Ixodes contrarius D. Apanaskevich 2022, n. sp.
Creators: name: Apanaskevich, Dmitry A.
name: Apanaskevich, Maria A.
name: Klimov, Pavel B.
name: Edgy, Brett M.
name: Bermúdez, Sergio E.
name: Labruna, Marcelo B.
name: Korzeev, Andrei I.
name: Barker, Stephen C.
Publisher: name: Zenodo
Year: 2022
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Arachnida
Ixodida
Ixodidae
Ixodes
Ixodes contrarius

description: Ixodes contrarius D. Apanaskevich n. sp.
Type-host: Thrush— Turdus sp. (Passeriformes: Turdidae).
Other hosts: Timberline wren— Thryorchilus browni (Bangs) (Passeriformes: Troglodytidae).
Type-locality: Costa Rica: San José: Cerra la Muerte, Pan American Highway, 2.8 miles north of Café la Georgina.
Type-material: Holotype female, from Turdus sp., 2.8 miles north of Café la Georgina (~ 9°34’N, 83°45’W), Pan American Highway, Cerra la Muerte, San José, Costa Rica, 23.viii.1963, R. S. Casebeer; deposited in the USNTC (USNMENT 00987233). Paratype: Costa Rica: unknown locality: 1 female, from T. browni, received 5.viii.1963, R. J. Tonn, USNMENT 00987235. Paratype is deposited in the USNTC.
ZooBank registration: The Life Science Identifier (LSID) for Ixodes contrarius n. sp. is urn:lsid:zoobank.org: act: 7C19F02D-B6D6-4EFD-B69F-1E18223CD651.
Etymology: The specific name is derived from the Latin contrarius meaning ‘opposite’ and refers to this species being the smallest of the species discussed, but having the longest internal projection on palpal segment I.
Description. Female [Based on 2 specimens; Figs. 17, 18.] Idiosoma (Fig. 17A, F) of moderately engorged specimen broadly suboval. Scutum (Fig. 17B, C) length 0.90–0.98 (0.94; n = 2), width 0.60–0.70 (0.65; n = 2), ratio 1.40–1.50 (1.45; n = 2); lateral margins diverging for approximately 1/2 of scutal length, then converging to broadly rounded posterior margin; lateral carinae absent; cervical grooves very shallow reaching posterior quarter of scutal length; relatively sparse very fine punctations evenly distributed throughout scutum; setae (Fig. 17B, C) relatively sparse, very short (c. 0.03 in anterolateral margin of scutum). Alloscutum (Fig. 17A) as illustrated; setae (Fig. 17A, D, E) numerous, evenly distributed, very short in center of alloscutum: c. 0.02 and long in area medial to marginal grooves: c.0.06–0.07 (avg. 0.06), setae in area medial to marginal grooves 3.50–4.00 (avg. 3.75) times longer than setae in the center of alloscutum, ratio scutal length to length of setae in area medial to marginal grooves 13.39–16.67 (15.03; n = 2). Venter (Fig. 17F) as illustrated; genital aperture (Fig. 17F) medial to coxae III; genital groove (Fig. 17F) well developed; anal groove (Fig. 17F) oval with open posterior margin; ventral setae (Fig. 17F) numerous, length of preanal setae c. 0.05, evenly distributed. Spiracular plates (Fig. 18A) length 0.20–0.23 (0.21; n = 2), width 0.18–0.24 (0.21; n = 2), ratio 0.95–1.10 (1.02; n = 2); broadly suboval.
