Bryodelphax meronensis, 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 : 6-8

Bryodelphax meronensis sp. n.

( Figs. 4, 5)

Material examined. Locality No. 19: Mt. Meron : near Har Bar-Yohai: holotype (slide No.5350) and 11 paratypes (slides Nos. 5347, 5349, 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. Intersegmental platelets (12), visible laterally to all the median plates, present. Dorsal plates with dark dots and many light points. Dark dots on terminal plate more evident than on the other plates. Apart from the head appendages and the lateral filaments A, no other lateral or dorsal appendages present. First pair of legs without spine; fourth pair of legs with dentate fringe and without papilla. Internal claws with a fine spur on all pairs of legs.

Description of the holotype. Body length about 150 µm (the specimen is a little deformed by crushing) ( Fig. 4A); colourless; eye spots absent (but we did not examine living specimens); first and second median plates divided into two portions; third median plate undivided; 12 lateral intersegmental platelets present ( Fig. 4, arrows); terminal plate faceted and without incisions. Median plates and paired plates with a transversal unsculptured grove ( Fig. 4A). Dorsal plates ornamentation similar to that of other species of the genus, i.e. with dark dots and many obvious light spots ( Fig. 5A). Dark dots on terminal plate more evident than on the other plates ( Figs. 5B, C). Dorsal plates (excluding scapular and terminal) with a smooth transverse band. Lateral intersegmental platelets with less visible ornamentation. Ventral surface without plates but with a regular, very fine, granulation. Apart from the head appendages and the lateral filaments A, no other lateral or dorsal appendages present. External and internal buccal cirri 14.2 µm and 6.2 µm long, respectively; cephalic papilla 4.2 µm long; clava not measurable; filament A, 32.7 µm long. Spine on the first pair of legs absent; fourth pair of legs with dentate collar (6–7 teeth) ( Fig. 4D, arrow a) and without papilla. External and internal claws of the second pair of legs 7.6 µm and 8.2 µm long, respectively ( Fig. 4C); external and internal claws of the hind legs 8.1 µm and 8.5 µm long, respectively. Internal claws with a fine spur on all pairs of legs ( Fig. 4D, arrow b).

The paratypes have the same qualitative characters as the holotype; the measurements for two paratypes and the holotype are provided in Table 2.

Etymology. The name meronensis refers to the type locality (Mt. Meron).

Differential diagnosis. The absence of ventral plates, presence of lateral intersegmental platelets and presence of dentate collar on the hind legs makes Bryodelphax meronensis sp. nov. similar to B. alzirae (Du Bois-Reymond Marcus, 1944) , B. tatrensis , and B. mateusi . However, the new species can be distinguished from B. alzirae in details of the plate sculpture ( B. alzirae has large granules), by possessing 12 lateral intersegmental platelets instead of 6, by the absence of both spine on the first pair of legs and papilla on the hind legs, and by having less than 12 teeth in the dentate collar.

The new species differs from B. tatrensis and B. mateusi by having more numerous light spots, some of which are also present in the central portion of the scapular and terminal plates, and in the caudal portion of the paired plates II and III, while in B. tatrensis ( Fig. 6A, B) and B. mateusi ( Fig.6C, D) they are very rare or absent. B. meronensis also differs from B. mateusi by having more evident dark dots on the terminal plate than those of the scapular plate ( Figs 5B, C and C, D). Bryodelphax meronensis sp. nov. is also similar to B. atlantis , but lacks eyes; has the very obvious cuticular light spots in the central portion of the paired plates, while they are densely distributed on the anterior and lateral portions of the plates in B. atlantis ; the dark cuticular dots on the terminal plate are clearly larger than those of the scapular plate ( Fig. 5B, C) and of other plates in comparison with B. atlantis where the dots of terminal and scapular plates are almost the same size ( Fig. 6 E, F).

In some specimens the hind legs may be contracted and, as a consequence, the dentate collar is not visible. In these cases the new species could appear similar to B. asiaticus Kaczmarek & Michalczyk, 2004 and B. parvulus , but B. meronensis sp. nov. can be distinguished because B. asiaticus lacks lateral intersegmental platelets (Kaczmarek, pers. com.), and B. parvulus has the cuticular ornamentation of the scapular and terminal plates clearly more evident than any of the other plates, and the dots of the terminal and scapular plates are similar in size. In addition, B. parvulus has a slightly shorter scapular plate expressed as a percent with respect to the body length ( Table 3). As a consequence of this difference, when specimens of B. meronensis sp. nov. and B. parvulus having similar body length are compared, structures having similar length (in µm) appear different if their length is considered as per cent of the scapular plate length ( Table 3, %sc).