Lestrigonus latissimus (Bovallius 1889)

Lestrigonus latissimus (Bovallius)

Hyperia latissima Bovallius, 1889:229–232, pl. 11: figs. 26–36.–Vosseler, 1901:67.–Chevreux & Fage, 1925:404–405.–Stephensen, 1928:590.–Candeias, 1934:4, fig. 3.–Vives, 1966:96, table 19; 1968:460, table 1.

Hyperia hydrocephala Vosseler, 1901:74–76, pl. 6: figs. 26–28, pl. 7: figs. 1–5.–Steuer, 1911:677–679, pl. 2.–Stephensen, 1924:91–92, Chart 14.–Gamulin, 1948:21.

Hyperia sp. ? hydrocephala Vosseler.–Pesta, 1920:30–31, fig. 5a-c.

Hyperia bengalensis (Giles).–Shoemaker, 1945b:238; 1948:12–13.

DERIVATION OF NAME.–Not given; presumably from the Latin “latus” [=broad], referring to the plump body.

TYPE-LOCALITY.–“The Southern temperate region of the Atlantic” (Bovallius, 1889).

DIAGNOSIS.–Length of ♀ 2–3 mm, of ♂ 3–4 mm. Head about 2.2 times as high as long, shorter than pereonites 1–4 combined. Pereonites 1–4 fused in ♀, 1–2 fused in ♂. Gland cone bluntly round below, not reaching ventral border of buccal mass. Md incisor and lacinia with 10 teeth. Mx1 outer lobe with truncate apex. Mxp outer lobes slender, with 3 apical setae and 2–4 setae on medial margin. P1 with pronounced bulge on anterior margin of s2; s4 with 4 posterodistal spines; s6 with 1 or 2 spines on anterior margin. P2 carpal process about half as long as s6; s6 with 2 spines on anterior margin. S7 of P5 about ¼-? length of s6, ⅓shorter than s7 of P6–7, armed with a few anterodistal spinules; s6 of P5–7 with spine on distal margin overlapping base of s7 medially. Telson triangular, in ♀ about 3/5, in ♂ about ½ as long as protopod of Up3.

RELATIONSHIPS.–L. latissimus is very similar to L. shoemakeri, but the two species appear to be allopatric, the former inhabiting the Atlantic, the latter the Pacific. The partial sutures on fused pereonites 1–4 of L. shoemakeri are absent in L. latissimus. L. macrophthalmus has a distinctly more globular head and is a smaller species.

I believe Vosseler’s H. hydrocephala is an immature L. latissimus in which pereonites 1–5 are fused and not, as Stephensen (1924) maintained, conspecific with L. macrophthalmus. I have examined the specimens identified by Stephensen (1924) as H. hydrocephala from Thor station 224. The sample contains mature females with pereonites 1–4 fused and immature females with pereonites 1–5 fused. S6 of P1 has 1 spine on the anterior margin in immature specimens; mature specimens usually have 2 spines, but some have only 1. The Thor specimens agree with L. latissimus rather than with L. macrophthalmus in body size, gland cone-buccal mass relationship, and length of the telson in relation to Up3 protopod. Contrary to Stephenson’s opinion, therefore, I consider macrophthalma to be distinct from hydrocephala, and believe the latter to be an immature L. latissimus.

DISTRIBUTION.–Reliably known only from the eastern Atlantic and the Mediterranean.