Acanthogonatus, KARSCH, 1880

Signorotto, Fiorella, Mancini, Mariana & Ferretti, Nelson, 2023, A new small Acanthogonatus Karsch, 1880 (Mygalomorphae, Pycnothelidae) species from Argentinean Patagonia: description of A. messii Signorotto & Ferretti n. sp. and its phylogenetic placement, Zoosystema 45 (17), pp. 499-512 : 508-510

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