Key to world species of Acherontides

1 Furca reduced; small mucro, reduced to small appendage or absent............................................. 2

- Furca normal, mucro present............................................................................ 7

2 Dens with 2+2 basal, dorsal chaetae...................................................................... 3

- Dens with 1+1 basal, dorsal chaetae...................................................................... 5

3 Two rows of chaetae on Abd. IV.................................................... A. atoyacensis Bonet, 1945

- Three rows of chaetae on Abd. IV........................................................................ 4

4 Ant. II with 11 chaetae, Ant. IV with one dorsal, 3 dorsolateral sensilla and 1 microsensillum; tenent hairs acuminate.................................................................. A. bullock Palacios-Vargas & Gómez-Anaya, 1996

- Ant. II with 12 chaetae, Ant. IV with one dorsal, 4 dosrsolateral sensilla and 1 microsensillum; tenent hairs clavate............................................................ A. juxtlahuacaensis Palacios-Vargas & Gómez-Anaya, 1996

5 Tenaculum 2+2 teeth.................................... A. pappogeomysae Palacios-Vargas & Gómez-Anaya, 1996

- Tenaculum 3+3 teeth.................................................................................. 6

6 Cephalic a0 present, Ant. IV with 3 large sensilla........................................ A. edaphicus Yossi, 1971

- Cephalic a0 absent, Ant. IV with 4 large sensilla....................................... A. tanasachiae (Gruia, 1969)

7 Mucro and dens fused, with 2+2 basal dorsal chaetae and 3 apical rounded protuberances....... A. peruensis Hüther, 1975

- Mucro and dens fused, with 1+1 or 2+2 basal dorsal chaetae without apical rounded protuberance..................... 8

8 Mucro and dens fused, with 1+1............................................. A. huetheri Deharveng & Diaz, 1984

- Mucro and dens fused, with 2+2 (Figs. 17-18).............................................................. 9

9 3–4 chaetae in ocular area, tenaculum with 2+2 teeth........................................................ 10

- 2 chaetae in ocular area, tenaculum with 3+3 teeth.......................................................... 11

10 Abd. VI with 10 heavy spine-like processes, and 2 anal spines................. A. spinus (Christiansen & Reddell, 1986)

- Abd. VI without heavy spine-like processes, with 2 anal spine.............................. A. potosinus Bonet, 1946

11 Tenent hairs acuminate, anal spine about 1/5 length of unguis III..... A. eleonorae Palacios-Vargas & Gnaspini-Netto, 1992

- Tenent hairs clavate., anal spine about 1/3 length of unguis III............................. A. serrasapoensis sp. nov.