*2.1. Sampling*

A moss sample was collected in Banff National Park (AB, Canada) in March 2019. It was then packed in a paper envelope, dried at a temperature of ca. 20 ◦C and delivered to the Department of Animal Taxonomy and Ecology at the Faculty of Biology, Adam Mickiewicz University in Pozna ´n (Poland). The tardigrade collection, extraction and mounting techniques followed the protocol of Stec et al. [16].

#### *2.2. Microscopy and Imaging*

In total, 163 animals (74 *Bryodelphax mareki* sp. nov. + 45 *Macrobiotus birendrai* sp. nov. + 44 *Mesobiotus skorackii*) and 31 eggs (12 *Macrobiotus birendrai* sp. nov + 19 *Mesobiotus skorackii*) were mounted on microscope slides in the Hoyer's medium, and then examined under Olympus BX41 Phase Contrast light Microscope (PCM) associated with Olympus SC50 digital camera (Olympus Corporation, Shinjuku-ku, Japan). The 44 animals and 8 eggs were prepared for scanning electron microscopy (SEM) analysis according to the protocol in Roszkowska et al. [17] and examined under high vacuum in Hitachi S3000N SEM. Thirty-one specimens were prepared for genotyping.

All figures were assembled in Corel Photo-Paint 2017. For deep structures that could not be fully focused in a single photograph, a series of 2–10 images were taken every ca. 0.5 μm and then manually assembled into a single deep-focus image in Corel Photo-Paint 2017.

#### *2.3. Morphometrics and Morphological Nomenclature*

All measurements are given in micrometers (μm]). Structures were measured only if their orientation was suitable. Body length was measured from the anterior extremity to the end of the body, excluding hind legs. The *sp* index in *Bryodelphax* is the ratio of the length of a given structure to the length of the scapular plate expressed as a percentage (length of structure × 100⁄length scapular plate) [18] and later independently proposed as the *psc* index by Fontoura and Morais [19]. Ventral plates configuration in *Bryodelphax* is given according to Kaczmarek et al. [20]. The types of bucco-pharyngeal apparatuses and claws of Macrobiotidae were classified according to Pilato and Binda [21]. All measurements and terminology of adults and eggs of Macrobiotidae were prepared according to Kaczmarek and Michalczyk [22] and Kaczmarek et al. [23]. Terminology describing the oral cavity armature (OCA) in *Macrobiotus* and *Mesobiotus* follows Michalczyk and Kaczmarek [24] and OCA morphotypes are given according to Kaczmarek and Michalczyk [22]. The macroplacoid length sequence in *Macrobiotus* and *Mesobiotus* was indicated according to Kaczmarek et al. [25]. The *pt* ratio is the ratio of the length of a given structure to the length of the buccal tube expressed as a percentage [26]. The terminology of cuticular bars in macrobiotid legs follows Kiosya et al. [27]. The classification of type of egg process, sculpture on egg processes, egg processes bases and egg shell surface between processes are given according to Kaczmarek et al. [23]. Genus abbreviations follow Perry et al. [28].

Morphometric data were handled using the "Parachela" ver. 1.8 and "Echiniscoidea" ver. 1.4 template available from the Tardigrada Register [29].

#### *2.4. Comparative Material*

For identification and differentiation of the new species, the key by G ˛asiorek et al. [30] for the genus *Bryodelphax* and the key by Kaczmarek and Michalczyk [22] for the genus *Macrobiotus* were used. We also compared our new species with the type material of *Bry. aaseae* Kristensen, Michalczyk and Kaczmarek [9], *Bry. asiaticus* Kaczmarek and Michalczyk [31], *Bry. brevidentatus* Kaczmarek, Michalczyk and Degma [32], *Bry. olszanowskii* Kaczmarek, Parnikoza, Gawlak, Esefeld, Peter, Kozeretska and Roszkowska [33], *Bry. parvuspolaris* Kaczmarek, Zawierucha, Smykla and Michalczyk [20], *Mac. dulciporus* Roszkowska, Gawlak, Draga and Kaczmarek [34], *Mac. kazmierskii* Kaczmarek and Michalczyk, [35], *Mac. marlenae* Kaczmarek and Michalczyk [36], *Mac. paulinae* Stec, Smolak, Kaczmarek and Michalczyk [16], *Mac. pisacensis* Kaczmarek, Cytan, Zawierucha, Diduszko and Michalczyk [25], *Mac. polonicus* Pilato, Kaczmarek, Michalczyk and Lisi [37], *Mac. polypiformis* Roszkowska, Ostrowska, Stec, Janko and Kaczmarek [38], *Mac. porifini* Kuzdrowska, Mioduchowska, Gawlak, Bartylak, Kepel, Kepel and Kaczmarek [39], *Mac. sottilei* Pilato, Kiosya, Lisi and Sabella [40] and *Mac. wandae* Kayastha, Berdi, Miaduchowska, Gawlak, Łukasiewicz, Gołdyn and Kaczmarek [41].
