Pseudotiron Chevreux, 1895

Just, Jean, 2022, Tirons of the world: a review of ‘ tironid’ amphipods, description of new genera and species, and establishment of a new subfamily Tironinae Stebbing, 1906 stat. nov. (Crustacea, Synopiidae), Zootaxa 5139 (1), pp. 1-89 : 71

Pseudotiron Chevreux, 1895

Type species. Pseudotiron bouvieri .—By monotypy.

Component species. Pseudotiron bouvieri Chevreux, 1895 ; P. coas J.L. Barnard, 1967 ;

P. golens J.L. Barnard, 1962 ; P. miratus sp. nov.

Distribution. Mediterranean Sea; California off Baja; Mexico; South Africa; Australia.

Diagnosis (new). Tironin Synopiidae . Head with dorsal margin and front straight meeting in even curve or blunt projection, rostrum triangular, apex rounded. Eyes and accessory eyes noted in some species. Interantennal head margin vertical, with rounded lower corner. Mandible palp present with 3 articles, article 2 straight. Coxal plate 1 with anterodistal projection, plate 2 rectangular, plate 3 pelagont (apparently less strongly so in P. coas ), plate 4 anteriorly and distally rounded, posterior margin straight or slightly concave, plates 5 and 6 strongly posterolobate, plate 7 wider than deep. Gnathopods 1 and 2 simple, basis straight, carpus straight, elongate, about as long as basis, propodus straight, dactylus with unguis nearly straight, about half to two third length of propodus. Pereopods 3–7 short, dactylus of 3–4 and to a lesser degree 5–7 with unguis short and curved, with stout, curved anterior margin robust seta opposing unguis (pre-stubby, Fig. 1b ). Uropods 1 longer than 2 reaching beyond posterior margin of peduncle of uropod 3, or uropod 1 shorter than 2. Uropod 3 rami reaching beyond elongate, fully cleft telson, outer ramus with small second article with 1 to 3 robust setae apically. Uropod and telson glands presently known only in Pseudotiron miratus sp. nov.

Key to species of Pseudotiron

1. Coxal plate 3 pelagont................................................................................. 2

- Coxal plate 3 indistinctly produced posterodistally....................................... P. coas J.L. Barnard, 1967

2. Head rounded anteriorly; coxal plate 3 posterior projection rectangular...................... P. bouvieri Chevreux, 1895

- Head projecting anteriorly; coxal plate 3 posterior projection broadly rounded..................................... 3

3. Head as long as combined pereonites 1–4 dorsally; uropod 1 much shorter than 2, peduncle reaching to posterior margin of urosome 2; dactylus of pereopods 3–7 nearly twice as long as wide at base (pre-stubby)....... P. golens J.L. Barnard, 1962

- Head longer than combined pereonites 1–3 dorsally; uropod 1 longer than 2, peduncle reaching posterior margin of urosome 3; dactylus of pereopods 3–6 as long as broad (nearly fully stubby).................................. P. miratus sp. nov.

Figures

FIGURE 1. Representative habitus illustrations of tironin genera. Tiron spiniferus (from Sars, 1895 pl. 140, ♀ 8 mm); Pseudotiron miratus sp. nov. (this paper, ♀, 4.5 mm); Tironella pervicax comb. nov. (from J.L. Barnard, 1967 fig. 84, ♂ 4.7 mm); Glandulotiron pilocaputis sp. nov. (this paper, ♀, 6.3 mm); Metatiron tropakis (from J.L. Barnard, 1967 fig. 45, ♀, 4.9 mm); Minitiron bellairsi comb. nov. (from Just, 1981 fig. 1, ♀ 2.4 mm). a and b, dactylus and unguis of pereopods 3–7: a, stubby; b, pre-stubby.