Three new soil mites of the genus Epidamaeus (Acari, Oribatida, Damaeidae) from Mongolia Badamdorj BAYARTOGTOKH Department of Zoology, Faculty of Biology, National University of Mongolia, Ulaanbaatar 210646 (Mongolia) Bayartogtokh B. 2001. — Three new soil mites of the genus Epidamaeus (Acari, Oribatida, Damaeidae) from Mongolia. Zoosystema 23 (1) : 29-49. ABSTRACT Three new species of oribatid mites belonging to the genus Epidamaeus are described from litter of birch forests and organic debris on soils in central and southern parts of Mongolia. Epidamaeus aokii n. sp. differs from closely relat- ed species in the very thick and densely barbed notogastral setae, the large and widely spaced postbothridial tubercles and spinae adnatae, the relatively short and finely barbed sensilli, the ratio in length of the solenidia σ to associated setae d of genua I-III, the presence of the enantiophysis E2, the number of the setae on the epimeral region and femur III, tarsus III, and the absence of the propodolateral apophysis. Epidamaeus angustirostratus n. sp. can be distin- guished from its congeners by the conspicuously pointed rostrum, the absence of the propodolateral apophysis, the large spinae adnatae, the pres- ence of the anteroventral projection on trochanter IV, the relatively long KEY WORDS femur IV, which is far longer than tibia IV, the relatively short trochanter IV, Arachnida, Acari, which is much shorter than femur IV, and the length of setae d’, l’ and v’ on Oribatida, genu IV. Epidamaeus tenuisetosus n. sp. is distinguishable from most other Damaeidae, known congeners by the absence of tubercles Vp, E2a and E2p from the ven- Epidamaeus, Mongolia, tral plate, the extremely minutely barbed prodorsal and notogastral setae, the new species. smal body size, and the number of setae on tarsi I, II and femur III. ZOOSYSTEMA • 2001 • 23 (1) © Publications Scientifiques du Muséum national d’Histoire naturelle, Paris. www.mnhn.fr/publication/ 29 Bayartogtokh B. RÉSUMÉ Trois nouveaux acariens de sol du genre Epidamaeus (Acari, Oribatida, Damaei- dae) de Mongolie. Trois nouvelles espèces d’acariens oribates appartenant au genre Epidamaeus sont décrites de la litière des forêts de bouleaux et des débris organiques sur des sols dans les régions centrales et méridionales de la Mongolie. Epidamaeus aokii n. sp. diffère des espèces les plus proches par les poils gastronotiques très épais et densément barbelés, les tubercules postbothridiques grands et large- ment espacés, les spinae adnatae, le sensillus relativement court et finement barbelé, la différence de longueur du solénidion σ et du poil associé d des génuaux I-III, la présence des énantiophysis E2, le nombre différent de poils dans la région épimérale, le nombre différent de poils sur le fémur III, les tarses III, l’absence de l’apophyse propodolatérale. Epidamaeus angustirostratus n. sp. peut être distinguée des espèces voisines par le rostre clairement aigu, l’absence de l’apophyse propodolatérale, les spinae adnatae plus grandes, la présence de la projection antéroventrale sur le trochanter IV, le fémur IV rela- tivement long, bien plus long que le tibia IV, le trochanter IV relativement MOTS CLÉS court, beaucoup plus court que le fémur IV, la longueur différente des poils Arachnida, Acari, d’, l’ et v’ sur le génual IV. Epidamaeus tenuisetosus n. sp. est distinguable de la Oribatida, plupart des autres espèces connues d’Epidamaeus par l’absence des tubercules Damaeidae, Vp, E2a et E2p de la région ventrale, par les poils du prodorsum et du noto- Epidamaeus, Mongolie, gaster extrêmement petits et barbelés, par la taille de corps plus petite, le nom- nouvelles espèces. bre différent de poils sur les tarses I, II et le fémur III. INTRODUCTION designated Oribata bituberculata Kulczynski, 1902 as the type species. In her another work (Bulanova- The members of the oribatid mite family Zachvatkina 1957c) she repeated the previous Damaeidae Berlese, 1896 are typical inhabitants diagnosis and described seven new species from the of forest litter and soil that primarily feed on former Soviet Union, and recombined six previ- decomposer fungi. ously known species to this genus. The genus Epidamaeus was proposed by Bulanova- The definition of Epidamaeus by Bulanova- Zachvatkina (1957a) within the family Zachvatkina (1957a, b, c) was not adequate, and Damaeidae, but in a problematical way. In her there has since been no fully acceptable diagnosis three papers, which were published almost at the for this genus. Later, Norton (1978a, 1979c) same time, Bulanova-Zachvatkina (1957a, b, c) defined the genera of Damaeidae including repeatedly proposed Epidamaeus as a new genus. Epidamaeus on the basis of ontogenetic and phylo- The first time she (Bulanova-Zachvatkina 1957a) genetic