Austrophthiracarus whirinaki, Liu & Zhang, 2018

Liu, Dong & Zhang, Zhi-Qiang, 2018, New Zealand Austrophthiracarus (Acari, Oribatida, Steganacaridae): two new species from the North Island, Zootaxa 4500 (3), pp. 443-450 : 445-448

Austrophthiracarus whirinaki sp. nov.

( Figs. 2A–H )

Diagnosis. Entire surface of idiosoma finely punctate; posterior furrows and lateral carinae absent; sensilli short with rounded head; interlamellar setae long, stout and sparsely barbed; lamellar setae vestigial; rostral setae short and spiniform, situated far from anterior margin of rostrum; exobothridial setae short and fine; 15 pairs of notogastral setae stout and sparsely barbed; vestigial setae f 1 positioned anterior to setae h 1; two pairs of lyrifissures ia and im present; h<h–h; formula of genital setae: 6(4+2):3; setae ad 1 and ad 2 vestigial, setae ad 3 finely barbed.

Description. Measurements. Holotype: Prodorsum: length 440, width 250, height 165, setae: ss 50, ro 82, in 185, ex 34; notogaster: length 815, width 570, height 600; setae: c 1 120, c 2 100, c 3 95, cp 85, d 1 115, e 1 110, h 1 110, h 3 80, ps 1 105, ps 4 69; ad 3 55, an 1 150, an 2 153; genito-aggenital plate 150×200, ano-adanal plate 135×320. Paratypes: Prodorsum: length 410–425, width 235–242, height 160–165; notogaster: length 795–805, width 550– 560, height 575–590.

Integument. Colour dark brown. Entire surface finely punctate.

Prodorsum ( Figs 2A–B ). Median crista, posterior furrows and lateral carinae absent; sigillar fields distinct, median field narrow and short, but longer than lateral fields; sensilli (ss) with short, with narrow pedicel and rounded head; interlamellar setae (in) long, stout, erect, and sparsely barbed in distal half; lamellar setae (le) vestigial; rostral setae (ro) spiniform, short, rough and semi-erect, inserted far from anterior margin of rostrum; exobothridial setae (ex) short and fine; comparative length: in> ro> ss> ex, in–in / ro–ro≈ 2.08.

Notogaster ( Fig. 2A ). 15 pairs of notogastral setae present, medium in length (c 1 / c 1 – d 1 ≈0.54), stout, erect, and sparsely barbed in distal half; setae c 2 further away from anterior border than setae c 1 and c 3, setae c 3 closest; vestigial setae f 1 positioned anterior to setae h 1; two pairs of lyrifissures ia and im present.

Gnathosoma ( Figs 2D–F ). Subcapitulum typical of family ( Fig. 2D ); setae h, m and a simple and smooth; setae h shorter than distance between them; adoral seta or 1 apparently flat with barbs; or 2–3 simple and smooth; palp ( Fig. 2E ) 4-segmented, with femur and genu fused; palpal setation: 0-2-2-7(1); supracoxal seta simple and smooth; chelicera ( Fig. 2F ) typical of family.

Ano-genital region ( Figs 2A, C ). Nine pairs of genital setae (g) arranged with formula: 6(4+2):3; ano-adanal plates each with five setae (ad, an), setae ad 1 and ad 2 vestigial, setae ad 3 short and finely barbed; anal setae sparsely barbed, straight and longer; comparative length: an 2> an 1> ad 3.

Legs ( Figs 2G–H ). Setal counts for leg segments: I: 1-4-2(2)-4(1)-17(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 on 1/3 of the length from the anterior part of femora; setae a’’ on tarsi I and setae ft’’ on tarsi II straight; setae 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: adult ( NZAC, in alcohol, 84/67), New Zealand: TO, Whirinaki SF 1, from litter, 12 Sep. 1984, leg. C. Crowe. Paratypes: two adults ( NIGA, in alcohol, 84/67), same data as holotype .

Type deposition. Holotype specimen is deposited in NZAC . Paratypes are deposited in NIGA .

1. SF = State Forest. This New Zealand forest is one of the prehistoric rainforests in the world and now part of the Whirinaki Te Pua-a-Tāne Conservation Park.

Etymology. Named after Whirinaki Forest and used as a noun in apposition.

Remarks. This new species is similar to Austrophthiracarus nicoleti ( Niedbała, 1987) in having similar shape of sensilli, lamellar setae vestigial, interlamellar setae long and thick, lateral carinae of prodorsum absent, 15 pairs of notogastral setae, but can be distinguished by the following characters: 1) surface of idiosoma finely punctate (versus surface of prodorsum and notogaster with foveoles in A. nicoleti ); 2) distance between setae ps 3 and ps 4 similar to that between setae ps 2 and ps 3 (versus more than twice longer than that between ps 2 and ps 3); 3) vestigial setae f 1 positioned anterior to setae h 1 (versus posterior to setae h 1); 4) two pairs of notogastral lyrifissures present (versus four pairs); 5) formula of genital setae: 6(4+2):3 (versus 5(4+1):4); 6) setae ad 1 and ad 2 vestigial (versus not vestigial); 7) setae d on femora I not forked distally (versus forked).

This new species is also similar to Austrophthiracarus latior ( Niedbała, 1982) , Austrophthiracarus tragardhi ( Niedbała, 1987) , Austrophthiracarus retrorsus Niedbała, 2003 and Austrophthiracarus ridiculus ( Mahunka, 1982) in sharing similar shape of sensilli, long and thick interlamellar setae (interlamellar setae more than six times longer than lamellar setae), 15 pairs of notogastral setae, median crista absent, but can be distinguished by the following combination of features: lamellar setae and setae ad 1 and ad 2 vestigial (versus not vestigial in these four species); surface of idiosoma finely punctate (versus surface of notogaster covered with weak concavities in A. retrorsus , margins of notogaster covered with concavities in A. ridiculus ); posterior furrows on prodorsum absent (versus present in A. ridiculus ); prodorsal lateral carinae absent (versus present in A. latior and A. ridiculus ); head of sensilli smooth (versus covered with spines in A. latior ); vestigial setae f 1 positioned anterior to setae h 1 (versus posterior to setae h 1 in A. latior and A. tragardhi ); two pairs of notogastral lyrifissures present (versus four pairs in A. retrorsus and A. ridiculus ); formula of genital setae: 6(4+2):3 (versus 9(4+5):0 in A. latior and A. tragardhi ); ano-adanal plates with five setae (versus six setae in A. tragardhi , A. retrorsus and A. ridiculus ); h<h–h (versus h=h–h in A. latior and A. ridiculus , h>h–h in A. tragardhi ).

Compared with Austrophthiracarus feideri ( Balogh & Csiszar, 1963) , they have similar shape of setae ad 1 and ad 2 and sensilli. However, the new species differs from A. feideri by 1) surface of idiosoma finely punctate (versus prodorsum foveolate in A. feideri ); 2) lamellar setae vestigial (versus not vestigial); 3) dorsal notogastral setae stout and not much longer than other setae (versus dorsal setae flagellate distally and much longer than others); 4) formula of genital setae: 6(4+2):3 (versus 5(4+1):4); 5) setae ad 1 and ad 2 vestigial (versus minute); 6) anal setae not flagellate distally (versus flagellate distally).

Figures

FIGURE 2. Austrophthiracarus whirinaki sp. nov.: A, lateral view of body (legs removed); B, prodorsum, dorsal view; C, left side of ventral plate; D, subcapitulum, palpi removed; E, palp, antiaxial view; F, chelicera, antiaxial view; G, tibia IV; H, femur I. Scale bars: A–C=100 µm; D–H=50 µm.