Nerudiella americana ( Roewer, 1961 ), 2024

Porto, Willians, Derkarabetian, Shahan, Giribet, Gonzalo & Pérez-González, Abel, 2024, Systematic revision of the South American “ Nuncia ” (Opiliones, Laniatores, Triaenonychidae), ZooKeys 1207, pp. 1-149 : 1-149

Nerudiella americana ( Roewer, 1961) comb. nov.

Figs 68 , 69 , 70 , 71 , 72 , 73

Nuncia americana Roewer 1961: 102, pl. 19, figs 13–15; Cekalovic 1968: 6; Besch 1969: 733; Muñoz-Cuevas 1971 a: 873, fig. 28; Kury 2003: 21.

Nuncia (Nuncia) americana : Muñoz-Cuevas 1971 b: 98, figs 1–17; Cekalovic 1985: 11; Pérez-Schultheiss et al. 2021: 410 , fig. 2 c, f.

Material examined.

Paratypes. Chile. Chepu Peninsula, Chiloé , mixed woodland shrubs, 1 ♂, 1 ♀ ( SMF RII / 13414 ) .

Additional material.

Chile. Chiloé: Lago Huillinco, M. Ramírez, M. Izquierdo, P. Michalik, C. Wirkner, K. Huckstorf coll., 16. II. 2012, 12 imm. ( MACN), 5 km of Quellón, N. Platnick, R. Schuh coll., 01. XII. 1981, 4 ♂ 8 ♀ 26 imm. ( AMNH), Isla Chiloé, R. Schuh, N. Platnick coll., 29. XI. 1981, 4 ♂ 3 ♀ 2 imm. ( AMNH), Cruce a Coinco, T. Cekalovic coll., 14. II. 1983, 3 ♂ 2 ♀ 6 imm. ( MACN); Mocopulli, T. Cekalovic coll., 20. II. 1986, 1 ♂ 3 ♀ 5 imm. ( MACN), Isla Chiloé, T. Cekalovic coll., 02. II. 1983, 6 ♂ 5 ♀ 8 imm. ( MACN); Isla Chiloé, T. Cekalovic coll., 26. II. 1972, 3 imm. ( MACN), Piruquina, T. Cekalovic coll., 26. II. 1976, 1 ♂ 1 ♀ 1 imm. ( MACN), Crossroad to San Pedro, T. Cekalovic coll., 27. II. 1976, 4 imm. ( MACN), Piruquina, T. Cekalovic coll., 10. II. 1981, 2 ♂ 2 ♀ 1 imm. ( MACN), same collector, 19. II. 1983, 3 imm. ( MACN); Chepu, 15 m, N. Platnick, O. Francke coll., 02. 02. 1985, 1 ♂ 2 imm. ( AMNH); 15 km N. Chepu, M. Ramírez coll., 03. 02. 1991, 3 imm. ( MACN), 15 km S de Chepu, M. Ramírez coll., 20. 02. 1991, 1 imm. ( MACN), Lago Huillinco, M. Ramírez, M. Izquierdo, C. Wirkner, K. Huckstorf coll., 15. ii. 2012, 1 ♂ ( MACN), Chilloé island, 5 km N of Quellón, R. Schuh, N. Platnick coll., 01. 12. 1981, 1 imm. ( AMNH), 8 km Ancud, Isla Chiloé, N. Platnick, O. Francke coll., 01. 02. 1985, 6 ♀ 22 imm. ( AMNH), Isla Chiloé, 8 km S Ancud, S. Peck, J. Peck coll., 01. 02. 1985, 8 ♂ 5 ♀ 21 imm. ( AMNH), 5 km N of Quellón, N. Platnick, R. Schuh coll., 01. 12. 1981, 1 ♂ 1 ♀ 1 imm. ( AMNH); Chepu, E. Maury coll., 29. 11. 1981, 3 ♂ 1 ♀ 3 imm. ( MACN). Llanquihue: Salto Petrohue, S. Peck, J. Peck coll., 23. 12. 1984, 1 imm. ( AMNH).

Diagnosis.

This species stands out from the others in the genus due to its sturdy capsula externa and distinctive “ T ” - shaped dorsal fold. The capsula externa apex is extremely delicate. It can also be differentiated from almost all species of the genus using somatic characters (except from N. cautin sp. nov. and N. jaimei sp. nov.) by having the dorsal scutum with a low, broad-based tubercles.

Distribution.

Chile: Los Lagos Region (Fig. 4 F ).

Redescription of male

paratype SMF RII / 13414. Measurements: Total length 2.73, dorsal scutum length 2.21, carapace max. width 1.47, mesotergum max. width 1.95. Appendage measurements: Pedipalps. Trochanter length 0.28, femora length 0.97, patella length 0.61, tibia length 0.74, tarsus length 0.71. Leg I: trochanter (tr) 0.26, femora (fe) 0.92, patella (pa) 0.54, tibia (ti) 0.69, metatarsus (mt) 0.82, tarsus (ta) 0.70. II: tr 0.32, fe 1.16, pa 0.57, ti 0.93, mt 1.07, ta 1.14. III: tr 0.30, fe 0.71, pa 0.43, ti 0.65, mt 0.59, ta 0.72. IV: tr 0.39, fe 1.08, pa 0.70, ti NA, mt NA, ta NA.

