Pseudechiniscus (Pseudechiniscus) totoro, Gąsiorek & Vončina & Kristensen & Michalczyk, 2021

Gąsiorek, Piotr, Vončina, Katarzyna, Kristensen, Reinhardt Møbjerg & Michalczyk, Łukasz, 2021, Fig. 7 in Fig. 4. A in Saphonecrus globosus Schweger and Tang 2015, Zoological Studies (Zool. Stud.) 60 (70), pp. 1-45 : 33-40

Pseudechiniscus (Pseudechiniscus) totoro sp.

nov. ( Figs. 28–29 , Tables 13–14) urn:lsid:zoobank.org:act:0BA6B1A7-A383-4648-8432-1DCD132D6D75

Tardigrada Register: http://www.tardigrada.net/ register/0114.htm

Description: Females (i.e., from the third instar onwards; measurements and statistics in table 13): Small, yellow to orange body ( Fig. 28A ) with minute black eyes; body colour and eyes may dissolve after mounting in Hoyer’s medium. Pseudohemispherical cephalic papillae and elongated (primary) clavae; cirrophores of cephalic cirri merged with flagellum. Cirrus A short.

Dorsal plate sculpturing of the Pseudechiniscus type, with heterogeneous pillars forming patches of similar size ( Fig. 28C ). Striae absent. Pentapartite cephalic plate adjacent to the scapular plate, which is divided into a large anterior portion reaching lateralmost plate margins and two narrow, rectangular posterior portions. Median plates m1–2 bipartite, two pairs of lateral intersegmental plates flanking margins of both m1–2 present; m3 unipartite and rhomboidal. Paired segmental plates I–II and paired pseudosegmental plate IV’ present. Caudal plate small and narrow, with short sclerotised incisions ( Fig. 28C ).

Ventral sculpturing well-developed and reaching lateral body portions ( Figs. 28C–D , 29), with larger accumulations of pillars only in the subcephalic and genital areas, and at the level of legs I–III ( Fig. 29). A sexpartite gonopore placed anteriorly to legs IV, and a trilobed anus between legs IV. Pedal plates formed as belts of large, widely spaced pillars in the central portions of legs ( Fig. 28C ). Pulvini absent. Papillae or spines on legs I absent. Papilla IV elongated and small. Claws minute and isonych; internal claws with delicate, but evident primary spurs positioned at ca. 20–25% of the branch height and divergent from it ( Fig. 28A , insert).

Males: Sexual dimorphism evident. Circular gonopore. Body elongated (123–156 μm in length, sc = 18.2–18.5 μm, n = 2) and slim ( Fig. 28B ). Cephalic appendages lengths: cirrus internus 8.4–9.1 μm, cephalic papilla 3.5–4.0 μm, cirrus externus 12.0–13.0 μm, (primary) clava 3.9–5.0 μm, cirrus A 25.3–27.5 μm. Clear patches of larger pillars present in the anterior portions of paired segmental plates, in the posterior part of the caudal plate, and on central limb portions. Pulvini clearly marked. Papilla IV length 3.9–4.3 μm. Claws: branch heights 6.4–7.7 μm, spurs 1.8–2.3 μm.

Juveniles (i.e., the second instar; measurements and statistics in table 14): Gonopore absent. Smaller than females, but the body length range overlaps with that of males.

Larvae: Not found. Eggs: Up to one orange egg per exuvia was found. Molecular markers and phylogenetic position: Single haplotypes were found in 18S rRNA (OK048616–9) and 28S rRNA (OK048635–8) and four haplotypes were uncovered in ITS-1 (intraspecific

p -distances = 0.2–1.6%; OK048648–51). In the updated phylogeny from Gąsiorek et al. (2021c), the closest relative of P. (P.) totoro sp. nov. is P. (P.) shintai from Japan ( Fig. 30 ).

Type material: Holotype (adult female on the slide TW.005.11), allotype (adult male on the slide TW.005.12), 24 paratypes: 13 adult females, 6 adult males, and 5 juveniles on the slides TW.005.08–16. Six specimens were used for DNA sequencing, including two retrieved as hologenophores. Holotype deposited in the Biodiversity Research Center of Academia Sinica ( ASIZ01000035 ), two paratypes (NHMD-915765) deposited in the Natural History Museum of Denmark, and the remaining material stored at the Jagiellonian University .

