Tetracanthella sylvatica

Discussion. The remarks to chaetotaxy of the species were given by Yosii (1961), the complete redescription was provided by Deharveng (1987). After our materials, the species has complete set of guards in labial palp (Fig. 3) that is common for the species of eastern groups (' sylvatica ', ' stebaevae ', ' grinbergsi '). Tetracanthella sylvatica, T. annulata sp. nov., and T. dorsoduplex Xie, Potapov, Sun, 2019 combine a natural group of species distributed in East Asia. They share long furca with annulated dorsal side of dens, well developed reticulation with broad canals between polygons (Figs 51 - 52), and few macrochaetae on body tergites. Tetracanthella sylvatica differs from other two species by better develop ment of medial macrochaetae on body (Figs 5, 21, 22), from T. annulata sp. nov. by the presence of anterior chaeta on dens, from T. dorsoduplex by common position of lateral s on Abd. IV. The specimens from Kamigamo have 3 + 3 postlabial chaetae that could be an additional differentiated character of the species if confirmed by wider Japanese materials. In the alpine zone of Ezop Range (western part of Khabarovski Krai, leg. A. B.) we discovered a form which shares many essential characters with typical T. sylvatica from which it differs by larger body (~ 2 mm), 4 + 4 postlabial chaetae and absence of annulations on posterior side of dens.