Key to Gamasiphis species from the Neotropical Region (females)

The following key was prepared based on available descriptions and redescriptions of mites of this genus known from the Neotropical region. Gamasiphis trituberosus Karg, 1990, described from Saint Lucia, was not included because its female is unknown.

1. With one pair of presternal shields ............................................................. Gamasiphis illotus Fox, 1949; Puerto Rico

- With two pairs of presternal shields.............................................................................................................................. 2

2. Peritreme extending anteriorly at most to anterior margin of coxa II; central projection of anterior margin of epis- tome distally expanded and denticulate ........................................................................................................................ 3

- Peritreme extending anteriorly to level of coxa I; central projection of anterior margin of epistome aciculate and smooth........................................................................................................................................................................... 5

3. Seta Z 4 about as long as Z 5 ............................................................. Gamasiphis holocapillus Karg, 1990; Saint Lucia

- Seta Z 4 shorter than Z 5 .................................................................................................................................................4

4. Central projection of anterior margin of epistome spatulate .................. Gamasiphis furcatus Karg, 1990; Saint Lucia

- Central projection of anterior margin of epistome lanceolate ........................................................................................ ........................................................................................... Gamasiphis plenosetosus Karg, 1994b; Galapagos Islands

5. At least Z 5 and post-anal seta blunt or distally expanded............................................................................................. 6

- All idiosomal setae with sharp tips............................................................................................................................. 10

6. Ventri-anal shield with seven pairs of setae in addition to circum-anal setae ................................................................ ........................................................................................................... Gamasiphis mediosetosus Karg, 2003; Ecuador

- Ventri-anal shield with eight pairs of setae in addition to circum-anal setae ............................................................... 7

7. Ventri-anal shield smooth; unsclerotised line between dorsal and ventri-anal shields barely surpassing base of seta Zv 3............................................................................................................. Gamasiphis pinnatus Karg, 1998; Ecuador

- Ventri-anal shield ornamented; unsclerotised line between dorsal and ventri-anal shields reaching region between bases of setae Jv 3 and Jv 4 [V 3 and V 7 of Hirschmann (1957)].................................................................................... 8

8. Sternal and ventri-anal shields reticulate; most of the longer dorsal shield setae distinctly expanded distally ............. ................................................................................................................... Gamasiphis silvestris Karg, 2007; Ecuador

- Sternal shield with sparse diagonal striae; ventri-anal shield transversely striated; dorsal shield setae either slightly expanded distally or aciculate....................................................................................................................................... 9

9. Anteriormost transverse striae of ventri-anal shield roughly straight; most of the longer dorsal shield setae slightly expanded distally ................................................................................... Gamasiphis hamatellus Karg, 1998; Ecuador

- Anteriormost transverse striae of ventri-anal shield distinctly curved backward; except for Z 5, dorsal shield setae aciculate ......................................................................... Gamasiphis undulatus Karg & Schorlemmer, 2009; Ecuador

10. Post-anal seta about as long as para-anal setae; dorsal shield reticulate; opisthonotal region with two pairs of setae much longer than others................................................................. Gamasiphis quadruplicis Karg, 1990; Saint Lucia

- Post-anal seta more than twice as long as para-anal setae; dorsal shield reticulate or smooth; opisthonotal region with one or two pairs of setae much longer than others.............................................................................................. 11

11. Dorsal and ventri-anal shields extensively reticulate; seta j 3 at most half as long as distance between their bases and bases of the subsequent setae ................................................................. Gamasiphis adanalis Karg, 1990; Saint Lucia

- Dorsal shield smooth; ventri-anal shield only with transverse striae or with transverse striae and a few diagonal striae connecting them; seta j 3 at least two-thirds as long as distance between its base and the base of j 4 ............... 12

12. Opisthonotal region with two pairs of setae (including Z 5) much longer than others.................................................... ................................................................................................................ Gamasiphis hyalinus Karg, 2003; Costa Rica

- Opisthonotal region with a single pair of setae (Z 5) much longer than others........................................................... 13

13. Pre-anal setae distinctly anterior to anterior margin of anal opening ...... Gamasiphis pinguis Karg, 1990; Saint Lucia

- Posterior-most pre-anal seta (Jv 5) about level with anterior margin of anal opening. ............................................... 14

14. Seta Jv 5 about 1.1 times as long as para-anal seta.................................................. Gamasiphis paulista n. sp.; Brazil

- Seta Jv 5 at least twice as long as para-anal seta ......................................................................................................... 15

15. Unsclerotised line between dorsal and ventri-anal shields reaching base of seta Zv 3; seta Jv 5 distinctly shorter than post-anal seta................................................................................... Gamasiphis hemicapillus Karg, 1990; Saint Lucia

- Unsclerotised line between dorsal and ventri-anal shields reaching base of seta Jv 3; seta Jv 5 as long as or longer than post-anal seta....................................................................................................................................................... 16

16. Idiosomal setae aciculate; four pairs of J setae; seta Jv 5 about twice as long as post-anal seta .................................... ................................................................................................................. Gamasiphis decoris Karg, 1990; Saint Lucia

- Many dorsal shield setae as well Jv 5 and post-anal seta lanceolate, with constricted base; three pairs of J setae; seta Jv 5 about 1.2 times as long as post-anal seta ............................... Gamasiphis vinculi Karg, 1994a; Galapagos Islands