Oudemansia, Schott, 1893

Palacios-Vargas, José G. & Bu, Yun, 2020, New records of Collembola from marine littoral sand of Hainan Island, China with description of a new Oudemansia species (Neanuridae: Pseudachorutinae), Zootaxa 4810 (1), pp. 117-130 : 128

Key to species of Oudemansia * (Modified from Massoud, 1967)

1 Abd. VI with 2 anal spines. Ant. IV with 2 sensilla. Mandible several teeth in one row. Ungues with one internal and not lateral tooth. Dens with 6 setae. Colour black. 0.8 mm .......... O. shoetti Denis, 1948 ; Vietnam (Nha-Trang) and New Caledonia

- Abd. VI with more than 2 anal spines or spiniform setae...................................................... 2

2 Abd. VI with 4 true anal spines well defined................................................................ 3

- Abd. VI only with spiniform setae. Ant. IV with 6 to 8 sensilla. Mandible with up to 20 teeth in one row. Ungues with internal tooth and no lateral. Dens with 6 setae. Color blue violet, blue indigo. 2 mm long....... O. esakii ( Kinoshita, 1932) ; Japan

3 Ungues with one internal tooth........................................................................... 4

- Ungues without internal teeth............................................................................ 5

4 Ratio dens: mucro = 2.15. Ungues III: mucro = 1 to 1.05. Posterior surface of dens with coarse granulations. Anal spines slightly curved. Color black. Length 1.1 mm ......................................... O. subcoerulea Denis, 1948 ; Vietnam

- Ratio dens: mucro = 2.6. Ungues III: mucro = 1 to 1.4. Posterior surface of dens with fine granulations................. 7

5 Ungues with inner or lateral teeth........................................................................ 6

- Ungues without inner tooth, but one small tooth dorso-lateral. Ant. IV with 4 sensilla, the subapical thicker and curved. Mandible with many teeth in two rows, Maxilla styliform, dens with 6 setae. Anal spines straight and sharp. Color red violet. 1.2 mm ................................. O. petiti Delamare Debouteville & Massoud, 1964 ; Madagascar (Port-Dauphin)

6 Anal spines long and acuminate on individual papillae. Mandible with 5 or 6 teeth. Mucro as long as half dens. 5 dental setae. Color blue................................................ O. coerulea Schött, 1893 ; Indonesia (Belitung Island).

- Anal spines short with oval apex, without individual papillae. 6 dental setae. Mucro slightly curved. Color blue. 1.4 mm ...................................................................... O. barnardi ( Womersley, 1934) ; Australia

7 Anal spines acuminate and slightly curved. Color black. Mandible with 15 teeth of similar size. Two dental setae longer than others. Ocular seta Oc2 thicker and longer than subdorsal cephalic setae...................................................................................................... O. dubia Denis, 1947 ; Madagascar (Cap d’Ambre)

- Anal spines with round apex, not curved. Color blue-black. Mandible with 14 teeth, the two basal bigger than others. One dental seta longer than others. Ocular setae Oc2 subequal to subdorsal cephalic setae..................................................................................................... O. chenorum sp. nov.; China (Hainan Island).