Redescription of two species of Oplitis Berlese (Acari, Mesostigmata, Oplitidae) from Iran

Abstract Two new species records of Oplitidae, Oplitis exopodi Hunter & Farrier, 1975 and Oplitis sarcinulus Hunter & Farrier, 1976 are redescribed based on Iranian specimens from leaf-litter forest in Mazandaran province, northern Iran. A key to the Iranian species of Oplitis is presented.


Introduction
The suborder Uropodina is the most morphologically and ecologically diverse group of mesostigmatic mites. They are free-living or associated with arthropods, mammals, or birds. Worldwide, this suborder comprises approximately 300 genus-group names and 2000 described species (Wiśniewski andHirschmann 1993, Halliday 2015). Oplitis is one of the largest genera of uropodine mites, with nearly 150 described species worldwide. The genus was proposed by Berlese (1884) with Uropoda paradoxa Canestrini & Berlese, 1884 as the type species. It has been considered by some authors to be a member of the family Uropodidae (Berlese 1903, 1904, Sellnick 1926, Vitzthum 1942, Hirschmann 1961, Hirschmann and Zirngiebl-Nicol 1964, 1967, Zirngiebl-Nicol 1973a, 1973b, 1973c, Hunter and Farrier 1975, 1976, Hiramatsu 1979, Wiśniewski 1979, Hirschmann 1991, Trachyuropodidae (Karg 1989, Mašán 2001, Kontschán 2013 or Oplitidae (Kontschán 2014, Lopes et al. 2015, Pereira et al. 2016. They are mostly associated with ants but some species were collected from soil and litter. The most recent review of the genus was by Hirschmann (1991), who used a broad concept of the genus and divided Oplitis into 16 species-groups, mostly on the basis of features such as presence or absence of a perigenital ring, pre-anal and post anal lines, and the shape of the peritremes and dorsal setae. To date, two species of Oplitis, O. paradoxa (Canestrini & Berlese, 1884) and O. iranicus Kazemi & Kontschán, 2007 have been reported from soil and litter in Iran (Kazemi and Rajaei 2013).
In the present work, two new records of Oplitis are reported on the basis of material collected in Mazandaran province, northern Iran, during a survey on Uropodina mites. Also, an identification key to the Iranian species of this genus is presented.

Material and methods
Mites were extracted from soil detritus and leaf-litter using Berlese-Tullgren funnels, and picked out under a stereomicroscope. After clearing in Nesbitt's fluid, all specimens were mounted in Faure's medium on permanent microscope slides. Morphological observations, measurements, and illustrations were made using a BX51 phase contrast Olympus microscope equipped with a drawing tube. Measurements were made from slide-mounted specimens, and are presented as ranges (minimum-maximum) in micrometers (µm). Length of shields and legs were measured along their midlines, and widths at their widest point (if not otherwise specified in the description). Legs I-IV were measured from the bases of coxa to their tips but without the pretarsal ambulacra.
Diagnosis. The most detailed diagnosis of Oplitis was provided by Farrier (1975, 1976). Species of this genus have dorsal setae spatulate, cuneiform, scimitar-shaped and setiform, but usually have one (sometimes more) basal asymmetric protuberance. Corniculi relatively short; female genital shield free, oval and without setae, located between coxae II-IV; usually with perigenital ring; palp apotele threetined. Cheliceral digits nearly of similar length; ventral shield with 4-10 pairs of setae; with or without pre-anal line, anal shield bearing two pairs of circumanal setae (Ad1, Ad2) and a post-anal seta; epistome 3-5 partite and with denticulate margins. Deutosternum moderately wide, smooth and deliminated posteriorly, bearing 3-4 transverse lines of fine denticles between hypostomal setae h3 and pc and behind pc.
Our specimens of O. exopodi show some variations with illustration given by Hunter and Farrier (1975), especially shape of anterior section of peritreme (notched in our specimens, but smooth in with Hunter and Farrier's illustration), shape of pedofossae III (foot-shaped in our specimens, but wide and pointed in Hunter and Farrier's illustration) and the number of scimitar-shaped setae on ventral region (4-5 pairs in our specimens, but 6-8 pairs in Hunter and Farrier's illustration).

1.
Distance between anterior margin of genital shield to anterior margin of perigenital ring is longer than posterior distance, peritremes mushroom-like .