A new species of the genus Epidamaeus (Acari, Oribatida, Damaeidae) from China

Abstract The oribatid mite genus Epidamaeus Bulanova-Zachvatkina, 1957 from China is reviewed, and a list and key to all known species from China are provided. A new species, Epidamaeus conjungenus sp. n. is identified, and its morphological descriptions and illustrations are also given. The distinct characteristics of Epidamaeus conjungenus sp. n. is the coterminous ridge connected to the base of the notogastral setae. Pseudanal setae undulating attenuate, the proximal half with obvious, thorn-like barbs, the distal half smooth.


Introduction
Oribatid mites of the genus Epidamaeus Bulanova-Zachvatkina, 1957 are known to be very diverse throughout the Northern Hemisphere, especially in Europe and North America (Bayartogtokh 2004). Most species of this genus inhabit the litter of forests, mosses, decaying woods and organic soil layers, and primarily feed on decomposer or plant pathogenic fungi, therefore, they play an important role in regulation of the density of plant harmful fungi (Bayartogtokh 2000). Epidamaeus shows high taxonomic diversity in Europe and some parts of Asia. The genus comprises more than 70 species, that cosmopolitan distributed (Subías 2011). Up to now, only 6 valid species: E. grandjeani, E. cincinnatus, E. elegantis, E. longispinosus, E. yunnanensis, E. alticola from China were described (Wen 1990a, Wang and Norton 1993b, Enami et al. 1994, Wang and Cui 1996a, Chen et al. 2010), but the collection material from different vegetation zones of the country revealed species-richness as that in the other parts of the Palaearctic and Oriental Region. This may be related to the dynamic history of the area, which had a different climate and biota found throughout China.
In the present paper, a new species Epidamaeus conjungenus sp. n. were described from Henan Provinces. In addition, a list and key to all known Chinese species were present.

Material and methods
Measurements and descriptions are based on specimens mounted in temporary cavity slides that were studied using a light microscope equipped with a drawing attachment. Body length is measured in lateral view, from the tip of the rostrum to the posterior edge of the ventral plate. Length of leg segments, including the portion inserted into the next segment, is measured in the lateral aspect. The number of specimens measured does not always equal the number of specimens examined because structures are sometimes indiscernible under the circumstances where the specimens are not slide-mounted.
Terminology generally developed by Grandjean (1960) as applied by Norton (1979). All type specimens and other material studied are kept in Oudemans' fluid and deposited in the Institute of Entomology, Guizhou University, Guiyang, China (GUGC).
Integument. Microtuberculate on all enantiophyses and apophyses, rostrum, lateral prodorsum and around leg acetabula. Cerotegument granules, thick, dense on most of body and legs, except digital part of tarsi. Notogaster with exuvial scalps, legs segments and lateral part of body with dense fungus micelles and adherent debris.
Ventral region. Epimere I with medial pit and associated groove. Enantiophyses E 2 and V well developed, broadly triangular in ventral view. Tubercle Vp bearing epimeral seta 3b. Parastigmatic tubercle Sa long, acuminate and triangular. Sp triangular, distinct in ventral view. Length of lateral aspect Sp twice as broad as Sa. Discidium acuminate, smaller than Sp, directed posterolaterad. Ventral setae faintly barbed. Setae 3c, 4d very long, flagelliform. Epimeral setation: 3-1-3-4. Anogenital region normal, seta ad 3 close to anal valves. Fissure iad minute, represented by small, inconspicuous pore in lateral corner of valve. Anal aperture appreciably equal to genital aperture.