Castianeira spinipalpis Mello-Leitão, 1945

Figs 2–5

Castianeira spinipalpis Mello-Leitão, 1945: 259, fig. 44.

Type material. Holotype ♀: ARGENTINA: Misiones Province, San Ignacio, 1941, leg. Birabén (MACN-Ar 16.570) (examined by photos, Figs 1A–F).

Material examined. PARAGUAY: 4♂, 2 juv., Alto Paraguay department, Parque Nacional Defensores del Chaco, Madrejón, -20.633, -59.866, 10.xi.1982, “undisturbed low forest”, leg. J.A. Kochalka (IBNP-JAK-CR 000.00.2.742) ; 2♀, Alto Paraguay department, Parque Nacional Defensores del Chaco, 1-6.ix.1982 (IBNP-JAK-CR 000.00.2.744) ; 1♂, 3♀, Alto Paraguay department, Parque Nacional Defensores del Chaco, Cerro León, -20.423, -60.309, 19–27.xi.1984, leg. J.A. Kochalka (IBNP-JAK-CR 000.00.2.747 and IBNP-JAK-CR 000.00.2.748) ; 3♀, Ñeembucú department, Pilar military base, -26.844, -58.305, 17.vi.2020, “pasture grassland”, leg. B.L. Pett & V . Vladimirova (CIPLT-Ar 689) ; 2♂, Itapúa department, Distrito Alto Verá, Cangue Cuá, Estancia Mendieta, -26.578, -55.653, 9–12.ii.1999, leg. J.A. Kochalka (IBNP-JAK-CR 000.00.2.723) . BOLIVIA: 3♂, 4♀, Santa Cruz department, Santa Cruz de la Colina, Urubo, “ Cerrado-like grassland in urbanization”, -17.760, -63.24, 432 m a.s.l., 21–28 Dec. 2019, leg. R . Perger (CBF) .

Remarks. The conspecificity of the males and females cited in the material is supported by the collection of a series of male and females co-occurring in the same microhabitats in Paraguayan and Bolivian locations.

Diagnosis. Castianeira spinipalpis can be distinguished from other known Neotropical Castianeira by the following combination of characters: tibia I with 4-4 ventral spines (Figs 2C, D, 4B); relatively long and erect setae covering abdomen (Figs 3A, B, 4A); eyes all equal and relatively large (i.e. larger eye diameter / cephalic region surface area than other Castianeira) (Fig. 2B). Males can be recognized by the prolaterally-projected hook-like embolus with four coils (Figs 5A, B), largest and thickest coil at the basal curvature of the embolus, to very fine coils at apex. Sperm ducts convoluted. Females can be recognized by the ventral spines of tibia I strongly developed (Figs 2C, 3B), the conspicuous paddle-shaped ST with wide, longitudinal slit-like CO positioned postero-laterally to ST II (Figs 3C–F); CDs with one moderately well-sclerotized twist.

Remarks. Castianeira vittatula Roewer, 1951 (replacement name for Castianeira vittata Keyserling, 1891) and C. luteipes Mello-Leitão, 1922 (both species described from Brazil) are the only other new world Castianeira with tibia I ventral spination 4-4. These species additionally have erect abdominal setae. However, since the descriptions of those species cite AME twice as large as the ALE (Keyserling 1891; Mello-Leitão 1922), they clearly could not be synonymous with C. spinipalpis .

Description. Female (IBNP-JAK-CR 000.00.2.744)

Measurements. Total length 6.04. Carapace: length 2.42, width 1.60, index 66. Cephalic region: width 0.77, index 32. Sternum: length 1.10, width 0.92. Abdomen: length 3.62, width 2.59. Clypeus height 0.45. Chelicerae: length 0.82, width 0.36. Eyes: AME 0.15, ALE 0.13, PME 0.14, PLE 0.14. Legs: formula 4132; I = 6.60 (1.83, 0.61, 1.71, 1.33, 1.12); II = 5.86 (1.50, 0.60, 1.41, 1.35, 1.00); III = 6.15 (1.92, 0.56, 1.42, 1.27, 0.98); IV = 8.18 (2.23, 0.72, 2.14, 2.29, 0.80).

Carapace: Long and wide, ranging from deep orangish-brown (Figs 2B, D) to brown, with quite intense black mottling (Figs 3A, B), narrowed anteriorly and ocular region darkest.

Eyes: Medium to large, all roughly equal in diameter. PER procurved, AER row recurved.

Chelicerae: Chelicerae with two retromarginal teeth, two teeth on promargin, with distal one about twice the size, one very small denticle present just distal from larger tooth.

Sternum: Shield-shaped, with dark edges (Fig. 2F).

Legs: Coxae all pale (Fig. 2F). Femora I dark brown, otherwise all leg segments brown to orange, darkening at apices of tibiae. With 4-4 tibial spines on anterior legs (Fig. 2C).

Abdomen: Oval, light brown to grey, with pale spots (areas without pigment showing pale cuticle underneath) throughout entire surface of abdomen (Figs 2B, E, F, 3A, B). Dorsal sclerite brown, sub-rectangular, around ¼ abdomen length. Relatively long, erect setae throughout abdomen giving hairy appearance (Figs 3A, B), hairs longer at final 1/3 of abdomen. Two roughly triangular white patches just posterior to dorsal sclerite (Figs 2B, 3A, B). Two strong spines present at anterior margin of dorsal sclerite. Venter lighter, with faint white markings where ventral sclerite is present in males (Fig. 2F). Epigastric sclerite weakly sclerotized, translucent orangish-brown.

Epigyne: Clearly visible externally (Fig. 2E). ST appear paddle-like, with large anterior ST II oval, posteriorly extending into narrower and smaller ST I, with indistinct separation. COs distinct, slit-like and longitudinal, situated lateral of posterior end of ST II, directed posterolaterally (Figs 3C–F).

Leg spination: I: F = d2 pl1 (rlv7 macrosetae), T = plv4 rlv4, Mt = plv2 rlv2; II: F = d3 (plv8 rlv8 macrosetae), T = plv4 rlv3, Mt = plv2 rlv2; III: F = d2 (plv9 rlv10 macrosetae), T = plv3 rlv4, Mt = plv2 rlv2; IV: F = d2, T = d3 (pl1), plv3 rlv3, Mt = d1, pld1 rld1, plv1 rlv2.