Actinopus casuhati, Ríos-Tamayo & Goloboff, 2018

Ríos-Tamayo, D. & Goloboff, P. A., 2018, Taxonomic Revision And Morphology Of The Trapdoor Spider Genus Actinopus (Mygalomorphae: Actinopodidae) In Argentina, Bulletin of the American Museum of Natural History 2018 (419), pp. 1-84 : 32-34

Actinopus casuhati , sp. nov.

Figures 13A–G, 14A–D, 45

TYPE MATERIAL: HOLOTYPE ♂ (MACN-Ar 36609): Buenos Aires. Sierra de la Ventana [38°8′ S 61°48′ W], Mar. 1972, Cesari, 1♂. PARATYPE: 1♀ ( LZI 0141). Parque Provincial “Ernesto Tornquist” [38°3′ S 62°1′ W], 8 Apr. 2010, G. Pompozzi.

ETYMOLOGY: The specific epithet casuhati comes from the indigenous Puel language; it is the name by which the Puelche aborigines knew the Ventania System.

DIAGNOSIS: Females of A. casuhati can be distinguishes by the shape of their spermathecae (fig. 14C); basally wide, with well-truncated fundus, dorsally concave with external lobes projecting diagonally, and arising after a well-marked constriction (this last character is similar to A. argenteus and A. gerschiapelliarum ). They differ from A. argenteus by the presence of spines apical to the crown on tibia III, and from A. gerschiapelliarum by their larger size and larger number of retrolateral thorns on tibiae II (fig. 14B); they differ from both by their dark brown coloration. Males can be differentiated by a copulatory bulb with ATA and BTA well developed (fig. 13D–F); and many retrolateral thorns on tibia II (this differentiates males from those of A. coylei , A. ariasi , and A. cordobensis ). They differ from A. szumikae by the legs with metatarsi-tarsi lighter. Cheliceral prolongation without cusps (different from A. insignis , A. gerschiapelliarum , A. taragui , A. puelche , and A. palmar ).

DESCRIPTION: Holotype male (MACN-Ar 36609, fig. 13A–G): Total length: 8.64. Carapace (fig. 13A): length 3.84, width 3.72. Cephalic region: length 2.10, width 2.40; clypeus small with a large bristle and 5–7 on both sides, 8 bristles between PME and 2–3 behind each PME- PLE; 4–6 small bristles and one large central on both sides of the OQ. Fovea: length 0.54, width 1.20. Eyes, diameters and interdistances: AME 0.20 (small), ALE 0.24, PME 0.12, PLE 0.16, OQ length 0.64, anterior width 1.92, 1.68 posterior width; AME-ALE 0.48, PME-PLE 0.08, AME- PME 0.20, ALE-PLE 0.36, AME-AME 0.20. Chelicerae: Length 1.72, width 1.00; cheliceral apex with 10 recumbent and elongated bristles that cover the base of the fang. Cheliceral prolongation without cusps; furrow with 6 large promarginal teeth and 5 retromarginal ones (a small one between 2nd-3d, 3th-4th and 4th-5th) and 6 denticles, near the promarginal teeth. Labium: length 0.76, width 0.64. Maxillae: anterior length 0.60, posterior length 1.56, width 1.00. Sternum: Center flat (fig. 13G); length 2.52, maximum width 2.20, minimum width 0.78. Postlabial sigillum shallow, posterior sigilla well defined. Abdomen: length 3.12, large covered by bristles, thicker on dorsum. PMS: length 0.36; PLS: length of basal:medial:apical segments 0.36:0.30:0.18. Spigots: 2 large, 15 small on PMS; PLS, numbers of large(small) spigots on basal:medial:apical article 3(13):2(25):2(33). Lengths of legs and palp: I: 3.60, 1.38, 2.16, 2.64, 1.50, 11.28. II: 3.72, 1.38, 2.10, 2.82, 1.56, 11.58. III: 2.70, 1.50, 1.50, 2.70, 1.50, 9.90. IV: 3.60, 1.50, 2.70, 3.00, 1.74, 12.54. Palp: 3.84, 1.80, 3.42, –, 0.96, 10.02.

Chaetotaxy: Femora: I-II-IV, 0; III, 1 D A. Patellae: I-II, 0; III, 32 P SUP-D ANT +8 on the margin, 2-1-1-1 D (1:2 B), 7 R (1:2 A) +8 on the margin; IV, 42 P SUP-D ANT, 1 D B. Tibiae: I, 1-1-1 R INF, 1-1-1-1-3 V; II, 1-1-1-1-2-4-1-4 R INF, 1-2-2-1-2 V; III, 2-1 P (1:2 A),1 D B, with an apical crown of 21 thorns, 2 R M, 1-1-1 V POST, 1-2 V ANT; IV, 1-1- 1-1-1-2 P INF, 1-2-1-2-4 V. Metatarsi: I, 2-1-1-1-1 P INF, 2-2-2-1-1-1-2 R INF, 1-1-2-V POST; II, 1-1- 1-2-2-1-2-1-4 V POST, 2-2-2-1-1-2 V ANT; III, 1-2-1-1-2 D ANT, 1-1-1-1-1 D POST, 2-2-1-2-3-2 V ANT-P INF, 1-2-1-1-2-1-2-1-4 V POST-R INF; IV, 2-2-1-1-2-1-2 P, 2-2-2-3-2-1-1-4 V. Tarsi: I, 1-1- 1-1-1 P INF, 1-2-1-2-1-2-2-3 R INF, 1-2 V A; II, 1-1-2-1-1-1-1 P INF, 4-3-3-2-4-1-2 R INF, 1-1 V (1:2 A); III, 1-1-1-1-1-1-3-2-3 P INF, 1-2-3-2-1-4- 2-1 R INF, 1 V A; IV, 2-1-2-1-1-4-3-2-3-1-2 P INF, 1-1-2-1-1-6-1-1-2-4 R INF. Total number of retrolateral spines on tibiae I and II (fig. 13B): 3 and 15 respectively. Palp: Tibiae short and thickened (width/length: 0.35±0.004) (fig. 13C). Bulb (fig. 13D–F) with ATA and BTA developed; embolus long, with a series of denticles at the base, without MRk; Ak extended to the apex. Pseudoscopula: Tarsi: I, sparse (A); II, sparse (1:2 A); III-IV, dense and uniform. Metatarsi: IV with a few apical small bristles. Trichobothria: Tibiae: I 3-2; II 4-3; III 5-3; IV 6-5. Metatarsi: I-II 10; III 7; IV 5. Tarsi: I-II 6; III-IV 7. Color: Carapace reddish brown, darker chelicerae; two triangular dark spots reaching the fovea. Abdomen dark brown, booklungs with dark markings. Sternum, labium, and maxillae lighter reddish brown. Spinnerets light yellowish. Legs like carapace with metatarsi-tarsi lighter; palp tibiae lighter.

