Peruvian oribatid mites (Acari, Oribatida) from the German Biological Expedition, with description of a new species of the genus Pergalumna

Abstract The present study is based on oribatid mite material (Acari, Oribatida) collected during the German Expedition in 2011 in Peru. An annotated checklist of identified oribatid mites, including 16 species from 14 genera and 8 families, is provided. Thirteen species and two genera (Notohermannia, Zetomimus) are recorded for the first time in Peru; the genus Notohermannia and species Notohermannia obtusa are recorded for the first time in the Neotropical region. A new species of the genus Pergalumna (Galumnidae), Pergalumna paraboliviana sp. n., is described. The new species is most similar to Pergalumna boliviana Ermilov, 2013 from Bolivia, however, it differs from the latter by the body size, morphology of porose areas A1 and the presence of interlamellar setae.

Our investigation is based on Peruvian material collected during a one-month German Expedition organized by Bavarian State Collection of Zoology in September (second half) and October (first half) 2011. The primary goal of the paper is to present the checklist of the identified species with new records for Peru as well as for the Neotropical region.
In the course of taxonomic identification, we found one new species of the genus Pergalumna (Galumnidae). The secondary goal of this paper is to describe and illustrate this species. Pergalumna is a large genus that was proposed by Grandjean (1936) with Oribata nervosa Berlese, 1914 as type species. Currently, it comprises more than 130 species having a cosmopolitan distribution collectively (Subías 2004(Subías , updated 2014. The generic characters of the genus are summarized by Ermilov et al. (2013a), and an identification key to known species from the Neotropical region was presented by Ermilov et al. (2014a).

Materials and methods
Samples were collected from six localities in Peru, Panguana, basin of the Río Yuyapichis (9°36'49.32"S, 74°56'8.16"W) by D.J. Gwiazdowicz: -Locality 6, rotting wood, 26.09.2011;-Locality 12, forest litter, 29.09.2011;-Locality 16, forest litter, 29.09.2011;-Locality 28, rotting wood, 3.10.2011;-Locality 29, forest litter, 5.10.2011;-Locality 44, forest litter, 8.10.2011. 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. 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. Microscope figures were made with a drawing tube using a Carl Zeiss transmission light microscope "Axioskop-2 Plus". General terminology used in this paper follows that of Grandjean (summarized by Norton and Behan-Pelletier 2009).

Checklist 1
This annotated checklist includes the specific localities where oribatid mites were co llected, and notes new records and overall known distribution 2 .
Integument. Body color light brown to brown. Body surface punctate. Ventral part of pteromorphs with slightly developed reticulate pattern in one paratype. Prodorsum with one transverse and two longitudinal striate bands (s): transverse band located anterior to insertions of interlamellar setae; longitudinal bands parallel, each located from the transverse band medially to insertions of lamellar setae. Posterior part of notogaster with two parallel, longitudinal striate bands located medially to notogastral alveoli h 1 . Between these longitudinal bands, two arcuate bands present, which fused medially by the transverse band. Ventral body side with one pair of diagonal striate bands nearly of pedotecta I (Pd I), one transverse striate band located anteriorly to genital plates, two lateral, transversal striate bands located between genital and anal plates, and one arcuate striate band located posteriorly to anal plates, extending marginally into the anoadanal region. All striate bands well visible only in light colored or dissected specimens.
Type deposition. The holotype is deposited in the collection of the Senckenberg Institution Frankfurt, Germany; three paratypes are deposited in the collection of the Tyumen State University Museum of Zoology, Tyumen, Russia; one pratype is deposited in the collection of the Natural History Museum, Lima, Peru.