Actinopus insignis ( Holmberg, 1881 )

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 : 45-48

Actinopus insignis ( Holmberg, 1881)

Figures 21A–G, 22A–F, 44

Aussereria insignis . Holmberg, 1881: 171, pl. 1, fig. 2 (Dm).

Actinopus insignis . Simon, 1892: 80.

Actinopus insignis was described by Holmberg (1881), based on a male specimen from Chacabuco (Buenos Aires) under the genus Aussereria . Simon (1892) later placed Aussereria Holmberg, 1881 , into the synonymy of Actinopus Perty, 1833 . The original publication of the species, although extensive and quite detailed, does not provide characters to identify the species easily, and although figures are cited in the text, these figures were not published (possibly due to a printing error). The type material of A. insignis was destroyed in a flood in the basement of the house of Eduardo L. Holmberg, where his entire collection was housed (M.E. Galiano, personal commun. to P.A.G.).

TYPE MATERIAL: Holotype male from Chacabuco [34°39′ S 60°28′ W], Buenos Aires (destroyed). The description given below is from the male (MACN-Ar 36535), Buenos Aires. Castelar [34°40′ S 58°40′ W], Mar. 1966, A. Piran, 1♂; and the female (MACN-Ar 36536), Capital Federal [34°36′ S 58°22′ W], 14 Dec. 1980, A. Zanetic and P. Goloboff, 1♀.

EMENDED DIAGNOSIS: Females of A. insignis can be distinguished by the shape of their spermathecae that have an almost squared base and a slight external projection (fig. 22E, F). Males have large AME, a copulatory bulb with well developed ATA and BTA; Ak extending to the apex; MRk developed. No dorsal spiniform bristles on femur III (present in A. gerschiapelliarum ). Females differ from A. gerschiapelliarum by the wider fovea and sternum; more abundant retrolateral thorns on tibia II; and presence of apical thorns to the crown of thorns on tibia III.

REDESCRIPTION: Male (MACN-Ar 36535, figs. 21A–G): Total length: 8.10. Carapace (fig. 21A): length 3.66, width 3.42. Cephalic region: length 2.10, width 2.28; clypeus short with one central bristle and some small ones to the sides; 19 small bristles between PME and 4–5 behind each PME-PLE dyad; 5 bristles on each side of the OQ. Fovea: length 0.48, width 0.96. Eyes, diameters and interdistances: AME 0.20, ALE 0.28, PME 0.12, PLE 0.16, OQ length 0.60, anterior width 1.88, 1.64 posterior width; AME-ALE 0.40, PME-PLE 0.00, AME-PME 0.20, ALE-PLE 0.16, AME-AME 0.20. Chelicerae: length 1.38, width 0.84, with shallow dorsal grooves; cheliceral apex with 9 recumbent and elongated bristles that cover the base of the fang. Rastellum with 8 marginal blunt cusps and 1–2 dorsal small attenuated ones. Cheliceral furrow with 5 large promarginal teeth and 5 retromarginal (a small one between 3d–4th and 4th–5th) and 6 denticles, near the promarginal teeth. Labium: length 0.76, width 0.66. Maxillae: anterior length 0.84, posterior length 1.38, width 0.96. Sternum (fig. 21E): Center flat; length 2.40, maximum width 2.20, minimum width 0.72. Postlabial sigillum shallow, posterior sigilla well defined. Abdomen: length 3.30, with dark bristles, largest in the dorsal part. Spinnerets: length (approximate, as they are highly compressed): PMS: length 0.36; PLS: length of basal:medial:apical segments 0.44:0.16:0.04. Spigots: could not be observed. Lengths of legs and palp: I: 4.20, 1.60, 2.48, 2.96, 1.80, 13.04. II: 4.00, 1.60, 2.40, 3.00, 1.80, 12.80. III: 2.80, 1.60, 1.76, 2.00, 1.68, 9.84. IV: 3.92, 1.76, 2.96, 3.20, 1.88, 13.72. Palp: 4.40, 2.00, 3.80, –, 0.96, 11.16.

