3.2. 1.
Echiniscus osiejukisp. nov. Warguła, Dmuchowska, Polishchuk, Stec, KaczmarekFigures 5, 6, 7, 8, 9; Tables 2, 3
Material examined.
Twelve specimens; UGANDA; Kibale NP, Kabarole District; 00°34'1.253"N 30°22'34.642"E; ca. 1535 m asl; 4 Jul. 2022; coll. Barbara Wiśniewska; moss on tree trunk; barcodes at GenBank: PZ 127154 -5, PZ 129998, PZ 127159, PZ 127161; specimen code UG 77.
Type repository.
The holotype (slide: UG 77 / 13 and 8 paratypes (slides: UG 77 / *, where the asterisk can be substituted by any of the following numbers: 11, 13, 14, 15, 16, 17) are deposited in the Department of Animal Taxonomy and Ecology, Institute of Environmental Biology, Adam Mickiewicz University, Poznań, Uniwersytetu Poznańskiego 6, 61-614 Poznań, Poland. Two paratypes (slide: UG 79 / 12) are deposited in Institute of Systematics and Evolution of Animals, Polish Academy of Sciences, Sławkowska 17, 31-016, Kraków, Poland.
Etymology.
We dedicate this species to our friend, Professor Tomasz Osiejuk from the Department of Behavioural Ecology, Faculty of Biology, Adam Mickiewicz University in Poznań, who initiated the Tropical Biology course series at the Faculty of Biology.
Description.
Adults (measurements and statistics in Tables 2, 3). Before mounting, the body orange and plump (Figs 5, 6 A, B), with red eyespots. Bulbous cirrophores are present at the base of all cirri (Fig. 7 A, B). Dactyloid / ovoid cephalic papillae (secondary clavae) and minute (primary) clavae present (Fig. 7 A, B). Cirrus A short. The spines configuration is A- (B) - C-C d - (D) - D d - E (Figs 5 A, 5 B, 6 A, 6 B, 8). Spines D and E may have serrated margins (Fig. 6 A). Asymmetry in the development of appendages is frequently observed, with one of the spines B or D, which are sometimes absent. Specifically, the absence of spine B was noted in one of the eight specimens examined, while spine D was absent in three of the eight specimens. Considerable variation in the length of all spines is observed across all examined individuals. The female gonopore is rosette-shaped (Fig. 9 D).
The dorsal plates with spinulosus type of sculpture, characterized by irregularly distributed pores, across all plates (Figs 5 A, 5 B, 6 A). However, pores on anterior portion of the first paired plate often gradually become smaller in the direction from the head to the caudal region. Most of pores on the dorsal plate have a diameter ranging from 1.1–2.0 μm in all measured females, 0.9–2.2 μm in all measured males. Dark central rings in pores absent (Figs 5, 7 A). Intracuticular pillars not visible under PCM. The ventral sculpture is visible as tiny granulation, but only in PCM. The cephalic plate is narrow and with an anterior incision (Fig. 7). The cervical (neck) plate is also narrow and formed as a thin dark belt without pores (Figs 5 B, 7 A). A smooth, thin transverse stripe divides the first and second paired plates into smaller, narrower anterior and larger posterior parts (Figs 5 B, 6 A). Median plates I and III are unipartite, whereas median plate II is divided into a narrower anterior and a wider posterior part (Figs 5 B, 6 A). Median plate III is tiny, but densely covered by pores, often partially hidden under the paired plate II and the caudal plate (Figs 5 B, 6 A). The caudal plate with well visible incisions (Fig. 5 B). Pedal plates absent but pulvini present (Fig. 6 B). The first pair of legs with small spine, the fourth pair of legs with papilla (Fig. 9 A). Dentate collar with 7–12 large teeth, present on leg IV (Fig. 9 C). All claws of similar length. External claws smooth. Internal claws with small, slender spurs located close to the claw bases (Fig. 9 B).
One juvenile (identified by the absence of reproductive organs) was found in the sample and its morphology is similar to that of adult females, including appendage configuration and sculpturing (measurements and statistics in Table 3). Pores on dorsal plates are well visible. Gonopore absent.
No eggs and larvae were found.
DNA sequences.
The sequences obtained from one specimen for all five molecular markers analysed in this study were of good quality. The 28 S rRNA sequences (GenBank: PZ 127155) 711 bp long; 18 S rRNA sequences (GenBank: PZ 127154) 758 bp long; COI sequences (GenBank: PZ 129998) 650 bp long; ITS- 1 sequences (GenBank: PZ 127159) 607 bp long; ITS- 2 sequences (GenBank: PZ 127161) 380 bp long.
Genetic distances.
