Ethiopian Oribatid Mites (Acari: Oribatida) from the Joint Russian-Ethiopian Biological Expedition (2012), With Description of a New Species

ABSTRACT The present study is based on oribatid mite material collected during October and November 2012 in the course of a Russian-Ethiopian expedition to southern Ethiopia. An annotated checklist of identified taxa is provided, with 22 species, 19 genera and 15 families recorded. A new species, Perscheloribates paratranslamellatus sp. n., from xerophytic forest litter is described. It is most similar morphologically to Perscheloribates translamellatus (Pérez-Iñigo & Baggio, 1991), but differs from the latter by larger body size, presence of a rudimentary translamellar line, absence of prolamellar lines, longer setae p 1 and elongate openings of sacculi Sa, S1. A supplementary description of Paroppia breviseta (Balogh, 1962) based on Ethiopian specimens is presented.


INTRODUCTION
Currently, oribatid mite (Acari: Oribatida) fauna of Ethiopia includes little more than 150 species (Ermilov et al. 2012a, b;Ermilov & Rybalov 2013a, b). This work forms part of our ongoing study of the Ethiopian oribatids. The present investigation is based on new material collected in the course of a two-month Russian-Ethiopian expedition during October and November 2012. An annotated checklist of identified oribatid mite taxa is provided (Table 1).
The collected material further included Paroppia breviseta (Balogh, 1962) (Oppiidae), a species described from Tanzania (Balogh 1962). The original description of this species is, however, incomplete and brief (lacking information about the measurements of morphological structures, leg setation, and solenidia together with the morphology of the gnatho soma). P. breviseta is redescribed based on newly sampled Tanzanian specimens.

MATERIAL AND METHODS
Mosses on trees were collected by hand (total volume = 0.03 m 3 ). Litter was collected by taking 10 samples using a stainless steel frame (50 × 50 cm) and passed through a sifter (mesh size 2 × 2 cm). Oribatid mites were extracted into 75 % ethanol using Berlese fun nels with ambient light for the first three days and 160 W electric lamps (at a distance of 25-30 cm) from the fourth until the seventh day.
Specimens were mounted in lactic acid on temporary cavity slides for measurement and illustration. All body measurements are presented in micrometres. The body length was measured in lateral view, from the tip of the rostrum to the posterior edge of the ventral plate. Notogastral width refers to the maximum width in dorsal view. The leng ths of body setae were measured in lateral view. Formulae for leg setation are giv en in parentheses according to the sequence: trochanter-femur-genu-tibia-tarsus (famulus included). Formulae for leg solenidia are given in square brackets according to the sequence: genu-tibia-tarsus. General terminology used in this paper follows that summarised by Coetzer (1967Coetzer ( -1968, and Norton and Behan-Pelletier (2009).
The holotype material is deposited at the Zoological Institute of the Russian Academy of Sciences, St Petersburg, Russia (ZISP). The paratype material is deposited at the Siberian Zoological Museum, Novosibirsk, Russia (SZMN) and in the personal collection of the first author (PC).

Measurements
Material examined: 2 ♂ 5♀ ETHIOPIA: Et-12-10. Preserved in ethanol (PC). Distribution: At present, this species is only known from Tanzania and Ethiopia. Remarks: The present Ethiopian specimens of P. brevipes are morphologically and in general appearance comparable to the Tanzanian specimens (Balogh 1962), although with slight differences: lamellar and interlamellar setae similar in length (interlamellar setae shorter in Tanzanian specimens), anterior part of sensillar heads with several poor ly visible barbs (sensillar heads smooth in Tanzanian specimens), interlamellar muscle sigillae removed from each other (sigillae dense in Tanzanian specimens). We regard these differences as intraspecific (perhaps geographical) variability within the species.