Pseudechiniscus indistinctus, 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: 476-480

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.3804845

persistent identifier

http://treatment.plazi.org/id/554F87D9-0768-F751-00C1-F9615283C81C

treatment provided by

Carolina

scientific name

Pseudechiniscus indistinctus
status

sp. nov.

5. Pseudechiniscus indistinctus   sp. nov. Roszkowska, Grobys, Bartylak & Kaczmarek

( Table 7, Figs 1 View FIGURE 1 , 13–14 View FIGURE 13 View FIGURE 14 )

Pseudechiniscus   sp. 5 ( Grobys et al. 2020)

Material examined: 77 animals (holotype and 76 paratypes (all females)) mounted on microscope slides in Hoyer’s medium, 97 animals prepared for SEM and 7 prepared for barcoding.

Description

Animals (measurements and statistics in Table 7)

Females. Body ( Fig. 13 View FIGURE 13 A–B) orange-yellow 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 clava]), only lateral cirrus A present (with finger-like clavae near the base [primary clava]) ( Fig. 13 View FIGURE 13 A–B, D).

Dorsal plates with small hemispherical granules/upper ends of cuticular pillars (dots by PCM) 0.4–1.0 μm in diameter (except of the cap), densely (spaces between granules 0.4–1.3 μm) and uniformly distributed and joined by very thin striae forming indistinct hexagonal pattern (which are in fact a thin stripes positioned under epicuticle) ( Fig. 14A View FIGURE 14 ). Granules/upper ends of cuticular pillars slightly larger in the centre and anterior parts of the plates and much larger (1.1–1.3 μm in diameter) on the caudal plate (cap), especially in the central area between Y-shaped bifurcated ridges ( Fig. 13A View FIGURE 13 ).

Dorsal plates typical for the genus Pseudechiniscus   (cephalic plate (cp), neck plate (np), scapular plate (scp), median plates (m1, m2, m3), paired segmental plates (s1, s2), pseudosegmental plate (psp) and caudal plate (cap), see also Dorsal and ventral plates and sculpture in Grobys et al. 2020) well developed. The cp with W-shaped pattern divided into five parts ( Fig. 13A View FIGURE 13 ). The scp divided by transversal fold, which forms a long narrow stripe in posterior part of the plate. Narrow stripe sometimes divided by three longitudinal folds which form four plate parts/ subplates ( Fig. 13A View FIGURE 13 ). The entire scp divided by median longitudinal fold into two parts ( Fig. 13 View FIGURE 13 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 ( Fig. 13C View FIGURE 13 , indented arrowhead). Plates m1 and m2 divided in two portions by transverse fold, plate m3 undivided ( Fig. 13 View FIGURE 13 A–B, filled indented arrowheads). Laterally to the median plates, lateral intersegmental plates (lip) present. On the plates s1 and s2 darker stripes also visible ( Fig. 13 View FIGURE 13 A–B, filled arrows). The psp divided by a longitudinal fold. Posterior margin of the psp straight, i.e. without projections, teeth or spines ( Fig. 13 View FIGURE 13 A–B, empty indented arrowhead). The cap concave with two Y-shaped bifurcated ridges ( Fig. 13 View FIGURE 13 A–B, filled arrowhead). Ventral cuticle with tiny granulation (formed by dense granules/upper ends of cuticular pillars, 0.1–0.3 μm) forming unique pattern ( Figs 1 View FIGURE 1 , 13 View FIGURE 13 C–D). Ventral PGs present (granulation 0.3–0.6 μm in diameter, spaces between granules 0.4–0.7 μm) with configuration PG:I-II-III-IV-V-VI-VIII a ( Figs 1 View FIGURE 1 , 13 View FIGURE 13 C–D). The PG VI (in line of leg III) is not uniformly granulated, i.e. line of granules is present in the center of the PG and two smooth areas clearly visible below and above of this line ( Fig. 1 View FIGURE 1 ). The female gonopore with the typical six-petal rosette. ( Fig. 13 View FIGURE 13 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 leg IV with uniform wide stripes of granulation (slightly larger in the centre of these stripes) ( Fig. 14 View FIGURE 14 B–C). Triangular spine on leg I and dentate collar on leg IV absent. A fingerlike papillae on leg IV present ( Fig. 14B View FIGURE 14 , arrow). External claws of all legs smooth, internal with spurs directed downwards, identical in legs I–IV ( Fig. 14C View FIGURE 14 ).

Males. Unknown.

Juveniles. Unknown.

Larvae. Unknown.

DNA sequences

We obtained good quality sequences for the applied molecular markers:

– COI sequence (GenBank: MN528471 View Materials ), 622 bp long;

– ITS-2 sequence (GenBank: MN537867 View Materials ), 434 bp long.

Etymology.

The specific epithet ‘ indistinctus   ’ means, in Latin, ‘indistinct’ and refers to the delicate and poorly marked ventral sculpture.

Type locality.

58°33’33’’N, 06°26’24’’E, 273 m asl: Norway, Rogaland Province, Lund Region, Førland Sletthei Landscape Protection Area, S Førlandsvatnet, Betula pubescens   forest, lichen ( Cladonia squamosa (Scop.) Hoffm., 1796   ), 12.08.2018, coll. Terje Meier, Elisabeth Stur, Karstein Hårsaker, Tommy Prestø, Lasse Topstad.

