Contribution to the knowledge of the oribatid mite genus Pilobatella (Acari, Oribatida, Haplozetidae)

The genus Pilobatella (Oribatida, Haplozetidae) comprises 10 species, which are distributed in the Palaeotropical region; this includes two new species described herein on the basis of adult specimens sampled from forest leaf litter in Andasibe-Mantadia National Park of eastern Madagascar. Pilobatella mikoi n. sp. is similar to Pilobatella baloghi Mahunka, 2003 in having long interlamellar setae and adanal setae ad1 and ad2, but differs by having monodactylous legs (versus tridactylous) and a bothridial seta that is gradually expanded to a narrow head (versus setiform, without head). Pilobatella kovaci n. sp. is similar to P. mikoi n. sp. in having monodactylous legs, long interlamellar setae and adanal setae ad1 and ad2, but differs by the presence of lineolate notogaster and anogenital region (versus lineolate markings absent), long tutoria (versus tutoria of medium length), rounded trochanters distodorsally (versus pointed) and clearly distanced medial ends of apodemes 2 (versus nearly touching at midline). A revised generic diagnosis and an identification key to known species of Pilobatella are presented.


Introduction
The oribatid mite genus Pilobatella of the family Haplozetidae (Acari, Oribatida) was proposed by Balogh and Mahunka (1967) with Pilobatella punctulata Balogh and Mahunka, 1967 as type species. According to Subías (online version 2020), the genus currently comprises eight species, which are collectively distributed in the Palaeotropical region. Like Subías, we exclude three other species from the genus: P. lowmanae Ermilov, Winchester and Wassie, 2012;P. maurensis Scull, 1985;P. pseudovermiseta Corpuz-Raros, 1979. Subías offered no justification, but these species possess only one pair of aggenital setae instead of the three pairs indicated in the original generic diagnosis. While Subías (2020) suggested recombinations of these three species, his website is not formally published, and their placement should be considered separately in the future . We do not support the subgeneric division of Pilobatella proposed by Subías (2017), which was based on a single trait that is known to be variable within numerous oribatid mite groups. He recognized the subgenus Pilobatella (Tripilobatella) as including those species with tridactylous legs, contrasted with those having monodactylous legs in the nominate subgenus. In the larger context of the family Haplozetidae, several other genera include species with a different number of claws (e. g., Haplozetes Willmann, 1935;Protoribates Berlese, 1908;Trachyoribates Berlese, 1908).
Our main goal is to describe and illustrate two new species of Pilobatella that were discovered during taxonomic identification of oribatid mites from Andasibe-Mantadia National Park, Madagascar. A second goal is to summarize and update information about the genus. The main diagnostic characteristics of Pilobatella were summarized by Balogh and Mahunka (1967) and Balogh (1984, 1992), and augmented by Ermilov et al. 2012, but many traits were not discussed in these works; we present a more complete treatment below. We also expand on the species identification key of Ermilov et al. (2012) to include all 10 species currently included in Pilobatella.

Methods
Specimens were mounted in lactic acid on temporary cavity slides for measurement and illustration. Body length was measured in lateral view, from the tip of the rostrum to the posterior edge of the notogaster. Notogastral width refers to the maximum width of the notogaster in dorsal view (behind pteromorphs). Lengths of body setae were measured in lateral aspect. All body measurements are presented in micrometers. Formulas for leg setation are given in parentheses according to the sequence trochanter-femur-genu-tibia-tarsus (famulus included). Formulas for leg solenidia are given in square brackets according to the sequence genu-tibia-tarsus.
Drawings were made with a camera lucida using a Leica transmission light microscope"Leica DM 2500".
Morphological terminology used in this paper follows that of F. Grandjean: see Travé and Vachon (1975) for references, Norton (1977) for leg setal nomenclature, and Norton and Behan-Pelletier (2009), for overview.
Juvenile instars -Not known.
Integument -Body light brown to dark brown. Surface of body and all legs microporose (visible under high magnification, ×1000). Antiaxial side of femur II and paraxial side of femora III and IV striate.
Remarks -In having long interlamellar setae and adanal setae ad 1 and ad 2 , Pilobatella mikoi n. sp. is morphologically most similar to Pilobatella baloghi Mahunka, 2003 from Kenya. It differs from the latter by having monodactylous legs (versus tridactylous legs) and a bothridial seta that is gradually expanded to a narrow head (versus setiform, without head).
Integument -Body light brown. Surface of body and all legs microporose (visible under high magnification, ×1000). Notogaster, anogenital region and anal plate lineolate, with short depressed, distinct lines. Epimeral region and genital plate microlineolate. Lateral part of body microgranulate. Antiaxial side of femora I, II and paraxial side of femora III and IV striate.
Type deposition -The holotype is deposited in the collection of the Senckenberg Institute, Görlitz, Germany. Three paratypes are deposited in the collection of the Tyumen State University Museum of Zoology, Tyumen, Russia. Specimens are preserved in ethanol with a drop of glycerol.
Etymology -The species name is dedicated to our friend and colleague, the well-known soil ecologist Prof. Dr. Ľubomír Kováč (Slovakia, Košice), for his extensive contribution  to our knowledge of taxonomy and ecology of soil and troglophilous species of springtails (Collembola) and other groups of cave mesofauna.