Haplomesus angustus Hansen 1916

• Main Authors: Kavanagh, Fiona A., Wilson, George D. F., Power, Anne Marie
• Format: Other/Unknown Material
• Language: unknown
• Published: Zenodo 2006
• Subjects: Biodiversity; Taxonomy; Animalia; Arthropoda; Malacostraca; Isopoda; Ischnomesidae; Haplomesus; Haplomesus angustus; Denmark Strait
• Online Access: https://doi.org/10.5281/zenodo.6256238; http://treatment.plazi.org/id/03BFFB72FFA19053713B90FAFC596FFE

Haplomesus angustus Hansen, 1916 (Figs 13–14) Haplomesus angustus Hansen, 1916: 61 –62, pl. V, fig. 2a–e; Gurjanova, 1932: 43, tabl. XIV, 50; 1933: 410; Gorbunov, 1946: 76 –77; Menzies, 1962: 119, fig. 20A–D; Wolff, 1962: 86, 217, 262, 289; Gurjanova, 1964: 259; Kussakin, 1988: 454 –456, fig. 375. Remarks on Type Material . The holotype male is in relatively good condition. The spines on pereonite 1, however, have been broken off since Hansen's original illustration. Hansen also designated a male paratype that he illustrated but did not describe. The paratype specimen is missing the head and anterior pereonites 1 and 2, but otherwise is in good condition. Pereonite 5 of the paratype is 4 times as long as wide, whereas the holotype has a ratio of five times as long as wide; this may be due to the smaller size of the paratype. A small difference in the posterolateral spines of the pleotelson may be attributed to slight damage of both specimens. Material examined . Holotype male 4.8 mm, ZMUC CRU­ 5338, Ingolf Station 18, south of Denmark Strait, 61º44'N, 30º29'W, 1135 Danish fathoms (2137 m). Paratype male 4 mm (estimated), ZMUC CRU­ 5338, Ingolf Station 125, 68º08'N, 16º02'W, 729 Danish fathoms (1373 m). Diagnosis. Male with anterolateral spines on pereonite 1 only. Pereonite 7 length reduced, less than pereonite 6. Pleotelson posterolateral margin anterior to uropods with simple spines, length subequal to uropods. Antennula with 3 distal flagellar articles. Pereopod I carpus ventral margin with 1 proximal robust seta and 1 robust seta on palm. Pleopod I of male without simple setae on lateral or distal margins. Description of male (female unknown). Body length 4.8 mm. Head length 0.9 width. Head cuticular structure granulated; pereonite 7 length reduced, less than pereonite 6. Head lobe on ventrolateral margin absent in lateral view. Pereonite 1 width 0.1 total body length, anterolateral simple spines, short, length near pereonite 1 length, acutely pointed. Pereonite 5 length 5 width, 0.5 total body length. ...