Indotritia (Indotritia) tumenensis, Liu, 2015

Liu, D., 2015, Review of Indotritia (Acari, Oribatida, Oribotritiidae) with a world checklist, a key to all known species, and a description of a new species from China, Acarologia 55 (4), pp. 397-416 : 398-400

Indotritia (Indotritia) tumenensis n. sp.

( Figure 1 )

Diagnosis — Prodorsum with one pair of long lateral carinae; sensilli club-like, with slightly obtuse apex; interlamellar, rostral and notogastral setae robust, erect and sparsely covered with small spines; lamellar setae procumbent and thinner; exobothridial setae vestigial; vestigial setae f 1 situated anterior to setae h 1; ano-genital cleft short; formula of genital setae 5:4; ag 2> ag 1; two pairs of anal and two pairs of adanal setae; lyrifissures iad situated laterally between setae ad 2 and an 2; femur I with strong triangular spine in anterodorsal end.

Description — Measurement of holotype: prodorsum: length 275, width 208, height 95, setae: ss 55, ro 52, in 75, le 46; notogaster: length 545, width 350, height 440; c 1 87, d 1 90, e 1 85, h 1 90, ps 1 88 genito-aggenital plate 152 × 90, ano-adanal plate 260 × 65. Range of variations for measurements of paratypes: prodorsum: length 270 – 295, width 205 – 215, height 92 – 100; notogaster: length 555 – 575, width 360 – 365, height 450 – 465.

Integument — Colour brown. Integument finely dotted, anterior part of prodorsum with longitudinal striations.

Prodorsum — One pair of long and strong lateral carinae present; sensilli (ss) rough and club-like, with slightly obtuse apex; interlamellar setae (in) strongly erect, robust, sparsely covered with small spines; rostral setae (ro) semi-erect, sparsely covered with small spines, slightly thinner than interlamellar setae; lamellar setae (le) smooth, procumbent, much thinner than rostral and interlamellar setae; exobothridial setae (ex) vestigial; comparative lengths: in> ss> ro> le, in -in / ro -ro ≈ 2.1.

Notogaster — Notogastral setae relatively short (c 1 / c 1 - d 1 ≈ 0.6), curved, robust, sparsely covered with small spines; setae c 1 and c 2 remote from anterior border, setae c 3 near the border; vestigial setae f 1 situated anterior to setae h 1.

Ventral region — Suture between genital and aggenital plates reaching the level of setae g 7; nine pairs of genital setae (g) present, among which four pairs in progenital position; two pairs of aggenital setae (ag), setae ag 2 longer than ag 1; ano-genital cleft short; two pairs of short anal setae (an) and two pairs of adanal setae (ad) present; lyrifissures iad situated laterally between setae ad 2 and an 2.

Legs — Setal counts for leg segments: I: 1-4-5(2)- 5(1)-22(3); II: 1-4-4(1)-3(1)-19(2), III: 3-2-3(1)-3(1)-14, IV: 3-2-2(1)-3(1)-11; femur I with strong triangular spine in anterodorsal end.

Material examined — Holotype: 1 adult ( NIGA, in alcohol), China: Jilin Province, Yabian, Tumen , from litter near border of China and North Korea, 4 Apr. 2015, leg. Dong Liu and Yuting Huang. Paratypes: 3 adults ( NIGA, in alcohol), same data as holotype .

Etymology — The new specific name " tumenensis " refers to the type locality Tumen in Jilin Province, China.

Remarks — This new species is distinguished from all congeneric species with two pairs of anal and two pairs of adanal setae and by the shape of sensilli (swollen and club-like versus thin and setiform in other species).

In this genus, only three species, I. (I.) lanceolata , I. (I.) nunomurai and I. (I.) clavata , have swollen sensilli. Compared with I. (I.) lanceolata and I. (I.) nunomurai , this new species differs by following combination of features:

1) sensilli with slightly obtuse apex (versus with sharp pointed apex in I. (I.) lanceolata , with thin and long apex in I. (I.) nunomurai );

2) one pair of prodorsal lateral carinae present (versus two pairs in I. (I.) lanceolata and I. (I.) nunomurai ); 3) two pairs of anal setae (versus one pair);

4) two pairs of adanal setae (versus three pairs).

The new species is distinguished from I. (I.) clavata by

1) sensilli longer (in> ss> ro> le) and clublike (versus short (ro> le = in> ss) and fusiform in I. (I.) clavata );

2) exobothridial setae vestigial (versus not vestigial);

3) two pairs of anal and two pairs of adanal setae present (versus one pair of anal and three pairs of adanal setae);

4) formula of genital setae 5:4 (versus 4:5).

Figures

FIGURE 1: Indotritia (Indotritia) tumenensis n. sp.: A – lateral view of body (legs removed); B – prodorsum, dorsal view; C – ventral plate; D – mentum of infracapitulum; E – trochanter, femur, genu and tibia of leg I. Scale bars: A – C, E = 100 µm; D = 50 µm.