Actinopus magnus, 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 : 52-53

Actinopus magnus , sp. nov.

Figures 25A–G, 45

TYPE MATERIAL: HOLOTYPE ♂ (MACN-Ar 36622): Córdoba: Villa General Belgrano [31°58′ S 64°33′ W], 12 Mar. 2010, G. Villafarie, 1♂.

ETYMOLOGY: The specific name, magnus , a Latin adjective, refers to the size of the species, with the largest male of all Argentine species.

DIAGNOSIS: Males of A. magnus can be distinguished by their large size. The copulatory bulb (fig. 25D–F) with Ak extending to the apex and MRk developed, different from all other species (except A. puelche , A. patagonia , and A. ramirezi ; from which A. magnus differs by the the low number of retrolateral spines in tibiae II; fig. 25B). Cheliceral prolongation without cusps, different from A. insignis , A. gerschiapelliarum , A. taragui , A. puelche , and A. palmar .

Female: Unknown.

DESCRIPTION: Holotype male (MACN-Ar 36622, fig. 25A–G): Total length: 15.60. Carapace (fig. 25A): length 6.00, width 5.88. Cephalic region: length 3.48, width 4.32; clypeus small with a central bristle and 12 on both sides, 26 bristles between PME and 10–12 behind each PME-PLE, 10–12 small bristles on each side of the OQ, a larger central bristle. Fovea: length 0.78, width 1.80. Eyes, diameters and interdistances: AME 0.40 (large), ALE 0.48, PME 0.48, PLE 0.32; OQ length 1.20, anterior width 3.24, 3.00 posterior width; AME- ALE 0.84, PME-PLE 0.12, AME-PME 0.48, ALE- PLE 0.64, AME-AME 0.24. Chelicerae: Length 2.52, width 1.62; cheliceral apex with 11 recumbent and elongated bristles that cover the base of the fang. Cheliceral prolongation without cusps; furrow with 6 large promarginal teeth and 5 retromarginal (a small one between 3d-4th) and 19 denticles, near the promarginal teeth. Labium: length 1.44, width 1.14. Maxillae: anterior length 1.50, posterior length 2.40, width 1.62. Sternum (fig. 25G): With slight central depression; length 3.90, maximum width 3.42, minimum width 1.32. Postlabial sigillum shallow, posterior sigilla well defined and shallow. Abdomen: Length 6.48, large, covered by dark bristles. PMS: length 0.68; PLS: length of basal:medial:apical segments 0.76:0.36:0.20. Spigots: 3 large, 18 small on PMS; PLS, numbers of large(small) spigots on basal:medial:apical article 4(24):4(35):(65). Lengths of legs and palp: I: 6.00, 2.58, 3.30, 4.20, 2.22, 18.30. II: 5.82, 2.58, 3.30, 4.38, 2.34, 18.42. III: 4.74, 2.70, 2.34, 4.80, 2.70, 17.28. IV: 6.30, 2.88, 4.62, 5.22, 2.82, 21.84. Palp: 5.70, 2.70, 5.10, –, 1.68, 15.18.

Chaetotaxy: Femora: 0. Patellae: I-II, 0; III, 29 P SUP-D ANT +8 on the margin, 1-1-1 D, 5 R A +6 on the margin; IV, 58 P SUP-D ANT. Tibiae: I, 1-2-1-2 V; II, 1-1-1-2 R (1:2 A), 4 V A; III, 1-1 P (1:2 A), 1 D B, 1-1 R (1:2 A), 1-2 V (1:4 A), with na apical crown of 17 thorns; IV, 1-1-2 V ANT

(longer), 1-1-1 V POST. Metatarsi: I, 2-2-1-2 R INF-V POST, 1-1-1-1 V, 1-1-1 V ANT; II,, 2-1-2- 1-2-2 R INF-V POST, 1-1 V (1:2 B), 1-1-2 V ANT; III, 1-1-1-2 P INF, 1-1-1-1-1 D ANT, 1-1-2-1-1-3 D POST-R, 1-1 V, 1-1-2 V POST; IV, 1-1-2-3 P, 1-1-1 V POST (longer), 1-1-1 V, 1-1-2 V ANT (2:3 A). Tarsi: I, 1-1-1-2 P INF, 1-1-3-3-6 R INF, 1-1 V A; II, 1-1-1-1-1-2 P INF, 1-1-2-4-6-2-4 R INF, 1-2-1 V (1:2 A); III, 1-1-2-2-1 P INF, 2-2-1- 2-1 R INF (2:3 A), 2 V A; IV, 2-4-2-4-5 P INF, 1 V A. Total number of retrolateral spines on tibiae I and II: 1 and 5 respectively. Anterior angle of coxae I projected. Palp: Tibia long and slender (width/length: 0.31±0.01) (fig. 25C). Bulb (fig. 25D-F) robust, ATA and BTA developed; embolus short, with a series of denticles at the base; Ak extended to the apex and MRk well developed. Pseudoscopula: Tarsi: sparse, I (1:2 A); II (throughout the segment); III-IV, dense (uniformly distrib- uted throughout the segment). Metatarsi: without pseudoscopula. Trichobothria: Tibiae: I-II 5-7; III 5-8; IV 5-7. Metatarsi: I 13; II 16; III 12; IV 9. Tarsi: I 10; II-III 11; IV 8. Color: Carapace dark reddish brown, cephalic region and chelicerae darker. Abdomen dark brown, booklungs with light markings. Spinnerets yellowish. Sternum, labium, and maxillae lighter reddish brown. Legs like carapace, palp tibiae light.

DISTRIBUTION: Known only from the type locality.

ADDITIONAL MATERIAL EXAMINED: None.