Spectrarcturus hystrix ( Sars, 1877 ) Stransky & Svavarsson & Poore & Kihara, 2020

Stransky, Bente, Svavarsson, Jörundur, Poore, Gary C. B. & Kihara, Terue Cristina, 2020, Revision of Pleuroprion zur Strassen, 1903 (Holidoteidae) and re-evaluation of Spectrarcturus Schultz, 1981 (Arcturidae) (Crustacea, Isopoda, Valvifera), Zootaxa 4894 (1), pp. 1-52 : 37-42

Spectrarcturus hystrix ( Sars, 1877) comb. nov.

( Figs 29–30 )

Arcturus hystrix Sars, 1877: 250–251 (erroneously labelled 350–351).— Sars, 1885: 104–106, pl. IX, figs 23–26.— Norman, 1904: 446.

Pleuroprion hystrix . — Hansen, 1916: 194–195, pl. XV, fig. 6a–b.— Gurjanova, 1936: 200, fig. 128.— Kussakin, 1982: 421–424, figs 313–314.

Material examined: Syntypes, F1683, Norwegian North-Atlantic Expedition 1876–1878, stations 18, 124, 164, 4 females.

Other material. Female, WH 233, stn. 1023; male, Voucher 52975, POS 456 IceAGE 2, stn. 873-6 EBS from DZMB 43.916.

Diagnosis: Body with several long and slender, bluntly pointed spines; pair on anterior part of head; posteriorly row of spines across head; pereonite 1 with row of spines across pereonite; pereonites 2 and 3 with row of spines across pereonites; two rows of spines on pereonite 4; pereonite 4 0.2 times body length; trapezoid, 2.1 times longer than third pereonite. Pleotelson intermediate in length, with 5 pairs of long and slender spines near midline of pleotelson, lateral margins with spines; posterior part of pleotelson tapering towards bifid apex; pleotelson upturned distally. Antennula short, reaching little beyond distal end of second peduncular segment of antenna. Antenna short, about 0.6 of total body length; slender, with 3 large spines on second segment; large spine laterodistally on third segment, spine laterodistally on fourth segment. Spines present on basis of pereopods 5–7. Oostegites present on pereopod 1–5.

Male smaller than female. Pattern of spination as in females, spines smaller than in females and more robust; middle part of pereonite 4 narrow, without spines. Posterior part of pleotelson tapering towards bifid apex; cleft of apex not as pronounced an in females. Endo- and exopod fringed with fine setae, distally with plumose setae; endopod with 7 setae; exopod with 11 setae; endopod slightly longer than exopod; pleopod 2 appendix masculina long and curved in distal half, about 1/3 longer than expodite, fringed with fine setae.

Remarks: The species differs from all other Spectrarcturus species in the pattern of spination of the body. Other characteristics are the shape of the pleotelson and the long distolateral spine on article 3 of the antenna.

Distribution: Northernmost North Atlantic, Nordic Seas: the Faeroe Islands, Norway, Greenland, at depths between 600–1150 m ( Hansen 1916).

Figures

FIGURE 29. Spectrarcturus hystrix (Sars, 1877).A–B, D–H, female syntype; C, other female material. A, habitus, dorsal view; B, habitus, lateral view; C, pereopod 1; D, pereopod 2; E, pereopod 3; F, pereopod 4; G, pereopod 5; H, pereopod 6; I, pereopod 7. Scales: a = 1 mm (A); b = 1 mm (B); c = 1 mm (D–I).

FIGURE 30. Spectrarcturus hystrix (Sars, 1877). Other material, male.A, habitus, lateral view; B, habitus, dorsal view. Scales: a = 1 mm (A); b = 1 mm (B).