Paramacrobiotus klymenki, Pilato, Giovanni, Kiosya, Yevgen, Lisi, Oscar & Sabella, Giorgio, 2012

Pilato, Giovanni, Kiosya, Yevgen, Lisi, Oscar & Sabella, Giorgio, 2012, New records of Eutardigrada from Belarus with the description of three new species, Zootaxa 3179, pp. 39-60 : 49-54

Paramacrobiotus klymenki sp. nov.

( Fig. 6 )

Type material. Vitebsk Oblast, Sennensky district, spruce forest, vicinity of Margoitsy village (54°40'19"N, 29°37'27"E); moss sample collected (June 2002) by G.O. Mazepa: holotype, 71 paratypes and 45 eggs.

Type repository. Holotype (slide No. 5425), 23 paratypes and 14 eggs (slide No. 5425) are deposited in the collection of Binda & Pilato (Museum of the Department of Animal Biology “Marcello La Greca”, University of Catania, Italy). Other specimens and eggs are deposited in the collection of Kiosya (Kharkiv National University, Ukraine).

Specific diagnosis. Colourless, cuticle smooth without pores; small dots present on all legs. Eye spots absent. Pharyngeal bulb with three macroplacoids; microplacoid absent; buccal tube not very wide (pt 14.7–16.6); stylet supports inserted on the buccal tube at 79–80%. Claws, of hufelandi - type, slender, with accessory points on the main branches; lunules present. The eggs, freely laid, were spherical, with 10–11 conical processes on the circumference. The processes’ surface had a well visible reticular design consisting of elongate mesh with rectilinear margins. Egg shell areolated; the central area of each areola slightly thickened and not subdivided.

Description of the holotype: Body length 340 µm; colourless, cuticle smooth without pores; small dots present on the legs. Eye spots absent. Bucco-pharyngeal apparatus of Macrobiotus - type ( Fig.6 A); mouth terminal with ten peribuccal lamellae; buccal armature with an anterior ring of small teeth, a posterior ring of triangular teeth and a system of three dorsal and three ventral transverse ridges. Buccal tube 42.1 µm long and 6.6 µm wide externally (pt = 15.7). Stylet supports inserted on the buccal tube at 79.8 % of its length (pt = 79.8). Pharyngeal bulb with apophyses and three macroplacoids; microplacoid absent ( Fig. 6 A). Length of first macroplacoid 7.4 µm (pt = 17.6), second 5.2 µm (pt = 12.4), third 7.3 µm (pt = 17.3); entire macroplacoid row 21.2 µm long (pt = 50.4)

Claws, of hufelandi - type, slender, with accessory points on the main branches ( Fig. 6 B–D). External and internal claws of the first pair of legs 10.4 µm (pt = 24.7) and 10.2 µm (pt = 24.2) long respectively; those of the second and third pair of legs 11.7 µm (pt = 27.8) and 10.9 µm (pt = 25.9) long respectively; posterior and anterior claws of the hind legs 13.0 µm (pt = 30.9) and 11.8 µm (pt = 28.0) long respectively. Lunules present, small and smooth on the first three pairs of legs, larger and with indented margin on the hind legs. Two cuticular bars present below the claws on the first three pairs of legs ( Fig. 6 B, arrow).

Description of the eggs. The eggs, freely laid, were spherical, with 10–11 conical processes on the circumference and 22–26 on the hemisphere. The diameter was 69–71 µm excluding the processes, 101–109 µm including. The processes were conical, elongate (sometimes with slightly forked apices), 14.5–18.5 high with basal diameter of 16.4–18.2 µm. The processes surface had a well visible reticular design consisting of elongate mesh with rectilinear margins ( Fig. 6 E). A short apical portion of each process was smooth ( Fig. 6 E, arrows). Egg shell areolated and the central area of each areola slightly thickened.

Remarks. The paratypes were similar to the holotype in both qualitative and metric characters (we referred to the pt index values when the specimens had different body length). The measurements of some specimens, the smallest and the largest ones included, are presented in Table 3.

Etymology. The specific name is in honour to Prof. Vyacheslav Klymenko (Kharkiv National University, Ukraine), the scientific adviser of Ye. Kiosya.

Differential diagnosis. Prior to the new species described above, six species of the genus Paramacrobiotus were described with a smooth cuticle, three macroplacoids, lacking the microplacoid and producing eggs with areolated shell and conical processes: P. areolatus , P. crenatus , P. walteri , P. centesimus , P. huziori and P. de r k a i. Comparing adults of, where possible, comparable size the new species can be from the other species (Table 3) as follows:

Paramacrobiotus klymenki sp. nov. was very similar to P. a re o l a t u s but differed in lacking eye spots; in having the buccal tube narrower and slightly longer with respect to the body length (Table 3; Figs. 6 A and 7A); and with slightly shorter claws (Table 3) (however, the pt values may appear similar as the buccal tube of P. a re o l a t u s was slightly shorter with respect to the body length).

The new species differed from P. crenatus in having a narrower buccal tube; lunules on the hind legs less developed; smaller eggs (diameter 69–71 µm excluding the processes in P. klymenki sp. nov., 92–128 µm in P. c re - natus); smaller egg processes (14.5–18.5 µm high in P. klymenki sp. nov., 40–44 µm in P. crenatus , with basal diameter 16.4–18.2 µm in P. klymenki sp. nov. and 24–28 µm in P. crenatus ).

Paramacrobiotus klymenki sp. nov. differed from P. w al te r i in lacking eye spots; in having the stylet supports inserted on the buccal tube in a more caudal position (Table 3), shorter claws (Table 3), also different in shape (in P. walteri the difference in length between main and secondary branch was markedly higher, as seen in Figs. 6 B–D and 7D).

Paramacrobiotus klymenki sp. nov. differed from P. centesimus in having a narrower buccal tube (Table 3; Figs. 6 A and 8A), lunules on the hind legs indented; longer egg processes (14.5–18.5 µm in P. klymenki sp. nov., 7–11 µm in P. centesimus ), slightly different reticular design of the processes (the design was less dense, and the mesh larger and more elongate in P. klymenki sp. nov., while the design was more dense and the mesh almost isodiametric in P. centesimus ( Figs. 6 E and 8B).

Paramacrobiotus klymenki sp. nov. differed from P. h u z i o r i in lacking eye spots, in having a narrower buccal tube, lunules on the hind legs indented, egg processes with less dense reticular design and more clearly elongate mesh with more rectilinear margins ( Figs. 6 E and 8C, D, arrow a); and egg shell areolae not subdivided ( Figs. 6 E and 8C, D, arrow b, and 8C,D, arrows b).

Lack of eye spots, indented lunules on hind legs, claws with less developed accessory points, egg shell areolae not subdivided, egg processes with basal diameter longer than the process height and reticular design less dense, distinguishes Paramacrobiotus klymenki sp. nov. from P. derkai .

Figures

FIGURE 6. Paramacrobiotus klymenki sp. nov. A, Bucco-pharyngeal apparatus of the holotype (slide No. 5425). B, C, D, Claws of the second, third and fourth pairs of legs respectively of the holotype (slide No. 5425). The arrow in B indicates the cuticular bar below the lunules. E, Detail of an egg (slide No. 5425). The arrows indicate the unsculptured apices of egg processes. (Scale bars = 10 µm).