Pseudechiniscus dastychi, Roszkowska & Grobys & Bartylak & Gawlak & Kmita & Kepel & Kepel & Parnikoza & Kaczmarek, 2020

Roszkowska, Milena, Grobys, Daria, Bartylak, Tomasz, Gawlak, Magdalena, Kmita, Han- Na, Kepel, Andrzej, Kepel, Marta, Parnikoza, Ivan & Kaczmarek, Łukasz, 2020, Integrative description of five Pseudechiniscus species (Heterotardigrada Echiniscidae: the suillus-facettalis complex), Zootaxa 4763 (4), pp. 451-484: 461-466

publication ID

http://doi.org/ 10.11646/zootaxa.4763.4.1

publication LSID

lsid:zoobank.org:pub:urn:lsid:zoobank.org:pub:0DE45665-F3A9-474B-B438-1022FABB6BD1

DOI

http://doi.org/10.5281/zenodo.3804849

persistent identifier

http://treatment.plazi.org/id/554F87D9-077B-F743-00C1-FC3D55C2CEB5

treatment provided by

Carolina

scientific name

Pseudechiniscus dastychi
status

sp. nov.

2. Pseudechiniscus dastychi   sp. nov. Roszkowska, Grobys, Bartylak & Kaczmarek

( Table 3, Figs 1 View FIGURE 1 , 5–6 View FIGURE 5 View FIGURE 6 )

Pseudechiniscus suillus ( Ehrenberg, 1853)   ( Dastych (1984)

Pseudechiniscus   sp. 2 ( Grobys et al. 2020)

Material examined: 80 animals (holotype and 79 paratypes, all females) mounted on microscope slides in Hoyer’s medium, 40 animals prepared for SEM and 7 prepared for barcoding.

Description

Animals (measurements and statistics in Table 3)

Females. Body ( Fig. 5 View FIGURE 5 ) orange in living specimens (transparent after mounting on slides), black eyes present after mounting on slides. Apart from the head appendages (cirri interni and externi and elongated cephalic papillae [secondary clavae]), only lateral cirrus A present (with finger-like clavae near the base [primary clava]) ( Fig. 5 View FIGURE 5 A–B,D). Cephalic papillae smaller than clavae.

Dorsal plates with small hemispherical granules/upper ends of cuticular pillars (dots in PCM) 0.5–1.2 μm in diameter, densely (spaces between granules 0.5–0.8 μm) and uniformly distributed and joined by thin striae forming indistinct hexagonal pattern (which are in fact thin stripes positioned under epicuticle) ( Fig. 5A View FIGURE 5 ). Granules/upper ends of cuticular pillars slightly larger in the anterior and posterior parts of the plates.

Dorsal plates typical for the genus Pseudechiniscus   (cephalic plate (cp), neck plate (np), scapular plate (scp), median plates (m1, m2, m3), paired segmental plates I and II (s1, s2), pseudosegmental plate (psp) and the caudal plate (cap), see also Dorsal and ventral plates and sculpture in Grobys et al. (2020)) well developed. The cp with Wshaped pattern divided into five parts ( Fig. 6A View FIGURE 6 , filled arrowhead). The scp divided by transversal fold which forms a long narrow stripe in posterior part of the plate. This narrow stripe is often divided by three longitudinal folds forming four plate parts/subplates ( Fig. 5A View FIGURE 5 ). The entire scp divided by median longitudinal fold into two parts ( Fig. 5 View FIGURE 5 A–B, empty arrow). Additionally, lateral portions of the scp appear detached from the dorsal plate, forming small plate-like structures separated from the scp by a thin bright stripe. Plates m1 and m2 divided in two portions by transverse fold, plate m3 undivided ( Fig. 5 View FIGURE 5 A–B, filled indented arrowheads). Laterally to the median plates, lateral intersegmental plates (lip) present. The psp divided by a longitudinal fold. Posterior margin of the psp straight, i.e. without projections, teeth or spines ( Fig. 5 View FIGURE 5 A–B, empty indented arrowhead). The cap concave with two Y-shaped bifurcated ridges ( Fig. 5 View FIGURE 5 A–B, filled arrowhead). Ventral cuticle with tiny granulation (formed by dense granules/upper ends of cuticular pillars, 0.1–0.4 μm) forming unique pattern ( Figs 1 View FIGURE 1 , 5 View FIGURE 5 C–D, 6B). Ventral PGs present (granula- tion 0.4–0.5 μm in diameter, spaces between granules 0.4–0.5 μm) with configuration PG:I-II-III-IV-V-VI-VII-VIII a ( Figs. 1 View FIGURE 1 , 5 View FIGURE 5 C–D). The female gonopore with the typical six-petal rosette. ( Fig. 5 View FIGURE 5 C–D, asterisks).

