Raiarctus Renaud-Mornant, 1981

Jørgensen, Aslak, Boesgaard, Tom M., Møbjerg, Nadja & Kristensen, Reinhardt M., 2014, The tardigrade fauna of Australian marine caves: With descriptions of nine new species of Arthrotardigrada, Zootaxa 3802 (4), pp. 401-443 : 424

Genus Raiarctus Renaud-Mornant, 1981

Diagnosis (emended): Styraconyxinae with the dorso-lateral epicuticular coat supported by long thin pillars 5–6 µm regularly arranged in close parallel lines. With 3-pointed claws, with or without heart-shaped pads on the internal digits. With or without peduncles on every tarsus. Minor primary clava with a cone or tube-like shape; the short, secondary clavae either reduced or minor. Body dorso-ventrally flattened. With lateral tube-like openings to the seminal receptacles. Halechiniscid male gonopore (oval papilla with a crescent-shaped opening).

Type species: Raiarctus colurus Renaud-Mornant, 1981

Additional species: Raiarctus aureolatus Renaud-Mornant, 1981 ; Raiarctus variabilis D’Addabbo Gallo, Grimaldi de Zio & Morone De Lucia, 1986

Remarks. The genus Raiarctus currently consists of Raiarctus colurus , R. aureolatus and R. variabilis . The large variation in size and shape of several characters such as primary clava, cuticular pillars and cirrus E, meant that R. colurus and R. aureolatus were considered as variable forms of R. variabilis (Grimaldi de Zio et al. 1983). After a more detailed study of a larger number of Raiarctus samples the taxonomic status was re-established by D’Addabbo Gallo et al. (1986). The description of R. variabilis fits on several characters to both of the new Australian Raiarctus species, e.g. the size and arrangement of the pillars in parallel lines. Genital papillae, which are openings for the seminal receptacles, as described in R. variabilis and seen in several specimens of Mediterranean R. colurus and R. aureolatus , were not clearly visible in the Australian species.