CALOHYPSIBIIDAE, Pilato, 1969

Gąsiorek, Piotr, Morek, Witold, Stec, Daniel, Blagden, Brian & Michalczyk, Łukasz, 2019, Revisiting Calohypsibiidae and Microhypsibiidae: Fractonotus Pilato, 1998 and its phylogenetic position within Isohypsibiidae (Eutardigrada: Parachela), Zoosystema 41 (6), pp. 71-89 : 83

TAXONOMIC ACCOUNT OF THE CALOHYPSIBIIDAE SENSU STRICTO

Superfamily HYPSIBIOIDEA Pilato, 1969 (emended by Bertolani et al. 2014a)

Family CALOHYPSIBIIDAE Pilato, 1969 (emended by Bertolani et al. 2014a)

EMENDED DIAGNOSIS. — Very small eutardigrades (typically below 150 μm) with elliptical organs on the head. Dorsum covered with irregular, multangular protuberances, and sometimes also with spines ( Figs 3C, D ; 4 ; 5E, F ). Claws miniaturised, but not reduced, of the Calohypsibius - type, i.e. asymmetrical with respect to the sequence of primary and secondary branches (2-1-2-1), but similar in their size, with bases as large as the sum of the primary and secondary branch widths, but devoid of sutures. Pseudolunulae absent. Accessory points symmetrical ( Figs 11E ; 12C, D ). Six peribuccal papulae present ( Fig. 6B ). AISM asymmetrical with respect to the frontal plane, with the dorsal apophysis subdivided in two portions of different shape ( Fig. 9B ). Stylet furcae of the Hypsibius - type ( Fig. 10B ). Pharyngeal apophyses smaller than the tiny granular macroplacoids. Smooth eggs laid in exuviae.

COMPOSITION. — A monotypic family, comprising the genus Calohypsibius .

Figures

FIG. 3. — Fractonotus verrucosus (Richters, 1900) n. comb., habitus (SEM): A, lateral view; B, dorsal view; Calohypsibius ornatus (Richters, 1900), habitus (SEM): C, lateral view; D, dorsal view. Scale bars: A, 30 μm; B-D, 20 μm.

FIG. 4. — Genus Calohypsibius Thulin,1928 s.s., after exclusion of F.verrucosus n. comb. (PCM): A, Calohypsibius ornatus (Richters, 1900); B, Calohypsibius maliki Michalczyk & Kaczmarek, 2005; C, Calohypsibius schusteri Nelson & McGlothlin, 1996. Scale bars: 10 μm.

FIG. 5. — A-D, Fractonotus verrucosus (Richters, 1900) n. comb.; E, F, Calohypsibius ornatus (Richters, 1900), cuticle morphology (SEM): Fractonotus-type: A, smooth, obtuse tubercles of the smallest specimens (Calohypsibius scabrosus sensu Murray 1911, Calohypsibius verrucosus sensu da Cunha 1947); B, scabrous tubercles occurring in the caudal part of the smallest specimens and on the whole body of adults; C, D, dorsal plaques of adults (Calohypsibius placophorus sensu da Cunha 1943, Calohypsibius verrucosus sensu Thulin 1911,Marcus 1928 and Cuénot 1932), arrowheads indicate coarse portions of the plaques; Calohypsibius-type: E, irregular, multangular tubercles of the cephalic part; F, rows of tubercles of the trunk in close-up. Scale bars: A, B, F, 2 μm; C-E, 20 μm.

FIG. 11. — Comparison of Fractonotus-type (A-D, F), Calohypsibius-type (E), Microhypsibius-type (G), and Isohypsibius-type (H, I) claws (all but Fig. 11F PCM): Fractonotus verrucosus (Richters, 1900) n. comb.: A, claws I, arrowhead indicates weakly developed pseudolunula; B, claws II, interrupted line designates isohypsibioid claw curvature; C, claws IV, arrowhead indicates weakly developed pseudolunula; Fractonotus gilvus (Biserov, 1986) n. comb.; D, claws III, arrowhead indicates weakly developed pseudolunula; Calohypsibius ornatus (Richters, 1900); E, claws IV; Fractonotus caelatus (Marcus, 1928); F, claws IV; Microhypsibius truncatus Thulin, 1928; G, claws III (DIC); Isohypsibius prosostomus (Thulin, 1928); H, claws II; Isohypsibius coulsoni Kaczmarek, Zawierucha, Smykla & Michalczyk, 2012; I, claws II. Scale bars: 10 μm.

FIG. 12. — A-B, Fractonotus verrucosus (Richters,1900) n. comb.;C-D, Calohypsibius ornatus (Richters,1900); E-F, Isohypsibius spp., claws (SEM):Fractonotus- type: A, claws III; B, claws IV; Calohypsibius-type; C, claws II; D, claws IV; Isohypsibius-type; E, Isohypsibius prosostomus (Thulin, 1928),claws I; F, Isohypsibius coulsoni Kaczmarek, Zawierucha, Smykla & Michalczyk, 2012, claws II. Scale bars: A, B, 3 μm; C, D, 1 μm; E, F, 4 μm.

FIG. 6. — Fractonotus verrucosus (Richters,1900) n. comb.and Calohypsibius ornatus (Richters,1900),peribuccal structures (SEM):A, Fractonotus verrucosus n.comb., with six peribuccal lobes typical for Isohypsibiidae;B, Calohypsibius ornatus with six small and roundish peribuccal papulae typical for Calohypsibiidae.Scale bars:1 μm.

FIG. 9. — Schematic comparison of the AISM (lateral view) in: A, Fractonotus Pilato, 1998; B, Calohypsibius Thulin, 1928; C, Isohypsibius Thulin, 1928.

FIG. 10. — Schematic comparison of stylet furcae in: A, Fractonotus Pilato, 1998; B, Calohypsibius Thulin, 1928; C, Isohypsibius Thulin, 1928.