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2 January 2014 Ethiopian Oribatid Mites (Acari: Oribatida) from the Joint Russian-Ethiopian Biological Expedition (2012), With Description of a New Species
Sergey G. Ermilov, Leonid B. Rybalov
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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 p1 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 genus Perscheloribates (Scheloribatidae) was proposed by Hammer (1973) with Perscheloribates clavatus Hammer, 1973 as type species. The genus comprises 44 species that collectively have pan- and subtropical distributions (Subías 2004; online version 2013). Up to now, eight species have been recorded from the Ethiopian region (Ermilov et al. 2011): P. crassisetosus Ermilov, Rybalov & Franke, 2011, P. ethiopicus (Mahunka, 1986), P. luminosus (Hammer, 1961), P. minimus (Mahunka, 1992), P. minutus (Pletzen, 1965), P. rustenburgensis (Pletzen, 1963), P. shiraensis (Evans, 1953) and P. tzitzikamaensis (Pletzen, 1963). The identification key to aforementioned species and generic diagnostic characters were presented by Ermilov et al. (2011). The new species is described as Perscheloribates paratranslamellatus sp. n.

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 gnathosoma). P. breviseta is redescribed based on newly sampled Tanzanian specimens.

MATERIAL AND METHODS

Mosses on trees were collected by hand (total volume = 0.03 m3). 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 funnels 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 lengths of body setae were measured in lateral view. Formulae for leg setation are given 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 (1967–1968), 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).

  • List of collecting sites:

  • Et-12–10: 09°04′N 38°08′E, 10 km north of Ginchi city, Chilimo forest (Hagenia abyssinica and Juniperus sp. forming the canopy), 2900 m, mosses on trees, 25.x.2012 (collected by L.B. Rybalov and A.I. Bastrakov).

  • Et-12–11: 08°58′N 37°51′E, Ambo Plant Protection Research Center, xerophytic forest on vertisols, 2077 m, litter (sifter), 20.xi.2012 (collected by L.B. Rybalov and A.I. Bastrakov).

TAXONOMY

Samples from the collecting sites yielded 22 species, 19 genera and 15 families. Pedrocortesella africana Pletzen, 1963, Liacarus shipitsyni Ermilov, Rybalov & Kemal, 2011, Zetorchella pedestris Berlese, 1916 and Scheloribates discifer Balogh, 1959 were the only species recorded from mosses on trees; all other species were recorded only from forest litter (Table 1).

Family Scheloribatidae Grandjean, 1933
Genus Perscheloribates Hammer, 1973
Perscheloribates paratranslamellatus sp. n. Figs 12

  • Etymology: From the Latin prefix para (near) referring to the the similarity between the new species and the species Perscheloribates translamellatus (Pérez-Iñigo & Baggio, 1991).

  • Diagnosis: body size 481-531 × 298-348; rostrum rounded; rudimentary translamellar line; prolamellar lines absent; prodorsal setae setiform, barbed; sensilli spindle-form, ciliate; exobothridial setae short; one pair of notogastral setae p 1 present; sacculi Sa, S1 with elongate openings, S2, S3 with rounded openings; ventral setae setiform, slightly barbed, and with little difference in length; leg claws serrate on dorsal side.

  • Description:

  • Measurements. Body (length × width): 481 × 298 (holotype ♂); 481-531 × 298-348 (paratypes: l♂ 4♀).

  • Integument. Body brown and light brown. Dorsal and ventral surfaces of body smooth, lateral surfaces weakly microgranulate.

  • Prodorsum (Figs 1A, 1B, 1D; 2A, 2B). Rostrum slightly protruding, rounded. Lamellae located dorsolaterally, as long as half of prodorsum (in lateral view), without cusps. Translamellar line (tr) rudimental, at tips of lamellae. Prolamellar lines absent. Sublamellar lines distinct, long. Sublamellar porose areas (Al) very small, rounded (2–4). Keel-shaped chitinised ridges (kf) distinct. Rostral (ro, 61–69), lamellar (le, 90–102) and interlamellar (in, 114–127) setae setiform, barbed. Sensilli (ss, 110–118) spindle-form (with long stalk, elongated lanceolate head and well developed thin apex), with numerous cilia. Exobothridial setae (ex, 4–6) short, thin, smooth.

  • Notogaster (Figs 1A, 1C). Anterior notogastral margin convex medially. Dorsophragmata (D) of medium size, widely rounded. Nine pairs of notogastral setae represented by alveoli; only one pair of thin, smooth setae developed (p 1 8–10). Four pairs of sacculi present: Sa,