Type depositories.

Holotype: slide NR255/17 and 10 paratypes (slides: NR255/*, where the asterisk can be substituted by any of the following numbers: 17, 17/S, 18/S, 19/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; 66 paratypes (slides: NR255/*, where the asterisk can be substituted by any of the following

numbers: 3, 4, 8, 10, 11, 14, 15, 16, 19, 21) are deposited at the collection NTNU University Museum, NO-7491 Trondheim, Norway.

Morphological differential diagnosis*

*only measurements of adult females are used in differential diagnosis

Pseudechiniscus indistinctus   sp. nov. differs specifically from:

1. Pse. angelusalas   sp. nov., see Morphological differential diagnosis of Pse. angelusalas   sp. nov. above.

2. Pse. beasleyi, by: the scp not divided in anterior part (the scp divided into four parts in Pse. beasleyi), short- er cirri interni (7.0–9.2 μm in Pse. indistinctus   sp. nov. vs 10.4–15.7 μm in Pse. beasleyi), longer clavae (4.2–5.4 μm in Pse. indistinctus   sp. nov. vs 3.1–3.9 μm in Pse. beasleyi) and different claws length arrangement (shortest claws II and III, and longest claws IV in Pse. indistinctus   sp. nov. vs claws I and II shortest and III and IV longest in Pse. beasleyi) and shorter claws (see Table 7 in this paper and Table 2 View TABLE 2 in Li et al. 2007).

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), longer cirri A (27.6–34.2 μm [sp=123.0– 144.9] in Pse. indistinctus   sp. nov. vs 21.4–27.5 μm [sp=96.0–111.1] in Pse. chengi), higher cirrus A /body length ratio (18–22% in Pse. indistinctus   sp. nov. vs 13–17% in Pse. chengi) and shorter claws I–III and lower sp of claws I–III (see Table 7 herein and Table 2 View TABLE 2 in Xue et al. 2017).

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

5. Pse. dastychi   sp. nov., see Morphological differential diagnosis of Pse. dastychi   sp. nov. above.

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

7. 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. indistinctus   sp. nov.. See also Morphological differential diagnosis of Pse. suillus   and Discussion in the paper Grobys et al. (2020).

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. indistinctus   sp. nov.. See also Morphological differential diagnosis of Pse. suillus   and Discussion in the paper Grobys et al. (2020).

9. Pse. lacyformis   sp. nov., see Morphological differential diagnosis of Pse. lacyformis   sp. nov. above.

10. Pse. megacephalus   , by: different shape of cephalic papillae (elongated in Pse. indistinctus   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 and 13 View FIGURE 13 C–D for Pse. indistinctus   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-VIII a in Pse. indistinctus   sp. nov. vs PG:I-II-III-IV-VI-VIII g in Pse. suillus   ), granules visibly larger on cap in comparison with other dorsal plates in Pse. indistinctus   sp. nov. (granules on cap similar in size to other dorsal plates in Pse. suillus   ), dorsal granules joined by striae, lower sp of cirri interni (34.1–38.5 in Pse. indistinctus   sp. nov. vs 44.0– 49.6 in Pse. suillus   ), lower sp of cephalic papillae (15.5–17.3 in Pse. indistinctus   sp. nov. vs 19.1–24.3 in Pse. suillus   ), lower sp of cirri externi (54.3–59.3 in Pse. indistinctus   sp. nov. vs 62.1–75.0 in Pse. suillus   ), shorter papillae on leg IV (2.2–2.9 μm, [sp=9.8–11.9] in Pse. indistinctus   sp. nov. vs 3.3–4.3 μm, [sp=14.7–18.4] in Pse. suillus   ) and higher spur/branch length ratio (28–34% in Pse. indistinctus   sp. nov. vs 21–27% in Pse. suillus   ).

12. Pse. xiai   , known only from China ( Wang et al. 2018), by: different ventral pattern ( Figs 1 View FIGURE 1 and 13 View FIGURE 13 C–D for Pse. indistinctus   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, smaller body size (140.0–166.0 μm in Pse. indistinctus   sp. nov. vs 179.0–215.0 μm in Pse. xiai   ), higher cirrus A / body length ratio (18–22% in Pse. indistinctus   sp. nov. vs 13–16% in Pse. xiai   ) and shorter claws (see Table 7 herein and Table 1 View TABLE 1 in Wang et al. 2018).

Genotypic differential diagnosis

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

COI: 25.9–30.9% (27.9% 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 section in Grobys et al. 2020) and the least similar being Pse. aff. suillus   ( MK804907 View Materials , Cesari et al. 2020).

ITS-2: 6.8–38.0% (25.3% on average), with the most similar being Pse. suillus   sp. nov. ( MN537863 View Materials ) and the least similar being Pse. angelusalas   sp. nov. ( MN537864 View Materials , present study).

Kingdom

Animalia

Phylum

Tardigrada

Class

Heterotardigrada

Order

Echiniscoidea

Family

Echiniscidae

Genus

Pseudechiniscus

Loc

Pseudechiniscus indistinctus

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

Pseudechiniscus

Thulin 1911
1911