Haplomacrobiotus utahensis, Pilato, Giovanni & Beasley, Clark, 2005

Pilato, Giovanni & Beasley, Clark, 2005, Haplomacrobiotus utahensis new species of Calohypsibiidae (Eutardigrada) from North America, Zootaxa 879, pp. 1-7 : 2-6

Haplomacrobiotus utahensis sp. n.

Material examined: Utah, Canyonlands National Park in Moab, 20 specimens (holotype and 19 paratypes) in two samples (collection dates: June 2003, June 2004).

Type repository: Holotype and three paratypes are deposited in the Maria Grazia Binda and Giovanni Pilato collection; 16 paratypes in the collection of Clark Beasley.

. Description of the holotype: Body length 417 m, colourless, eye spots present, cuticle smooth without pores. Bucco­pharyngeal apparatus with rigid buccal tube and ventral lamina ( Figs. 1 A; 2 A, B; 3). Mouth antero­ventral rounded by six well evident peribuccal lobes ( Fig. 1 B). Peribuccal lamellae absent. Peribuccal papulae present, these structures different in size ( Fig. 3 B) and probably, as reported by Pilato (1993) for H. hermosillensis , some of them are forked. A crown of fine teeth is present in the anterior portion of the buccal cavity ( Fig. 2 B). Posterior portion of the buccal cavity without teeth but two laterodorsal and two ventro­lateral transversal ridges present. Medio­dorsal and a medio­ventral ridges seem to be absent. Buccal tube 43.1 m long and 6 m width (pt = 13.9). Stylet supports inserted on the buccal tube at 67.4 % of its length (pt = 67.4). Pharyngeal bulb with apophyses and three rod­shaped macroplacoids ( Figs 1 A; 2 A, B; 3 A); microplacoid absent. First macroplacoid 5.0 µm long (pt = 11.6), second 4.6 µm (pt = 10.7), third 5.6 µm (pt = 13.0); entire row of macroplacoids 16.6 µm long (pt = 38.5). All legs with two single, thin and small claws ( Figs 2 C, D). Internal claw on the second and third pairs of legs 5.2 µm long (pt = 12.1), external claw on the same pairs of legs 5.7 µm long (pt = 13.2); anterior claw on the hind legs 5.8 µm long (pt =13.4), posterior claw of the same pair of legs 6.4 µm long (pt = 14.8). Lacking lunules and cuticular thickenings on the legs. Eggs unknown.

Etymology: The name utahensis is derived from the state of Utah, where the specimens were collected.

Differential Diagnosis: Haplomacrobiotus utahensis sp. n. is the second species of the genus; it is similar to H. hermosillensis in many characters, but differs from it in the some features: more evident peribuccal lobes ( Figs. 1 B and 4 D); wider buccal tube ( Table 1 ); thinner and shorter claws ( Figs. 2 C, D and 4 A, B, C; Table 1 ); first macroplacoid different in shape (in H. hermosillensis the first macroplacoid with a longer, thin anterior portion ( Fig. 4 B) and therefore in some focal positions that macroplacoid appears shorter than the second ( Fig. 4 A), but in another focal position the true length of that placoid appears evident ( Fig. 4 B). In H. utahensis sp. n. the anterior portion of the first placoid is shorter and therefore the true length of that macroplacoid is better evident ( Figs. 1 A; 2 A). For this reason, when specimens of H. hermosillensis and H. utahensis sp. n. are compared not very carefully, placoids of the same length may seem to be, in some focus positions, different in length.

Remarks: We emphasize that peribuccal lobes in H. hermosillensis were considered absent by Schuster et al. (1980; page 292, Table 1 ), but Fig. 4 D demonstrates that they are present. They are less visible when the buccal tube is retracted. The peribuccal papulae, as in H. hermosillensis ( Pilato, 1993) may have different dimensions ( Fig. 3 B) from one another; it is not clear whether they are forked or not. The characters of Haplomacrobiotus utahensis sp. n, particularly the presence, the number and the symmetry of peribuccal lobes and peribuccal papulae confirm the opinion (expressed by Pilato since 1969) that the genus Haplomacrobiotus must be ascribed to the family Calohypsibiidae .

Figures

FIGURE 1. Haplomacrobiotus utahensis sp. n. A, on ventral view. Portion of the buccal tube is indicated which must be measured to calculate the percentage ratio pt. B, the figure shows the very evident peribuccal lobes.

FIGURE 2. Haplomacrobiotus utahensis sp. n .. A, bucco­pharyngeal apparatus of the holotype; the figure in particular shows the shape of the first macroplacoid. B, same bucco­pharyngeal apparatus in a different focus position; the figure shows the teeth of the buccal armature (arrow). C, claws of the third pair of legs of the holotype. D, claws of the fourth pair of legs of the holotype. Scale bar = 10 µm.

FIGURE 3. Haplomacrobiotus utahensis sp. n. A, bucco­pharyngeal apparatus of a paratype; the figure shows in particular the peribuccal papulae; B, bucco­pharyngeal apparatus of the same paratype; the figure shows in particular that the peribuccal papulae can be different in size from one another. Scale bar = 10 µm.

FIGURE 4. Haplomacrobiotus hermosillensis. A, bucco­pharyngeal apparatus and claws of the first and second pairs of legs. B, same bucco­pharyngeal apparatus in a different focus position; the figure shows in particular the shape of the first macroplacoid; the figures A and B show that the first macroplacoid appear of different shape and of different size in different focus positions. C, claws of the fourth pair of legs; one of the claws has a basal spur (arrow). D, peribuccal lobes. Scale bar = 10 µm.