Arctocypris fuhrmanni Petkovski, Scharf & Keyser, 2016, n. gen.

Arctocypris fuhrmanni n. gen., n. sp.

(Figs 2–5)

Etymology. The species is named in honour of the ostracod researcher Roland Fuhrmann, Leipzig, Germany.

Holotype. 1 female Nr. ZMH K- 42963

Paratypes. 40 females Nr. ZMH K- 42964

Type locality. ‘Thorshühnchen-Teich’, a pond on the island Måkeøyane in the Liefdefjord (Northern Spitsbergen, Svalbard, Norway). Collected by H.-J. Spitzenberger in August 1990 and August 1991.

Material examined. 41 adult females, mostly decalcified and slightly or strongly macerated. Associated fauna: In the sample of August 13, 1991 from ‘Thorshühnchen-Teich’ 2 females of Tonnacypris glacialis (Sars, 1890) and 1 female of Fabaeformiscandona sp.

Description (Figs 2–5):

Carapace. LV (Figs 2 A, 5): In lateral view dorsal margin blunt at point of greatest height, slightly bulged antero-dorsally. Anterior margin broadly rounded. Dorsal margin also slightly bulging postero-dorsally and with small indentation. Posterior margin narrower than anterior. Ventral margin slightly indented and bulging around mouth region. Surface covered with distinct, rounded depressions, frontally with small wart-like pores. Whole carapace with simple open pores. Calcified inner lamella broader anteriorly than posteriorly. Inner list more elevated in the anterior than in the posterior. Selvage peripheral, fused zone anteriorly broader than posteriorly.

RV (Figs 2 B and 5): In lateral view nearly triangular. Greatest height frontal from the middle, higher than half of the length. Dorsal margin bluntly angled at point of greatest height, slightly sloping towards frontal end, then gently indented and extending into the broadly rounded frontal margin. Dorsal margin more inclined towards posterior than towards anterior end, postero-dorsally with small indentation. Posterior end narrow. The ventral margin slightly concave and enlarged around mouth. Surface ornamentation as on LV. An outer list exists and is running parallel to the flange. Two parallel inner lists present more pronounced on the anterior calcified inner lamella than on the posterior one. Calcified inner lamella wider anteriorly than posteriorly. Fused zone broader anteriorly than posteriorly. Selvage peripheral.

Dimension. Length: 1.04–1.09 mm, height: 0.57–0.59 mm, width: 0.53 mm.

Antennula (A1) (Fig. 3 A): 7-jointed, distal segments 5, 6, 7 with very long distal setae. The length of the distal setae is about twice the length of the distal 6 segments. Rome organ present. Ya present; Wouter’s organ or a seta at that place not visible.

Antenna (A2) (Figs 3 B,C): Distal claws rather strong. G1 slightly longer than G2 and G3 and 120 % of length of penultimate segment. GM about three times as long as ultimate segment. Gm and g about twice as long as ultimate segment, y3 about half the length of Gm and g. Z1-3 setae of similar length, about four times the length of the ultimate segment, y2 not observed. T1-4 with different lengths. The longest about as long as penultimate segment, y1 not found. Five natatory setae reaching slightly beyond the tips of the distal claws, the six th is short, reaching only to the middle of the next segment. The aesthetasc Y rather short, reaching just 30 % of the length of first endopodial segment. Exopodit with two short seta and one long seta reaching 114 % of length of first endopodial segment.

Maxillula (Mx 1) (Fig. 3 E): Final segment of the palpus twice as long as broad, cylindrical. The distal segment of the palp with four setae. The two teeth setae on the third masticatory process serrate.

Maxilliped (T1) (Figs. 3 F,G): Maxilliped with two a-setae and one b, c and d-seta. Vibratory plate with 6 rays. Palp with 3 setae, the longest about 120 % of the length of the palp.

Walking leg (T2) (Fig. 4 A): Basipodit with only one seta (d1). Endopodit with 4 segments in proportions of 3.6: 2.1: 1.7: 0.7. Distal claw strong with two rows of serrate structures distally and with a length of 75 % of endopodit.

Cleaning leg (T3) (Fig. 4 B): 4-jointed (penultimate segment undivided), with 3 setae at the basal segment and a long (h3) and a small hook-like seta (h2) at the distal segment. The length of h3 is similar to the length of the penultimate segment.

Uropod (U) (Fig. 4 C): Rod-shaped with two strong claws and two small setae. Longest claw not quite as long as half of the length of the rami. Uropodal attachment simply forked without “Triebel loop. At the base without triangular structures.