Bellorchestia Serejo & Lowry, 2008

Hughes, Lauren E. & Lowry, James K., 2023, Review of New Zealand Coastal Talitroids with description of three new genera (Crustacea, Amphipoda, Senticaudata), Zootaxa 5268 (1), pp. 1-81 : 25-26

Bellorchestia Serejo & Lowry, 2008

Bellorchestia Serejo & Lowry, 2008: 169 .— Lowry, 2012: 2 .

Type species. Bellorchestia richardsoni Serejo & Lowry, 2008 , original designation (junior subjective synonym of B. pravidactyla (Haswell, 1880)) .

Included species. Bellorchestia includes 3 species: B. pravidactyla (Haswell, 1880) ; B. quoyana (Milne Edwards, 1884; B. spadix ( Hurley, 1956) .

Category. Mascupod ( Lowry & Myers 2019).

Habitat. Sand-hopper ( Lowry & Myers 2019).

Diagnostic description (male). Eye medium (1/5–1/3 head length). Antenna 1 short, not reaching midpoint of peduncular article 5 of antenna 2. Antenna 2 peduncular articles slightly incrassate (expanded); article 3 without plate or process ventrally. Upper lip epistome with many large robust setae over surface; median groove without robust setae. Mandible left lacinia mobilis 5-cuspidate. Maxilliped outer margin of precoxa not stepped; palp broad; palp article 2 with distomedial lobe; article 4 reduced, button-shaped. Pereonites without transverse ridges. Gnathopod 1 sexually dimorphic; subchelate, or parachelate; posterior margin of propodus with lobe covered in palmate setae; carpus longer than propodus; propodus anterior margin with 5–7 groups of robust setae, propodus subrectangular, palm transverse. Gnathopod 2 subchelate; posterior margin of merus, carpus and propodus each without lobe covered in palmate setae; propodus palm acute; dactylus not modified distally, blunt, shorter than posterior margin of propodus. Oostegites setae with simple smooth tips. Pereopods 3–7 bicuspidactylate. Pereopod 4 significantly shorter than pereopod 3; carpus significantly shorter than carpus of pereopod 3; dactylus thickened proximally with notch midway along posterior margin. Pereopod 5 short, less than 2/3 length of pereopod 6; merus broad, longer than broad, expanded distally; dactylus long, slender. Shorter than pereopod 7; pereopod 6 not sexually dimorphic or weakly to strongly sexually dimorphic, male merus and carpus expanded; basis expanded. Pereopods 6–7 without row of short setae along posterior margin of dactyli. Pereopod 7 not sexually dimorphic or weakly to strongly sexually dimorphic; sexually dimorphic (merus and carpus slightly incrassate); male basis not expanded into plate-like structure; basis expanded; merus unexpanded; carpus unexpanded. Pleonites 1–3 without dorsal spines. Pleopods 1–3 all well-developed. Epimera 1–3 slits absent. Uropod 1 male exopod not sexually dimorphic, peduncle distolateral robust seta absent. Uropods 1–2 rami without apical spear-shaped setae. Uropod 1 exopod with marginal robust setae in 1 row; endopod with marginal robust setae in 2 rows. Uropod 3 ramus bud-like (broad); longer than peduncle or subequal in length to peduncle. Telson broader than long, rounded distally, apically incised, complete dorsal ridge, with apical and marginal robust setae, with at least 7–10 robust setae per lobe.

Remarks. Three genera Bellorchestia , Capeorchestia Lowry & Baldanzi, 2016 and Tatahipeke gen. nov. have gnathopod 1 with a palmate lobe only on the propodus.

Bellorchestia is distinguished from Capeorchestia and Tatahipeke gen. nov. in having many large robust setae over the surface of the upper lip. While four talitrid genera Bellorchestia , Hermesorchestia Hughes & Lowry 2017 , Platorchestia Bousfield, 1982 , and Transorchestia have pereopods 6 and 7 sexually dimorphic. Bellorchestia is distinguished from these genera by having a gnathopod 1 palmate lobe confined to the propodus.

Distribution. Australia. New Zealand.