Genus Synaldotrema Belokobylskij & Tobias, 2002, stat. nov.

Synaldotrema Belokobylskij & Tobias, 2002: 3 (as subgenus of Dinotrema Foerster); Belokobylskij and Tobias 2007: 11; van Achterberg and Vikberg 2014: 3; Yu et al. 2016.

Type species.

Dinotrema (Synaldotrema) speciosum Belokobylskij & Tobias, 2002, by original designation (Figs 28, 29).

Material examined.

Holotype ( Dinotrema (Synaldotrema) speciosum) Russia: • ♀, Primorskiy kray, 10 km SSW of Partizansk, border of forest, 12–13. vii. 1996 (S. Belokobylskij) (ZISP) . Paratypes ( Dinotrema (Synaldotrema) speciosum) Russia: • ♀, Primorskiy kray, 50 km N of Olga, mixed forest, 29. vii. 1979 (S. Belokobylskij) (ZISP) ; • ♀, Primorskiy kray, Pogranichnyi District, Barabash-Levada, forest, 3–6. vi. 1980 (S. Belokobylskij) (ZISP) ; • ♀, Primorskiy kray, 42 km S of Plastun, forest, 24. vi. 1979 (S. Belokobylskij) (ZISP) ; • ♀, Republic of Tuva, 14 km E of Kyzyl, lowland of Ka Khem River, 31. v. 1975 (D. Kasparyan) (ZISP) .

Diagnosis.

Synaldotrema Belokobylskij & Tobias shares the main characters of Dinotrema sensu stricto but differs by having the hypopygium of the female strongly retracted under the posterior tergites of metasoma and the fourth tergite strongly elongated, ~ 2.5 × longer than fifth tergite (vs approximately of equal length in Dinotrema s. str.).

Remarks.

The type species of Synaldotrema ( D. speciosum Belokobylskij & Tobias, 2002) has a variable vein 2 - SR of the fore wing. This vein is usually present, but sometimes, mostly discoloured and its posterior half or sometimes entire vein 2 - SR is absent (Belokobylskij and Tobias 2002). Previous studies showed that the value of the reduction of this vein illustrates well the subgeneric division (Belokobylskij and Tobias 2002), however the current diagnostic character study proved that retraction of hypopygium has enough value to consider Synaldotrema as a valid genus.