Type locality: 24°23'18"N, 121°15'39"E, 3 200 m asl: Taiwan, Snow Mountain (Xueshan), East Peak. Mosses from rocks exposed to sun.

Etymology: The specific epithet is derived from the Japanese animated movie My Neighbour Totoro (Tonari no Totoro) by Hayao Miyazaki (1988) and commemorates Totoro, the forest spirit and the symbol of Studio Ghibli. Noun in apposition.

Differential diagnosis: Due to the absence of projections/appendages on the posterior margin of the pseudosegmental plate IV’, the same species must be compared with P. (P.) totoro sp. nov. as for P. (P.) formosus sp. nov. Specifically, Pseudechiniscus (P.) totoro sp. nov. differs from:

P. (P.) beasleyi , by a different body colour (yelloworange in P. (P.) totoro sp. nov. vs red in P. (P.) beasleyi ) and shorter claws (6.1–8.0 μm in P. (P.) totoro sp. nov. vs 9.1–13.1 μm in P. (P.) beasleyi ).

P. (P.) chengi , by a different body colour (yelloworange in P. (P.) totoro sp. nov. vs brown in P. (P.) chengi ) and shorter claws (6.1–8.0 μm in P. (P.) totoro sp. nov. vs 7.9–12.2 μm in P. (P.) chengi ).

P. (P.) ehrenbergi , by the absence of papilla I (present in P. (P.) ehrenbergi ).

P. (P.) formosus sp. nov., by the dorsal epicuticular ornamentation (present in P. (P.) totoro sp. nov. vs absent in P. (P.) formosus sp. nov.) and the spacing of dorsal pillars (widely spaced in P. (P.) formosus sp. nov. vs densely arranged in P. (P.) totoro sp. nov.).

P. (P.) lacyformis , by the lengths of peribuccal cirri (cirrus internus 5.8–11.0 μm, cirrus externus 7.8–14.0 μm in P. (P.) totoro sp. nov. vs cirrus internus 10.6–14.0 μm, cirrus externus 14.1–19.4 μm in P. (P.) lacyformis ).

P. (P.) shintai , by the density and size of pillars present in leg patches (dense and large in P. (P.) totoro sp. nov. vs more widely spaced and smaller in P. (P.) shintai ).

P. (P.) suillus , by the morphology and position of primary spurs on internal claws (delicate spurs positioned lower on claw branches in P. (P.) totoro sp. nov. vs robust spurs positioned higher on claw branches in P. (P.) suillus , see Grobys et al. 2020).

P. (P.) xiai , by the division of the pseudosegmental plate IV’ (divided by a median longitudinal suture in P. (P.) totoro sp. nov. vs uniform in P. (P.) xiai ) and slightly shorter claws I–III (6.1–7.5 μm in P. (P.) totoro sp. nov. vs 7.6–10.5 μm in P. (P.) xiai ).

Moreover, P. (P.) totoro sp. nov. is distinguishable from all abovementioned species by the ventral sculpturing pattern.

Figures

Fig. 28. Morphology of Pseudechiniscus (Pseudechiniscus) totoro sp. nov. (PCM): A, holotypic female in dorsolateral view (insert shows claws III); B, allotypic male in dorsolateral view; C, dorsal sculpturing; D, ventral sculpturing. Scale bars in μm.

Fig. 30. Position of the Taiwanese species on the phylogenetic tree of the genus Pseudechiniscus based on the concatenated matrix (18S rRNA+28S rRNA+ITS-1). Values at nodes separated by forward slashes signify Bayesian posterior probability and bootstrap values (ML), respectively. Maximum supports, i.e., 1.00 for BI and 100 for ML, are indicated by asterisks (*), whereas nodes unsupported in either analysis are marked by hashtags (#). The scale refers to the Bayesian consensus tree and represents substitutions per site. Species numbering preserved from Gąsiorek et al. (2021c).