Vallorchestia Lowry, 2012

Lowry, J. K. & Myers, A. A., 2022, Platorchestiinae subfam. nov. (Amphipoda, Senticaudata, Talitridae) with the description of three new genera and four new species, Zootaxa 5100 (1), pp. 1-53 : 43

Vallorchestia Lowry, 2012

Vallorchestia Lowry, 2012: 19 , figs 11–14.

Type species. Orchestia dispar Dana, 1852 , monotypy.

Included species. Vallorchestia includes 1 species: V. dispar ( Dana, 1852) .

Category. Mascupod.

Ecological type. Beach-hoppers.

Habitat. Sand beaches, living under Zostera , leaves and debris in the supralittoral.

Diagnostic description (male). Based on Lowry (2012).

Head. Antenna 2 peduncular articles slightly incrassate. Mandible left lacinia mobilis 4-cuspidate. Maxilliped palp article 2 with distomedial lobe; article 4 reduced, button-shaped.

Pereon. Gnathopod 1 sexually dimorphic; subchelate; posterior margin of carpus and propodus each with lobe covered in palmate setae (merus vestigial); propodus anterior margin with 3 groups of robust setae, ‘subtriangular’ with well-developed posterodistal lobe, palm transverse; dactylus simplidactylate. Gnathopod 2 subchelate; propodus palm acute; without sinuses; without proximal spine or thumb defining palm; dactylus attenuated distally. Pereopods 3–7 dactyli bicuspidactylate. Pereopod 4 significantly shorter than pereopod 3; carpus similar in length to that of pereopod 3; dactylus homobasidactylate, similar to pereopod 3 dactylus, not thickened proximally or notched. Pereopod 6 incrassate (merus and carpus with T-setae); basis expanded; male merus and carpus not expanded. Pereopod 7 incrassate; basis expanded; merus expanded distally, subtriangular, anterior margin straight; carpus expanded, subrectangular; carpus shorter than propodus; propodus slender; length 7.7 × width; propodus without large distal tuft of setae. Oostegites (female) setae with simple smooth tips.

Pleon. Pleopods 1–3 all well-developed. Uropod 1 peduncle distolateral robust seta present; exopod without marginal robust setae; endopod with marginal robust setae in 1 row. 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 7–9 robust setae per lobe.

Remarks. Vallorchestia shares homoplasies with Mexorchestia from Central America and Miyamotoia from Japan. It is distinguished from other platorchestiines by the autoapomorphic setae on the male pereopod 6.

Distribution. Australia: New South Wales ( Lowry 2012).