Actinopus balcarce, 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 : 73-76

Actinopus balcarce , sp. nov.

Figures 38A–G, 46

TYPE MATERIAL: HOLOTYPE ♂ (MACN-Ar 2864): Buenos Aires: Balcarce [37°51′ S 58°15′ W], Apr, 1950, C. de la Serna, 1♂.

ETYMOLOGY: The specific name is a noun in apposition that refers to the type locality.

DIAGNOSIS: Actinopus balcarce can be distinguished from A. goloboffi and A. excavatus by having the bulb with BTA developed and ATA little developed (fig. 38D–F), and by the lower number of retrolateral thorns on tibia II (fig. 38B). It differs from A. goloboffi by the absence of projections on the anterior angle of coxae I–II.

Female: Unknown.

DESCRIPTION: Holotype male (MACN-Ar 2864, figs. 38A–G): Total length: 11.28. Carapace (fig. 38A): length 4.08, width 3.60. Cephalic region: length 2.52, width 2.40; clypeus short with one central bristle and 10 small ones to the sides, 14 bristles between PME and 4–6 behind each PME-PLE dyad, with one larger medial bristle on each side of the OQ. Fovea (fig. 38A): length 0.78, width 1.32. Eyes, diameters and interdistances: AME 0.12, ALE 0.24, PME 0.12, PLE 0.16, OQ length 0.68, anterior width 1.80, 1.72 posterior width; AME-ALE 0.48, PME-PLE 0.12, AME-PME 0.32, ALE-PLE 0.40, AME-AME 0.20. Chelicerae: Length 2.12, width 1.00; cheliceral apex with 9 recumbent and elongated bristles that cover the base of the fang. Rastellum with 9 marginal blunt cusps and 7 small dorsal attenuated ones. Cheliceral furrow with 5 large promarginal teeth and 6 retromarginal (3d-5th and 6th smaller) and 14 denticles, near the promarginal teeth. Labium: length 0.88, width 0.80, with basal shallow grooves. Maxillae: anterior length 0.90, posterior length 1.50, width 1.08. Sternum (fig. 38G): Length 2.48, maximum width 2.40, minimum width 0.78. Postlabial sigillum shallow, posterior sigilla shallow, converging in the central depression. Abdomen: Length 4.56, with dark bristles. PMS: length 0.36; PLS: length of basal:medial:apical segments 0.52:0.20:0.12. Spigots: 1 large, 15 small on PMS; PLS, numbers of large(small) spigots on basal:medial:apical article (20):1(18):1(30). Lengths of legs and palp: I: 3.90, 1.56, 2.28, 2.76, 1.80, 12.30. II: 3.84, 1.56, 2.28, 3.00, 1.92, 12.60. III: 2.88, 1.62, 1.80, 3.00, 1.92.11.22. IV: 3.90, 1.80, 3.00, 3.30, 2.10, 14.10. Palp: 4.56, 2.46, 3.60, –, 0.90, 11.61.

Chaetotaxy: Right legs II and IV missing, only left legs described. Trochanter: I-II-IV-palp 0; III, 1 P SUP, 1 R INF. Femora: I-II-IV-palp, 0; III, 1 D A. Patellae: I-II, 0; III, 1-2-2 P, 28 P SUP-D ANT +8 on the margin, 1 D B, 4 R A +9 on the margin; IV, 53 P SUP-D ANT. Tibiae: I, 1-2 R INF A, 2-1-2-2-1-3 V; II, 1-2-2-2 R INF (1:2 A), 2-1-1-2-1-3 V; III, 2-1- 1-2 P, 1 D B, 1-1-1 R, 1-2 V POST (1:2 A), 2-0-1-2 V ANT, with a crown of 17 thorns; IV, 1-1-1 P INF (1:2 A), 1 R A, 1-1-1-1-3 V. Metatarsi: I, 2-2-2-1-3- 4-3 R INF-V POST, 1-1-1 V (1:2 B), 1-1-1-1-1 V ANT; II, 2-1-1-1-1-1 P INF, 1-1-2-2-1-2-2 R INF, 2-2-1-2-1-1-3 V; III, 1-1-2-1-1-1-1-2 P, 1-1-0-1-2 D POST-R, 2-1-4-2-3-3 V, 1-1 D ANT (1:2 B); IV, 1-1- 2-1-1-2-2 P, 1-1-1-0-1-4 V. Tarsi: I, 1-1-1-1 P INF,

1-1-2-2-1-3 R INF, 1-0-1 V; II, 1-1-1-1-1-1-2 P INF, 3-1-1-2-4-2-5 R INF, 1-1-2 V; III, 1-1-1-1-4 P INF, 1-2-3-1-2 R INF, 1 V A; IV, 2-1-3-2-3-2-5-4 P, 1 P A SUP, 1-2-1-1-1-2 R INF, 1 V A. Total number of retrolateral spines on tibiae I and II (fig. 38B): 3 and 7 respectively. Palp: Tibia long and slender (width/ length: 0.27±0.01) (fig. 38C). Bulb (fig. 38D–F), ATA poorly developed and BTA developed; embolus with a series of small denticles at the base and with Ak extending to the apex; MRk present. Pseudoscopula: tarsi: I-II, sparse (uniformly distributed throughout the segment); III-IV, dense and uniform. Trichobothria: Tibiae: I-III 4-3; IV 5-4. Metatarsi: I 9; II 10; III 9; IV 8. Tarsi: I 7; II 8; III-IV 6. Color: Carapace reddish brown, cephalic region and chelicerae darker. Abdomen brown, booklungs with dark markings. Spinnerets yellowish. Sternum, labium, and maxillae lighter reddish brown. Legs as the carapace, tarsi light. Palpal tibia light.

DISTRIBUTION: Only known from the type locality.