Microrchestiinae, Myers & Park & J.-P, 2025

Myers, Alan A., Park, Eunji & J. - P, Olivier, 2025, A revision of the family Protorchestiidae (Amphipoda: Talitroidea) with the description of two new subfamilies, three new genera and one new species, Zootaxa 5725 (3), pp. 371-390 : 373

Microrchestiinae subfam. nov.

Included genera. Cochinorchestia Lowry & Peart, 2010 ; Microrchestia Bousfield, 1984 .

Diagnostic description. Antenna 1 long, reaching to at least midpoint of peduncular article 5 of antenna 2. Male and female gnathopod 1 posterior margin of merus, carpus and propodus each with palmate lobes. Gnathopod 2 subchelate in male, propodus palm often variously excavate, mitten-shaped in female. Pereopods 3–7 simplidactylate. Pereopod 6 subequal in length or shorter than pereopod 7. Coxal gill 6 plate-like with or without distinct lobes, not convoluted. Uropod 1 exopodite with or without marginal robust setae. Telson with apical robust setae only or with apical and marginal robust setae, with 1–6 robust setae per lobe. Oostegite setae with simple tips or multifurcate tips.

Discussion. The important distinctions between this subfamily and the Protorchestiinae subfam. nov. are the tips on the female oostegite setae that are curl or coil tipped in the Protorchestiinae subfam. nov., simple or multifurcate in the Microrchestiinae subfam. nov. ( Fig. 3 ) and the palm of the male gnathopod 2 which is variously modified with excavations and protuberances in the Microrchestiinae subfam. nov., but unmodified, evenly rounded or substraigh t in the Protochestiinae subfam. nov. Some Microrchestiinae subfam. nov. have marginal robust setae on the exopodite of uropod 1 which are always absent in the Protorchestiinae subfam. nov. Some Microrchestiinae subfam. nov. have lobes on the coxal gills which are never present in the Protorchestiinae subfam. nov.

Distribution. India, Africa ( Mozambique), Madagascar, Thailand, Indonesia, Papua New Guinea including the Bismark Archipelago and Northern Australia.

Figures

FIGURE 3. Oostegites of A. Microrchestinae and B. Protorchestinae. Cochinorchestia metcalfeae redrawn from Lowry & Peart (2010); Microrchestia bousfieldi redrawn from Lowry & Springthorpe (2015); Protorchestia nitida redrawn from Bousfield (1982); Lowryorchestia campbelliana redrawn from Bousfield (1964); Richardsonorchestia palustris redrawn from Richardson (1993); Serejorchestia lakei redrawn from Richardson (1996).