Onchodellus acrophilus Özbek 2023, sp. nov.
Creators: name: Özbek, Hasan Hüseyin
Publisher: name: Zenodo
Year: 2023
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Arachnida
Mesostigmata
Pachylaelapidae
Onchodellus
Onchodellus acrophilus

description: Onchodellus acrophilus sp. nov.
(Figures 3–4, 10, 13, 17, 20–21, 26–27, 32, 37, 42)
Diagnosis: Length of dorsal setae J5 almost half that of J4; lateral and opisthogastric soft integument with 13 pairs of setae; anterior tips of peritremes extending to dorsal surface of shield; one pair of posterolateral teat-like gland pores gdS4 on shield. In male, cheliceral spermatodactyl about 5 times length of moveable digit, gradually tapering distally; spur-like distal seta pl1 slightly longer and larger than opposite anterolateral process.
Material examined: Holotype, female, Gümüþhane, Taşlıca Willage, Tahtamur Wold, 40° 45′ N, 39° 04′ E, alt. 1917 m, 24 November 2013, soil under a stone. Paratypes: one male and one female, same data as holotype; three females, Çıkrıkdüzü Wold, 40° 39′ N, 38° 59′ E, alt. 1994 m, 12 October 2013, moss on a stone; Çıkrıkdüzü Wold, 40° 39′ N, 39° 00′ E, alt. 1845 m, 28 October 2013, moss and soil; four females, Çetlüce Wold, 40° 44′ N, 39° 02′ E, alt. 1570 m, 24 November 2013, in moss on a stone.
Female
Dorsum (Figure 3). Dorsal shield 514–541 long, 320–350 wide at widest point, length/width 1.52–1.69, oval, reticulate on surface, with 30 pairs of smooth and pointed setae, clunal setae J5 23–26, J4 48–54, ratio J4 / J5 2.08–2.34; a pair of posterolateral teat-like gland pores gdS4 on shield, gdZ1 subcircular and paraxial to line Z1–Z2. Dorsal setae, j1 30–33; z1 about 13–16, other dorsal setae lengths between 45 and 70 long.
Venter (Figure 4). Sternal shield 172–175 long, 90–95 wide at level of coxae II, its surface ornamented with reticulate pattern, bearing four pairs of pointed setae and three pairs of pores; st1 and st2 of equal length (about 55); st3 shortest (about 40), st4 48. Genitiventral shield wider than long or equal in length, length/width 0.94–1.02 ornamented with polygonal pattern, with two pairs of setae (Fig. 37). Anal shield 63–65 long, 100–105 wide, length/ width 0.61–0.64, triangular, with some lines on edges of shield. One pair of bar-shaped metapodal shields present. Lateral and opisthogastric soft integument with 13 pairs of setae (six pairs marginal and seven pairs opisthogastric). Anterior tips of peritremes extend to dorsal surface of shield and lie between setae z1 and z2.
Spermathecal apparatus. Sperm access system connected with coxae III, tubes long, distinct, their ends broadened apically (Fig. 13).
Gnathosoma. Hypostome with seta h3 longest, h2 and palp coxal seta pc shortest and subequal in length; corniculi horn-like and lanceolate, deutosternal groove with six rows of denticles. Epistome with straight denticulate lateral margins and central projection with strong apical serration (Fig. 10), its surface decorated as in Fig. 42. Chelicera well developed with strong subdistal teeth; movable digit about 60 long, with a large median tooth, a small subdistal denticle and unidentate terminal hook, fixed digit about 58 long (to the dorsal seta), with a pilus dentilis (Fig. 26). Arthrodial brush short.
Legs. Chaetotaxy normal for the genus (Mašán, 2007). Tarsus II with a thicker spur-like seta pl1 (Fig. 17).
Male
Dorsum. Dorsal idiosoma 490 long, 315 wide at widest point, length/width 1.55. Ornamentation and dorsal chaetotaxy for female.
