Hypsibius septulatus, Pilato & Binda & Napolitano & Moncada, 2004

Pilato, G., Binda, M. G., Napolitano, A. & Moncada, E., 2004, Remarks on some species of tardigrades from South America with the description of two new species, Journal of Natural History 38 (9), pp. 1081-1086 : 1084-1085

Hypsibius septulatus n. sp.

(figure 2)

Material examined. Peru: Pomata : holotype and one paratype from a moss sample (Dydymodon fallax) .

Description of the holotype. Body length about 250 Mm (figure 2a) (the paratype is 261 Mm long), colourless; cuticle unsculptured but with about 22 dorsal undulations; eyes present; mouth ventral.

Bucco-pharyngeal apparatus of Hypsibius type (figure 2b): buccal tube rigid without ventral lamina; peribuccal lamellae absent; apophyses for the insertion of the stylet muscles in the shape of semilunar hooks symmetrical with respect to the frontal plane. The buccal tube, measured from the anterior margin of the stylet sheaths to the base of the pharyngeal apophyses, 24.5 Mm long and 2.2 Mm wide (pt =9); the stylet supports are inserted on the buccal tube at 64.5% of its length (pt =64.5).

The pharyngeal bulb, 20.1 Mm×15.2 Mm, has two rod-shaped macroplacoids and septulum; the microplacoid is absent. First macroplacoid, with a central constriction, 5.2 Mm long (pt =21.2); second macroplacoid 3.9 Mm (pt =15.9); septulum 1.9 Mm (pt =7.8); placoid row length (including septulum) 12.2 Mm (pt =49.8), excluding septulum 9.2 Mm (pt =37.6).

Claws, of Hypsibius type, well developed (figure 1c, d), with enlarged bases (crenate in the external claws); main branches with accessory points. External claw length 15.6 Mm (pt =63.7) and 16 Mm (pt =65) on the second and third pair of legs, respectively; internal claws 10.4 Mm (pt =42.4) and 10.9 Mm (pt =44.5), respectively. The unfavourable orientation did not allow us to measure the claws of the hind legs; we measured them in the paratype (having the buccal tube 25.3 Mm in length): the anterior claw length was 11 Mm (pt =43.5), the posterior 17.4 Mm (pt =68.8). Lunulae absent. A cuticular bar is present (figure 1c, d) near the bases of the internal claws on the first three pairs of legs and near the base of the anterior claw on the hind legs. A shorter cuticular thickening is present between the bases of the claws on all legs.

Eggs were not found.

The paratype is similar to the holotype.

Etymology. Septulatus =provided with septulum.

Hypsibius septulatus in some characters is similar to Hypsibius marcelli Pilato, 1990 described from Tierra del Fuego, but it differs from this species in the following features: cuticle with dorsal undulations but without tubercles, longer buccal tube (in relation to the body length), more slender claws.

Hypsibius septulatus differs from Hypsibius iskandarovi Tumanov, 1997 in the following characters: dorsal cuticle with about 22 undulations, wider buccal tube, longer placoids, pseudoseptulum absent, lunulae absent, a short cuticular bar present between the claws also on the first three pairs of legs.