Tatahipeke, Hughes & Lowry, 2023

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 : 57

Tatahipeke gen. nov.

Type species. Talorchestia tumida Thomson, 1885 , original designation.

Included species. Tatahipeke includes 3 species: T. cookii ( Filhol, 1885) ; T. kirki ( Hurley, 1956) ; T. tumida ( Thomson, 1885) .

Etymology. From the Maori words for beach and jump.

Diagnostic description (male).

Head. 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 slender; article 3 without plate or process ventrally. Upper lip epistome without robust setae. Maxilliped outer margin of precoxa not stepped; palp broad; palp article 2 with distomedial lobe; article 4 reduced, button-shaped.

Pereon. Pereonites without transverse ridges. Gnathopod 1 sexually dimorphic; subchelate or parachelate; posterior margin of carpus and propodus each with lobe covered in palmate setae; carpus longer than propodus; propodus anterior margin with 6 or 7 groups of robust setae, propodus subrectangular or ‘subtriangular’ with welldeveloped posterodistal lobe, palm transverse. Gnathopod 2 subchelate; posterior margin of merus, carpus and propodus each without lobe covered in palmate setae; propodus palm extremely acute or transverse, evenly rounded or sinuous, with straight robust setae lining margin, with broad sinus near dactylar hinge, without proximal sinus, without posteromedial groove; dactylus not modified distally, blunt, shorter than posterior margin of propodus; posterior margin with projection near dactylar hinge. Oostegites setae with simple smooth tips. Pereopods 3–7 cuspidactylate (quadricuspidactylate). 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, almost as broad as long, not distally expanded; dactylus long, slender, not inflated. Pereopod 6 sexually dimorphic, male merus and carpus expanded; basis broadly expanded. Pereopods 6–7 without row of short setae along posterior margin of dactyli. Pereopod 7 not sexually dimorphic; basis expanded.

Pleon. Pleonites 1–3 without dorsal spines. Pleopods 1–3 all well-developed. Epimera 1–3 slits absent. Uropods 1–2 rami without apical spear-shaped setae. Uropod 1 male exopod not sexually dimorphic, peduncle distolateral robust seta absent; endopod with marginal robust setae in 2 rows; exopod with marginal robust setae in one row. Uropod 2 exopod with marginal robust setae in 1 row; endopod with marginal robust setae in 2 rows. Uropod 3 ramus linear (narrowing); subequal in length to peduncle. Telson rounded distally, entire, without groove, with apical and marginal robust setae, with 3–10 robust setae per lobe.

Remarks. While sexually dimorphic pereopods are common within the talitrid, only five genera have a sexually dimorphic pereopod 6: Bellorchestia ; Hermesorchestia ; Platorchestia ; Tatahipeke gen. nov.; and Transorchestia . Both Tatahipeke and Bellorchestia have a palmate lobe present only on the propodus of gnathopod 1, separating them from Hermesorchestia , Transorchestia and Platorchestia . The absence of robust setae on the lower lip in Tatahipeke separates it from Bellorchestia . In Tatahipeke only pereopod 6 is sexually dimorphic, while in both Hermesorchestia and Transorchestia pereopod 7 is also sexually dimorphic.

Distribution. New Zealand.