studies, and he proposed a new subgenus provided only a brief diagnosis of the genus, but Akrodamaeus Norton, 1978 with Oribata longiseta did not designated a type species and therefore, it Banks, 1906 as the type species. The latter sub- might be considered a nomen nudum. In the same genus is distinguished from its nominate subgenus paper she mentioned the names of two new species, Epidamaeus in the absence of spinae adnatae. E. pavlovskii and E. microspinus, which should Epidamaeus is one of the largest genera of belong to her newly proposed genus, but no Damaeidae, and more than 70 species have been descriptions of the above species were presented in included. On the basis of the present knowledge that work. In her subsequent paper, Bulanova- only a few species, such as E. grandjeani (Bulanova- Zachvatkina (1957b) redefined Epidamaeus and Zachvatkina, 1957), E. arcticolus (Hammer, 30 ZOOSYSTEMA • 2001 • 23 (1) New species of Epidamaeus (Acari, Oribatida, Damaeidae) from Mongolia 1952), E. fortispinosus (Hammer, 1967), E. tatri- region (Balogh & Mahunka 1969; Norton cus (Kulczynski, 1902), have wide distribution in 1979b; Palacios-Vargas 1984). the Holarctic region, and most other species seem Although the family Damaeidae shows greatest to be distributed in restricted areas or are known taxonomic diversity in the whole European conti- only from the type localities. nent and some parts of Asia, the Mongolian Adults of Epidamaeus are unique among Damaei- damaeid fauna remains completely unknown. dae in having the following combination of char- However, according to my collections from dif- acter states: tibiae I-IV without setae d; setal ferent regions of Mongolia, the country appears to formula of genua I-IV: 4-4-3-3; associated setal be as species-rich as others in the Palaearctic region. (setae d) formula of genua I-IV: 1-1-1-0; setal This work is a part of the continuing study on formula of trochanters I-IV: 1-1-2-1; spinae the oribatid mite fauna of Mongolia, and it adnatae present (subgen. Epidamaeus) or absent includes the descriptions of three new species of (subgen. Akrodamaeus); propodolateral apophy- Epidamaeus. All three belong to the nominate ses P rarely present. subgenus Epidamaeus, since they have well-devel- In a recent classification of the oribatid mite ge- oped spinae adnatae. The results of study on the nera, Balogh & Balogh (1992) considered that remaining species of this genus and other repre- apophyses P are absent in Epidamaeus, but several sentatives of Damaeidae of Mongolia will be species of both the subgenera of this genus (e.g., published in several future works. E. longiseta [Banks, 1906], E. mackenziensis [Hammer, 1952], E. bakeri [Hammer, 1952], E. tecticola [Michael, 1888], E. nasutus Behan- MATERIAL AND METHODS Pelletier & Norton, 1985, E. verrucatus Enami & Fujikawa, 1989, E. fragilis Enami & Fujikawa, All three species were collected between 1991 and 1989, E. johnstoni Tolstikov, 1997) have strongly 1996, from central (from litter of birch forest) and or conspicuously developed apophyses P, which southern (organic debris on soils of dry semidesert direct anteriad or anterolaterad. habitat) parts of Mongolia. All type specimens are Epidamaeus is known to be widespread through- preserved in alcohol. The type locality and habitat out the Northern Hemisphere, but the taxonomy characterization for each species are given in the of this genus is somewhat difficult. Representa- “material examined” section after the description. tives are known from Palaearctic and Nearctic Immatures are unknown for any of these species. regions and widespread in both (Michael 1885, Specific terminology used in this paper is based 1888; Kulczynski 1902; Banks 1906; Sellnick on that (with a few modifications) developed by 1925; Hammer 1952, 1953, 1955, 1967; Will- Grandjean (1960), Norton (1977b, 1978b, mann 1953; Bulanova-Zachvatkina 1957b, c, 1979b) and Behan-Pelletier & Norton (1983, 1964, 1967, 1973, 1975, 1979; Kunst 1961; 1985). The nomenclature of leg setation was Aoki 1966; Bernini 1970; Norton 1978a, 1979a; summarized by Norton (1977a). Behan-Pelletier & Norton 1983, 1985; Fujikawa All measurements are given in micrometres (µm), & Fujita 1985; Marshall, Reeves & Norton and the average measurement values are given in 1987; Enami & Fujikawa 1989; Luxton 1989; parentheses after the range. Both sexes are includ- Saloña & Iturrondobeitia 1989; Moraza, Moreno ed in the measurements. Body length is measured & Saloña 1990; Pérez-Iñigo Jr 1990; Lyashchew in lateral view from the tip of rostrum to the pos- & Tolstikov 1993; Wang & Norton 1993; terior edge of ventral plate, to avoid discrepancies Enami, Aoki & Hu 1994; Pérez-Iñigo 1994; Tol- caused by different degrees of notogastral disten- stikov