IDENTIFICATION KEY FOR ACANTHOGONATUS KARSCH, 1880 UPDATED FROM INDICATTI ET AL. (2015)

Males

Males of A. alegre Goloboff, 1995, A. brunneus (Nicolet, 1849), A. incursus (Chamberlin, 1916), A. juncal Goloboff, 1995, A. mulchen Goloboff, 1995, A. parana Goloboff, 1995, A. peniasco Goloboff, 1995, A. tolhuaca Goloboff, 1995 and A. vilches Goloboff, 1995 are unknown.

1. ITC IV absent ............................................................................................................................................. 2

— ITC IV present .......................................................................................................................................... 16

2. Apophysis with two apical laminar spines on the same base; palpal tibia with two dorsal sinuous long setae; bulb with no keels, or with lateral keels ............................................................................................................... 3

— No tibial apophysis of any kind; ITC I absent; forests in southern Chile and Argentina ................................. ............................................................................................................................. A. confusus Goloboff, 1995

3. Bulb with a lateral keel forming a concavity; central Chile (regions IV, V) ........... A. huaquen Goloboff, 1995

— Bulb different .............................................................................................................................................. 4

4. Dorsal abdomen yellowish with a chevron; apical article of PLS short, triangular; Argentina (dry regions of Patagonia) and southern Chile .................................................................................................................... 5

— Dorsal abdomen with pattern formed by numerous mottles; apical article of PLS longer, digitiform; Argentina (north of Patagonia) .................................................................................................................................... 9

5. Large spiders (about 20 mm total length, carapace over 9 mm; bulb with two lateral flanges delimiting concave triangular area; palpal tibia rather elongate) ...................................................... A. patagonicus (Simon, 1905)

— Medium to small spiders (total length 15 mm or smaller, carapace below 6 mm); bulb variable; palpal tibia shorter ......................................................................................................................................................... 6

6. Bulb with low lateral keels (or with single keel); metatarsi I with at least 1 or 2 ventral spines ..................... 7

— Bulb with more developed lateral keels; metatarsi I with no ventral spines ..... A. notatus (Mello-Leitão, 1940)

7. Bulb with a single keel; patella III with 1-1-1 P ........................................................................................... 8

— Bulb with a double keel; patella III with only 0-0-1; slightly larger (carapace length about 5 mm) ................. ........................................................................................................................... A. chilechico Goloboff, 1995

8. Bulb with slightly developed keel, maxillae without cuspules ................................ A. birabeni Goloboff, 1995

— Bulb with well-developed keel, maxillae with more than 15 cuspules ..... A. messii Signorotto & Ferretti n. sp.

9. Dorsal abdomen blackish with yellowish whitish oblique lines; bulb with widened, flanged tip; extremely common in central-southern Chile (regions IV-VIII) ........................................................ A. pissii (Simon, 1889)

— Dorsal abdomen with only white dots not forming continuous lines, or mottled; bulb with narrower tip, flanged in the base or without flanges .................................................................................................................... 10

10. Bulb with no keels; total length c. 13 mm; central Argentina (Córdoba, San Luis, San Juan, and Buenos Aires) ................................................................................................................... A. centralis Goloboff, 1995

— Bulb with serrated, curved and long embolus; central Chile Uruguay and southern Brazil ......................... 11

11. Metatarsus I slightly curved downward; central Chile ......................................... A. quilocura Goloboff, 1995

— Metatarsus I straight .................................................................................................................................. 12

12. Presence of flanges along the embolus ....................................................................................................... 13

— Absence of flanges on embolus .................................................................................................................. 14

13. One flange on palpal embolus apex; southern Brazil ............ A. ericae Indicatti, Lucas, Ott & Brescovit, 2008

— Bulb with three perpendicular flanges along embolus ................................................ A. francki Karsch, 1880

14. Bulb with a winglike projection; PLS apical segment digitiform ............................. A. recinto Goloboff, 1995

— Bulb different; PLS apical segment triangular ............................................................................................ 15

15. Presence of tibial spur on tibia I; Uruguay and southern Brazil ....................................................................... ........................................................................................... A. tacuariensis (Pérez-Miles & Capocasale, 1982)

— Absence of tibial spur on tibia I; Argentina (Patagonia) ....................................... A. fuegianus (Simon, 1902)

16. Anterior tibia with dense prolateral shield of setae ..................................................................................... 17

— Anterior tibia without such shield ............................................................................................................. 19

17. Palpal tibia widest in basal third, and then uniformly tapering; retrolateral thicker setae present along apical 2/3 of article ................................................................................................................................................ 18

— Palpal tibia of uniform width along medial half, more abruptly narrowed in the apical third; retrolateral thicker setae present only on apical third .......................................................................... A. hualpen Goloboff, 1995

18. Bulb with its basal portion rounded, abruptly tapered to form embolus base; basal portion of the bulb duct strongly sinuous .............................................................................................. A. patagallina Goloboff, 1995

— Bulb with its basal portion not rounded, tapering more gradually to form embolus base basal portion of the bulb duct little sinuous .................................................................................... A. nahuelbuta Goloboff, 1995

19. Tibia I with a strong apical retrolateral megaspine; palpal bulb with twisted embolus; total length less than 5 mm; Brazil (Rio de Janeiro) ............... A. minimus Indicatti, Folly-Ramos, Vargas, Lucas & Brescovit, 2015

— Tibia I with no retrolateral megaspine; palpal bulb with slightly curved embolus; total length more than 13 mm ...................................................................................................................................................... 20

20. No apophysis on anterior tibia ............................................................................. A. confusus Goloboff, 1995

— Low prolateral tibial apophysis, bearing two spines on common base ........................................................ 21

21. Palpi long, about three times of the cymbium length; embolus c. half-length of palpal bulb ............................ ..................................................................................................................... A. subcalpeianus (Nicolet, 1849)

— Palpi normal, about two times of the cymbium length; embolus c. 2/3 length of palpal bulb ............................ .................................................................................................... A. campanae (Legendre & Calderón, 1984)

Females

Females of A. birabeni, A. chilechico and A. patagallina are unknown.

