Demodex bialoviensis Izdebska & Rolbiecki & Bielecki 2022
Creators: name: Izdebska, Joanna N.
name: Rolbiecki, Leszek
name: Bielecki, Wojciech
Publisher: name: Zenodo
Year: 2022
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Arachnida
Trombidiformes
Demodecidae
Demodex
Demodex bialoviensis

description: 3.1. Descriptions
FEMALE (n =33 and 1 holotype): Body slender, elongated, spindleshaped, with distinctly separated gnathosoma, 239 (200–268) long and wide 35 (30–40) (holotype, 250 ×39). Gnathosoma rectangular (length close or greater to width at base); on dorsal surface in central part of basal (coxal) segment, pair of wedge-shaped supracoxal spines (setae elc. p) present, ca. 4.0 long (holotype, 4.0), directed medially, slightly oblique. Palps 3-segmented, terminating in three bifurcated spines (one large ca. 3.0, one medium and one small) on tibio-tarsus; conical setae v ’’ F near external edge of middle segment (trochanter-femur-tarsus) present. On ventral surface, horseshoe-shaped pharyngeal bulb with pair of conical subgnathosomal setae (setae n) situated anterior on both sides. Podosoma rectangular; four pairs of short legs, with coxa integrated into ventral idiosomal wall and five free, overlapping segments (trochanter-tarsus); two forked claws, ca. 5.0 long (holotype, 5.0), with large, pointed subterminal spur on each tarsus. Epimeral plates (coxal fields) distinctly sclerotized; pair I triangular, II-IV trapezoidal, posterior edges of pair IV deeply arched with vulva inside. On the dorsal side of podosoma podosomal shield present, with distinct vertical striation, reaching level of legs III; posterior edge convex. Opisthosoma constitutes 65% (60–69%) of body length (holotype, 65%); conical, pointed or slightly rounded at end. Whole opisthosoma distinctly annulated;
annulation reaches level of legs III dorsally; annuli relatively wide ca. 1.5–2.0. Opisthosomal organ tubular-shape (ca. 10 in length) and is located in posterior part of opisthosoma; its posterior edge is located ca. 20 from end of opisthosoma. Vulva 12 (10–17) long (holotype, 13).
MALE (n =12): Slightly larger and slender than female, 176 (158–198) long, 31 (30–35) wide. Gnathosoma shape similar to female, but smaller. Pharyngeal bulb and morphological details of gnathosoma similar to those in female, but supracoxal spines smaller (ca. 2 in length). Shape of podosoma and legs similar to those in female, but claws smaller (4 in length), and posterior edge of epimeral plate IV without archwise. Opisthosoma constitutes 62% (57–65%) of body length; whole opisthosoma, similar to female, distinctly annulated; annuli relatively wide at ca. 1.5–2.0. Opisthosomal organ similar to female, but smaller, its posterior edge is located ca. 15 from end of opisthosoma. Aedeagus 21 (18–29) long, on dorsal surface, located between epimeral plates II and IV. Genital opening located on dorsal surface, slightly above on border between epimeral plates I and II.
DEUTONYMPH (n =5): Body elongated, club shaped, strongly tapering towards end, 202 (188–218) long, 36 (35–38) wide. Gnathosoma rectangular (width similar to or longer than width at base), smaller than in adults. Supracoxal spines conical, ca. 1 long, located on dorsal side at external edges of gnathosoma. Pharyngeal bulb round, subgnathosomal setae not visible. Palps 3-segmented, terminating in three small spines on tibio-tarsus. Four pairs of small, unsegmented legs, equipment with two 3-pointed claws. Four pairs of ventral scutes (I pair smaller), located between legs in middle part of podosoma. Opisthosoma
constitutes 66% (63–68%) of body length; whole opisthosoma distinctly annulated.
3.2. Material deposition
Female holotype (reg. no. UGDIZPBBbDDb11f), 33 female paratypes (reg. no. UGDIZPBBbDDb01f 10f, UGDIZPBBbDDb12f 34f), 12 male paratypes (reg. no. UGDIZPBBbDDb01m 12m), and five deutonymphs (reg. no. UGDIZPBBbDDb01d 05d); skin of the nasal region; host Bison bonasus (reg. no. MABBb01/2011, MABBb03/2011, MABBb03/2012); Białowieza ˙Forest, Poland; July 2011 and December 2012; parasites coll. J.N. Izdebska and L. Rolbiecki; deposited within the framework of the Collection of Extant Invertebrates in Department of Invertebrate Zoology and Parasitology, University of Gdansk´, Poland.
