Oribotritia aokii Mahunka, 1987

Niedbała, Wojciech & Ermilov, Sergey G., 2017, New species and records of ptyctimous mites (Acari, Oribatida) from the Philippines, Zootaxa 4231 (1), pp. 119-128 : 122

Oribotritia aokii Mahunka, 1987

( Fig. 3 , A–E)

Description. Measurements of specimen 1. Prodorsum: length 382, width 268, height 162; setae: ss 182, in 114; notogaster: length 727, width 545, height 565; setae: c 1 114, c 1/ c 1– d 1=0.6. Measurements of specimen 2. Prodorsum: length 394, width 273, height 151, ss 157, in 86; notogaster: length 707, width 424, height 404; setae: c 1 94, c 1/ c 1– d 1=0.6.

Material examined. Two specimens: Philippines, Polillo Island , Quezon Province, Polillo Municipality , 5382— Sibulan watershed , 27.IX.2003 (I.L. Lit, Jr. and O.L. Eusebio), from sample of decaying log.

Remarks. Principal characters that distinguish this species from others are: lateral carinae of prodorsum consisting of three lines, shape and number of notogastral setae, presence of five pairs of genital setae posteriorly of progenital position and the number of anal and adanal setae.

This species appears to be highly morphologically variable. This variation is noted in the holotype, between two specimens from sample 5382 from the Philippines and specimens found in Sumatra ( Niedbała 2000).

In the holotype from Sabah ( Mahunka 1987, Fig. 4 ) on the right side setae ad 2 are located between ad 1 and ad 3 but on left side they are closer to setae ad 3. Between the specimens from sample 5382 ( Philippines) the following divergences should be noted: different shape of weak median crista of prodorsum, different shape of rostral setae and different position of setae c 1 of notogaster ( Figs 3A, C ).

Other morphological differences are: the specimens from Sumatra ( Niedbała 2000) and from Philippines (sample 5382) are slightly smaller than the holotype from Sabah, Malaysia ( Mahunka 1987). Both specimens from sample 5382 have a weak median crista which is absent in the holotype and the specimens recorded from Sumatra ( Niedbała 2000, fig.24). Setae c 1 in specimen 1 is more remote from anterior border than in the holotype and the specimens from Sumatra. Specimens from the Philippines and from Sumatra have 3 pairs of aggenital setae (2 pairs in holotype), adanal setae ad 2 are situated near ad 3 and distanced 3–4 times from ad 1 (versus 1.1–1.6 times in holotype), lyrifissures iad are situated between ad 2 and ad 3 setae (not marked in holotype), and the distal spines of femora I differ in specimen 1 and 2 and in the specimens from Sumatra ( Niedbała 2000).

All of these observed differences show that there is no morphological conformity between the populations from Sabah, Sumatra and Philippines, but all populations contain the principal characters listed at the beginning of these remarks and are therefore only seen as geographic variants of a single species.

Figures

FIGURE 3 A – E. Oribotritia aokii Mahunka, 1987, specimens from Philippines: A, B, specimen 1. A—prodorsum with anterior part of opisthosoma, lateral view; B—anterior part of femur I. C – E, specimen 2. C—prodorsum with anterior part of opisthosoma, lateral view; D—right anal and adanal plates with lower part of genital and aggenital plates; E – anterior part of femur I. Scale bars 100 µm (A, C), 50 µm (D), 25 µm (B, E).

FIGURE 4 A – G. Hoplophthiracarus illinoisensis (Ewing, 1909), specimen 1: A—prodorsum, dorsal view; B—prodorsum, lateral view; C—lateral view of body (gnathosoma and legs removed); D—mentum of subcapitulum; E—left genito-aggenital and ano-adanal plates; F—trochanter and femur I; G—tibia IV. Scale bars 100 µm (A – C, E), 25 µm (D, F, G).