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