Tethorchestia Bousfield, 1984

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 : 39-40

Tethorchestia Bousfield, 1984

Tethorchestia Bousfield, 1984: 204 .— LeCroy, 2011: 743, 759.— Wildish & LeCroy, 2014: 557 , 558, key.— Lowry & Myers, 2019: 84, 87, figs 38, 39.

“ Tethorchestia ”.— LeCroy, 2011: 743, key, 757 diagnosis.

Type species. Tethorchestia antillensis Bousfield, 1984 , original designation.

Included species. Tethorchestia contains 3 species: T. antillensis Bousfield, 1984 ; T. karukerae Ciavatti, 1989 ; T. palaeorchestes Bousfield & Poinar, 1995 (fossil, terrestrial, Oligocene).

Ecological type. Beach-hoppers.

Habitat. Living on semi-protected beaches sand beaches.

Diagnostic description (male). Based on Ciavatti (1989) and Wildish & LeCroy (2014).

Head. Antenna 2 peduncular articles slender. Mandible lacinia mobilis 4-cuspidate. Gnathopod 1 sexually dimorphic; subchelate; posterior margin of carpus and propodus each with lobe covered in palmate setae; propodus anterior margin with 4 groups of robust setae, ‘subtriangular’ with well-developed posterodistal lobe, palm transverse; dactylus cuspidactylate. Gnathopod 2 subchelate; propodus palm acute; propodus palm evenly rounded; without palmar sinus; without proximal sinus; without large distal sinus; without proximal spine or thumb defining palm; without large projection near dactylar hinge; dactylus short, strongly curved, longer than palm; recurved distally, attenuated distally or slender, distally acute. Pereopods 3–7 dactyli bicuspidactylate. Pereopod 4 significantly shorter than pereopod 3; carpus significantly shorter than that of pereopod 3; dactylus amplidactylate, thickened proximally with notch midway along posterior margin. Pereopod 6 shorter than pereopod 7, not incrassate; basis moderately expanded; male merus and carpus not expanded. Pereopod 7 not incrassate; basis moderately expanded, or broadly expanded; posterior margin with distinct minute serrations, each with a small seta, posterodistal lobe present, shallow, broadly rounded; carpus unexpanded (subrectangular); subrectangular, or subtriangular (slightly); carpus subequal to propodus; propodus broad; length 3.3–6.5 × width; propodus with large distal tuft of setae. Oostegites (female) setae with simple smooth tips.

Pleon. Pleopods 1–3 all well-developed, or all reduced (slightly). 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 completely cleft or apically incised, with 3–6 robust setae per lobe or with 7–9 robust setae per lobe.

Remarks. Tethorchestia is very similar to Mexorchestia . Tethorchestia has a posterodistal lobe on the basis of pereopod 7 (absent in Mexorchestia ) and the oostegites have simple tips in Tethorchestia (oostegites with spatulate tips in Mexorchestia ).

Distribution. Mexico and Caribbean Sea ( Bousfield 1984, Ciavatti 1989).