New records of Eutardigrada from Belarus with the description of three new species

Abstract

The list of tardigrade species recorded from Belarus is provided; nine were new records for this geographic area and three,Macrobiotus sottilei sp. nov., Paramacrobiotus klymenki sp. nov. and Hypsibius valentinae sp. nov. were new to science.Macrobiotus sottilei sp. nov. had smooth cuticle; eye spots present; the dorsal transverse ridges of the buccal armaturejoined to form a continuous arc; pharyngeal bulb with two macroplacoids and microplacoid; eggs with processes in shapeof inverted goblets with indented distal discs; egg shell with a very dense reticular design.Paramacrobiotus klymenki sp. nov. had smooth cuticle; eye spots absent; buccal armature similar to that of P. areolatus;buccal tube not very wide; stylet supports inserted on the buccal tube at about 80% of its length; pharyngeal bulb withthree macroplacoids; microplacoid absent; eggs with conical processes with a reticular design similar to that of P. areola-tus; egg shell areolated; central area of each areola slightly thickened but not subdivided.Hypsibius valentinae sp. nov. had smooth cuticle; eye spots present; buccal tube very narrow; pharyngeal bulb with twomacroplacoids and a small septulum, claws of the Hypsibius type; small, smooth, flexible lunules present; a short cuticular bar is present between the bases of the claws of the hind legs; no cuticular bar on the first three pairs of legs.

An integrative redescription of Hypsibius dujardini (Doyère, 1840), the nominal taxon for Hypsibioidea (Tardigrada: Eutardigrada)

“…It should be noted that specimens, from undefined localities, classified by Pilato et al (2006aPilato et al ( , 2011Pilato et al ( , 2012 as H. dujardini and used by them in their works for comparisons with various dujardini group species differ substantially from the neotypic population of H. dujardini presented here. Therefore, those individuals most likely represent a new species (see also Discussion below).…”

“…Ramazzotti & Maucci (1983) defined the species as not strictly aquatic, but related to hydrophilic substrates. Miller et al (2005) and Pilato et al (2006aPilato et al ( , 2011Pilato et al ( , 2012 used individuals collected from undefined localities as a comparative material aiding descriptions respectively of H. heardensis, H. seychellensis, H. pallidoides, and H. valentinae. Miller et al (2005) did not provide detailed morphometrics of the specimen they classified as H. dujardini, but the body length of 500 μm seems quite large and may indicate a new species (max 339 μm in the neotype series).…”

“…2728 in the Binda and Pilato collection). However, in Pilato et al (2012) a different specimen, also classified as H. dujardini, has a tube with an equal diameter throughout its length (figure 11D in Pilato et al 2012;slide no. 4138 in the Binda and Pilato collection).…”

“…Since other discriminative morphometric traits given by Pilato et al (2006) fall within the variability range of H. dujardini, they are invalid. Hypsibius valentinae, known from central and northern Belarus (Pilato et al, 2012), only by shorter external and posterior primary branches (5.9-14.0 μm in H. dujardini vs 14.5-17.2 μm in H. valentinae), and by and internal and anterior primary branches (4.6-9.4 μm in H. dujardini vs 9.3-11.5 μm in H. valentinae). Pseudolunulae under internal and anterior claws are present in both species (these structures were defined as "lunulae" in Pilato et al 2012 but the term "pseudolunula" is more appropriate to differentiate the weak cuticular outlines present under claws in hypsibiids and isohypsibiids from well-defined lunulae connected with the claw by a peduncle observed in macrobiotids and eohypsibiids; see Gąsiorek et al 2017b).…”

Macrobiotus naskreckiisp. nov., a New Tardigrade (Eutardigrada: Macrobiotidae) of theHufelandiGroup from Mozambique

“…The great majority of the hufelandi group species exhibit restricted distributions or are known only from their type localities (see Bertolani and Rebecchi 1993 for the review and Maucci 1993, Biserov 1994, Bertolani et al 1996, Binda and Pilato 2001, Dastych 2002, Kaczmarek and Michalczyk 2004, Dastych 2005, Fontoura et al 2008, Bartels et al 2009, Kaczmarek and Michalczyk 2009, Bertolani et al 2011, Pilato et al 2012, Guidetti et al 2013, Stec et al 2015 for species described after the review).…”