Macrobiotus dimentmani, Pilato & Lisi & Binda, 2010

Pilato, Giovanni, Lisi, Oscar & Binda, Maria Grazia, 2010, Tardigrades of Israel with description of four new species, Zootaxa 2665, pp. 1-28 : 12-15

Macrobiotus dimentmani sp. nov.

( Fig. 7)

Material examined. Localities: Nos. 1, 2, 5, 19, 20, 26, 27, 29, 30 and 32.

Locus typicus. No. 1: Mt. Hermon : Makam Ibraim el Khalil: holotype (slide No. 5360), more than 168 paratypes and 11 eggs (slides Nos. 5337-9; 5342-6; 5350-6; 5359-65; 5367-80; 5388) .

Type repository. Holotype and paratypes are deposited in the collection of Binda & Pilato. Museum of the Department of Animal Biology “Marcello La Greca”, University of Catania .

Specific diagnosis. This species belongs to the Macrobiotus ‘ harmsworthi group’; cuticle smooth without pores; eyes generally present; buccal armature and placoids as in M. harmsworthi . Stylet supports inserted on the buccal tube at c. 77 % of its length. Claws long and slender; external and internal claws of different length on the first three pair of legs, but almost equal length on the fourth pair of legs.

Conical egg processes with a ring of well defined basal dots and with apical portion subdivided into two to six long and flexible terminal points. Surface of the conical egg processes with a reticular design of small isodiametric mesh; egg shell dotted but not areolated.

Description of the holotype. Body length about 480 µm (the body is a little contracted), colourless, cuticle smooth without pores; eye spots present (but were absent in some paratypes). Mouth terminal with ten peribuccal lamellae, an anterior band of small teeth, a posterior ring of triangular teeth and a system of three dorsal and three ventral transverse ridges. Buccal tube ( Fig. 7A) 49.2 µm long and 11.3 µm wide (pt = 23.0); stylet supports inserted on the buccal tube wall at 77.2 % of its length (pt = 77.2). Pharyngeal bulb with apophyses, three macroplacoids and a microplacoid near to the third macroplacoid ( Fig.7A). First macroplacoid, without a central narrowing, 8.9 µm long (pt = 18.1), second 7.3 µm (pt = 14.8), third, with a preterminal narrowing, 8.7 µm (pt = 17.7), microplacoid 5.7 µm (pt = 11.6); entire row of placoids 33.1 µm long (pt = 67.3), macroplacoid row 26.8 µm (pt = 54.5).

Claws, of the ‘ hufelandi type’, are very long and slender ( Fig. 7B, C); external and internal claws of different length on the first three pair of legs, almost of equal length on the fourth pair of legs. Main and secondary branches of the claws joined with a longer common tract on the fourth pair of legs than on the first three. Due to the orientation of the specimen on the slide it is very difficult to measure all the claws. External and internal claws on the second pair of legs 18.2 µm (pt = 37.0) and 15.8 µm long (pt = 32.1), respectively; anterior and posterior claws on the fourth pair of legs 18.3 µm (pt = 37.2) and 18.7 µm long (pt = 38.0) respectively. In Table 4 additional claw measurements are given for six of the paratypes. Main claw branches with thin, short accessory points. Lunules present; on the first three pairs of legs these are well developed and smooth, on the fourth pair of legs they are wider, with a dentate margin. A faint cuticular bar is present below the lunules on the first three pars of legs ( Fig. 7B, arrow).

Eggs ( Fig.7D, E), freely laid, spherical, with 15–17 conical processes around the circumference (56–71 in the hemisphere); diameter excluding processes 79–90 µm, including, 106–120 µm; apical portion of the conical processes subdivided into two to six long, flexible terminal points ( Fig. 7E); processes 16–17 µm long, with basal diameter 10–14 µm. Surface of the conical processes with a reticular design of small isodiametric mesh ( Fig. 7D); a ring of distinct basal dots is present; egg shell is not areolated, but has dots smaller than those of the basal ring ( Fig. 7D).

The paratypes are similar to the holotype in both qualitative and metric characters. Measurements of structures of the holotype and of the smallest and largest specimens are indicated in Table 4.

Etymology. The specific name is in honour to Prof. Chanan Dimentman (University of Jerusalem).

Differential diagnosis. Macrobiotus dimentmani sp. nov. is very similar to M. diffusus but has more slender claws and the external claws are slightly longer (see Fig. 7B, C and 7F, G; Table 5). The eggs show some obvious differences: in Macrobiotus dimentmani sp. nov. each egg process has a distinct ring of basal dots that is absent from M. diffusus eggs; the terminal points, generally, are not thin filaments; the egg shell has an obvious granulation that is absent from M. diffusus , and lacks the thin radial stripes that are present on the eggs of M. diffusus .