The ranges of uncorrected genetic p - distances between the molecular markers of Ech. osiejuki sp. nov. obtained in our study and the sequences of all species of the genus Echiniscus available in GenBank are as follows (File S 3):
28 S rRNA: 0.01–0.6 % (0.3 % on average), with the most similar being Ech. manuelae Gąsiorek et al., 2019 (GenBank: MK 529708) and the least similar being Ech. perarmatus Gąsiorek et al., 2022 (GenBank: OM 517009).
18 S rRNA: 0.0–3.9 % (1.8 % on average), with the most similar being Ech. succineus Gąsiorek & Voncina, 2019 (GenBank: MK 675903) and the least similar being Ech. evelinae Gąsorek et al., 2021 (GenBank: MZ 467757).
COI: 16.3–25.3 % (19.2 % on average), with the most similar being Ech. tristis Bochnak et al., 2020 (Genbank: MT 374161) and the least similar being Ech. tantulus Bochnak et al., 2020 (GenBank: MT 107427).
ITS 1 rRNA: 1.9–13.8 % (10.64 % on avarage), with the most similar being Ech. cavagnaroi Gąsiorek et al., 2022 (Genbank: OM 516846) and the least similar being Ech. spinulosus Gąsiorek & Voncina, 2023 (GenBank: PQ 283268).
ITS 2 rRNA: 1.4–14.9 % (14.2 % on average), with the most similar being Ech. tristis Bochnak et al., 2020 (GenBank: MT 374184) and the least similar being Ech. aonikenk Gąsiorek et. al., 2021 (GenBank: MZ 467833).
Differential diagnosis.
Echiniscus osiejuki sp. nov. is diagnosed by the combination of the following morphological characters: a spines configuration [A – (B) – C – C d – (D) – D d – E], lacking internal dark rings inside pores and pores not connected by striae, and the presence of spurs on internal claws of all legs. Taking these diagnostic features the new species is similar to nine Echiniscus species, but it differs specifically from:
(1) Echiniscus dikenli Maucci, 1972, known only from the type locality in Turkey (Maucci 1972), by: the presence of median plate III, shorter cirrus A (15.6–23.5 μm in Ech. osiejuki sp. nov. vs. 60.0–115.0 μm in Ech. dikenli), shorter spine C d (3.5–15.2 μm in Ech. osiejuki sp. nov. vs. 22.0–34.0 μm in Ech. dikenli) and shorter spine E (5.2–15.5 μm in Ech. osiejuki sp. nov. vs. 42.0–90.0 μm in Ech. dikenli).
(2) Echiniscus kosickii Kaczmarek and Michalczyk, 2010, known only from the type locality in Costa Rica (Kaczmarek and Michalczyk 2010), by: a longer cirrus internus (9.5–14.5 μm in Ech. osiejuki sp. nov. vs. 8.2–9.1 μm in Ech. kosickii), shorter cephalic papilla (4.6–6.2 μm in Ech. osiejuki sp. nov. vs. 6.3–6.8 μm in Ech. kosickii), a cirrus A / body length ratio (11–13 % in Ech. osiejuki sp. nov. vs. 14–17 % in Ech. kosickii) and a longer spurs on claws I and IV (I: 1.3–2.2; IV: 1.6–2.4, respectively in Ech. osiejuki sp. nov. vs. I and IV: ca. 1.0 in Ech. kosickii).
(3) Echiniscus marcusi Pilato, Claxton and Binda, 1989, known only from the type locality in Australia (Pilato et al. 1989; Claxton 2004), by: the absence of granulation on legs I – III, shorter cephalic papilla (4.6–6.2 μm in Ech. osiejuki sp. nov. vs. ca. 10.2 μm in Ech. marcusi), a shorter cirrus A (15.6–23.5 μm in Ech. osiejuki sp. nov. vs. ca. 37.8 μm in Ech. marcusi), shorter spine C d (3.8–15.2 μm in Ech. osiejuki sp. nov. vs. ca. 22.5 μm in Ech. marcusi) and longer spine D (12.9–22.0 μm in Ech. osiejuki sp. nov. vs. ca. 8.6 μm in Ech. marcusi).
(4) Echiniscus minutus Gąsiorek and Michalczyk, 2024, known only from the type locality in Indonesia (Gąsiorek and Michalczyk 2024), by the absence of pedal plates on legs I – III, longer spine D d (12.9–22.0 μm in Ech. osiejuki sp. nov. vs. 3.3–9.8 in Ech. minutus) and a longer spurs on claws III (1.5–1.8 μm in Ech. osiejuki sp. nov. vs. 1.0–1.4 μm in Ech. minutus).