The outer cuticle on legs I–III with round patches of granulation (with larger granules but more sparse in the centre and smaller and denser in peripheral parts), on legs IV with uniform, wide stripes of granulation (slightly larger in the centre of these stripes) ( Fig. 6 View FIGURE 6 C–D). Triangular spine on leg I and dentate collar on leg IV absent. A finger-like papillae on leg IV present ( Fig. 6D View FIGURE 6 , filled arrow). External claws of all legs smooth, internal with spurs directed downwards, identical in legs I–IV ( Fig. 6 View FIGURE 6 E–F).

Males. Unknown.

Juveniles. Unknown.

Larvae. Unknown.

DNA sequences

We obtained good quality sequences for the applied molecular markers:

– COI sequence (GenBank: MN528469 View Materials ), 641 bp long;

– ITS-2 sequence (GenBank: MN537865 View Materials ), 452 bp long.

Etymology.

We dedicated this species to the distinguished Polish tardigradologist Dr Hieronymus Dastych, who originally reported specimens of this species from Antarctica as Pse. suillus   .

Type locality.

65°14’57.30”S, 64°15’13.20”W, 8 m asl: maritime Antarctic, Argentine Islands, Galindez Island, Carolina Point, Charybda Tover   , 15 m from sea, moss ( Sanionia georgicouncinata   ) and lichens ( Cladonia   sp.), 29.01.2016, coll. Ivan Parnikoza.

Type depositories.

Holotype: slide AT2940/2 and 67 paratypes (slides: AT2940/*, where the asterisk can be substituted by any of the following numbers: 2, 3, 4, 6, 7, 8, 9, 10, 12, 19, 5/S) are deposited at the Department of Animal Taxonomy and Ecology, Institute of Environmental Biology, Adam Mickiewicz University in Poznań, Uniwersytetu Poznańskiego 6, 61-614 Poznań, Poland; 12 paratypes (slides: AT2940/5 and AT2940/18) are deposited at the collection of Binda and Pilato, Museum of the Department of Animal Biology ‘Marcello La Greca’, University of Catania, Italy.

Morphological differential diagnosis*

*only measurements of adult females are used in differential diagnosis

Pseudechiniscus dastychi   sp. nov. differs specifically from:

