Angursa abyssalis Renaud-Mornant, 1981

Trokhymchuk, Roman, Schmidt-Rhaesa, Andreas, Utevsky, Serge, Kristensen, Reinhardt Møbjerg & Kieneke, Alexander, 2024, Towards a better understanding of deep-sea tardigrade biogeography: numerous new records from the Southern Ocean, Zootaxa 5543 (1), pp. 1-39 : 17

Angursa abyssalis Renaud-Mornant, 1981

N= 238 specimens occurrence: ANDEEP I, II, III, ANDEEP-SYSTCO; 1,088–5,213 m bsl.

Fig. 8A–D ; Supplementary Table 1.5

Short description

Angursa with slender body (120–180 µm long, 20–35 µm width, n=5) and primary clavae longer than cirri A. Secondary and tertiary clavae are usually clearly visible ( Fig. 8A, B, B 2 ). Distance between both secondary clavae on the dorsal side of the head is 1.5–4.0 μm ( Fig. 8B, B 2 ). Cirrus E short (8.0–12.0 µm, n=5) (Fig. D). The hemispherical sensory organ with a small apical spine on leg IV is sometimes a bit elongated (as in Angursa capsula ) ( Fig. 8C ).

Remarks

The two species A. abyssalis and A. capsula are quite similar in the shape of the sensory organ of leg IV (Hansen and Fujimoto 2019). However, the main identifying trait for this species is the short (less than 4 µm) distance between the secondary clavae and the shorter cirri E ( Fig. 8D ).

Figures

FIGURE 2. Absolute abundances of Tardigrada from all 130 analysed core samples of expeditions ANDEEP-1 to 3 and ANDEEP-SYSTCO to the Southern Ocean plotted against depth. Samples were taken at different working areas in the Cape Basin, in the Lazarev Sea, in the Weddell Sea, in the Ona Basin, and at different working stations in the Drake Passage

FIGURE 8. Angursa bicuspis group. A Angursa abyssalis, male, light microscopy (DIC), ventral view. B female, light microscopy (DIC), head, dorsal view. B2 female, light microscopy (DIC), head, dorsal view, secondary clavae indicated. C male, light microscopy (DIC), dorsal view. D female, light microscopy (DIC), caudal region. E Angursa capsula, female, light microscopy (DIC), dorsal view. E2 Angursa capsula, female, light microscopy (DIC), dorsal view, secondary clavae indicated. F Angursa capsula, female, light microscopy (DIC), ventral view. Abbreviations: cE—cirrus E, ec—external cirrus, pb—pharyngeal bulb, pc—primary clava, sc—secondary clava, se—leg sensory organ, tc—tertiary clava.