Key to species of Sandersellus (males)

1. Male pygofer in lateral view with caudoventral process nearly reaching to or exceeding apex of caudodorsal lobe or process...........................................................................................................................................................................2

- Male pygofer in lateral view with caudoventral process not reaching apex of caudodorsal lobe or process.............. 6

2. Aedeagus with prominent spines or processes on shaft................................................................................................ 3

- Aedeagus glabrous or with small serrations or teeth on shaft ...................................................................................... 4

3. Aedeagus with paired ventral processes on middle of shaft. (Bolivia) ....................................... S. bigladius sp. nov.

- Aedeagus with single digitate process on apex of shaft ...................................................(Brazil) S. digitatus sp. nov.

4. Style with subapical spine or process (Nielson 1975: Figs 35, 40) .............................................................................. 5

- Style glabrous (Nielson 1975: Figs 50, 51) ................................................................ (Bolivia) S. linnavuorii Nielson

5. Aedeagus with shaft narrow in lateral and dorsal views, lateral margins parallel or nearly so (Nielson 1975: Figs. 37, 38) ...................................................................................................................................... (Bolivia) S. delongi Nielson

- Aedeagus with shaft broad in lateral and dorsal views, lateral margins not parallel (Nielson 1975: Figs 43, 44)......... ............................................................................................................................................... (Peru) S. ornatus Nielson

6) Aedeagus with distinctive processes on shaft............................................................................................................... 7

- Aedeagus glabrous, without processes ........................................................................................................................ 8

7. Aedeagus with paired long, distal processes ...................................................................... (Peru) S. bilanceus sp. nov.

- Adeagus with paired medial processes ......................................................................................................................... 9

8. Adeagus with serrated processes apically (Nielson 1975: Figs. 55, 56); style with row of teeth in distal 1/3 (Nielson 1975: Fig. 57)..................................................................................................................... (Peru) S. peniculus Nielson

- Aedeagus with glabrous processes (Fig. 62); style with subapical spine (Nielson 1975: Fig. 60)................................. .........................................................................................................................................(Bolivia) S. retrorsus Nielson

9. Style with distinctive subapical spine (Nielson 1975: Figs. 25, 29)......................................................................... 10

- Style with serrated flange subapically (Nielson 1981: Figs. 2, 3) ........................... (Panama) S. panamensis Nielson

10. Aedeagus with very broad shaft (Nielson 1975: Figs. 31, 32) .............................................. (Peru) S. simplex Nielson

- Aedeagus with very narrow shaft (Nielson 1975: Fig. 26)............................................... (Peru) S. carinatus DeLong