Plonaphacarus cristatus, Liu, Dong, Wu, Donghui & Chen, Jun, 2011

Liu, Dong, Wu, Donghui & Chen, Jun, 2011, Review of Plonaphacarus (Acari: Oribatida: Steganacaridae), with descriptions of eight new species from China, Zootaxa 2739, pp. 1-26 : 8-11

Plonaphacarus cristatus sp. nov.

( Figs. 19–26 )

Material examined. Holotype: adult (in alcohol, W-89-86), China: Hubei Province, Hefeng County (29°53'15.83"N, 110° 1'58.59"E), from litter under broadleaf, 30 Jul., 1989, leg. Yun-Qi Cui. Paratypes: two adults (in alcohol, W-89–86), same data as holotype; six adults (in alcohol, W-89–84), same data as holotype, Fenshuiling Forestry Centre, 1300M, from litter under broadleaf and moss; one adult (in alcohol, L-0076), China: Anhui Province, Huangshan Mt. (29°42'52.91"N, 118°20'14.91"E), Xihai, from litter under Indocalamus latifolius , 26 Oct., 1995, leg. Qing-Tian Li.

Etymology. The new specific name “ cristatus ” is from Latin, and refers to the strong dorsal crista of prodorsum.

Measurements: Holotype: Prodorsum: length 350, width 235, height 216, setae: ss 115, ro 55, in 220, le 75, ex 20, distance between setae: ro -ro 30, in -in 110, le -le 150; notogaster: length 715, width 500, height 485; setae: c1 185, c2 170, c3 175, c p 140, d1 136, d2 100, e1 150, e2 125, h1 185, h2 155, h3 95, ps1 190, ps2 160, ps3 120, ps4 35; distance between setae: c1-d1 170, d1-e1 250, e1-h1 150, h1-ps1 130; ventral region: ad1 140, ad2 145, ad3 35, an1 75, an2 75; genitoaggenital plate 180×160, anoadanal plate 185×120. Paratypes: Prodorsum: length 285–435, width 196– 316, height 145–280; notogaster: length 555–940, width 375–670, height 322–628.

Colour grey-yellowish to brown. Surface of body reticulate.

Prodorsum with one very strong crown-like crista, protruding in an oval shape in dorsal view and in an semicircular shape in lateral view; lateral carinae weakly developed, not reaching sinus; dorsal and lateral region invisible; posterior furrows present; sensilli long with narrow pedicel and sickle-like head, covered with small spines; interlamellar setae long, robust, erect, densely covered with small spines; lamellar setae thin, relatively long, semi-erect and smooth; rostral setae thin, smooth and procumbent; exobothridial setae short and fine; comparative length: in>ss> le>ro> ex.

Notogaster with 15 pairs of setae, long (c1> c1-d1), robust, densely covered with small spines, setae ps1 longest, setae ps4 shortest; setae c1-3 slightly remote from anterior border, setae c2 more so than c1 and c3, setae c2 situated close to c3 and nearly situated in one row; vestigial setae f1 and lyrifissures not observed.

Nine pairs of genital setae present, arranged in two rows with formula: 6(4+2): 3; one pair of aggenital setae present; anoadanal plates each with five well-developed setae, setae ad2 longest, setae ad3 shortest, shorter than anal setae.

Setae h of mentum slightly longer than distance between them; chaetotaxy of legs (without tarsi): I: 1-4-2(2)- 5(1); II: 1-3-2(1)-3(1), III: 2-2-1(1)-2(1), IV: 2-1-1-2(1); v’’ / v’ (femora I)=3.25; setae d on femora I situated near distal end of article; setae a’’ on tarsi I and setae ft’’ on tarsi II straight distally; setae a’’ on tarsi II curved distally; setae s and pv’ on tarsi IV and setae s on tarsi I and II present; setae l’ on genua IV reduced; setae d on tibiae IV long, independent of solenidions; all legs monodactylous.

Distribution. China (Hubei, Anhui).

Remark. This new species is easily distinguished from other species of this genus by: prodorsum with one very strong crown-like crista; sensilli long with narrow pedicel and sickle-like head, covered with small spines; rostral setae procumbent; exobothridial setae not vestigial.

Figures

FIGURES 19 – 26. Plonaphacarus cristatus sp. nov.: 19, lateral view of body (legs removed); 20, prodorsum, dorsal view; 21, mentum of infracapitulum; 22, left side of ventral plate; 23 – 26, trochanter, femur, genu and tibia: 23, leg I; 24, leg II; 25, leg III; 26, leg IV. Scale bars: 19 – 22 = 100 μm; 23 – 26 = 50 μm.