(5) Echiniscus pooensis Rodriguez-Roda, 1947 known only from the type locality in Ecquatorial Guinea (Rodriguez-Roda 1947), by the orange body color, the presence of papilla on leg IV, a shorter cirrus A (15.6–23.5 μm in Ech. osiejuki sp. nov. vs. ca. 30.0 μm in Ech. pooensis), shorter spine B (3.8–12.7 μm in Ech. osiejuki sp. nov. vs. ca. 22.0 μm in Ech. pooensis), shorter spine C (6.6–16.4 μm in Ech. osiejuki sp. nov. vs. ca. 28.0 μm in Ech. pooensis), shorter spine C d (3.8–15.2 μm in Ech. osiejuki sp. nov. vs. ca. 20.0 μm in Ech. pooensis), shorter spine D (5.9–15.3 μm in Ech. osiejuki sp. nov. vs. ca. 24.0 μm in Ech. pooensis) and shorter spine E (5.2–15.5 μm in Ech. osiejuki sp. nov. vs. ca. 22.0 μm in Ech. pooensis).
(6) Echiniscus rugospinosus Marcus, 1927 known from Uganda and Kenya (McInnes et al. 2017), by the presence of median plate III. However, considering that Ech. rugospinosus is regarded in the literature as a nomen inquirendum (Gąsiorek and Michalczyk 2024), it is impossible to carry out a detailed morphological comparison between these two species.
(7) Echiniscus siticulosus Gąsiorek and Michalczyk, 2020, known only from the type locality in Australia, by: the lack of pedal plates, the lack of caudal plate faceting, a larger body size (144–202 μm in Ech. osiejuki sp. nov. vs. 110–132 μm in Ech. siticulosus), longer cirrus internus (9.5–14.5 μm in Ech. osiejuki sp. nov. vs. 4.9–5.1 μm in Ech. siticulosus), longer clava (4.2–6.7 μm in Ech. osiejuki sp. nov. vs. 2.2–3.6 μm in Ech. siticulosus) and longer papilla on leg IV (2.4–4.2 μm in Ech. osiejuki sp. nov. vs. 1.9–2.3 μm in Ech. siticulosus).
(8) Echiniscus spinulosus (Doyère, 1840), known from Asia, Europe and Hawaiian Islands (McInnes 1994; Gąsiorek and Vončina 2023), by: the presence of pedal plates on legs I – III, the lack of granulation on legs, a smaller body size (144–202 μm in Ech. osiejuki sp. nov. vs. 236–314 μm in Ech. spinulosus), narrower scapular plate (25.6–36.5 μm in Ech. osiejuki sp. nov. vs. 54.3–64.8 μm in Ech. spinulosus), shorter cephalic papilla (4.6–6.2 μm in Ech. osiejuki sp. nov. vs. 8.6–10.5 μm in Ech. spinulosus), a shorter cirrus externus (11.8–15.9 μm in Ech. osiejuki sp. nov. vs. 20.2–29.1 μm in Ech. spinulosus), shorter cirrus A (15.6–23.5 μm in Ech. osiejuki sp. nov. vs. 117.1–166.6 μm in Ech. spinulosus), lower cirrus A / body length ratio (11–13 % in Ech. osiejuki sp. nov. vs. 44–56 % in Ech. spinulosus), longer spine C (6.6–16.4 μm in Ech. osiejuki sp. nov. vs. 2.2–5.2 μm in Ech. spinulosus), shorter spine C d (3.8–15.2 μm in Ech. osiejuki sp. nov. vs. 48.7–62.2 μm in Ech. spinulosus), shorter spine D d (12.9–22.0 μm in Ech. osiejuki sp. nov. vs. 43.6–56.1 μm in Ech. spinulosus), shorter spine on leg I (1.1–2.7 μm in Ech. osiejuki sp. nov. vs. 4.2–6.1 μm in Ech. spinulosus), smaller papilla on leg IV (2.4–4.2 μm in Ech. osiejuki sp. nov. vs. 4.5–5.5 μm in Ech. spinulosus), shorter claws on legs I – IV (I: 7.6–10.8 μm; II: 7.1–10.5 μm; III: 7.1–10.2 μm; IV: 8.3–12.4 μm, respectively in Ech. osiejuki sp. nov. vs. I: 19.1–22.4 μm; II: 16.2–21.5 μm; III: 15.6–22.6 μm; IV: 19.5–28.5 μm, respectively in Ech. spinulosus) and shorter spurs on legs I – IV (I: 1.3–2.2 μm; II: 1.4–1.9 μm; III: 1.5–1.8 μm; IV: 1.6–2.4 μm, respectively in Ech. osiejuki sp. nov. vs. I: 2.4–3.3 μm; II: 2.3–3.4 μm; III: 2.6–3.4 μm; IV: 3.0–4.5 μm, respectively in Ech. spinulosus).
(9) Ech. tropicalis Binda and Pilato, 1995, known from (Indonesia, Malaysia and Seychelles (type locality) Singapore (Binda and Pilato 1995; Kiosya et al. 2021), by: the presence of pores on the entire median plates I and II (lack of pores on anterior part of median plates I and II in Ech. tropicalis) and a shorter spine D d (12.9–22.0 μm in Ech. osiejuki sp. nov. vs. 5.6–6.6 μm in Ech. tropicalis).
Publication Date: 2026-06-23