Coronarctus tenellus Renaud-Mornant, 1974

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 : 14

Coronarctus tenellus Renaud-Mornant, 1974

N= 3 specimens: 1 female, 1 male, 1 juvenile occurrence: ANDEEP-SYSTCO; 2,891 m bsl. Fig. 6 ; Supplementary Table 1.3

Short description

Large tardigrades (205–294 µm, n=2) of elongated body, with coelomocytes and other spherical cells. Secondary clavae have clearly visible ventral side shape as in original description ( Fig. 6G, G 2 ). On the dorsal side the median cirrus is placed between the secondary clavae ( Fig. 6F ). Claws without heteromorphy. Accessory spines only on the internal claws of leg IV ( Fig. 6H ). Juvenile (205 µm) with internal claws and sometimes with external claws developing inside the femur ( Fig. 6I ). The female has a gonopore and seminal receptacles.

Remarks

C. tenellus is recognisable by the secondary clavae shape and median cirrus position. All representatives have accessory spines on each leg IV internal claw ( Renaud-Mornant, 1974).

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 6. Genus Coronarctus. A Coronarctus dissimilis, female, light microscopy (DIC), ventro-sagittal view. B Coronarctus dissimilis, female, light microscopy (DIC), head, dorsal view, note leg I accessory spines on the external and internal claws (arrowheads). C Coronarctus dissimilis, female, light microscopy (DIC), head ventral view. C2 Coronarctus dissimilis, female, light microscopy (DIC), head ventral view, secondary clava indicated. D Coronarctus dissimilis, female, light microscopy (DIC), leg IV, note leg IV accessory spines on the both external and internal claws (arrowheads). E Coronarctus tenellus, male, light microscopy (DIC), ventral position. F Coronarctus tenellus, male, light microscopy (DIC), head, dorsal view. G Coronarctus tenellus, male, light microscopy (DIC), head, ventral view. G2 Coronarctus tenellus, male, light microscopy (DIC), head, ventral view, secondary clava indicated. H Coronarctus tenellus, light microscopy (DIC), leg IV, note leg IV accessory spines just on the both internal claw (arrowhead). I Coronarctus tenellus, juvenile, light microscopy (DIC), sagittal position, note leg IV with two internal claws and two growing external claws (arrowhead).Abbreviations: bt—buccal tube, cE—cirrus E, mc—median cirrus, pb—pharyngeal bulb, sc—secondary clava, se—leg sensory organ.