Mideopsis orbicularis

Pešić, Vladimir, Bańkowska, Aleksandra, Zawal, Andrzej, Rewicz, Tomasz & Smit, Harry, 2023, Molecular diversity and species delimitation in the genus Mideopsis Neuman, 1880 in Europe (Acari, Hydrachnidia, Mideopsidae), Ecologica Montenegrina 70, pp. 101-115 : 110-112

Mideopsis orbicularis Clade 1

Material examined — Poland, River Bukowa near Szewce , 50.5905° N, 22.509° E, leg. Stryjecki, 3♂, two of them dissected and slide mounted (201021-011_M05_1F41SAA001G3.ab1, 201021- 011_M05_1F41SAA001A4.ab1) . Netherlands: Maarseveense Plas, Prov. Utrecht, 13.vi.2011 52.14403° N, 5.08472° E, leg. Smit, 1♂ dissected and slide mounted ( RMNH.ACA.374); Dompekolk, Kamperveen, Overijssel, 52.50611° N, 5.93046° E, 17.viii.2012, leg Smit 1♀, dissected and slide mounted ( RMNH.ACA.1248); Ruenbergerbeek E of Overdinkel, Prov. Overijseel , 52.24427° N, 7.03805° E, 18.v.2012 leg. Smit 1♂, 1♀ dissected and slide mounted ( RMNH.ACA.1102,-1103); Roggelsche Beek, Prov. Limburg, 51.25371° N, 5.93691° E, 30.iv.2012 leg. Smit, 2♀ dissected and slide mounted ( RMNH.ACA.876,-877)

Remarks — In this study, we barcoded three males from the Bukowa River in east-central Poland, and they perfectly match the description given by Biesiadka & Kowalik (1979) for the populations of Mideopsis orbicularis from neighbouring Roztocze region. According to the description of Biesiadka & Kowalik (1979) from the sympatric and often syntopic M. roztoczensis , M. orbicularis can be separated by a less elevated, nearly flattened dorsal shield with evident but less pronounced anteriorly diverging lines of particularly faint fine porosity ( Fig. 3B ), the comparatively slender and less sclerotized genital acetabula ( Figs. 3 F-G) and the excretory pore more distant from the posterior margin of the idiosoma (comparatively twice further than in M. roztoczensis ).

Further differences, according to Biesiadka & Kowalik (1979), are found in the shape of an ejaculatory complex with the anterior keel narrow and weakly sclerotized and a rounded anterior ramus in M. orbicularis (see fig. 3L, taken from Biesiadka & Kowalik 1979). Re-examination of males from our Polish material, which belongs morphologically to M. orbicularis sensu Biesiadka & Kowalik morphotype, reveals that the shape of the anterior ramus depends on the angle of observation and that it is more or less a wedge-shaped (see Fig. 3M ), although not as clearly accentuated as in M. roztoczensis (see Fig. 3K ).

Molecular data revealed that examined specimens of M. orbicularis sensu Biesiadka & Kowalik 1979 from Poland belong to the same BIN ACS0476. The latter BIN also includes sequences from Netherlands (n = 6), Russia (n = 1), Norway (n = 3) and Germany (n =2).

Figures

Figure 3. A-D Photographs of dorsal shield: A – M. roztoczensis, ♂, CCDB38233 C11, River Zeta, Montenegro. B – M. orbicularis Clade 1, ♂, River Bukowa, Poland. C – M. orbicularis Clade 2, ♀, RMNH.ACA.373, Netherlands. D – M. orbicularis, ♂, Tjeukemeer, Netherlands. E-H Genital field: E – M. roztoczensis, ♂, CCDB38233 C11, Montenegro. F-G – M. orbicularis Clade 1, ♂: F – River Bukowa, Poland; G – RMNH.ACA.374, Netherlands. H-I – M. orbicularis Clade 2, ♀, RMNH.ACA.373, Netherlands. K-O Ejaculatory complex. K – M. roztoczensis, ♂, Roztocze, Poland (from Biesiadka & Kowalik 1979: fig. 10), inset: photograph of anterior ramus, CCDB38233 C11, Montenegro). L – M. orbicularis Clade 1, Roztocze, Poland (from Biesiadka & Kowalik 1979: fig. 12). M – M. orbicularis Clade 1, ♂, River Bukowa, Poland (inset: photograph of anterior ramus). N – M. milankovici, paratype ♂, Montenegro (from Pešić & Smit 2020). O – M. orbicularis, ♂, Tjeukemeer, Netherlands. Scale bars = 100 µm (for K-L = 50 µm).