Minibiotus formosus, Zawierucha, Krzysztof, Dziamiecki, Jakub, Jakubowska, Natalia, Michalczyk, Lukasz & Kaczmarek, Lukasz, 2014

Zawierucha, Krzysztof, Dziamiecki, Jakub, Jakubowska, Natalia, Michalczyk, Lukasz & Kaczmarek, Lukasz, 2014, New tardigrade records for the Baltic states with a description of Minibiotus formosus sp. n. (Eutardigrada, Macrobiotidae), ZooKeys 408, pp. 81-105: 90-92

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scientific name

Minibiotus formosus

sp. n.

Minibiotus formosus   sp. n. Tables 2-3, Figs 8-15

Type material.

Holotype and 23 paratypes, 24 specimens (including 2 simplexes) and 3 unembryonated eggs).

Type locality.

57°10'33"N, 24°50'32"E, ca. 45 m asl: Latvia, Vidzeme region, Sigulda municipality, Gutmana Cave in the Gauja National Park; moss from rock (1 sample, slide codes: ŁO 2427/*, where the asterisk can be substituted by any of the following numbers: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12).


(measurements in Table 2). Body white/colourless (Fig. 8). Eyes present in 18 of 24 (75%) specimens mounted in Hoyer’s medium. Entire cuticle covered with small (0.4-1.1 μm) and large (1.9-2.5 μm) round or oval pores (Fig. 9). Pores arranged in 9-10 poorly defined transverse bands. Pores on the dorsal cuticle arranged more densely than on the ventral cuticle. A single large pore (diameter: 2.1-2.9 μm) present on external side of legs I–III (Fig. 12, arrow). A ring of pores around the mouth opening absent. Cuticle without granulation, except for legs which are all covered with fine and regular granulation (better developed on legs IV) visible only in larger specimens (Fig. 12, arrowhead).

Mouth antero-ventral. Ten peribuccal papulae present. Bucco-pharyngeal apparatus of the Minibiotus   type (Figs 10-11). Oral cavity armature absent or not visible under PCM. Buccal tube with a poorly visible ventral lamina and with an anterior and a posterior bend (both visible in lateral view only, Fig. 11). Buccal tube walls thickened just below the stylet supports insertion point. Pharyngeal apophyses triangular, very near to the first macroplacoid. Three granular macroplacoids and a minute microplacoid present in the pharyngeal bulb. All macroplacoids of similar but not identical sizes, the macroplacoid length sequence: 2<1<3. Septulum absent.

Claws of the Macrobiotus   type (Figs 12-13). Primary branches of claws with thin, but obvious accessory points detaching at the apogee of the primary branch curve. Smooth lunules present on all legs, distinctly larger under external and posterior claws. Bars and other cuticular thickenings on legs absent.

Eggs (measurements in Table 3). White/transparent, laid freely (Fig. 14). Spherical, without areolation. Processes in the shape of short, smooth, slightly flexible cones (Fig. 15). Processes are distributed on the surface of the egg close one to another but never in contact. Surface between processes smooth under PCM (Fig. 15).


Since ventral lamina is very poorly visible, the measurements of this structure are not included in Table 2. Three unembryonated eggs have been found alongside the described specimens. Given that Minibiotus formosus   sp. n. was the only Minibiotus   species in the sample and because no Ramazzottius   Binda & Pilato, 1986 was found in the samples, we assumed that these eggs belong to the new species.


Given that we found the composition of small and large pores in the new species beautiful, we decided to name the animal after this impression (in Latin ‘formosus’ means ‘beautiful’).

Type depositories.

Holotype 23 paratypes and 3 eggs are deposited in the Department of Animal Taxonomy and Ecology at the Adam Mickiewicz University ( Poznań, Poland).