Protogamasellus, Karg, 1962

Yamada, Mariana & De Moraes, Gilberto J., 2020, A key to the species of Protogamasellus (Acari: Ascidae), with a new species from the Brazilian Pantanal, Zootaxa 4801 (2), pp. 343-354 : 349-351

Key to the species of Protogamasellus , based on adult females

1. Unsclerotised region between genital and ventrianal shield reduced, so that none or only one of the most anterior opisthogastric setae (Jv 1, Zv 1) inserted in this region..................................................................... 2

- Unsclerotised region between genital and ventrianal shields with two pairs of setae................................ 13

2. Ventrianal shield without incisions on the anterior margin; without transverse line just posteriad j 4..................... 3

- Ventrianal shield with a pair of incisions on the anterior margin at level of Jv 1– Zv 1; with or without transverse line just posteriad j 4.............................................................................................. 5

3. Unsclerotised region between genital and ventrianal shields with a pair of opisthogastric setae; corniculus not divided distally; posterior margin of the sternal shield with central tapered projection............... P. sternalis Nasr, Afifi & Hassan, 1988

- Unsclerotised region between genital and ventrianal sields without opisthogastric setae; corniculus distally bifurcate; posterior margin of the sternal shield without central projection........................................................ 4

4. Dorsal shield setae short, so J 1, J 2 and Z 1 0.5–0.6 times as long as distances between their bases and bases of the respective subsequent setae of same series........................................... P. bifurcalis Genis, Loots & Ryke, 1967

- Dorsal shield setae long, so J 1, J 2 and Z 1 0.8–0.9 times as long as distances between their bases of the respective subsequent setae of same series.............................................. P. ascleronodulus ( Shcherbak & Petrova, 1987)

5. Setae J 1 and J 2 about 1/3 as long as distances between their bases and bases of respective subsequent setae of same series.. 6

- Setae J 1 at least half the distance between its base and the base of J 2, which in turn is at least 0.8 times as long as distances between its base and base of J 3.......................................................................... 8

6. Transverse line at level of J 1 continuous.................................... P. elongatus Shcherbak & Petrova, 1987

- Transverse line at level of J 1 interrupted between bases of those setae............................................ 7

7. Z 1 about twice as long as J 1................................................. P. dispar Genis, Loots & Ryke, 1967

- Z 1 approximately as long as J 1................................................ P. brevisaetosus Shcherbak, 1976

8. Seta J 4 as long as distance J 4– J 5; transverse line at level of J 1 interrupted between bases of those setae...................................................................................... P. machadoi Genis, Loots & Ryke, 1967

- J 4 shorter than distance J 4– J 5; transverse line at level of J 1 continuous or interrupted between bases of those setae....... 9

9. Transverse line at level of J 1 continuous; epistome anteriorly subtriangular; ventrianal shield 1.4 times longer than wide............................................................. P. indica Bhattacharyya, Sanyal & Bhattacharya, 2000

- Transverse line at level of J 1 interrupted between bases of those setae; epistome with three anterior extensions; ventrianal shield at most 1.2 times longer than wide....................................................................... 10

10. Dorsal shield with a pair of incisions between j 1 and z 1; with few diagonal lines between anterior margin of opisthonotal shield and transverse line at level of J 1..................................... P. biscleronodulus Shcherbak & Petrova, 1987

- Dorsal shield without incisions between j 1 and z 1; without diagonal lines between anterior margin of the opisthonotal shield and transverse line at level of J 1........................................................................ 11

11. Setae J 1– J 3 distinctly shorter than distance between their bases and bases of respective subsequent setae of same series; st 5 off genital shield................................................................. P. mica ( Athias-Henriot, 1961)

- Setae J 1– J 3 approximately as long as distance between their bases and bases of respective subsequent setae of same series; st 5 on genital shield..................................................................................... 12

12. Seta j 3 approximately as long as distance j 3– j 4; posterior margin of sternal shield without median projection............................................................................................. P. americanus Karg, 2007

- Seta j 3 distinctly shorter than the distance j 3– j 4; posterior margin of the sternal shield with distinct median projection............................................................................. P. similis Genis, Loots & Ryke, 1967

13. First two opisthogastric setae of each side approximately in longitudinal line, if not, anterior pair closer together than posterior pair............................................................................................... 14

- First two opisthogastric setae of each side in approximately transverse line, if not, anterior pair farther apart than posterior pair............................................................................................... 18

14. Anterior margin of the epistome with elongate median spine; opisthonotal shield without transverse line at the level of J 1; ventrianal shield elongate, with preanal opisthogastric setae of each side almost in longitudinal line......................................................................... P. keralaensis Bhattacharyya, Sanyal & Bhattacharya, 2000

