Mesotritia bicarinata, Liu, Dong & Chen, Jun, 2010

Liu, Dong & Chen, Jun, 2010, A review of Mesotritia (Acari: Oribatida: Oribotritiidae) in China, with descriptions of two new species and a checklist of known taxa, Zootaxa 2479, pp. 39-58 : 44-46

Mesotritia bicarinata sp. nov.

( Figs. 1–13 )

Material examined: Holotype: Adult (in alcohol, Yao-21), China: Jiangxi Province, Lushan Mt. (29°33'14.57"N, 115°59'0.34"E), Sanbaoshu, from litter, 2 Sep., 1983, leg. Wen-Bing Yao.

Etymology. The specific name “ bicarinata ” is from Latin, and refers to the two median carinae.

Diagnosis: Prodorsum with one pair of lateral carinae and one pair of distinct median carinae; sensilli short, smooth and spindle-shaped, other prodorsal setae long, smooth and attenuate, except exobothridial setae short; rostral setae located between interlamellar and lamellar setae but nearer to interlamellar setae; genito-aggenital plates with six pairs of genital and two pairs of aggenital setae of unequal length, setae g4 and g5 far from each other; one pair of anal and three pairs of adanal setae present; ad2-ad3 <ad2-ad1; lyrifissures iad situated posterior to anal setae.

Measurements: Holotype: Prodorsum: length 410, width 270, height 120, setae: ss 55, ro 205, in 120, le 145, ex 45, distance between setae: ro -ro 50, in -in 205, le -le 175; notogaster: length 860, width 235, height 530; setae: c1 115, c2 110, c3 110, c p 115, d1 115, d2 100, e1 105, h1 120, h2 115, h3 85, ps1 120, ps2 105, ps3 85; distance between setae: c1-d1 205, d1-e1 232, e1-h1 300, h1-ps1 215; ventral region: ad1 155, ad2 85, ad3 25, genito-aggenital plate 202×80, ano-adanal plate 400×70.

Colour brown. Surface of body finely dotted.

Prodorsum with one simple, long and strong lateral carina on each side; two low and distinct median carinae present, not reaching anterior margin of prodorsum; sensilli short, smooth and spindle-shaped; lamellar, interlamellar and rostral setae long, smooth and attenuate; rostral setae much longer than other prodorsal setae, and located between interlamellar and lamellar setae, but nearer to interlamellar setae; mutual distance between interlamellar setae longer than that between lamellar setae; exobothridial setae short and fine; comparative length: ro> le> in>ss> ex.

Notogaster with fine, relatively short (c1 / c1-d1 =0.56), attenuate setae; setae of row c remote from anterior border, setae c3 less than setae c1 and c2.

Genital plates with six pairs of minute setae, setae g4 and g5 far from each other; two pairs of aggenital setae present, setae ag2 longer than ag1; anal plates with one pair of minute anal setae; three pairs of adanal setae present, setae ad2 situated more close to ad3 than to ad1, setae ad1 longest, ad3 shortest; lyrifissures iad situated posterior to anal setae.

Setae h of mentum considerably longer than distance between them; setation of legs (without tarsi): I: 1-3- 4(2)-5(1); II: 1-4-4(1)-4(1), III: 2-3-2(1)-2(1), IV: 2-3-2-2(1); all legs heterotridactylous.

Distribution. Known only from the type locality.

Remarks. This new species is similar to M. maerkeli Sheals, 1965 , but differs from the latter species by following characters: In M. bicarinata , prodorsum with two distinct median carinae; setae g4 and g5 far from each other; lyrifissures iad situated posterior to anal setae. In M. maerkeli , prodorsum without median carina; setae g4 and g5 not distanced from each other; lyrifissures iad situated anterior to anal setae. In addition, these two species differ from each other by slightly different shape of sensilli.

If M. spinosa Aoki, 1980 is proved to be a valid species, these two species are distinguished from each other by following characters: in M. bicarinata , two distinct median carinae present; rostral setae much longer than other prodorsal setae; lyrifissures iad situated posterior to anal setae; surface between bothridia without teeth-like spines. In M. spinosa , only one low median carina present; rostral setae relatively shorter; lyrifissures iad situated anterior to anal setae; surface between bothridia with teeth-like spines.

Figures

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

FIGURES 9 – 13. Mesotritia bicarinata sp. nov.: 9, lateral view of body; 10 – 12, median carinae of prodorsum (indicated by the black arrow); 13, sensillus, dorsal view (indicated by the black arrow).