Chaetotaxy: All femora: 0. Patellae: I-II, 0; III; 22 P SUP-D ANT +7 on the margin, 1-1 D (1:2 B), 3 R A +7 on the margin; IV, 25 P SUP-D ANT +4 near the edge. Tibiae: I, 1-2-2-1-4/1- 1-3 V; II, 2-2-2-2-3-3 R INF, 1-2-2 V POST, 2 V A ANT; III, 1 P M, 1 D B, with a crown of 14 thorns, 1-1-1 R (1:2 A), 1 V A POST, 1-1 V ANT (1:2 A); IV, 1 V A ANT, with some bristles. Metatarsi: I, 1-1-1-1-0-2 / 1-2-1 V ANT, 1-2-1-2-1-1-1-3 / 2-1-2-2 V POST; II; 1-1 V (1:2 B), 1-2-1-1-2-1-1-4 V POST, 1-2-1-1-1 V ANT; III, 1-1-1-1 P INF, 1 D M, 1-1-2 R (1:2 A), 1-1-1-1 V POST; IV, 1 V A POST. Tarsi: I, 1-1-1-1 P INF, 1-1-3-1-2-2 R INF, 1-1 V (1:2 A); II, 1-1-1-1-1 P INF, 1-2-2-1-2-2-2 R INF, 1-1 V (1:2 A); III, 1-1-2 P A, 3 R A; IV, 2-2-1-2-1-3- 1-1 P INF. Total number of retrolateral spines on tibiae I and II (fig. 21F): 0 and 10 respectively. Palp: Tibia long and slender (width/length: 0.27±0.01) (fig. 21G). Bulb (figs. 21B–D) with ATA and BTA developed; Ak extending to the apex, with series of denticles at the base; MRk developed. Pseudoscopula: Tarsi: I–II, sparse (uniformly distributed throughout the segment); III–IV, dense and uniform. Metatarsi: IV, sparse 1:4 A. Trichobothria: Tibiae: I 5-3; II-IV 6-4. Metatarsi: I-III 6; IV 4. Tarsi: I-III 7; IV 4. Color: Carapace and cephalic region reddish brown, central ocular area light. Abdomen brown; booklungs with light markings. Sternum, labium, and maxillae reddish brown. Legs like carapace. Spinnerets yellowish.

Female (MACN-Ar 36536, figs. 22A–F): Total length: 17. 52. Carapace (fig. 22A): length 5.16, width 5.40, with 15 bristles on each posterior margin. Cephalic region: length 2.88, width 4.32; clypeus short with 40 bristles, chilum small with 20 bristles, 22 bristles between PME and 6–8 behind each PME-PLE dyad, 4-6 bristles on each side of the OQ. Fovea: wide; length 0.66, width 1.92. Eyes, diameters and interdistances: AME 0.16, ALE 0.40, PME 0.24, PLE 0.32, AME-ALE 0.84, PME-PLE 0.20, AME-PME 0.48, ALE-PLE 0.40, AME-AME 0.32, OQ length 1.00, anterior width 3.12, 2.88 posterior width. Chelicerae: Length 2.82, width 1.86; cheliceral apex with 12 recumbent and elongated bristles covering the base of the fang. Rastellum with 11 blunt, marginal cusps, and 5/7 small dorsal ones. Fang groove with 7 large promarginal teeth and 5 retromarginal ones (a small one between 4th and 5th) and 11 denticles in the furrow, near the promargin. Labium: length 1.44, width 1.20, with 10 anterior cuspules. Maxillae: anterior length 1.74, posterior length 2.40, width 1.60, with +100 cuspules 1:3 V ANT, extending to the anterior face. Sternum (fig. 22D): Center flat; length 4.00, maximum width 3.56, minimum width 1.44. Postlabial sigillum shallow, posterior sigilla well defined. Abdomen: length 9.36, globose, with

bristles. PMS: length 0.68; PLS: length of basal:medial:apical segments 0.88:0.56:0.40. Spigots: 1 large, 30 small on PMS; PLS, numbers of large(small) spigots on basal:medial:apical article 5/7(38):8(60):3(53). Lengths of legs and palp: I: 2.70, 1.92, 1.32, 1.62, 0.78, 8.34. II: 2.40, 1.80, 1.32, 1.80, 0.78, 8.10. III: 2.70, 2.10, 1.20, 1.92, 0.84, 8.76. IV: 3.42, 2.10, 2.04, 2.04, 0.84, 10.44. Palp: 2.64, 1.80, 1.80, –, 1.86, 8.10.

