Dastychius, Pilato, Giovanni, 2013

Dastychius View in CoL gen. nov.

Fig. 2 View FIGURE 2 .

Material examined. I examined 15 specimens from Antarctic: Enderby Land: Evening Mountain (67°, 39’S, 46° 06’E). Legit K. Jazdzewki.

Type repository. 6 specimens (paratypes) are deposited in the Binda and Pilato collection (Department of the Animal Biology, University of Catania, Italy, slide No. 3278); the Holotype is deposited in the Department of Animal Morphology A. Mickiewicz University of Poznan ( Poland), and paratypes in the Dastych collection (Zoologisches Museum of Hamburg, Germany), British Antarctic Survey Data Resource Collection ( UK), National Museum of Natural History, Washington and National Museum of New Zealand, Wellington.

Diagnosis. Claws of the Isohypsibius type ( Fig. 2 View FIGURE 2 E); double claws of the same leg slightly different in shape and size; rigid buccal tube without ventral lamina but with a dorsal and a ventral apophysis for the insertion of the stylet muscles in shape of long, continuous ridges tailing off caudally and almost reaching the level of the stylet supports ( Fig. 2 View FIGURE 2 A, B, C); anterior portion of both apophyses with caudal processes pointing backwards and sideways ( Fig. 2 View FIGURE 2 C). At about a quarter the length of the ridged apophyses is an incision and septum ( Fig. 2 View FIGURE 2 A, B). Six peribuccal lobes present; peribuccal lamellae absent; structures in the form of peribuccal papulae present ( Fig. 2 View FIGURE 2 D), but this should be confirmed. Stylet furcae typically shaped, i.e. the basal portion of the two caudal branches are enlarged with thickened, swollen, and rounded apices ( Fig. 2 View FIGURE 2 B); pharyngeal bulb with apophyses and placoids ( Fig. 2 View FIGURE 2 C). Lunules present in the monotypic species ( Fig. 2 View FIGURE 2 E). Smooth eggs laid in the exuvium.

Type species. Isohypsibus improvisus Dastych, 1984 .

Composition. Dastychius improvisus comb. nov. (Dastych, 1984) is the only species to date attributable to the new genus.

Etymology. The name Dastychius is attributed to the new genus in honour of Hieronym Dastych (University of Hamburg, Germany) author of the type species Isohypsibius improvisus Dastych, 1984 .

Remarks. Ramajendas is currently the only known eutardigrade genus having the AISM in shape of long ridges. Dast y chius clearly differs from Ramajendas in having all claws of Isohypsibius type ( Fig. 2 View FIGURE 2 E); the external claws of Ramajendas are of Hypsibius type with an extremely long main branch. A comparison between Dastychius gen. nov. and Ramajendas is particularly interesting as regards the AISM. In Dastychius gen. nov. the apophyses are longer and gradually thin out caudally ( Fig. 2 View FIGURE 2 A, B, C), whereas in Ramajendas the apophyses are shorter, and the caudal portion ends abruptly ( Fig. 3A View FIGURE 3. A ), not gradually. In Dastychius gen. nov., though the apophyses are clearly uninterrupted, a septum is present dividing an anterior and posterior portion ( Fig. 2 View FIGURE 2 A, B), which is not visible in Ramajendas ( Fig. 3A View FIGURE 3. A ).