- Anterior margin of the epistome acuminate without elongate median spine; opisthonotal shield with transverse line at the level of J 1; ventrianal shield elongate to rounded, with preanal opisthogastric setae of each side in a transverse line or with the median pair slightly anteriad the lateral one.................................................................. 15

15. Pre-anal opisthogastric setae in transverse line; transverse line at the level of J 1 interrupted between bases of those setae...................................................... P. similiscuticalis Bhattacharyya, Sanyal &Bhattacharya, 2000

- Median pair of pre-anal opisthogastric setae slightly anteriad the lateral one; transverse line at the level of J 1 continuous.. 16

16. Post-anal seta distinctly shorter than Jv 5; para-anal seta slightly longer than Jv 5..... P. scuticalis Genis, Loots & Ryke, 1967

- Post-anal seta distinctly longer than Jv 5; para-anal seta slightly shorter than Jv 5................................... 17

17. Opisthonotal shield with wavy U-shaped line around J 4 connected at the base of each side to a diagonal line that reaches base of Z 4; the latter about 2/3 distance between its base and base of J 5; ventrianal shield with three lines parallel to margins of the shield anteriad of Jv 5 and other lines around anus.................................. P. massula ( Athias-Henriot, 1961)

17’. Opisthonotal shield smooth in the vicinity of J 4; the latter about half the distance between its base and base of J 5; ventrianal shield with 2–3arched, anteriorly convex lines between Jv 2 and anal opening................................................................................................. P. sigillophorus Mineiro, Lindquist & Moraes, 2009

18. Ventrianal shield with subparallel lateral margins.................................... P. minutus Nasr, in Zaher, 1986

- Ventrianal shield rounded or with lateral margins converging anteriorly......................................... 19

19. Ventrianal shield winder at the level of posterior margin of the anal opening or behind.............................. 20

- Ventrianal shield wider anteriad anal opening.............................................................. 21

20. Ventrianal shield trapezoidal; Jv 5 about twice as long as post-anal seta; without transverse line at J 1 level.................................................................................... P. angustiventris ( Athias-Henriot, 1961)

- Ventrianal shield subtriangular, with rounded anterior angle; post-anal seta about 1.5 times as long as Jv 5; with transverse line at J 1 level................. P. cognatus ( Athias-Henriot, 1961) (probably = P. paradioscorus Nasr, Afifi & Hassan, 1988 )

21. With three scleronoduli in region between j 5 and j 6; most opisthonotal shield setae long; Z 2 much longer than distance Z 2– Z 3............................................................................... P. longipellis ( Karg, 2000)

- Without scleronoduli in podonotal shield; most opisthonotal shield setae short, if long, Z 2 distinctly shorter than distance Z 2– Z 3............................................................................................. 22

22. Setae J 4 about twice as long as J 1; anterior margin of ventrianal shield rounded............................................................................................. P. caleraensis Rueda-Ramírez, Varela & Moraes, 2016

- Setae J 4 at most 1.7 times as long as J 1; anterior margin of ventrianal shield rounded to approximately rectilinear........ 23

23. Anterior margin of the ventrianal shield approximately rectilinear............... P. brevicornis Genis, Loots & Ryke, 1967

- Anterior margin of the ventrianal shield rounded........................................................... 24

24. With slightly curved line connecting bases of j 4 and z 3; seta J 3 about 0.7 times distance J 3– J 4.... P. singularis ( Karg, 1962)

- Without line connecting bases of j 4 and z 3; setae J 3 about 0.5– or 0.9–times distance J 3– J 4.......................... 25

25. Opisthonotal shield setae relatively long, so J 1– J 3 0.8–0.9 times as long as distance between their bases and bases of subsequent setae of same series................................................................... P. pantanal n. sp.

- Opisthonotal shield setae relatively short, so J 1– J 3 about half as long as distance between their bases and bases of subsequent setae of same series.................................................................................. 26

26. Opisthonotal shield about twice as long as wide; ventrianal shield longer than wide................ P. evansi ( Karg, 2000)

- Opisthonotal shield about 1.5 times as long as wide; ventrianal shield wider than long.............................. 27

27. Epistome with two pairs of spines, the median distinctly longer than the lateral; opisthonotal shield with short transverse marginal lines; genital shield rounded posteriorly, with distal end forming a punctate semi-circl....... P. minimus Jordaan, 1988

- Epistome with serrate anterior margin, about 13 teeth; opisthonotal shield without transverse marginal lines; genital shield truncate posteriorly, without distal punctate semi-circle................................... P. hibernicus Evans, 1982