1. Claw tufts present; Peru ................................................................................................................ A. incursus

— Claw tufts absent ......................................................................................................................................... 2

2. ITC IV absent ............................................................................................................................................. 3

— ITC IV present .......................................................................................................................................... 17

3. Patella IV with 1-1-1 ................................................................................................................................... 4

— Patella IV with 0-0-1 or (more often) no spines at all .................................................................................. 7

4. Spermathecae thick, sclerotized ..................................................................................................... A. peniasco

— Spermathecae slightly sclerotized ................................................................................................................. 5

5. Spermathecae cactus like; Argentina .............................................................................................. A. centralis

— Spermathecae different; Chile ...................................................................................................................... 6

6. Spermathecae with short duct, slightly curved from the internal side ............................................... A. francki

— Spermathecae without basal dome, long twisted receptaculum duct ................................................ A. recinto

7. Apical article of PLS triangular .................................................................................................................... 8

— Apical article of PLS longer, digitiform ...................................................................................................... 11

8. Spermathecae branched (bi- or trifurcated) .................................................................................. A. fuegianus

— Spermathecae with a basal mound or protuberance ..................................................................................... 9

9. Small spiders (total length about 12, carapace length 5-6 mm); carapace slightly patterned, with margins and medial line lighter; lateral stripes of dorsal abdominal chevron conspicuous; general coloration yellowish ... 10

— Larger spiders (total length well over 20 mm, carapace length 10 mm or more); carapace not appreciably patterned; dorsal abdominal pattern limited mostly to cardiac area; general coloration brown with golden hairs ................................................................................................................................................ A. patagonicus

10. Scopula IV absent ................................................................................. A. messii Signorotto & Ferretti n. sp.

— Scopula IV light ............................................................................................................................. A. notatus

11. Spermathecae with a main branch and a lateral secondary internal branch arising from middle of main branch ....................................................................................................................................................... 12

— Spermathecal duct arising from the inner side of basal mound or protuberance ......................................... 13

12. Main spermathecal branch widened distally; central Argentina ...................................................... A. centralis

— Main spermathecal branch not widened distally; eastern Argentina (Entre Rios) ............................. A. parana

13. Dorsal abdomen blackish with yellow-white oblique lines; spermathecae with low basal dome; central and southern Chile (regions IV-VIII) ........................................................................................................ A. pissii

— Dorsal abdomen with white dots or spots not forming continuous lines, or yellowish with darker mottles .... 14

14. Small spiders (total length about 10 mm, carapace 4 mm or smaller); spermathecae weakly sclerotized, very short duct; patella III with p0-1-1 spines .......................................................................................... A. juncal

— Larger (total length 20 mm or more, carapace 8 mm or more); patella III with p1-1-1 spines ................... 15

15. Spermathecae with blunt basal mound, and duct strongly curved at the base .............................. A. quilocura

— Spermathecae with basal mound tapering more gradually .......................................................................... 16

16. Carapace brownish, dorsal abdomen irregularly mottled; with (weak) rastellum; spermathecae with basal dome narrow, duct strong curvate to inner side; central Chile ................................................................ A. huaquen

— Carapace reddish, dorsal abdomen with oblique lines of dots; rastellum absent ......................................... 17

17. Spermathecae with short copulatory ducts, arising from basal dome side; Uruguay and southern Brazil ......... ................................................................................................................................................ A. tacuariensis

— Spermathecae with short copulatory ducts, arising from the basal dome apex; southern Brazil ........... A.ericae

18. ITC I present ............................................................................................................................................ 19

— ITC I absent .............................................................................................................................................. 26

19. Spermathecae very long, twisted; fovea T-shaped; Brazil (Rio de Janeiro) ...................................... A. minimus

— Spermathecae short, not twisted; fovea normal, procurved ........................................................................ 20

20. Spermathecae two wide (but flat) plates ..................................................................................................... 21

— Spermathecae different .............................................................................................................................. 22

21. Sternum long; spermathecae fused, without copulatory duct, with shallow medial notch ............. A. mulchen

— Sternum normal ........................................................................................................................................ 23

22. Color uniform blackish; patella III with p0-1-1 spines ................................................................. A. tolhuaca

— Color brownish, with mottled abdomen; patella III with p0-1-1 or p1-1-1 spines ....................... A. brunneus

23. Spermathecae strongly sclerotized, with a wide cavity, opening through wide passage ................................ 24

— Spermathecae weakly sclerotized, flat and with no appreciable cavity; duct opening not conspicuous ........ 25

24. Spermathecae finger like, strongly curved ......................................................... A. nahuelbuta and A. hualpen

— Spermathecae wider, shaped like two pockets .................................................................................. A. vilches

25. Carapace patterned, legs ringed; spermathecae with short copulatory ducts, arising from the external side of basal dome ............................................................................................................................ A. subcalpeianus

— Carapace and legs uniform brown; spermathecae single, undivided; central Chile (regions IV, V) ................... .................................................................................................................................................. A. campanae

26. Epigastrium posteriorly produced; spermathecae long; northern Chile (Region II) ............................ A. alegre

— Epigastrium normal; spermathecae shorter; southern Chile (Regions VIII-X) and Argentina (Neuquén) ........ ..................................................................................................................................................... A. confusus