Eustigmaeus pinnatus, (Kuznetsov, 1977 a)

Khaustov, Alexander A., 2019, Contribution to systematics of the genus Eustigmaeus (Acari: Stigmaeidae) of Russia, Acarologia 59 (1), pp. 152-173 : 171

and E. pinnatus ( Kuznetsov, 1977a)

Eustigmaeus pinnatus ( Kuznetsov, 1977a) was described from European Russia based on

two females ( Kuznetsov 1977a). This species is unique in having 4 pairs of pseudanal setae.

I examined the female holotype of this species. It has abnormal number of aggenital and pseudanal setae. Left side of ano-genital area with 2 aggenital and 3 pseudanal setae, while right side with 3 aggenital and 4 pseudanal setae ( Fig. 19A ). Undoubtedly, the presence of unpaired additional pseudanal seta ps (on Fig. 19A ) is abnormal. The normal number of pseudanal setae in Eustigmaeus is 3 pairs ( Fan & Zhang 2005). The most similar species to E. pinnatus with normal 3 pairs of pseudanal setae is E. ioanninemsis Kapaxidi and Papadoulis, 1999 . I compared female holotype of E. pinnatus with description of E. ioanninensis and specimens reported from Western Siberia ( Khaustov & Tolstikov 2014) and did not find any sufficient differences. One female from Western Siberia identified as E. ioanninensis also has abnormal number of aggenital and pseudanal seta. Left side of aggenital area with 1 aggenital and 2 pseudanals, while right side with normal 3 aggenital and 3 pseudanal setae ( Fig. 19B ). Variability in number of setae in ano-genital area was also observed in Turkish specimens of E. ioanninensis ( Bingül et al. 2017b) . Based on the variability in number of setae in ano-genital area, I consider E. ioanninensis as a junior synonym of E. pinnatus .

Figures

Figure 19 DIC micrographs of ano-genital area of females: A –Eustigmaeus pinnatus(Kuznetsov, 1977), holotype, B – Eustigmaeus ioanninensis, specimen from Western Siberia.