereopod 7 not incrassate; basis broadly expanded; posterior margin with distinct minute serrations, each with a small seta, posterodistal lobe present, shallow, narrowly rounded; merus unexpanded; carpus unexpanded; propodus broad, 6.1 × width, without large distal tuft of setae. Oostegites (female) setae with simple smooth tips. Pleon. Pleopods all reduced . Uropod 1 peduncle distolateral robust seta present or absent; exopod without marginal robust setae; endopod with marginal robust setae in 2 rows . Uropod 2 exopod with marginal robust setae in 1 row; endopod with marginal robust setae in 2 rows. Uropod 3 ramus shorter than peduncle. Telson apically incised, with 3 to at least 10 robust setae per lobe. Remarks. Miyamotoia is similar to Laniporchestia from Hawaii . See remarks under Laniporchestia . Miyamotoia is also similar to Tethorchestia . The main differences are gnathopod 1 dactylus is simplidactylate (cuspidactylate in Tethorchestia ), pereopod 7 propodus without a large, distal tuft of setae (present in Tethorchestia ), uropod 1 peduncle without a distolateral robust seta (present in Tethorchestia ) and the endopod of uropod 1 with marginal setae in two rows (one row in Tethorchestia ). Distribution. Japan : Ogasawara Islands and Daitojima Islands, Southern Japan ( Morino 2020 ).