Chaetotaxy: All femora: 0. Patellae: I-II, 0; III, 10 P (1:2 A) +10 on the margin, 10 R (1:2 A) +12 on the margin; IV, 64 P SUP-D ANT +5 near the edge; palp, 1-1- 1 P. Tibiae : I, 15 R INF, 1-1-1 P (1:3 A) ; II, 1 D B, 95 R (3:4 A), 1-1 V POST; III, 1 P A, with a crown of 18 thorns and 4 apical (at the apex, anterior to the crown) (fig. 22B), 35 R; IV, 0; palp, 1-1-1-1-1 P, 1-2-2 R INF (1:2 A). Metatarsi : I, 18 P INF, 14 R INF, 1-1-2 V POST ; II, 9 P INF (3:4 A), 8 R INF (3:4 B), 1-1-2 V POST; III, 6-3-2-2-1-1-2 D ANT, 36 on row D POST-R (more abundant R A), 2 V A, numerous small spines D B; IV, 12 P (3:4 A), 1 D ANT. Tarsi : I, 9 P INF, 14 R INF, 1 V A ANT ; II, 12 P INF, 9 R INF, 1 V A; III, 13 R, 48 V-P; IV, 46 V-P; palp, 19 P INF, 21 R INF, 2 V A. Total number of retrolateral spines on tibiae I and II (fig. 22C): 15 and 95 respectively. Trichobothria: Tibiae: I 5-6 ; II-III 5-7; IV 8-7 . Metatarsi : I 12 ; II-III 14; IV 11 . Tarsi: I 12 ; II 14 ; III-IV 10. Color: Carapace reddish brown, darker cephalic region and chelicerae. Abdomen light brown ; booklungs with light markings. Sternum yellowish, labium and maxillae darker. Legs like carapace, tarsi dark .

DISTRIBUTION: ARGENTINA. Provinces of Buenos Aires, Córdoba, and Isla Martín García. URUGUAY. Province of Maldonado.

OTHER MATERIAL EXAMINED: ARGENTINA. Buenos Aires. Zárate [34°6′ S 59°2′ W], 27 Feb. 1981, M. Ramírez and P. Goloboff, 2♀ (MACN- Ar 36537). Otamendi [34°14′ S 58°53′], 13 Feb. 1983, P. Goloboff, 1♀ (MACN-Ar 36538). Villa Malaver [34°33′ S 58°32′ W], 30 Nov. 1964, E. Maury, 4♀, 2 immature (MACN-Ar 36539); same data and collector, 1♀ (MACN-Ar 36540); same data and collector, 2♀ (MACN-Ar 36541); Alsina (Ferrocarril Mitre) [33°54′ S 59°23′ W], 12 Oct. 1981, Col. Goloboff, P., 1♀ (MACN-Ar 36542). Same data, 20 Jun. 1983, M. Ramírez and P. Goloboff, 1♀, 1 immature (MACN-Ar 36543). Atucha (Ferrocarril Mitre) [33°58′ S 59°17′ W], Aug. 1984, P. Goloboff, 1♀ (MACN- Ar 36544). Lima [34°2′ S 59°11′ W], 16 Nov. 1980, S. Grodzki, A. Zanetic, and P. Goloboff, 1♀ (MACN-Ar 36545). Same data, Dec. 1981, M. Ramírez and P. Goloboff, 1 immature (MACN-Ar 36546). Las Palmas (Ferrocarril Mitre) [34°4′ S 59°10′ W], 26 Apr. 1981, A. Zanetic and P. Goloboff, 1♀ (MACN-Ar 36547). Capital Federal [34°36′ S 58°22′ W], 14 Dec. 1980, A. Zanetic and P. Goloboff, 1♀ (MACN- Ar 36548). Same data, Jun. 1985, P. Goloboff, 3♀ (MACN-Ar 36549). Ramallo [33°29′ S 60°0′ W], 2 Apr. 1983, E. Maury and P. Goloboff, 1♂; 1♀, 5 immature (MACN-Ar 19831). 15 km N Puerto Obligado [33°30′ S 59°56′ W], 2 Mar. 1983, A. Zanetic and P. Goloboff, 1♀ (MACN- Ar 19841). 10 km N Puerto Obligado [33°31′ S 59°53′ W], 20 Mar. 1983, A. Zanetic and P. Goloboff, 1♂ (MACN-Ar 36550); same data and collector, 1♀ (MACN-Ar 36551). Adrogué [34°48′ S 58°23′ W], 2 May. 1971, C. Pujols, 1♂ (MACN-Ar 36552). Hurlingam [34°36′ S 58°38′ W], 29 Sep. 1955, no collector, 1♀ (MACN-Ar 38146). Moreno [34°39′ S 58°47′ W], Jan. 1965, E. Maury, 6♀ (MACN-Ar 38161). Isla Martín García [34°11′ S 58°14′ W]. 5 Mar. 2005, Bermeche, 1♂ (LZI 441). Córdoba. El Sauce. Calamuchita, [31°58′ S 64°34′ W]. Dec. 1941. M. Viana, 1♂ (MACN-Ar 36553). Material without collection data or collector, 1♀ (MACN-Ar 27094); 13♀ (MACN-Ar 27093). URUGUAY. Maldonado. Montevideo, Sayago [34°50′ S 56°12′ W], 15 May 1966, R. Capocasale, 1♀ (MNHN 453).

