Neotrionymus Borchsenius, 1948

Neotrionymus Borchsenius, 1948: 581; 1949: 182; Ter-Grigorian, 1973: 75; Danzig, 1980: 189; 1998: 156.

Type species: Neotrionymus monstatus Borchsenius, 1948, by original designation.

Key to species of genus Neotrionymus in China.

1. Circuli numbering 3–4. Sparse trilocular pores present on all body surface ............................................... N. monstatus Воrchsenius Circuli numbering 1–2. Trilocular pores absent or present only on derm near spiracles, on lips of ostioles and in cerarii ..................2

2. With 2 circuli ........................................................................................................................................... N. cynodontis (Kiritshenko) With only one circulus .........................................................................................................................................................................3

3. Oral collar tubular ducts of 2 sizes, with collar occupying more than half of total length of duct. Two pairs of cerarii, each cerarius containing 5–10 trilocular pores........................................................................................................... N. yunnanensis (Воrchsenius) Oral collar tubular ducts of 1 size, with collar occupying no more than half of total length of duct. One pair of cerarius, each cerarius containing trilocular pores no more than 5........................................................................................................................................... 4

4. Circulus very large, longer than width, quadrate or hour-glass shaped. Trilocular pores present near spiracles, on lips of ostioles and sometimes in cerarii. Anal ring with 2 or 3 rows of cells ..................................................................................... N. chinensis sp. nov. Circulus small, quadrate. Trilocular pores entirely absent. Anal ring simple, with reduced numbers of cells........................................ .......................................................................................................................................................... N. guandunensis (Воrchsenius)