Serejorchestia, 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 : 386

Serejorchestia gen. nov.

( Figs 4–5 )

Type species. Protorchestia lakei Richardson, 1996: 574 figs 1–4.

Included species. S. ceduna ( Serejo & Lowry, 2008) ; S. lakei ( Richardson, 1996) .

Etymology. In recognition of the work on the taxonomy of Australian and Brazilian Talitroidea and Hyaloidea by Dr Cristiana S. Serejo.

Diagnostic description. Antenna 1, reaching from middle to near to the end of peduncle of antenna 2. Mandible left lacinia mobilis 5-dentate. Maxilliped palp article 4 longer than broad. Gnathopod 1 with palmate lobes on merus, carpus and propodus in both sexes. Gnathopod 2 strongly sexually dimorphic, subchelate in male, mitten-shaped in female. Pereopods 3–7 simplidactylate and amplidactylate. Coxal gills unlobed, plate-like. Pleopods all well developed, peduncles naked or minutely setose; rami elongate and setose. Uropod 1 exopodite without marginal robust setae. Uropod 2 exopodite with or without marginal robust setae. Telson strongly cleft. Female oostegite setae with curl tips.

Remarks. Serejorchestia gen. nov. shares the divided telson lobes character state with Protorchestia but it differs from that genus in a number of ways. Antenna 1 extends midway along article 5 of antenna 2 (not reaching end of article 4 in Protorchestia ), the peduncle of antenna 2 is short and unexpanded (long and incrassate in Protorchestia ), the ramus of uropod 3 has no marginal robust setae (1–2 marginal robust setae in Protorchestia ) and the female oostegites have fewer than 35 setae (more than 50 in Protorchestia ). Serejorchestia gen. nov. is close to Richardsonorchestia gen. nov., from which it differs in the strongly divided telsonic lobes ( Fig. 5 ) and the 5-dentate left lacinia mobilis. It differs from Eorchestia in having a palmate lobe on the merus of the female gnathopod 1. It differs from Lowryorchestia in the distally narrow cleft telson (distally broad in Lowryorchestia ) and in the female oostegites which terminate in curl tips (coil tips in Lowryorchestia ).

Figures

FIGURE 4. Antenna 1 and antenna 2 of Protorchestiinae. P. nitida Bousfield redrawn from Bousfield (1982); R. palustris redrawn from Richardson (1993); S. lakei redrawn from Richardson (1996).

FIGURE 5. Telsons of species of A) Serejorchestia gen. nov., B) Richardsonorchestia gen. nov. and C) Lowryorchestia gen. nov. S. lakei redrawn from Richardson (1996); S. ceduna redrawn from Serejo & Lowry (2008); R. rupestris and R. palustris redrawn from Richardson (1993); L. campbelliana redrawn from Bousfield (1964).