Sardorchestia Ruffo 2004

Sardorchestia Ruffo, 2004

(Fig. 3)

Sardorchestia Ruffo, 2004: 506.

Type species. Talorchestia pelecaniformis Bellan-Santini & Ruffo, 1986, original designation.

Included species. Sardorchestia includes 2 species: S. gracilis (Bousfield & Klawe, 1983); S. pelecaniformis (Bellan-Santini & Ruffo, 1986).

Diagnostic description (based on male). Eyes large (greater than 1/3 head length). Antenna 1 short, not longer than article 4 of antenna 2 peduncle. Antenna 2 peduncular articles slender; peduncular article 3 without ventral process. Labrum without robust setae. Mandible left lacinia mobilis 4-dentate . Maxilliped palp article 2 distomedial lobe well developed; article 4 fused to article 3. Gnathopod 1 parachelate; posterior margin of carpus and propodus each with lobe covered in palmate setae . Gnathopod 2 subchelate ; merus/carpus free; dactylus not modified distally. Pereopods 3–7 cuspidactylate. Pereopods 5–7 without setae along posterior margin of the dactylus. Pereopods 6–7 not sexually dimorphic. Pleonites 1–3 without dorsal spines. Pleopods all well developed. Epimera without vertical slits. Uropod 1 rami without apical separ-shaped setae; outer ramus slender; with marginal robust setae. Uropod 3 well developed; ramus subequal in length to peduncle. Telson apically incised, with 7 to at least 10 robust setae per lobe.

Remarks. Orchestoidea gracilis Bousfield & Klawe, 1963 was included in Pseudorchestoidea Bousfield, 1982, but it differs from other species in the genus by: gnathopod 1 is parachelate (simple or subchelate in Pseudorchestoidea); and the presence of marginal robust setae on the outer ramus of uropod 1 (absent in Pseudorchestoidea).

There appears to be no generic-level characters separating Pseudorchestoidea gracilis (Bousfield & Klawe, 1963) and Sardorchestia pelecaniformis (Bellan-Santini & Ruffo, 1986). Sardorchestia pelecaniformis is considered to have a slightly incrassate second antenna, but when compared with Pseudorchestoidea gracilis there is no discernible difference. We are therefore including P. gracilis in the genus Sardorchestia. An important corroboration of this change would be a molecular comparison of the two species. There is already CO1 information for S. pelecaniformis.

These relationships most likely reflect a situation at the time of the opening of the Atlantic Ocean when the ancestors of all these genera inhabited the beaches of Laurasia.

Distribution. Mexico: Baja California. Mediterranean: Sardinia.