Plonaphacarus bicarinatus, 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 : 6

Plonaphacarus bicarinatus sp. nov.

( Figs. 1–9 )

Material examined. Holotype: adult (in alcohol, H9405L2a), China: Hainan Province, Jianfengling National Forest Park (18º41'48.4"N, 108º47'18.0"E), from litter, May, 1994, leg. Chong-Hui Liao. Paratypes: ten adults (in alcohol, H9403L1b), same data as holotype, Mar., 1994; one adult (in alcohol, H9403L1a), same data as holotype, Mar., 1994; two adults (in alcohol, H9312L4a), same data as holotype, Dec., 1993.

Etymology. The new specific name “ bicarinatus ” is from Latin, and refers to the two dorsal carinae on prodorsum.

Measurements: Holotype: Prodorsum: length 242, width 170, height 105, setae: ss 55, ro 40, in 55, le 20, ex 12, distance between setae: ro -ro 15, in -in 60, le -le 100; notogaster: length 486, width 300, height 295; setae: c1 50, c2 40, c3 45, c p 40, d1 50, d2 40, e1 55, e2 50, h1 55, h2 55, h3 35, ps1 45, ps2 45, ps3 35, ps4 29; distance between setae: c1- d1 100, d1-e1 160, e1-h1 130, h1-ps1 95; ventral region: ad1 60, ad2 80, ad3 24, an1 45, an2 45; genitoaggenital plate 125×110, anoadanal plate 145×90. Paratypes: Prodorsum: length 205–255, width 155–190, height 85–115; notogaster: length 380–540, width 255–365, height 200–360.

Colour yellowish to brown. Surface of body covered with concavities.

Prodorsum with two low dorsal carinae; lateral carinae weakly developed, not reaching sinus; dorsal and lateral region distinct; posterior furrows present; sensilli relatively short with narrow pedicel and sickle-like head, covered with short spines; interlamellar setae bacilliform, short, robust, semi-erect, densely barbed in distal half; lamellar setae spiniform, thin, short, rough and semi-erect; rostral setae spiniform, rough and procumbent, thicker and longer than lamellar setae; exobothridial setae short and fine; comparative length: in=ss> ro> le>ex.

Notogaster with 15 pairs of setae, bacilliform, fairly short (c1 <c1-d1), robust, densely covered with small spines in distal half, setae e1, h1 and h2 longest, setae ps4 shortest; setae c1-3 slightly remote from anterior border, setae c2 more so than c1 and c3; vestigial setae f1 not observed; two pairs of lyrifissures ia and im present.

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 rough setae, setae ad1 and ad2 longer and thicker than anal setae, setae ad2 longest, setae ad3 shortest, shorter and thinner 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)=2.67; 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 present; setae s on tarsi I and II absent; setae l’ on genua IV reduced; setae d on tibiae IV long, independent of solenidions; all legs monodactylous.

Distribution. Known only from type locality.

Remark. This new species is similar to P. kugohi ( Aoki, 1959) but differs from the latter species by following characters: In P. bicarinatus , prodorsum with two low dorsal carinae; sensilli relatively short; interlamellar setae bacilliform, short, semi-erect, densely barbed in distal half; rostral setae procumbent; notogastral setae short and bacilliform; setae h of mentum slightly longer than distance between them. In P. kugohi , prodorsum without dorsal carina; sensilli long; interlamellar setae long, erect and setiform; rostral setae semi-erect and smooth; notogastral setae relatively long and setiform; setae h of mentum minute.

This new species is also similar to P. lanceolatus sp. nov. in having two dorsal carinae, but can be easily distinguished by following characters: In P. bicarinatus , sensilli relatively short with narrow pedicel and sickle-like head; lateral carinae weakly developed, not reaching sinus; interlamellar setae bacilliform, short, semi-erect, densely barbed in distal half; rostral setae procumbent; notogastral setae short and bacilliform; setae h of mentum slightly longer than distance between them; genital setae with formula: 6(4+2): 3. In P. lanceolatus sp. nov., sensilli long with narrow pedicel and lanciform head; lateral carinae strong and long, extend beyond sinus and reach end of rostrum; interlamellar setae setiform, long, erect, covered with small spines; rostral setae semi-erect; notogastral setae relatively long and setiform; setae h of mentum vestigial; genital setae with formula: 7(4+3): 2.

Figures

FIGURES 1 – 9. Plonaphacarus bicarinatus sp. nov.: 1, lateral view of body (legs removed); 2, prodorsum, dorsal view; 3, mentum of infracapitulum; 4, sensillus, dorsal view; 5, left side of ventral plate; 6 – 9, trochanter, femur, genu and tibia: 6, leg I; 7, leg II; 8, leg III; 9, leg IV. Scale bars: 1, 2, 5 = 100 μm; 3, 4, 6 – 9 = 50 μm.