The oribatid mite genus Benoibates (Acari, Oribatida, Oripodidae)

Abstract Two species of oribatid mites of the genus Benoibates (Oribatida, Oripodidae), i.e., Benoibates bolivianus Balogh & Mahunka, 1969(a) and Benoibates minimus Mahunka, 1985, are recorded for the first time in Costa Rica. Both are redescribed in details, using drawings, images and SEM micrographs, on the basis of Costa Rican specimens. An identification key to the known species of Benoibates is given.


Introduction
Benoibates (Acari, Oribatida, Oripodidae) is a genus of oribatid mites that was proposed by Balogh (1958) with Benoibates flagellifer Balogh, 1958 as type species. Currently, it includes 12 species, distributed in the Neotropical region (seven species), U.S.A. (two species), Ethiopian region (two species) and Polynesia (one species) (data summarized by Subías 2004Subías , updated 2014. Subías (2004Subías ( , updated 2014 includes additionally three genera as junior synonyms in Benoibates: Exoripoda Woolley 1961(with two species: E. excavatus Woolley, 1961E. suramericanus Mahunka, 1983), Haploripoda Balogh & Mahunka, 1967 (with one species: H. reductus Balogh & Mahunka, 1967) and Reductoripoda Mahunka & Palacios-Vargas, 1996 (with one species: R. absoluta Mahunka & Palacios-Vargas, 1996). Exoripoda was discribed by Woolley (1961) on bases of the presence of one pair of adanal setae (versus two pairs in Benoibates); Haploripoda - Balogh and Mahunka (1967) on bases of the presence of one pair of genital setae (versus two pairs in Benoibates); Reductoripoda -Mahunka and Palacios-Vargas (1996) on bases of the presence of one pair of adanal setae and the absence of anal setae (versus two and one pairs present in Benoibates, accordingly). Subías probably is right, but we cannot support his opinion at this moment, because many oripodid genera were proposed on the basis of distinctions in the number of anogenital setae -see also different views on classification of genera (for example, Woolley 1961Woolley , 1966Aoki and Ohkubo 1974;Balogh 1992, 1999;Subías 2004). Hence, the full and detail revision of all taxa in the family Oripodidae is necessary in the future.
The main generic characters of Benoibates in Oripodidae are (summarized by Balogh 1958, Aoki andOhkubo 1974;Balogh and Balogh 1990, including our additions): rostrum rounded; bothridial openings not covered by notogaster; body surface foveolate; anterior notogastral margin convex medially, transverse straight; 10 (exception 11) pairs on notogastral setae present; two pairs of genital, one pair of aggenital, two pairs of adanal and one pair of anal setae present, genital setae inserted in anterior part of genital plates, anal setae inserted in posterior part of anal plates; legs tridactylous.
In the course of proceeding taxonomic identification of oribatid mites from Costa Rica (Ermilov et al. 2014a, b), we have found two species of Benoibates, B. bolivianus Balogh & Mahunka, 1969(a) (described from Bolivia) and B. minimus Mahunka, 1985 (described from Antilles). Both species are recorded for the first time in Costa Rican fauna.
The original descriptions of B. bolivianus and B. minimus were based only on holotypes, and, hence, it is incomplete and brief (lacking information about the measures of morphological structures, leg setation and solenidia, morphology of gnathosoma; only dorsal and ventral sides of body are illustrated). We also notice that Benoibatesspecies are very similar morphologically, and species descriptions of this genus were brief. Therefore their supplementary descriptions are especially important now. The main goal of our paper is to present detailed redescriptions and illustrations of B. bolivianus and B. minimus, using drawings, images and SEM (Scanning Electron Microscopy) micrographs, of Costa Rican specimens.
The second goal of our paper is to present an identification key to the based on Benoibates known species.

Methods
The specimens were mounted in lactic acid on temporary cavity slides for measurement and illustration. The body length was measured in lateral view, from the tip of the rostrum to the posterior edge of the ventral plate. The notogastral width refers to the maximum width in dorsal aspect. Lengths of body setae were measured in lateral aspect. All body measurements are presented in micrometers. 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 of Grandjean (summarized by Norton and Behan-Pelletier 2009).
Drawings were obtained by a drawing tube using the Carl Zeiss transmission light microscope "Axioskop-2 Plus". Images were obtained by an AxioCam ICc3 camera using the Carl Zeiss transmission light microscope "Axio Lab.A1". SEM micrographs were obtained by the Jeol scanning electron microscope "JSM-6510 LV".
Integument. Body color yellowish brown to brown. Body surface weakly foveolate: prodorsum with distinct, round foveoles, larger in antero-medial part (up to 4) than in basal part (up to 1); notogaster, epimeral region, subcapitular mentum and gena, and genital plates with weak, round foveoles (up to 2); anogenital region and legs with distinct (except weak between genital and anal apertures), round or oval foveoles (up to 4), simultaneously also with longitudinal foveoles (length up to 16). Body surface of notogaster and ventral side covered by microgranular cerotegument (less than 1; visible only high magnification, ×1000).

(tc), (p), (u), (a), s, pv''
Roman letters refer to normal setae (ε to famulus), Greek letters to solenidia. Single prime (') marks setae on anterior and double prime (") setae on posterior side of the given leg segment. Parentheses refer to a pair of setae. Integument. Body color yellowish brown. Body surface heavily foveolate: prodorsum with distinct, round foveoles, larger in antero-medial part (up to 4) than in basal part (up to 1); epimeral region, subcapitular mentum and gena, and genital plates with round foveoles (up to 4); notogaster and anogenital region and legs with distinct (except weak between genital and anal apertures), round or oval foveoles (up to 4), simultaneously also with longitudinal foveoles (length up to 12). Body surface of ventral side covered by microgranular cerotegument (less than 1; visible only high magnification, ×1000).
Remarks. Costa Rican specimens of Benoibates minimus are similar in all morphological characters to Antilles specimens from the original description (Mahunka 1985).
Distribution. Neotropical region.  Benoibates crinitus (Berlese, 1910) was very poorly described by Berlese (1910), therefore we did not include this species in the key.