1. Pse. angelusalas   sp. nov., by: different ventral pattern ( Figs 1 View FIGURE 1 , 5 View FIGURE 5 C–D for Pse. dastychi   sp. nov. vs Figs 1 View FIGURE 1 , 7B View FIGURE 7 for Pse. angelusalas   sp. nov.), different ventral PG configuration (PG:I-II-III-IV-V-VI-VII-VIII a in Pse. dastychi   sp. nov. vs PG:I-II-III-IV-VI-VIII a in Pse. angelusalas   sp. nov.), larger body length (167.0–202.0 μm in Pse. dastychi   sp. nov. vs 113.0–143.0 μm in Pse. angelusalas   sp. nov.), wider scp (27.5–33.0 μm in Pse. dastychi   sp. nov. vs 17.4–20.9 μm in Pse. angelusalas   sp. nov.), longer cirri interni (10.4–12.7 μm, [sp=36.9–41.0] in Pse. dastychi   sp. nov. vs 6.0–7.3 μm, [sp=34.4–36.6] in Pse. angelusalas   sp. nov.), lower sp of cephalic papillae (14.7–16.9 in Pse. dastychi   sp. nov. vs 18.3–20.8 in Pse. angelusalas   sp. nov.), longer cirri externi (15.9–19.1 μm, [sp=54.7–61.4] in Pse. dastychi   sp. nov. vs 9.1–10.4 μm, [sp=49.0–54.3] in Pse. angelusalas   sp. nov.), lower sp of clavae (16.4–18.6 in Pse. dastychi   sp. nov. vs 22.4–25.7 in Pse. angelusalas   sp. nov.), longer cirri A (40.0–45.0 μm in Pse. dastychi   sp. nov. vs 24.1–28.0 μm in Pse. angulusalus sp. nov.), longer papillae on leg IV (2.6–3.5 μm in Pse. dastychi   sp. nov. vs 2.0–2.4 μm in Pse. angelusalas   sp. nov.) and longer claws (see Tables 3 and 4).

2. Pse. beasleyi, by: the scp not divided in the anterior part (the scp divided into four parts in Pse. beasleyi), longer clavae (4.5–5.7 μm in Pse. dastychi   sp. nov. vs 3.1–3.9 μm in Pse. beasleyi sp. nov.), longer cephalic papillae (4.2–5.3 μm in Pse. dastychi   sp. nov. vs 2.6–3.9 μm in Pse. beasleyi sp. nov.) and longer cirri A (40.0–45.0 μm in Pse. dastychi   sp. nov. vs 23.5–31.3 μm in Pse. beasleyi sp. nov.) and different claws length arrangement (shortest claws II and III, and longest claws IV in Pse. dastychi   sp. nov. vs shortest claws I and II, and longest claws III and IV in Pse. beasleyi).

3. Pse. chengi, known only from China ( Xue et al. 2017), by: dorsal granules joined by striae, plates m1 and m2 divided in two portions by transverse fold (unndivided in Pse. chengi), wider scp (27.5–33.0 μm in Pse. dastychi   sp. nov. vs 20.8–25.7 μm in Pse. chengi), longer cephalic papillae (4.2–5.3 μm in Pse. dastychi   sp. nov. vs 2.8–3.7 μm in Pse. chegi), longer cirri interni and externi (10.4–12.7 μm and 15.9–19.1 μm respectively in Pse. dastychi   sp. nov. vs 3.2–8.5 μm and 10.5–14.2 μm respectively in Pse. chegi), longer cirri A (40.0–45.0 μm [sp=135.2–149.1] in Pse. dastychi   sp. nov. vs 21.4–27.5 μm [sp=96.0 –111.1] in Pse. chengi) and higher cirrus A /body length ratio (22–26% in Pse. dastychi   sp. nov. vs 13–17% in Pse. chengi).

4. Pse. clavatus   , by: different shape of clavae (finger-like in Pse. dastychi   sp. nov. vs club-shaped in Pse. clavatus   ) and normally developed cephalic papillae (reduced in Pse. clavatus   ).

5. Pse. ehrenbergi   sp. nov. see Morphological differential diagnosis of Pse. ehrenbergi   sp. nov. above.

6. Pse. facettalis   , known from distant localities throughout the world ( McInnes 1994). Based on present study, an inaccurate description of this species makes it impossible to differentiate this taxon from Pse. dastychi   sp. nov.. See also Morphological differential diagnosis of Pse. suillus   and Discussion in the paper by Grobys et al. (2020).