Dorsum (Fig. 68 , 69 ). Eta (η) dorsal scutum in the shape of an hourglass. Ocularium slightly elevated. Dorsal scutum microgranulate with a group of low setiferous granules. Areas on scutum not clearly delimited. Along the back margin, with a row of low and broad setiferous granules. Free tergites with a row of low and broad setiferous granules.

Chelicerae (Fig. 70 A, B ). Segment I smooth in texture without prominent tubercles. Segment II with a small frontal tubercle and covered with scattered setae, giving it a textured appearance.

Pedipalps (Fig. 70 C, D ). Coxa I with a smooth surface without any notable tubercles. Trochanter with small tubercles on both the dorsal and ventral sides. In dorsal view, femora with three spines with subdistal setae. In ventral view, with one long bifurcated spine and two spines with subdistal setae. In mesal view, with six low setiferous tubercles on the femora. Patella with a mesal row of setiferous tubercles. Tibia with three ectal and two mesal spines with subdistal setae, and six low setiferous tubercles. Tarsus with three mesal and ectal spines with setae, with a few setae.

Legs (Fig. 71 ). Leg I with sparse setiferous tubercles. Leg II features two rows of setiferous tubercles, while legs III and IV exhibit only microgranulation without distinct tubercles. With three bridges connecting legs II and III, six bridges between legs III and IV, and four bridges connecting leg IV to the opisthosoma. Distal bridge longer than the others. Bridges do not obstruct the spiracles, although they appear partially covered with a subdistal tubercle. A smooth surface occupies ~ ¼ of leg II, ¾ of leg III, and 1 / 3 of leg IV. Sternum arrow-shaped. Femora III with a remarkable triangular tubercle. Leg IV with a row of four subtriangular tubercles. Legs I – IV covered in setae, with tarsal area and calcaneus densely setose. Calcaneus smaller than astragalus, ~ 3 × smaller in legs I – III, 4 × smaller in leg IV. Tarsal count: 4–6 – 4 – 4.

Penis (Figs 72 , 73 ). Pars distalis with a prominent ventral plate divided into two lamellae by a cleft. Each lamella equipped with three pointed macrosetae on the ventral surface and one on the dorsal surface. Dorsal and lateral surfaces covered by a capsula externa, with a cleft that separates the capsula externa into two halves. With an additional dorsolateral plate attached to the pars basalis. Capsula interna longer than capsula externa and partially covers ventral plate.

Female. Similar to male, with shorter pedipalpal femora.

Female measurements. Total length 2.88, carapace length 1.17, dorsal scutum length 2.21, carapace max. width 1.47, mesotergum max. width 2.07. Appendage Measurements: Pedipalps. Trochanter length 0.23, femora length 0.74, patella length 0.46, tibia length 0.58, tarsus length 0.62. Leg I: trochanter (tr) 0.21, femora (fe) 0.88, patella (pa) 0.50, tibia (ti) 0.65, metatarsus (mt) 0.79, tarsus (ta) 0.65. II: tr 0.32, fe 1.12, pa 0.56, ti 0.90, mt 0.98, ta 1.18. III: tr 0.32, fe 0.81, pa 0.46, ti 0.59, mt 0.67, ta 0.64. IV: tr 0.35, fe 1.16, pa 0.70, ti 0.89, mt 1.21, ta 0.87. Tarsal count: 3–6 – 4 – 4.

Figures

Figure 3. Phylogenetics relationships of Triaenonychidae, with clade names as discussed in the main text. Phylogeny is derived from the IQ-TREE analysis. Nodes without circles have < 95 % bootstrap support to AH-aLR and UFBoot.

Figure 4. Maps showing the distribution of the species used in this work. South America (Chile and western Argentina inset). Chile in green, Argentina / South America in grey. Terrestrial ecoregions (following Olson et al. 2001) highlighted in yellow (Chilean Matorral) and orange (Valdivian temperate forests).

Figure 68. Nerudiella americana comb. nov. habitus, male A dorsal view C lateral view E ventral view. Female B dorsal view D lateral view F ventral view. Scale bars: 1 mm. Species of Clade C, see Fig. 3.

Figure 69. Nerudiella americana comb. nov. male, SEM images of habitus A dorsal view B lateral view C, D ventral view. Scale bars: 500 µm (A, B, C); 200 µm (D).

Figure 70. Nerudiella americana comb. nov. chelicerae: mesal A ectal B Pedipalps: mesal C ectal D. Scale bars: 200 µm.

Figure 71. Nerudiella americana comb. nov. legs I A II B III C IV D. Scale bars: 200 µm (A, C); 500 µm (B, D).

Figure 72. Nerudiella americana comb. nov. penis: ventral A, B apical C lateral D, E dorsal F, G. Scale bars: 200 µm (A, D, F); 50 µm (B, C, G); 100 µm (E).

Figure 73. Nerudiella americana comb. nov. penis: ventral A apical B lateral C dorsal D. Colors: ventral plate (yellow), capsula externa (blue), capsula interna (red). Scale bars: 50 µm (A, B, D); 100 µm (C).