Austrophthiracarus paralongisetosus, Liu, 2020

Liu, Dong, 2020, Contribution to the knowledge of the ptyctimous mite genus Austrophthiracarus (Acari, Oribatida, Steganacaridae) with descriptions of two new species from China, Zootaxa 4786 (1), pp. 138-144 : 139

Austrophthiracarus paralongisetosus sp. nov.

( Figs 1 A–F)

Diagnosis. Surface of body densely punctate; median crista and posterior furrows of prodorsum absent; lateral ca- rinae reaching sinus; dorsal sigillar field broad in distal end, longer than laterals; sensilli long, thick and setiform; interlamellar setae long, robust, erect, sparsely barbed in distal half; lamellar setae short and thin; rostral setae thicker than lamellar setae, and curved inward; exobothridial setae vestigial; 17 pairs of long notogastral setae and two pairs of lyrifissures ia and im present; two additional setae inserted in h and ps series, respectively; vestigial setae f 1 posterior to setae h 1; formula of genital setae 6(4+2): 3; setae g 6 situated at level of setae g 5; four pairs of adanal setae present, setae ad 3 thinnest and shortest; h> h–h; setae d situated nearly in the middle of femora I, at level of setae v’’.

Description. Measurements. Holotype: Prodorsum: length 315, width 220, height 115; setae: ss 115, ro 95, le 30, in 195; notogaster: length 550, width 415, height 400; setae: c 1 245, cp 130, d 1 215, e 1 215, h 1 200, h 3 90, ps 1 200, ps 4 60; ventral region: ad 1 60, ad 2 100, ad 2 ’ 100, ad 3 30, an 1 48, an 2 50; genito-aggenital plate 165×120, anoadanal plate 205×150. Paratypes: Prodorsum: length 300–345, width 205–230, height 110–125; notogaster: length 525–570, width 405–435, height 385–405.

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

Prodorsum ( Figs 1 A–B). Median crista, posterior furrows absent; lateral carinae reaching sinus; sigillar fields distinct, dorsal region broad in distal end, longer than lateral regions; sensilli (ss) long, thick, rough and setiform, tapering distally; interlamellar setae (in) long, robust and erect, sparsely covered with small spines in distal half; lamellar setae (le) short spiniform, thin, rough and semi-erect; rostral setae (ro) rough, directed inwards, thicker than lamellar but thinner than interlamellar setae; exobothridial setae (ex) vestigial; comparative length: in>ss>ro> le; in / le ≈6.5, ro / le ≈3.2; mutual distance of setae: in–in / ro–ro ≈1.7.

Notogaster ( Fig. 1A ). 17 pairs of long (c 1 / c 1 – d 1 ≈1.8) setae present, sparsely barbed in distal half, except setae ps 4 and h 3 thinner and shorter; setae c 1 and c 2 slightly far from anterior border than setae c 3; two additional setae pres- ent (h 1 ’, and ps 1 ’) with distribution as depicted in Fig. 1A ; vestigial setae f 1 positioned posterior to setae h 1, vestigial setae f 2 present; two pairs of lyrifissures ia and im present.

Ventral region ( Figs 1A , 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 at level of setae g 5; ano-adanal plates each with six straight and rough setae; anal setae (an) thick and rough; setae ad 2 and ad 2 ’ longest and thicker; setae ad 1 and anal setae similar in length; setae ad 3 short and thinner; comparative length: ad 2 = ad 2 ’>ad 1>an 2>an 1>ad 3.

Legs ( Figs 1 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: Sichuan Province, Ganzi, Luding County, Moxi Town , Hailuogou National Park , from litter under coniferous and broad-leaved mixed forest, 4 Aug. 2018, leg. Dong Liu. Paratypes: 3 adults ( NIGA, in alcohol), same data as holotype .

Etymology. The prefix para is Latin meaning “near” and refers to the similarity of new species with Austrophthiracarus longisetosus Liu & Chen, 2014 .

Remarks. This new species is morphologically most close to Austrophthiracarus longisetosus Liu & Chen, 2014 and Austrophthiracarus villosus ( Niedbała, 1982) in the presence of long interlamellar and notogastral setae, lateral carinae present, and 17 pairs of notogastral setae, but can be differed by: (1) sensilli long, thick and setiform, tapering distally (versus distally dilated and barbed in A. villosus ; bacilliform with thin and smooth head in A. longisetosus ); (2) lateral carinae reaching sinus (versus not reaching sinus in A. longisetosus ); (3) dorsal sigillar field broad in distal end (versus narrow in A. villosus ); (4) distance between rostral setae longer (in–in / ro–ro =1.7) (versus in–in / ro–ro = 1.1 in A. longisetosus ; in–in / ro–ro ≈ 2.3 in A. villosus ); (5) no spines on surface between rostral setae (versus with spines in A. villosus ); (6) interlamellar setae not flagellate distally (versus flagellate distally) (7) lamellar setae thin and spiniform (versus thick, flagellate distally and strongly curved inward in distal half in A. longisetosus ); (8) rostral setae long, strong and curved inward (versus much shorter, spiniform and semi-erect); (9) exobothridial setae vestigial (versus not vestigial); (10) vestigial setae f 1 posterior to setae h 1 (versus anterior to setae h 1 in A. longisetosus ); (11) two pairs of lyrifissures present (versus three pairs); (12) mentum setae h> h–h (versus h <h–h in A. villosus ); (13) formula of genital setae 6(4+2): 3 (versus 7(4+3): 2 in A. villosus ); (14) four pairs of adanal setae present (three to four pairs in A. villosus ; three pairs in A. longisetosus ); (15) setae d situated nearly in the middle of femora I (versus near distal end of article in A. longisetosus ).

Figures

FIGURE 1. Austrophthiracarus paralongisetosus sp. nov.: A, lateral view of body (legs removed); B, prodorsum, dorsal view; C, left side of ventral plate; D, mentum of subcapitulum, palpi removed; E, femur I; F, tibia IV. Scale bars: A–D=100 μm; E–F=50 μm.