Venter. Holoventral shield ornamented with reticulate pattern and provided with five pairs of needle-like setae and three pairs of pores. Opisthogastric area of shield with three pairs of setae, three circum-anal setae. Dorso-lateral and opisthogastric soft integument with seven pairs of setae.
Gnathosoma. Epistome with denticulate anterolateral margins, median process short and wide, with strong apical dentition. Moveable digit of chelicera 50 long, with a large subterminal tooth near the unidendate terminal hook, spermatodactyl 245 long, almost five times (4.9) as long as length of moveable digit, progressively narrowed distally, whip-like (Fig. 27). Fixed digit with one median tooth, one large subdistal tooth, and terminal hook, pilus dentilis clearly visible. Palptibiae without any processes.
Leg II. Tarsus II with a spur-like seta p11 and opposite anterolateral apophysal spur; pl1 slightly longer and larger than apophysal spur (Figs 20, 32). Femur II with large, finger-shaped, distally tapered, spur-like process; genu and tibia each with small, ventral, distally tapered process (Fig. 21).
Etymology. The name of this species refers to the high altitude of the type locality (acro -).
Taxonomic notes. Mašán (2007) evaluated the species grouping of some species of the genus Onchodellus and found five species groups and some non-grouped species. The Onchodellus karawaiewi group includes three species, namely O. karawaiewi, O. montivagus Mašán, 2007 and O. zoborensis Mašán, 2007. The characters of this species group are presented in detail by Mašán (2007). Onchodellus acrophilus can be included in this species group, and is most similar to O. zoborensis. It distinctly differs from O. karawaiewi and O. montivagus in body shape (oval in O. karawaiewi and O. montivagus), a different number of setae on the soft integument of the idiosoma (14 pairs in O. karawaiewi and O. montivagus), a difference in the relative length of J4/J5 (1.7–3.04 in O. karawaiewi, 1.3–1.7 in O. montivagus), shorter setae J4, 48–56 (56–73 in O. karawaiewi, 56–62 in O. montivagus) and subcircular shaped gdZ1 (circular shaped in O. karawaiewi and O. montivagus). In addition, O. acrophilus differs from the most similar species O. zoborensis by shorter setae J5 (23–26 in O. acrophilus, 37–42 in O. zoborensis), a different number of setae on the soft integument of the idiosoma (14 pairs in O. zoborensis), a different relative length of J4/ J5 2.08–2.34 (1.3–1.7 in O. zoborensis) and subcircular shaped gdZ1 (circular shaped in O. zoborensis). The male specimens of these species are generally similar except for the process on leg II, but there is an important difference in the middle segments of leg IV. The males of this group have a triangular process on the distal part of the ventral side of the femur, genu and tibia of leg IV, which is absent in the male of O. acrophilus.
Onchodellus acrophilus is similar to O. longus Costa, 1971 but differs in smaller body size (514–541 in O. acrophilus, 590–610 in O. longus), different body shape (slightly oval O. acrophilus, elongate in O. longulus), different size of anal shield (63–65 long, 100–105 wide in O. acrophilus, 80 long, 120 wide in O. longus). It differs from O. euparadactylifer Mašán et al, 2013 and O. turcicus Şahin & Özbek, 2018 them because the anterior tip of the peritreme does not reach the base of setae z1 (in O. turcicus, the tips of the peritreme reach the base of setae z1; in O. euparadactylifer, the anterior tips of the peritreme extend beyond setae z1), and in the different number of setae on the soft integument of the idiosoma (13 pairs) (14 pairs in O. turcicus and O. euparadactylifer).
description: Published as part of Özbek, Hasan Hüseyin, 2023, The genus Onchodellus Berlese in Türkiye (Mesostigmata: Pachylaelapidae), with a new record and three new species, pp. 285-296 in Zootaxa 5263 (2) on pages 287-289, DOI: 10.11646/zootaxa.5263.2.7, http://zenodo.org/record/7801139