Umashtanchaeviella plethotricha, a new genus and species of the family Tetracondylidae (Acari, Oribatida)

Abstract A new genus of oribatid mites of the family Tetracondylidae, Umashtanchaeviella gen. n., with type species Umashtanchaeviella plethotricha sp. n., is proposed and described from forest litter, the Bu Gia Map National Park, southern Vietnam. The new genus is distinguishable from other otocepheoid genera by the presence of notogastral plethotrichy.1

During our studies of the oribatid mite fauna of Bu Gia Map National Park in southern Vietnam, we discovered a species of Tetracondylidae, representing as new genus, Umashtanchaeviella gen. n. and Umashtanchaeviella plethotricha sp. n.
The soil litter was collected by taking 16 samples using a stainless frame (50 × 50 cm) and passed through a sifter with the mesh size 2 × 2 cm. The fine fraction was placed in a Winkler extractor with a collection bottle containing 100 ml with 75% ethanol. The extractions were conducted at room temperature for more than 20 days.
Holotype and paratype 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. Formula for leg setation is given in parentheses according to the sequence trochanter-femur-genutibia-tarsus (famulus included). Formula for leg solenidia is given in square brackets according to the sequence genu-tibia-tarsus. General terminology used in this paper follows that of Aoki (1965) and Norton and Behan-Pelletier (2009).
Type species. Umashtanchaeviella plethotricha sp. n. Etymology. The specific name is dedicated to our colleague, the acarologist Dr. Umukusum Ya. Shtanchaeva (Universidad Complutense de Madrid, Madrid, Spain), for her extensive contributions to our knowledge of oribatid mites.
Remarks. Umashtanchaeviella gen. n. can clearly be distinguished from all the other genera of Otocepheoidea by the following apomorphic character: presence of strong (more 250 pairs) notogastral plethotrichy (versus notogastral plethotrichy absent).
Integument. Body color light brown. Body surface densely microfoveolate (diameter of foveolae less than 1) and microgranulate (granules elongate, length less than 1). Surface of dorsal part of prodorsum, lateral sides of notogaster, anterior part of epimere I, anogenital region and anal plates tuberculate (tub, diameter of tubercles up to 6). Genital plates with thin and numerous stria.
Type deposition. The holotype is deposited in the collection of the Zoological Institute of the Russian Academy of Sciences, St. Petersburg, Russia; one paratype is in the collection of the Tyumen State University Museum of Zoology, Tyumen, Russia.
Etymology. The specific name plethotricha refers to the presence of plethotrichial setae on notogaster.