Genus Leeonychiurus gen. nov.

Type species. Leeonychiurus fusongensis sp. nov.

Diagnosis. Cylindrical Onychiurini with slightly broadened region of Abd. III–IV, with anal spines on distinct papillae. Granulation uniform and fine. Furca reduced to finely granulated area with four small dental chaetae in one row posteriorly; three manubrial rows of chaetae present. Ant. III sensory organ with five papillae and granulated sensory clubs. Vesicles in PAO compound. Labial palp AC type. S-chaeta on body slightly differentiated. Chaeta d0 on head present or absent. Distal tibiotarsal whorl with 11 chaetae.

Discussion. The new genus belongs to the tribe Onychiurini as having compound vesicles in PAO and with four small dental chaetae in one row posterior to a granulated area in furca (Weiner 1996, Pomorski 1998). The genus shares almost all characters with Bionychiurus. Leeonychiurus gen. nov. differs from Bionychiurus in having a furcal rudiment reduced to finely granulated area with 4 posterior dental chaetae in one row (reduced to unpaired cuticular fold with 4 chaetae in Bionychiurus). The new genus is close also to the genera Onychiurus, Deuteraphorura, Absolonia and Formosanochiurus as having the furcal rudiment reduced to finely granulated area with 4 posterior dental chaetae in one row. But it can be distinguished from Onychiurus, Deuteraphorura and Formosanochiurus by the structure of sensory clubs of AIIIO (morel-like in the new genus and smooth curved in others) and number of tibiotarsal chaetae in the distal whorl (11 in the new genus and 9 or 7 in others); besides, it differs from Absolonia by the presence of anal spines (absent in Absolonia) and three manubrial rows of chaetae (only one row in Absolonia).

The structure of the sensory clubs have several morphological variants and it was applied by Salmon (1964) as one of the crucial characters in his generic key (Weiner 1996: 166). In the present paper, we have summarized the morphological variants of the structure of the sensory clubs in the tribe Onychiurini (Table 1) according to the original descriptions, showing that it is stable in the generic level in the tribe Onychiurini, although sometimes unstable in some genera of other tribes, for example smooth, ribbed or granulated in Thalassaphorura Bagnall, 1949 (Sun et a l., 2013), smooth or granulated in Hymenaphorura Bagnall, 1948 (Pomorski, 1998). So here we prefer to draw the four known species out of the genus Onychiurus and put them into the new genus with another new species.

Derivatio nominis. The genus is dedicated cordially to the Korean collembologist Byung-Hoon Lee.