Talitrus Latreille, 1802

Lowry, J. K. & Myers, A. A., 2019, Talitrus saltator (Montagu, 1808), a species complex (Amphipoda, Senticaudata Talitroidea, Talitridae), Zootaxa 4664 (4), pp. 451-480 : 452-453

Talitrus Latreille, 1802

Talitrus Latreille, 1802: 148 . — Stebbing, 1888: 1682.—G. O. Sars, 1890: 22.— Stebbing, 1891: 324.— Della Valle, 1893: 492.— Stebbing, 1906: 524.— Chevreux & Fage, 1925: 270.— Hurley, 1955: 145 (in part).— Bulycheva, 1957: 127 (in part).—J.L. Barnard, 1969: 472 (in part).— Lincoln, 1979: 226.— Bousfield, 1982: 45.

Thalitrus (sic).— Guérin-Méneville, 1836: 3.

Talitrus (Talitrorchestia) Brandt, 1851: 135 (type species Talitrus cloquetii ).

Talitrus (Talitrus) .— Hurley, 1975: 161 (in part).

Type species. Cancer (Gammarus) saltator Montagu, 1808 , selected by Latreille, 1810.

Included species. Talitrus includes 3 species: T. cloquetii Audouin, 1826 ; T. platycheles Guérin, 1832 ; T. saltator ( Montagu, 1808) .

Habitat. Supralittoral, intertidal substrate-modifying talitrids of sandy beaches.

Ecotype. Sand-hopper.

Diagnostic description (male). Head. Eye medium (1/5–1/3 head length), or large (greater than 1/3 head length). Antenna 1 short, not reaching midpoint of peduncular article 5 of antenna 2. Antenna 2 peduncular articles incrassate (expanded); article 3 without plate or process ventrally. Labrum epistome without robust setae; median groove without robust setae. Mandible left lacinia mobilis 5-, 3- or 2-cuspidate. Maxilliped palp broad or slender, article 2 with or without distomedial lobe; article 4 fused with article 3.

Pereon. Pereonites without transverse ridges. Gnathopod 1 not sexually dimorphic; simple; posterior margin of merus, carpus and propodus each without lobe covered in palmate setae; propodus tapering distally. Gnathopod 2 mitten-shaped; posterior margin of propodus with lobe covered in palmate setae; propodus palm obtuse; dactylus short, distally acute, shorter than posterior margin of propodus. Pereopods 3–7 bicuspidactylate. Pereopod 4 dactylus thickened proximally with notch midway along posterior margin. Pereopod 5 short, less than 2/3 length of pereopod 6; dactylus long, slender, not inflated. Pereopod 6 not sexually dimorphic; subequal in length or longer than pereopod 7. Pereopods 6–7 without row of short setae along posterior margin of dactyli. Pereopod 7 not sexually dimorphic propodus broad, length 4.8–5.8 × width.

Pleon. Pleonites 1–3 without dorsal spines. Oostegites setae with simple smooth tips. Pleopods 1–3 all welldeveloped. Uropod 1 male exopod not sexually dimorphic, peduncle distolateral robust seta absent; endopod with marginal robust setae in 1 or 2 rows; exopod with marginal robust setae in 1 or 2 rows. Uropod 2 exopod with marginal robust setae in 1 or 2 rows; endopod with marginal robust setae in 1 or 2 rows. Uropod 3 ramus subequal in length to peduncle. Telson broader than long, tapering distally or rounded distally, apically incised or entire, without groove, with marginal and apical robust setae, with 8–10 robust setae per lobe.

Remarks. Talitrus is the only member of the Talitridae with the combination of no sexual dimorphism in gnathopod 2 coupled with an incrassate antenna 2. It is also the only talitrid with the combination of an incrassate second antenna combined with no palmate lobes on gnathopod 1. Talitrus is the only European/Mediterranean talitrid genus with a non-enlarged male gnathopod 2 (apart from the cavernicolous Palmorchestia Stock & Martin, 1988 ).

Distribution. Eastern North Atlantic Ocean and Mediterranean Sea.