Gnathosoma (Fig. 18B–D) length from palpal apices to cornual apices dorsally 0.45–0.50 (0.48; n = 2), width of basis capituli dorsally 0.35–0.41 (0.38; n = 2), ratio 1.21–1.29 (1.25; n = 2). Dorsal basis capituli (Fig. 18B) length from medial insertion of palpal segment I to cornual apices 0.18 (n = 2), ratio width to length 2.00–2.36 (2.18; n = 2), subrectangular: lateral margins convex, without angular lateral projections or slightly subhexagonal: lateral margins with very short angular lateral projections, posterior margin nearly straight or slightly convex; cornua short, length 0.01 (n = 2), ratio total length of basis capituli, including cornua, to cornual length 14.00 (n = 2), triangular with broadly rounded apex; transversally suboval porose areas large, width 0.12–0.14 (0.13; n = 2), ratio basis capituli width dorsally to porose area width 2.95–3.00 (2.97; n = 2), clearly distinct, slightly indented, separated by distance of nearly 1/2 of their own width, openings discrete. Ventral basis capituli (Fig. 18C, D) pentagonal; auriculae long, length 0.04–0.06 (0.05; n = 2), ratio gnathosoma length to auriculae length 8.40–10.59 (9.50; n = 2), narrow, slightly longer than broad or nearly as long as broad, directed posteriorly, with narrowly rounded apex. Lateral surface of basis capituli slightly concave (Fig. 18C, D). Palpi (Fig. 18B, C, E) moderately long, length dorsally (segments II and III) 0.25–0.29 (0.27; n = 2), maximum width (in dorsolateral plane) 0.10–0.11 (0.11; n = 2), ratio 2.50–2.56 (2.53; n = 2), length of medial margin of palpal segment I ventrally 0.16–0.17 (0.17; n = 2); segment I with long internal projection directed anteriorly and giving L-shape to segment I dorsally and ventrally; length of internal projection ventrally from base of palpal segment II to anterior apex 0.13–0.16 (0.14; n = 2), ratio combined length of palpal segments II and III to length of internal projection on palpal segment I ventrally 1.83–1.92 (1.88; n = 2); dorsally segment I with slight transversal ridge at base, mesodorsal spur indistinct, dorsoapical denticle indistinct; segments II and III fused with indistinct or barely discernible (mostly medially) suture between them, narrow proximally and gradually widening to broadly rounded apex. Hypostome (Fig. 18C) length 0.29–0.31 (0.30; n = 2), width 0.10 (n = 1), ratio 2.83 (n = 1); base of hypostome nearly at same level as base of palpal segments II, club-shaped, widest close to mid-length; dental formula mostly 4/4, proximal rows 2/2 and then 3/3, distal rows 5/5; denticles sharply pointed; proximal part of hypostome without denticles moderate in length.
Legs moderately long, slender. Coxae (Fig. 18F–H): coxae I-III with internal and external spurs, coxa IV with external spur only; external spur on coxae I-IV moderately long, narrow, narrowly rounded at apex, directed slightly posteromedially; external spur on coxa I slightly longer than spur on other coxae; external spur on coxae II and III subequal; external spur on coxa IV shorter or subequal to spur on coxae II and III; internal spur on coxae I-III short, nearly subequal, narrow on coxa I and broader on coxae II and III, narrowly to moderately broadly rounded at apex; internal spur on coxa I directed slightly posteromedially; internal spur on coxae II and III directed posteriorly; external spur on coxa I at least twice as long as internal spur; no syncoxae. Distally trochanters I-IV (Fig. 18F–H) with moderate ventral spur with narrowly rounded apex. Tarsus I: length 0.56–0.62 (0.59; n = 2); tarsus IV length 0.52–0.59 (0.56; n = 2).
Remarks. The description and illustrations of I. auritulus in Keirans and Clifford (1978) are partially based on the female of I. contrarius n. sp.
By having a distinct, anteriorly directed internal projection on palpal segment I, the female of I. contrarius n. sp. most closely resembles the following Ixodes (Multidentatus) spp.: I. auritulus, I. brevisetosus n. sp., I. cornuae, I. guglielmonei n. sp., I. insulae n. sp., I. kerguelenensis, I. moralesi n. sp., I. paranaensis, I. percavatus, I. rio n. sp., I. robbinsi n. sp., I. tinamou n. sp. and I. zealandicus.
The female of I. contrarius n. sp. can be distinguished from the female of I. cornuae by having short cornua (vs very long cornua in that species); from females of I. kerguelenensis and I. percavatus by having the indistinct mesodorsal spur on palpal segment I (vs large, distinct spur in those species); and from the female of I. paranaensis by having longer auriculae (vs very short auriculae in that species) (see Arthur 1960; Wilson 1970; Barros-Battesti et al. 2003).
