Moebjergarctus clarionclippertonensis Bai, Wang, Zhou, Lin, Meng & Fontoura, 2020

N= 4 specimens: 2 females, 2 with undetermined sex occurrence: ANDEEP 1, ANDEEP-SYSTCO; 3,551–3,650 m bsl.

Fig. 7; Supplementary Table 1.4

Short description

Large and robust tardigrade 148–283 µm long and 52.3–99.7 µm width (n=2). Buccal apparatus with stylets (Fig. 7B). Cephalic cirri with annulated base, smooth portion of the scapus and short flagellum (Fig. 7E, F). Each leg with a sensory organ (Fig. 7E). Internal and external digits are of the same size and wrinkled (Fig. 7C, G). Caudal region is covered with a thick cuticular layer shown as a bulge (Fig. 7A, E). All the females have a patched seminal receptacle opening (Fig. 7D, H).

Remarks

The identification of this species is certain because of the morphology of cephalic cirri (annulated base, smooth scapus and short flagellum). The internal and external digits of all limbs are the same size that distinguishes this species from M. okhotensis (Bai et al. 2020, Saulenko et al. 2022). This species was previously reported from Pacific deep-sea plains with a high abundance of manganese or polymetallic nodules (Bai et al. 2020). At least the sampling stations of expedition ANDEEP 1 that contained M. clarionclippertonensis (Shackleton Fracture Zone, 59°52.30′S, 59°57.63′W) at the deep sea bottom of the Drake Passage are also close to areas with polymetallic sulfide deposits and hydrothermal vent activity (see discussion for details).