Austrophthiracarus bacilliformis Liu 2020, sp. nov.

Austrophthiracarus bacilliformis sp. nov.

(Figs 2 A–F)

Diagnosis. Surface of body densely punctate; median crista and posterior furrows of prodorsum absent; lateral ca- rinae reaching sinus; dorsal sigillar field narrow, longer than laterals; sensilli rough and bacilliform; interlamellar setae procumbent, thicker than lamellar and rostral setae; exobothridial setae vestigial; 16 pairs of notogastral setae of medium length and three pairs of lyrifissures ia, im and ih present; one additional setae present in ps series; ves- tigial setae f 1 anterior to setae h 1; formula of genital setae 6(4+2): 3; setae g 6 situated at level of setae g 5; ano-adanal plates each with five setae, setae ad 3 thinnest and shortest; h> h–h; setae d situated in the middle of femora I, at level of setae v’’.

Description. Measurements. Holotype: Prodorsum: length 255, width 200, height 102; setae: ss 45, ro 25, le 20, in 50; notogaster: length 515, width 375, height 345; setae: c 1 90, cp 55, d 1 85, e 1 80, h 1 85, h 3 50, ps 1 82, ps 4 30; ventral region: ad 1 60, ad 2 75, ad 3 25, an 1 45, an 2 45; genito-aggenital plate 150×115, ano-adanal plate 195×130. Paratypes: Prodorsum: length 270–285, width 205–220, height 105–115; notogaster: length 530–550, width 395– 405, height 365–385.

Integument. Colour light brown. Surface of body densely punctate.

Prodorsum (Figs 2 A–B). Median crista, posterior furrows absent; lateral carinae reaching sinus; sigillar fields distinct, dorsal region narrow, longer than lateral regions; sensilli (ss) rough along its entire length and bacilliform, almost equal in thickness throughout length; interlamellar setae (in) procumbent, rough and moderately thick; la- mellar setae (le) short and fine; rostral setae (ro) slightly thicker and longer than lamellar setae, but much thinner than interlamellar setae; exobothridial setae (ex) vestigial; comparative length: in> ss> ro> le; in / le =2.5, ro / le ≈1.3; mutual distance of setae: in–in / ro–ro ≈2.4.

Notogaster (Fig. 2A). 16 pairs of setae with medium size (c 1 / c 1 – d 1 ≈0.7), rough, nearly equally long and thick, except setae cp, h 3, ps 3 and ps 4 thinner and shorter; setae c 2 slightly far from anterior border than setae c 1 and c 3; one additional setae (ps 2 ’) present with distribution as depicted in Fig. 2A; vestigial setae f 1 positioned anterior to setae h 1, vestigial setae f 2 present; three pairs of lyrifissures ia, im and ih present.

Ventral region (Figs 2A, C–D). Setae h of mentum longer than distance between them. Nine pairs of genital setae (g) arranged in two rows with formula: 6(4+2): 3; setae g 6 situated between level of setae g 5; ano-adanal plates each with five rough setae; setae ad 2 longest and thicker; setae ad 1 intermediate length; setae ad 3 shortest and thinnest; comparative length: ad 2> ad 1>an 1 = an 2>ad 3.

Legs (Figs 2 E–F). Chaetotaxy of legs complete; setal counts for leg segments: I: 1-4-2(2)-5(1)-19(3); II: 1-3- 2(1)-3(1)-12(2), III: 2-2-1(1)-2(1)-10, IV: 2-1-1-2(1)-10; setae d on femora I inserted at level of setae v’’; setae a’’ on tarsi I, and setae ft’’ and a’’ on tarsi II curved distally; setae s and pv’ on tarsi IV present; setae s on tarsi I and II present.

Material examined. Holotype: 1 adult (NIGA, in alcohol), China: Heilongjiang Province, Jiamusi, Fujin County, Erlongshan, from forest litter under Quercus mongolica, 13 Aug. 2010, leg. Dong Liu, Donghui Wu, Xiaoqiang Yuan and Yabing Yuan. Paratypes: 3 adults (NIGA, in alcohol), same data as holotype.

Etymology. The new specific name “ bacilliformis ” refers to the shape of sensillus.

Remarks. This new species is similar to Austrophthiracarus filiformis Liu & Chen, 2014 and Austrophthiracarus setiformis Liu, 2017 in having 16 pairs of notogastral setae, similar shape of rostral and notogastral setae and sigillar field, but can be distinguished by following features: (1) sensilli bacilliform, nearly equally thick in whole length (versus setiform and tapering distally in A. filiformis and A. setiformis); (2) prodorsal lateral carinae present (versus absent in A. setiformis); (3) interlamellar setae thick and long (versus fine and much shorter); (4) lamellar short and fine (versus long and thick in A. setiformis); (5) exobothridial setae vestigial (versus not vestigial in A. filiformis); (6) one additional setae present in ps series (versus in h series); (7) three pairs of lyrifissures ia, im and ih present (versus four pairs of lyrifissures ia, im, ih and ips in A. filiformis; two pairs of lyrifissures ia and im in A. setiformis); (8) vestigial setae f 1 anterior to setae h 1 (versus posterior); (9) formula of genital setae 6(4+2): 3 (ver- sus 7(4+3): 2 in A. setiformis); (10) setae g 6 situated at level of setae g 5 (versus at level of setae g 4 in A. filiformis; between level of setae g 4 and g 5 in A. setiformis); (11) setae ad 2 three times longer than setae ad 3 (versus shorter than setae ad 3 in A. filiformis); (12) mentum setae h> h–h (versus h <h–h in A. filiformis); (13) setae d situated in the middle of femora I (versus near distal end of article in A. filiformis).

This new species is also similar to Austrophthiracarus inusitatus (Niedbała, 1983) and Austrophthiracarus jumbongiensis Niedbała, 2002 (Kaczmarek & Niedbała, 2002) in having similar shape of interlamellar setae, and similar arrangement of setae h and ps, but can be easily differed by: (1) sensilli bacilliform, nearly equally thick in whole length (versus setiform and pointed distally in A. inusitatus and A. jumbongiensis); (2) lamellar and rostral setae short and fine (versus robust and rough in A. inusitatus; flexible in A. jumbongiensis); (3) exobothridial setae vestigial (versus not vestigial); (4) one pair of lateral carinae present (versus absent in A. jumbongiensis); (5) one additional setae present in ps series (versus in h series); (6) vestigial setae f 1 anterior to setae h 1 (versus posterior); (7) three pairs of lyrifissures ia, im and ih present (versus two pairs of lyrifissures ia and im in A. inusitatus; three pairs of lyrifissures ia, im and ips in A. jumbongiensis); (8) setae of row c rough and robust (versus smooth and flexible in A. jumbongiensis); (9) setae ad 2 three times longer than setae ad 3 (versus less two times longer than ad 3); (10) setae g 6 situated at level of setae g 5 (versus between level of setae g 4 and g 5); (11) setae g 6, g 7, g 8 and g 9 similar in length (versus setae g 9 longer than others); (12) setae d situated in the middle of femora I (versus near distal end of article in A. jumbongiensis).