Talitrus platycheles Guérin, 1832

Lowry, J. K. & Myers, A. A., 2019, Talitrus saltator (Montagu, 1808), a species complex (Amphipoda, Senticaudata Talitroidea, Talitridae), Zootaxa 4664 (4), pp. 451-480 : 457-461

Talitrus platycheles Guérin, 1832

( Figs 2B , 3 , 7 , 8 )

Talitrus platycheles Guérin, 1832: 44 , 45.— Brandt, 1851: 137.— Chevreux, 1893: 124. — Gulia, 1873: 314.—Moore & Schem- bri, 1986: 71.— Spamer & Bogan, 1994: 42: 42. Talitrus saltator Della Valle, 1893: 492 , 947, fig. 57. Talitrus locusta forma mediterranea Chevreux, 1893: 124. Talitrus saltator . — Chevreux, 1911: 230.— Bellan-Santini, 1993: 760, fig. 520 (key).— Moore & Schembri, 1986: 68, 71.—?

Sezgin & Kataðan, 2007: 5, table 1. Talitrus saltator var mediterranea Chevreux & Fage, 1925: 272 . Talitrus saltator var. briani Ruffo, 1936: 28 . Type material examined. Male holotype, Methoni (Modon), Peloponnese, Greece, ANSP CA 2814.

Other material examined. 1 male, 1 female, Lido Alberoni, Venice, 3 September 1936, F. Zorzi; 1 male, 1 female, Cavallino, Venice, 28 May 1934, E. Gridelli; 1 male, 1 female, Cagliari, Sardinia, May 1936, S. Ruffo; 1 male, 1 female, St. Tropez , 1956, Dartorello ; 3 females, Tunisia, F. Charfi. Many specimens, Béjaïa (formerly Bougie), Algeria, sur la plage, Ed. Chevreux, stn 527, August 1892. Many specimens, Annaba (formerly Bône), Algeria, Ed .

Chevreux. Many specimens, Cherchell, Algeria, Ed. Chevreux, 1885. About 10 specimens, Stn 549, Golfe de Gabès (34°00′N 10°25′E), Plages de Mustapha et d’Hussein Dey, près Algeria, Ed. Chevreux, September, 1892.

Type locality. Methoni (Modon), Peloponnese, Greece .

Diagnosis (male). Antenna 1 peduncular articles 2 and 3 long and slender, 5 × as long as broad. Antenna 2 slightly incrassate, Gnathopod 1 merus posterior margin expanded; carpus:propodus length = 1:0.7; dactylus long, half length of propodus. Pereopod 6 basis expanded, posterior margin weakly convex. Pereopod 7 basis expanded, posterior margin convex, propodus 8 × as long as broad; dactylus extremely elongate and slender. Uropods elongate. Uropod 1 rami subequal with each other and a little shorter than peduncle. Uropod 2 endopod distinctly longer than exopod; endopod:peduncle ratio = 1:1.3. Uropod 3 peduncle longer than broad; ramus elongate, distally tapering, with about 8 marginal setae.

Description. Male (Cagliari) 15 mm.

Head. Eyes round, medium size. Antenna 1 short, reaching end of antenna 2 article 4; peduncular articles 2 and 3 long, slender, 1.5 × as long as broad; flagellum with 5 articles. Antenna 2 slightly incrassate, peduncular article 5 over 2 × length of article 4; flagellum longer than peduncular article 5 with 28 articles. Maxilla 1 inner plate slender with 2 terminal setae. Maxilla 2 without oblique setal row. Maxilliped palp article 4 fused with article 3.

Pereon. Gnathopod 1 coxa subtriangular; basis stout, anterior margin straight; merus posterior margin expand- ed; carpus stout, parallel-sided; carpus:propodus length = 1:0.7; dactylus long, half length of propodus. Gnathopod 2 mitten-shaped; basis sub-ovoid; carpus longer than propodus; 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; basis with large posterior lobe. Pereopod 6 subequal in length with pereopod 7; basis expanded, with margin of posterior lobe weakly convex. Pereopod 7 basis expanded, with margin of posterior lobe convex; propodus 8 × as long as broad; dactylus extremely elongate and slender.

Pleon. Epimeron 3 posterior margin weakly scalloped. Uropods elongate. Uropod 1 rami subequal with each other and a little shorter than peduncle. Uropod 2 endopod distinctly longer than exopod; endopod:peduncle ratio = 1:1.3. Uropod 3 peduncle longer than broad; ramus elongate, distally tapering, with about 8 marginal setae. Telson with 10–11 setae per lobe.

Female (sexually dimorphic characters). Not significantly different from male.

Remarks. Talitrus platycheles differs from the other species of Talitrus by having uropod 2 exopod markedly shorter than the endopod and uropod 3 elongate with the ramus strongly tapering distally. It is also characterized by having the male gnathopod 1 merus swollen.

Distribution. The known distribution of T. platycheles in the Mediterranean is patchy (fig. 1). There are no records of Talitrus along the southern coast of Spain or the south-western Mediterranean coast of France. Talitrus platycheles is known from Venice, Adriatic Sea (this paper). Sezgin & Kataðan (2007) reported T. saltator from the Black Sea. Based on records of T. platycheles from the Aegean Sea we consider the record of Sezgin & Kataðan (2007) to most likely represent T. platycheles . Talitrus platycheles is known from the Canary Islands ( Chevreux 1893) and along the coast of Morocco (Charfi & El Gitari 2008), Algeria ( Chevreux 1893) and Tunisia from Tabarka in the west to the Gulf of Hammamet in the east (this paper based on samples from Dr El Gtari and Dr Faouzia Charfi). There are no records from Tunisia east of the Gulf of Hammamet.

Western Mediterranean ( France, Sardinia, Corsica), Ligurian and Tyrrhenian Sea (Liguria, Tuscany); Adriatic sea (Venice, unconfirmed records fromMontenegro, Veneto, Emilia-Romagna, Apulia); western Peloponnese (Methoni); northern Aegean Sea (Anaifi, Astipálea, Kos, Tilos);? Black Sea; North Africa ( Algeria, Tunisia); Canary Islands.

Figures

FIGURE 2. Talitrus cloquetii Audouin, Gournes, Crete; B. Talitrus platycheles Guérin, Cagliari, Italy; C. Talitrus saltator Montagu, Ringabella Bay, Cork, Ireland.

FIGURE 3. Talitrus platycheles Guérin, Holotype, Methoni, Peloponnese, Greece.

FIGURE 7. Talitrus platycheles Guérin, male, 15 mm, Cagliari, Italy.

FIGURE 8. Talitrus platycheles Guérin, male, 15 mm, Cagliari, Italy.