7. Pse. indistinctus   sp. nov., by: different ventral pattern ( Figs 1 View FIGURE 1 , 5 View FIGURE 5 C–D for Pse. dastychi   sp. nov. vs Figs 1 View FIGURE 1 , 13 View FIGURE 13 C–D for Pse. indistinctus   sp. nov.), different ventral PG configuration (PG:I-II-III-IV-V-VI-VII-VIII a in Pse. dastychi   sp. nov. vs PG:I-II-III-IV-V-VI-VIII a in Pse. indistinctus   sp. nov.), granules on the cap similar in size to other dorsal plates (granules visibly larger on the cap in comparison with other dorsal plates in Pse. indistinctus   sp. nov.), larger body size (167.0–202.0 μm in Pse. dastychi   sp. nov. vs 140.0–166.0 μm in Pse. indistinctus   sp. nov.), wider scp (27.5–33.0 μm in Pse. dastychi   sp. nov. vs 20.5–24.9 μm in Pse. indistinctus   sp. nov.), longer cirri interni (10.4–12.7 μm in Pse. dastychi   sp. nov. vs 7.0–9.2 μm in Pse. indistinctus   sp. nov.), longer cirri externi (15.9–19.1 μm in Pse. dastychi   sp. nov. vs 11.3–14.4 μm in Pse. indistinctus   sp. nov.), lower sp of clavae (16.4–18.6 in Pse. dastychi   sp. nov. vs 19.3–22.5 in Pse. indistinctus   sp. nov.), longer cirri A (40.0–45.0 μm in Pse. dastychi   sp. nov. vs 27.6–34.2 μm in Pse. indistinctus   sp. nov.) and longer claws (see Tables 3 and 7).

8. Pse. juanitae   , known from Austria, Brazil (type locality), Italy and Galapagos Islands ( McInnes 1994). Based on present study, an inaccurate description of this species makes it impossible to differentiate this taxon from Pse. dastychi   sp. nov.. See also Morphological differential diagnosis of Pse. suillus   and Discussion in the paper by Grobys et al. (2020).

9. Pse. lacyformis   sp. nov., by: different ventral pattern ( Figs 1 View FIGURE 1 , 5 View FIGURE 5 C–D for Pse. dastychi   sp. nov. vs Figs 1 View FIGURE 1 , 10B View FIGURE 10 for Pse. lacyformis   sp. nov.), different ventral PG configuration (PG:I-II-III-IV-V-VI-VII-VIII a in Pse. dastychi   sp. nov. vs PG:I-II-III-IV-VI-VIII a in Pse. lacyformis   sp. nov.), dorsal granules joined by striae, wider scp (27.5–33.0 μm in Pse. dastychi   sp. nov. vs 20.4–26.0 μm in Pse. lacyformis   sp. nov.), lower sp of cirri interni (36.9–41.0 in Pse. dastychi   sp. nov. vs 48.4–53.9 in Pse. lacyformis   sp. nov.), lower sp of cirri externi (54.7–61.4 in Pse. dastychi   sp. nov. vs 66.5–77.8 in Pse. lacyformis   sp. nov.), lower sp of clavae (16.4–18.6 in Pse. dastychi   sp. nov. vs 23.4–26.8 in Pse. lacyformis   sp. nov.), longer cirri A (40.0–45.0 μm in Pse. dastychi   sp. nov. vs 26.5–35.0 μm in Pse. lacyformis   sp. nov.), higher cirrus A /body length ratio (22–26% in Pse. dastychi   sp. nov. vs 15–20% in Pse. lacyformis   sp. nov.), lower sp of papillae on leg IV (8.9–11.6 in Pse. dastychi   sp. nov. vs 14.7–17.2 in Pse. lacyformis   sp. nov.), longer spurs on all legs (2.1–2.8 μm in Pse. dastychi   sp. nov. vs 1.3–1.7 μm in Pse. lacyformis   sp. nov.) and lower spur/branch length ratio of all claws (23–30% in Pse. dastychi   sp. nov. vs 15–20% in Pse. lacyformis   sp. nov.).

10. Pse. megacephalus   , by: different shape of cephalic papillae (elongated in Pse. dastychi   sp. nov. vs mushroom-like in Pse. megacephalus   ), absence of papilliform projection between external buccal cirri and cirri A.