3.3. Etymology
The specific epithet bialoviensis refers to the geographic name (Białowie˙za) of the host locality.
3.4. Infestation and location in the host
Demodex bialoviensis sp. nov. was noted in 3 (prevalence 25%) European bison, with a density of 1.9 per 1 cm 2; 51 (12 males, 34 females, and 5 deutonymphs) individuals were noted. The demodecid mites were found in the nasal skin region. The observed mites did not cause any skin lesions in the examined bison.
3.5. Differential diagnosis
Compared to D. bisonianus previously described in bison (Kadulski and Izdebska, 1996; Izdebska, unpublished data), D. bialoviensis sp. nov. is much smaller, with a different body shape and proportions. In addition, D. bialoviensis sp. nov. shows a clear sexual dimorphism: the males are much smaller (Tables 1 and 2, Fig. 1 3).
The gnathosoma of D. bisonianus is trapezoidal, with a length less than the width at the base; in D. bialoviensis sp. nov. it is rectangular, almost square, with a length close to the width at the base. Supracoxal spines in D. bisonianus are relatively small, conical, situated in the anterior part of the basal segment of gnathosoma, directed vertically, while in D. bialoviensis sp. nov. they are relatively larger, wedge-shaped,
situated in the central part of the basal segment and directed horizontally (medially and slightly oblique). On the terminal segments of the palpi, two larger spines and one small spine are present in D. bisonianus, and three forked spines of different sizes in D. bialoviensis sp. nov. Subgnathosomal setae are located on the both sides in the lower half of the pharyngeal bulb in D. bisonianus, and at the anterior part of the pharyngeal bulb in D. bialoviensis sp. nov. The legs of D. bisonianus are very massive, clearly projecting beyond the margin of the podosoma, and the tarsi of the legs are equipped with very large (ca. 9–10 long), strongly forked claws; in contrast, the legs of D. bialoviensis sp. nov. are relatively smaller, with more delicate (4–5 long) and less forked claws.
The posterior edges of the IV pair of epimeral plates in D. bisonianus females is V-shaped, while in D. bialoviensis sp. nov. it is deeply arched. The aedeagus of D. bisonianus males is much longer, located at the level of the II-III pair of epimeral plates, while in D. bialoviensis sp. nov. it is shorter, stocky and located at the level of the II-IV pair of plates. The opisthosoma is narrow and long, cylindrical, rounded at the end in D. bisonianus, but tapers distinctly posteriorly in D. bialoviensis sp. nov, with a sharp or slightly rounded end. The opisthosomal organ is absent in D. bisonianus, but present in D. bialoviensis. The typical microhabitat is also different: D. bisonianus is found in the Meibomian glands of the eyelids, and D. bialoviensis sp. nov. in the nasal skin region.
In contrast, the shape of D. bialoviensis sp. nov. resembles that of D. tauri Bukkva, 1986 from domestic cattle Bos taurus Linnaeus, 1758. However, D. tauri is smaller, differs with regard to the shape of the gnathosoma (D. tauri – rectangular, length less than width at the base; D. bialoviensis sp. nov. – square with width close to length, if rectangular, length greater than width at base), and important taxonomic features, such as the location and shape of supracoxal spines (T. tauri – smaller, spatulate), spines on palpi (D. tauri – 2 similar, forked and one single), and the subgnathosomal setae (D. tauri – elongated structures located on both sides of the middle part of the pharyngeal bulb are visible); the shape of epimeral plates is also different, especially the IV pair of the female, only being slightly arched at the posterior edges; the shape of the aedeagus (straight, narrower, located a slightly lower). In addition, its typical microhabitat is the skin around the eyes.
description: Published as part of Izdebska, Joanna N., Rolbiecki, Leszek & Bielecki, Wojciech, 2022, Demodex bialoviensis sp. nov. (Acariformes, Demodecidae) a new, specific parasite of the European bison Bison bonasus (Artiodactyla, Bovidae), pp. 138-143 in International Journal for Parasitology: Parasites and Wildlife 17 on pages 139-142, DOI: 10.1016/j.ijppaw.2022.01.003, http://zenodo.org/record/10668202