Paratype female (LZI 0141, fig. 14A–D): Total length: 18.48. Carapace (fig. 14A): length 5.10, width 5.70; 15 bristles on each posterior margin. Cephalic region: length 3.30, width 4.80; clypeus small with 24 bristles, 16 on chilum; 17 bristles between PME and 8 behind each PME-PLE, 8 bristles and one larger on each side of the OQ. Fovea: length 0.84, width 2.28. Eyes, diameters and interdistances: AME 0.12, ALE 0.40, PME 0.28, PLE 0.24, OQ 1.04, anterior width 3.00, 2.68 posterior width; AME-ALE 0.96, PME-PLE 0.20, AME-PME 0.56, ALE-PLE 0.72, AME- AME 0.28. Chelicerae: Length 2.70, width 1.98, cheliceral apex with 12 recumbent and elongated bristles covering the base of the fang; dorsal anterior region with surface grooves. Rastellum with 9 marginal, blunt cusps, and 12 small dorsal ones. Fang groove with 7 promarginal teeth and 7 retromarginal ones (a small one between 4th- 5th, 5th-6th and 6th-7th) and 15 denticles in the furrow, near the promargin. Labium: length 1.38, width 1.20, with 16 anterior cuspules. Maxillae: anterior width 1.62, posterior width 2.10, length 1.62, with +100 cuspules 1:3 V ANT, extending to the anterior face. Sternum: Center flat (fig, 14D); length 3.60, maximum wide 3.18, minimum width 1.32. Postlabial sigillum shallow, posterior sigilla shallow and well defined. Abdomen: length 8.64, covered by dark bristles. PMS: length 0.88; PLS: length of basal:medial:apical segments 1.00:0.40:0.24. Spigots: 2 large, 48 small on PMS; PLS, numbers of large(small) spigots on basal:medial:apical article 5(60):7(65):6(73). Lengths of legs and palp: I: 3.30, 1.92, 1.50, 1.86, 0.84, 9.42. II: 3.30, 2.10, 1.50, 2.10, 0.72, 9.72. III: 3.00, 2.70, 1.20, 2.10, 0.90, 9.90. IV: 3.90, 2.58, 2.22, 2.40, 0.60, 11.70. Palp: 3.18, 1.92, 2.10, –, 2.22, 9.42.

Chaetotaxy: Femora: 0. Patellae: I-II, 0; III, 12 P (1:2 A) +10 on the margin, 18 R (1:2 A) +11 on the margin; IV, 82 P +3 near the edge; palp, 1-1 P A. Tibiae: I, 1-1-1 P A, 2-2-1-1/1 R INF, 1-1 V POST; II, 89 R INF, 1-1 V POST; III, 2-3 P (1:2 A), 1 D B, with a apical corwn of 18 thorns and 2 apical (at the edge, anterior to the crown), 58 R; IV, 0; palp, 9 P INF, 21 R INF. Metatarsi I; 21 P INF, 8 R INF, 1-1-2 V POST; II, 12 P INF, 13 R INF, 1-1-1-2 V POST; III, 3-1-2-2-3-2-2-2- 1-4 D ANT, 54 on row D POST-R (more abundant R A), 2 V A; IV, 19 P (3:4 A),1 D A ANT, 1 V A ANT. Tarsi: I, 9 P INF, 12 R INF, 1 V A ANT; II, 13 P INF, 10 R INF, 2 V A; III, 27 R, 72 V-P; IV, 58 V-P; palp, 17 P INF, 17 R INF, 2 V A. Total number of retrolateral spines on tibiae I and II (fig. 14B): 6/1 and 89 respectively. Trichobothria: Tibiae: I 4-5; II 5-6; III 5-7; IV 6-7. Metatarsi: I-III 12; IV 7. Tarsi: I 7; II-III 10; IV 8. Color: Carapace reddish brown; darker cephalic region with lighter ocular region. Chelicerae dark, almost black. Abdomen dark brown; booklungs with dark markings. Sternum light reddish brown, labium and maxillae darker. Spinnerets yellowish. Legs like carapace, tibia-metatarsitarsi lighter.

DISTRIBUTION: Province of Buenos Aires.

OTHER MATERIAL EXAMINED: Buenos Aires. Tandil [37°22′ S 59°9′ W], Mar. 1954, Andrae, 2♀ (MACN-Ar 36610). Sierra de la Ventana [38°8′ S 61°48′ W], no date, J. Rood, 1♂ and 1♀ (MACN-Ar 38194).