Austrotritia didyma, Liu, Dong, Chen, Jun & Qiao, Gexia, 2009

Liu, Dong, Chen, Jun & Qiao, Gexia, 2009, Review of Austrotritia (Acari: Oribatida: Oribotritiidae), with descriptions of two new species from China, Zootaxa 2144, pp. 54-64 : 57-59

Austrotritia didyma sp. nov.

( Figs. 1–8 )

Material examined: Holotype: adult (in alcohol, W-89-142), China: Beijing, Fangshan District, Yunshuidong (39°40'4.27"N, 115°48'48.92"E), from litter, 30 Aug., 1989, leg. Hui-Fu Wang and Xiao-Li Chen. Paratypes: three adults (in alcohol, W-89-133, W-89-141), same data as holotype; 15 adults (in alcohol, LD-07-145), China: Shandong Province, Qufu City, Konglin (35° 0'0.72"N, 116°39'3.28"E), from litter, 15 Nov., 2007, leg. Bin Cao.

Etymology. The new specific name “ didyma ” is from Latin, and refers to the double dorsal carinae of prodorsum.

Diagnosis: Prodorsum with two pairs of lateral carinae and two distinct dorsal carinae; sensillus long, setiform, rigid and smooth, other prodorsal setae rough, except minute exobothridial seta; lamellar seta fine; notogastral setae short, rigid and rough; genito-aggenital plates with nine pairs of genital and two pairs of aggenital setae; one pair of anal and three pairs of adanal setae present.

Measurements: Holotype: prodorsum: length 450, width 360, height 155, sensillus 135, setae: ro 52.5, in 80, le 45, ex 12.5, distance between setae: ro -ro 90, in -in 135, le -le 305, in -le 95, le -ro 260; notogaster: length 850, width 560, height 640; setae: c1 100, c2 80, c3 75, c p 75, d1 100, d2 85, e1 100, e2 90, h1 110, h2 95, h3 100, ps1 95, ps2 95, ps3 75; distance between setae: c1-d1 170, d1-e1 305, e1-h1 245, h1- ps1 205; ventral region: genito-aggenital plate 245×140, anal and adanal plates 480×115. Paratypes: prodorsum: length 420–455, width 360–385, height 160–185; notogaster: length 810–950, width 655–720, height 640–770; ventral region: genito-aggenital plate 246×138, anal and adanal plates 510×115.

Colour yellowish to grey-yellowish. Integument finely dotted, anterior part of prodorsum with longitudinal striations.

Prodorsum with two parallel lateral carinae on each side, upper carina stronger than lower one, anterior part of prodorsum with two distinct dorsal carinae; bothridial scale situated above bothridium, posterior median apodeme absent; sensillus long, setiform, rigid and smooth; rostral seta rough, semi-erect, inserted outside of dorsal carinae; interlamellar seta thick, rough, strongly erect; lamellar seta smooth, procumbent, thinner than rostral and lamellar setae, inserted close to interlamellar seta; exobothridial seta short and fine, not vestigial; comparative length: in> ro> le> ex.

Setae of notogaster short (c1 <c1-d1), curved, rigid and rough; setae c1 and c2 far from anterior border, seta c3 near the border; two pairs of vestigial setae f1 and f2 situated in normal position; openings of opisthosomal glands and five pairs of lyrifissures present.

Genito-aggenital suture absent; genito-aggenital plates with nine pairs of setae, among which four pairs in progenital position; two pairs of aggenital setae present, seta ag2 longer than ag1; anogenital cleft long and oblique; anal plates with one pair of short anal setae (except one paratype with two anal setae on right anal plate); three pairs of short adanal setae present, seta ad2 situated more close to ad3 than to ad1; lyrifissure iad situated laterally between setae ad2 and ad3.

Seta h of mentum considerably longer than their distance; palp five-segmented with setal formula: 0-2-0- 2-9(1); setation of legs (without tarsi): I: 1-4-5(2)-5(1); II: 1-4-4(1)-3(1), III: 3-2-3(1)-3(1), IV: 3-2-2(1)-3(1); anteriodorsal part of femur I with distinct triangular spine; tarsi heterotridactylous.

Distribution. China (Beijing, Shandong).

Remark. This new species is easily distinguished from other related species by: prodorsum with two pairs of lateral carinae and two distinct dorsal carinae; exobothridial seta minute, not vestigial; notogastral setae short, rigid and rough.

Figures

FIGURES 1 – 8. Austrotritia didyma sp. nov.: 1, lateral view of body (legs removed); 2, prodorsum, dorsal view; 3, prodorsum, dorso-lateral view; 4, left side of ventral plate; 5 – 8, trochanter, femur, genu and tibia: 5, leg I; 6, leg II; 7, leg III; 8, leg IV. Scale bars: 1, 2, 4 = 200 μm; 3, 5 – 8 = 100 μm.