Tetracanthella sylvatica Yosii, 1939

Potapov, Mikhail, Brinev, Alexey & Sun, Xin, 2019, Isotomidae of Japan and Asiatic part of Russia. II. The genus Tetracanthella of the Far East, ZooKeys 855, pp. 31-54 : 38-40

Tetracanthella sylvatica Yosii, 1939 Figs 3, 5, 21, 22, 52, 58

Material.

Japan, Honshu, Kyoto, Kamigamo experimental forest in Kyoto University, 2011, leg. S. Fujii.

Distribution.

Tetracanthella sylvatica was described from Osaka (central Honshu) and was numerously recorded around here afterwards, particularly from Kamigamo Experimental Forest of Kyoto University (e.g., Takeda 1973, Deharveng 1987, Fujii et al. 2014). A few records are known from Shikoku and more northern areas of Honshu ( Yosii 1969, Tamura and Chiba 1977, Yamauchi and Suma 1999, 2009, Nakamura et al. 2006, Niijima 1976) (Fig. 58). The species was recorded once from Hokkaido ( Suma 1990).

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.