11. Pse. suillus   , by: a small papilla-like structure on leg I absent, different ventral pattern ( Figs 1 View FIGURE 1 , 5 View FIGURE 5 C–D for Pse. dastychi   sp. nov. vs Figs 1 View FIGURE 1 herein and 4C–D in Grobys et al. (2020) for Pse. suillus   ), well-developed ventral patches of granulation, different ventral PG configuration (PG:I-II-III-IV-V-VI-VII-VIIIa in Pse. dastychi   sp. nov. vs PG: I-II-III-IV-VI-VIIIg in Pse. suillus   ), dorsal granules joined by striae, wider scp (27.5–33.0 μm in Pse. dastychi   sp. nov. vs 18.8–23.5 μm in Pse. suillus   ), lower sp of cirri interni (36.9–41.0 in Pse. dastychi   sp. nov. vs 44.0– 49.6 in Pse. suillus   ), lower sp of cephalic papillae (14.7–16.9 in Pse. dastychi   sp. nov. vs 19.1–24.3 in Pse. suillus   ), lower sp of cirri externi (54.7–61.4 in Pse. dastychi   sp. nov. vs 62.1–75.0 in Pse. suillus   ), lower sp of clavae (16.4–18.6 in Pse. dastychi   sp. nov. vs 20.9–26.8 in Pse. suillus   ), higher cirrus A /body length ratio (22–26% in Pse. dastychi   sp. nov. vs 17–21% in Pse. suillus   ), lower sp of papillae on leg IV (8.9–11.6 in Pse. dastychi   sp. nov. vs 14.7–18.4 in Pse. suillus   ) and longer claws (see Table 3 herein and Table 4 in Grobys et al. 2020).

12. Pse. xiai   , known only from China ( Wang et al. 2018), by: different ventral pattern ( Figs 1 View FIGURE 1 , 5 View FIGURE 5 C–D for Pse. dastychi   sp. nov. vs Figs 1B, F View FIGURE 1 and 2E View FIGURE 2 in Wang et al. (2018) for Pse. xiai   ), dorsal granules joined by striae, wider scp (27.5–33.0 μm in Pse. dastychi   sp. nov. vs 11.3–26.7 μm in Pse. xiai   ), longer cephalic papillae (4.2–5.3 μm in Pse. dastychi   sp. nov. vs 1.4–3.9 μm in Pse. xiai   ), longer cirri A (40.0–45.0 μm in Pse. dastychi   sp. nov. vs 24.7–31.9 μm

in Pse. xiai   ), and higher cirrus A /body length ratio (22–26% in Pse. dastychi   sp. nov. vs 13–16% in Pse. xiai   ). Genotypic differential diagnosis

The ranges of genetic distances between Pse. dastychi   sp. nov. and species of the genus Pseudechiniscus   , for which DNA sequences are available in GenBank, are as follows:

COI: 2.0–28.5% (24.0% on average), with the most similar being Pseudechiniscus   sp. ( KJ857005 View Materials , Velasco- Castrillón et. al. 2015 (described in GenBank as Echiniscus   sp.); for more details see Discussion in Grobys et al. 2020) and the least similar being Pse. aff. suillus   ( MK804907 View Materials , Cesari et al., 2020).

ITS-2: 7.7–36.8% (26.5% on average), with the most similar being Pse. ehrenbergi   sp. nov. ( MN537866 View Materials , present study) and the least similar being Pse. lacyformis   sp. nov. ( MN537868 View Materials , present study).

Kingdom

Animalia

Phylum

Tardigrada

Class

Heterotardigrada

Order

Echiniscoidea

Family

Echiniscidae

Genus

Pseudechiniscus

Loc

Pseudechiniscus dastychi

Roszkowska, Milena, Grobys, Daria, Bartylak, Tomasz, Gawlak, Magdalena, Kmita, Han- Na, Kepel, Andrzej, Kepel, Marta, Parnikoza, Ivan & Kaczmarek, Łukasz 2020
2020
Loc

Pseudechiniscus suillus ( Ehrenberg, 1853 )

Ehrenberg, 1853
Dastych (1984
Loc

Pseudechiniscus

Grobys et al. 2020 )