ASYMMETRIC VARIATIONS IN SOME SPECIES OF THE GENUS Raphignathus Dugès ( ACARI : RAPHIGNATHIDAE )

In this study, asymmetric variations in dorsal and ventral body setae in some adult females in three species of the genus Raphignathus Dugès; R. gracilis (Rack), R. hecmatanaensis Khanjani & Ueckermann and R. kuznetzovi Doğan & Ayyıldız were given and photographed. Records on asymmetric variations in Raphignathus species found in the literature were also reviewed.


Introduction
The mites show a variety of morphological variations, as in other living organisms, among which variations in the form of unilateral or bilateral absences of exoskeletal structures are very common, resulting in asymmetrical individuals.Asymmetric variations can be considered as the deviations from symmetry in bilaterally paired structures and are called as anomalies.Morphological variations in mites are inevitable results of a series of changes in genetic structures and ecological changes occurring in the environments.Considering that fact that asymmetric anomalies of taxonomically important structures may cause taxonomic errors, taxonomists should have more knowledge about morphological anomalies (Bingül et al. 2017a).In spite of many taxonomic and faunal works on mites of the genus Raphignathus, data on morphological variations in this group is very limited.Some asymmetric variations in only three species, Raphignathus gracilis (Rack), R. hecmatanaensis Khanjani & Ueckermann, R. collegiatus Atyeo, Baker & Crossley, of the genus were reported by Gerson (1968), Khanjani & Ueckermann (2003), Koç & Akyol (2004), Doğan (2006) and Akyol (2014).

The genus Raphignathus
During a faunal study on urban mites of Erzincan province in Turkey (Bingül 2016), asymmetric variations were observed in 13 specimens of Raphignathus gracilis, R. hecmatanaensis and R. kuznetzovi Doğan & Ayyıldız.In this study, we aimed to contribute to the knowledge on anomalies observed in Raphignathus mites.

Materials and Methods
Mite specimens were collected from grass, moss, soil and litter under Pinus nigra Arnold, P. sylvestris L., Pyrus sp., Rosa canina L. and Thuja sp.during a study carried on from 2014 to 2016 on biodiversity of urban mites in Erzincan city center (Turkey).The specimens were extracted by using Berlese funnels, cleared in 60% lactic acid and mounted on microscopic slides in Hoyer's medium.Asymmetric characters of some specimens were determined and photographed by using Olympus BX63-CBH DIC microscopes.

Species
Asymmetric variations

R. hecmatanaensis
1 ♀, right seta ag2 is duplex (Fig. 1) 2 ♀♀, right genital valve bears an extra seta (Fig. 2) 3 ♀♀, left genital valve bears an extra seta (Fig. 3) 1 ♀, left seta g2 is absent (Fig. 4) 3 ♀♀, right seta f1 located on striated integument (Fig. 5) R. gracilis 1 ♀, left aggenital seta ag2 is duplex (Fig. 6) 1 ♀, left seta f1 located on striated integument (Fig. 7)      Discussion Some authors reported asymmetric variations in the genus Raphignathus.Gerson (1968) reported that some specimens of R. gracilis either had ventral aggenital setae duplicated or had four genital setae on one side.Khanjani & Ueckermann (2003) determined variation in the number of genital setae in R. hecmatanaensis.The authors observed in one specimen that there were three setae on one side and four setae on other side on genital valves.Similar variations in the number of genital setae were recently reported for females of R. hecmatanaensis by Akyol (2014).Nine of the females Akyol (2014) investigated had 7 genital setae and one female had 5 genital setae.Koç & Akyol (2004) reported that one adult specimen of R. collegiatus Atyeo, Baker & Crossley had four genital setae on one of the genital valves while another specimen had two genital setae.Doğan (2006) reported two genital setae, instead of three, were present on the left side of holotype of R. ozkani Doğan.
The authors observed asymmetric variations only in the number of aggenital and genital setae in the studied mite group.Variations in the number of coxal setae (4c), humeral setae (c1) and the location of setae f1 are reported for the first time with this study.Furthermore, asymmetric variation in R. kuznetzovi is reported for the first time.
Within the same faunal study (Bingül 2016) with which the current study material was collected, morphological abnormalities in some stigmaeid species were also reported by Bingül et al. (2017a).Bingül et al. (2017a) mentioned numerical variations on some body setae and differences in length and shape of some body setae in the stigmaeid species.In our observations on Raphignathus mite specimens, numerical variations were also found in some setae as in the case of stigmaeid species.
Data on asymmetric variations in Raphignathus is very limited.Observed structural changes in the present work are easily detectable variations distorting bilateral symmetry.Such morphological variations, in other words anomalies, can be considered as minor changes distorting bilateral symmetry.These asymmetric variations may be induced by random environmental stresses, genetic problems during development or epigenetic changes, and are accord with the concept of fluctuating asymmetry (Bingül et al. 2017a).More detailed studies should be performed for confirmation of factors causing asymmetric variations.