Heteromesus longiremis Hansen, 1916

Cunha, Marina R. & Wilson, George D. F., 2006, The North Atlantic genus Heteromesus (Crustacea: Isopoda: Asellota: Ischnomesidae), Zootaxa 1192 (1192), pp. 1-76 : 48-49

Heteromesus longiremis Hansen, 1916

Heteromesus longiremis Hansen 1916: 68–69 , pl. VI, fig. 2a–f; Gurjanova 1932: 45, tabl. XV, 55; Menzies 1962: 122, fig. 22A–B; Wolff 1962: 85, 217, 262, 275, 289; Kussakin 1988: 481–483, fig. 394–396.

Not Heteromesus longiremis .– Chardy 1974: 1549–1551, fig. 8–9.

Material examined

None, data taken from Hansen (1916).

Remarks on type material. Syntypes mentioned in original description: female fragment (3.5 mm), male fragment (3.7 mm), North Atlantic: Davis Strait, 61º50’N, 56º21’W, 1895–1896, R / V Ingolf, stn 36, 2702 m (1435 Danish fathoms). Type material was missing from ZMUC, but according to Hansen (1916), it consisted of one mutilated female without head and pereonite 1, and one mutilated male without head and pereonites 1–4.

Diagnosis

Pereonite 2 in female with median tubercle, with 1 pair of anterolateral simple spines, with no lateral spines or tubercles. Pereonite 5 in female length 4.0 width, in male length 6.2 width. Pleotelson posterolateral margin anterior to uropods without spines or tubercles. Pereopod bases without spines. Uropods length in female 0.50, in male 0.65 length of pleotelson.

Description

Body granular. Pereonite 2 in female with median tubercle, 2–3 pairs of dorsal tubercles, 1 pair of anterolateral simple spines. Pereonite 3 in female with median tubercle, 2 pairs of dorsal tubercles. Pereonites 2–3 in female with dorsal tubercles arranged in transverse row, anterolateral simple spines short, length distinctly less than length of pereonite 1. Pereonite 4 in female length 0.55 width. Pleotelson in female length 1.35 width.

Male specific characters. Pleotelson length 1.3 width. Pleopod II protopod apex rounded.

Distribution

North Atlantic: Davis Strait, 2702 m. Wolff (1962: 262) mentions 2 localities (at 698 and 2702 m); not in accordance with Hansen (1916: 69).

Remarks

Heteromesus longiremis was scored according to original description by Hansen (1916), measurements having been obtained from his illustrations. This species is poorly characterised but is distinct from other species based on the following combination of features: pereopods II– VII bases lacking spines; female pereonite 5 length 4.0 width, 6.2 in male; and male uropods being longest of any recorded species, length 0.65 pleotelson length.