The female of I. contrarius n. sp. can be distinguished from females of other species by the narrow scutum: mean ratio length to width 1.45 (vs broader scutum: mean ratio 1.19 in I. auritulus, 1.25 in I. guglielmonei n. sp. and I. moralesi n. sp., 1.16 in I. robbinsi n. sp. and 1.11 in I. tinamou n. sp.); short setae in center of alloscutum and long setae in alloscutal area medial to marginal grooves: mean ratio length of setae in alloscutal area medial to marginal grooves to length of setae in center of alloscutum 3.75 (vs shorter setae in alloscutal area medial to marginal grooves: mean ratio 1.58 in I. brevisetosus n. sp., 2.65 in I. robbinsi n. sp. and 2.73 in I. tinamou n. sp.; longer setae in both center and area medial to marginal grooves of alloscutum: mean ratio 1.09 in I. guglielmonei n. sp., 2.00 in I. insulae n. sp. and 1.14 in I. zealandicus); long setae of alloscutum medial to marginal grooves: mean ratio length of scutum to length of alloscutal setae medial to marginal grooves 15.03 (vs shorter setae of alloscutum medial to marginal grooves: mean ratio 45.62 in I. brevisetosus n. sp., 20.89 in I. moralesi n. sp. and 26.93 in I. robbinsi n. sp.); broad gnathosoma: mean ratio length of gnathosoma to width of basis capituli 1.25 (vs narrower gnathosoma: mean ratio 1.33 in I. brevisetosus n. sp. and I. zealandicus and 1.34 in I. insulae n. sp.); lateral surface of basis capituli slightly concave (vs lateral surface flat in I. brevisetosus n. sp.); posterior margin of basis capituli slightly convex (vs sinuously concave in I. guglielmonei n. sp. and straight to very slightly concave in I. zealandicus); short cornua: mean ratio length of basis capituli to cornual length 14.00 (vs longer cornua: mean ratio 6.00 in I. auritulus, 5.95 in I. brevisetosus n. sp., 4.94 in I. guglielmonei n. sp., 4.60 in I. insulae n. sp., 5.87 in I. moralesi n. sp., 5.84 in I. robbinsi n. sp., 9.92 in I. tinamou n. sp. and 7.25 in I. zealandicus); broad porose areas: mean ratio width of basis capituli to width of porose area 2.97 (vs narrower porose areas: mean ratio 3.61 in I. brevisetosus n. sp. and 3.47 in I. rio n. sp.); auriculae moderately long: mean ratio length of gnathosoma dorsally to length of auriculae 9.50, narrow, directed posteriorly, with narrowly rounded apex (vs shorter auriculae: mean ratio 28.15 in I. guglielmonei n. sp., 14.59 in I. robbinsi n. sp., 40.07 in I. tinamou n. sp. and 19.54 in I. zealandicus; auriculae distinctly broader, with broadly rounded apex in I. guglielmonei n. sp., I. moralesi n. sp., I. robbinsi n. sp., I. tinamou n. sp. and I. zealandicus; auriculae directed slightly outwards in I. guglielmonei n. sp., I. tinamou n. sp. and I. zealandicus); lacking spur at base of palpal segment I dorsally (vs short mesodorsal spur at base of palpal segment I dorsally in I. insulae n. sp., I. moralesi n. sp. and I. zealandicus); very long internal projection on palpal segment I: mean ratio length of palpal segments II and III to length of projection on palpal segment I 1.88 (vs shorter projection in all other species: mean ratio 2.93 in I. auritulus, 2.77 in I. brevisetosus n. sp., 4.94 in I. guglielmonei n. sp., 3.55 in I. insulae n. sp., 3.08 in I. moralesi n. sp., 2.83 in I. rio n. sp., 3.02 in I. robbinsi n. sp., 3.57 in I. tinamou n. sp. and 4.50 in I. zealandicus); indistinct dorsoapical spur on palpal segment I (vs moderate spur in I. auritulus, I. brevisetosus n. sp., I. insulae n. sp. and I. zealandicus; large, hook-like spur in I. moralesi n. sp.); moderately broad palpal segments II and III: mean ratio length to width 2.53 (vs narrower segments: mean ratio 2.82 in I. brevisetosus n. sp., 2.64 in I. insulae n. sp. and 2.87 in I. rio n. sp.; broader segments: mean ratio 2.16 in I. guglielmonei n. sp.); external spur on coxae I-IV relatively narrow, sharp at apex (vs broader spur with broadly rounded apex in I. tinamou n. sp. and I. zealandicus); generally the smallest of all discussed species: see description for measurements (vs all other species noticeably larger. See descriptions for measurements).
Collection data for I. contrarius n. sp. are listed in the material above. Collections of this species were made in Costa Rica (San José Province) (Fig. 10C). Both known females of this species were collected from birds: the timberline wren, T. browni (Passeriformes: Troglodytidae) and unidentified thrush, Turdus sp. (Passeriformes: Turdidae). One of the females was collected during August.
description: Published as part of Apanaskevich, Dmitry A., Apanaskevich, Maria A., Klimov, Pavel B., Edgy, Brett M., Bermúdez, Sergio E., Labruna, Marcelo B., Korzeev, Andrei I. & Barker, Stephen C., 2022, Description of eight new species of Ixodes Latreille, 1795 (Acari: Ixodidae) and redescription of I. auritulus Neumann, 1904, parasites of birds in the Australasian, Nearctic and Neotropical Regions, pp. 1-73 in Zootaxa 5173 (1) on pages 28-30, DOI: 10.11646/zootaxa.5173.1.1, http://zenodo.org/record/6966076