COMMENTS: The original description of A. insignis (despite being very detailed) mentions only a few characters that allow recognition. The most relevant characters are “AME almost as large as the diameter of the ALE” and “metatarsi with a light pseudoscopula at the apex.” Only the males of the species here considered as A. insignis have those two characters. The other species found in the same region (sympatric with A. insignis ) is A. gerschiapelliarum , which does not present these characters. Other potentially relevant characters mentioned by Holmberg are “fovea ... a wide flange” (the fovea of A. gerschiapelliarum , is slightly narrower), and “lighter tarsi” (although the latter character is present in other species).

The most important character for distinguishing between A. insignis and A. gerschiapelliarum is the presence in A. gerschiapelliarum of serial spiniform bristles dorsally on femur III of males (fig. 18D), combined with differences in copulatory bulb morphology and shape of the sternum. As all the descriptions of spiders made by Eduardo L. Holmberg are very detailed and exhaustive (as noted by Schiapelli and Gerschman de Pikelin, 1958: 188; Gerschman de Pikelin and Schiapelli, 1962: 153; Gertsch and Platnick, 1979), it seems unlikely that he could have omitted this character, which is quite evident; the series of thorns on other legs and segments are explicitly mentioned in the description. This, therefore, suggests that the specimen described by Holmberg did not have the dorsal spiniform bristles on femur III of males. We have established the association between males and females in A. insignis and A. gerschiapelliarum , based on similarities in the form of the sternum and the width of the fovea. The females of A. insignis have a fovea (fig. 22A) and sternum (fig. 22D) wider than the specimens of A. gerschiapelliarum .

For mygalomorph spiders, eastern central Argentina and Uruguay share several species of various genera, e.g., Catumiri parvum (Keyserling, 1878) ; Stenoterommata platensis Holmberg, 1881 ; Neocteniza australis Goloboff, 1987 ; Grammostola burzaquensis Ibarra, 1946 ; Plesiopelma longisternale ( Schiapelli and Gerschman, 1942) ; Homoeomma uruguayense (Mello-Leitão, 1946) ; Mecicobothrium thorelli Holmberg, 1882 ; Xenonemesia platensis Goloboff, 1989 ; Eupalaestrus weijenberghi (Thorell, 1894) ; among others.

The study of specimens from Uruguay (D. R.-T., in prep.) allowed observation of a large morphological variability. The first author exam- ined the type specimen of A. longipalpis (kindly sent by Jason Dunlop and Anja Friederich) and this species is redescribed in this work by virtue of its presence in Argentina (Entre Ríos). Although the specimen is poorly preserved, several characters that are still observable (cheliceral prolongation without cusps; a very dark color; a rounded copulatory bulb; embolus with Bk little developed and without MRk) are different from those presented here for A. insignis . The original description of A. liodon mentions no characters that could assist in identifying the species, although the described specimen is 23 mm long, which is more than 2× larger than the male of A. insignis (8.1 mm). This species must be considered, for the time being, as a species inquirenda. From the above, we can conclude that A. insignis is different from both A. longipalpis and A. liodon .