Contributions to the knowledge of the mite genus Stigmaeus Koch , 1836 ( Acari : Stigmaeidae ) of Turkey

Based on the mite specimens collected within the scope of a study on Erzincan (Turkey) mite biodiversity, two species of the genus Stigmaeus are described and illustrated here: S. bifurcus sp. nov. as new to science and S. miandoabiensis Bagheri & Zarei, 2012 as a new record for Turkey. Some morphological abnormalities in the new species are noted. The deutonymph of S. miandoabiensis is described for the fi rst time in this study. Discovery of this stage from soil and litter under Pinus sylvestris in Turkey adds more data to our knowledge of the species.

The descriptions of Stigmaeus bifurcus sp.nov.and S. miandoabiensis Bagheri & Zarei, 2012-originally found in Iran, newly recorded for the Turkish fauna-are given in this survey.The deutonymph of S. miandoabiensis is described for the fi rst time.

Material and methods
The specimens were collected from Erzincan in 2014 and 2015.Methods used for specimen collection, extraction, material preservation and preparation were as discussed by Doğan (2006).The specimens were illustrated using a Leica DM 4000 B phase-contrast microscope.The nomenclature of the idiosomal shields follows that of Summers (1962).Dorsal setal and leg setal designations follow Kethley (1990) and Grandjean (1944), respectively.Setal counts of leg segments are given with solenidia in parentheses.All measurements are given in micrometers (μm) and refer to the length of the structure unless otherwise stated.For the new species, measurements of the holotype are given fi rst followed in parentheses by those of paratypes as a range.In newly recorded species, mean values are given fi rst and the range is given parenthetically.Body length measurements represent the distance between the base of the gnathosoma and the posterior part of the idiosoma; width was measured at the broadest point of the idiosoma.Setae were measured from the setal base to the tip of the seta; distances between setae were measured between the setal bases.Leg length was measured from the tip of the claws to the trochanter base.Palp length was measured from the tarsal tip to the trochanter base.Specimens examined were deposited in the collection of the Acarology Laboratory of Erzincan University, Turkey.

Description
The genus Stigmaeus Koch, 1836 (Acari: Stigmaeidae) can be defi ned by the following characters: idiosoma oval; chelicerae separate; palptibial claw subequal to or slightly shorter than palptarsus; accessory claw seta-like or spine-like, terminal eupathidion on palptarsus basally fused and split into two or three long prongs; counts of setae and solenidia from palptrochanter to palptarsus: 0, 3, 1-2, 2 + 1 claw + 1 accessory claw, 4 + 1ω + 1 subterminal spine-like eupathidion + 2 or 3 eupathidia (basally fused); subcapitulum with two pairs of subcapitular setae; prodorsum typically with a large shield, bearing three pairs of setae and a pair of platelets bearing setae sce; eyes present or absent, postocular bodies (pob) present or absent; dorsal hysterosomal area typically with one or two shields surrounded by three to fi ve pairs of platelets, setae d 1 and d 2 never on same shield; humeral shields dorso-or ventrolateral, with setae c 2 ; intercalary shields entire or divided, with a pair of setae (f 1 ); suranal shield entire or divided, with two or three pairs of setae; coxisternal shields present, divided along midline; ventral opisthosoma with three to fi ve pairs of aggenital setae; genital and anal valves fused or contiguous, with one to three pairs of genital setae and three pairs of pseudanal setae (Fan & Zhang 2005;Dönel & Doğan 2011;Doğan et al. 2015aDoğan et al. , 2016)).

LEGS (Figs
Male and immature stages Unknown.

Male and immature stages
Unknown.
Stigmaeus miandoabiensis is very close to S. planus Kuznetzov, 1978, but it can be distinguished from the latter by e 2 situated on minute platelets (on striate integument in S. planus), ag 1 -ag 4 on the same shield (ag 1,2 on one shield and ag 3,4 on another shield in S. planus), and longer ve.
Stigmaeidae, a family within the superfamily Raphignathoidea, is a large cosmopolitan group of genera distinguished by the position of the dorsal shields, number of subcapitular setae, size of the palptibial claw, shape of the terminal eupathidia on the palptarsus, cheliceral base fused or free, and presence of coxisternal shields (Dönel & Doğan 2011).Currently, it consists of 33 genera (excluding Erynglpusopsis Tseng, 1982 accepted as synonym of Eryngiopus Summers, 1964 by Doğan et al. [2015b]) and more than 575 species (Fan 2005;Dönel & Doğan 2011;Zhang et al. 2011;Fan & Flechtmann 2015;Doğan et al. 2015aDoğan et al. , 2015c;;Fan & Ueckermann 2016;Fan et al. 2016).The genus Stigmaeus is one of the oldest and most diverse genera in the Stigmaeidae (Fan & Zhang 2005) with 133 valid species (Fan & Zhang 2005;Doğan et al. 2015aDoğan et al. , 2016;;Dilkaraoğlu et al. 2016a, 2016b, Fan et al. 2016).To date, 36 species of the genus Stigmaeus have been reported from Turkey (Özkan et al. 1988, 1994;Erman et al. 2007;Doğan 2007;Doğan et al. 2015aDoğan et al. , 2016;;Dilkaraoğlu et al. 2016aDilkaraoğlu et al. , 2016b)).In this paper, we described one new species and reported a new record of Stigmaeus from Turkey.This raises the total number of Stigmaeus species for Turkey to 38.Some variations and asymmetric morphological abnormalities in the species are noted.In both Stigmaeus species, the shape of some dorsal body setae vary.Some setae are slightly serrated, whereas others are smooth (Figs 2A, 5A).Among the paratypes of Stigmaeus bifurcus sp.nov., in one specimen the left seta c 1 is about two times as long as the right (Fig. 1C).Seta h 3 is absent on right suranal shield in another paratype of the new species (Fig. 1D).