Arboriticus petropolis Borges and Bertani, 2025

Borges, Leandro Malta, Abegg, Arthur Diesel, Paladini, Andressa & Bertani, Rogério, 2025, A new genus and five new species of arboreal tarantulas (Araneae: Theraphosidae) from Brazil, Zootaxa 5679 (4), pp. 521-551 : 534-536

Arboriticus petropolis Borges and Bertani gen. nov. sp. nov.

( Figs 1 , 30 –37, 85)

Gen. sp. 6; Bertani, 2023: 14–15, 19, 23.

Diagnosis. Males resemble those of A. minor gen. nov. sp. nov. and A. tarsicrassus gen. nov. comb. nov. by the reduced male palpal bulb keels (Figs 32–34) in conjunction with the metatarsus I touching the retrolateral process of the tibial spur laterally when flexed. They can be distinguished from those of A. minor gen. nov. sp. nov. by the PP of tibial spur not thickened and the RP longer than the PP (Figs 35–37). From A. tarsicrassus gen. nov. comb. nov., they can be distinguished by the tegulum elongated and embolus tapering from the tegulum (Figs 32–34).

Etymology. The specific epithet refers to the type locality, the Municipality of Petropolis, state of Rio de Janeiro, Brazil, where the types were collected.

Type material. Holotype male from Brazil, state of Rio de Janeiro, Petrópolis [22º30’S, 43º10’W] 821 m a.s.l., J. C. Marques col., 25 March 1983, MNRJ 13258 ; Paratype male from same locality, J. P. L. Guadanucci & F. Cunha col., January 2000, IBSP 8523 .

Description. Holotype male ( Figs 30 –37) MNRJ 13258. Carapace 11.25 long, 10.37 wide, chelicerae 6.42. Legs (femur, patella, tibia, metatarsus, tarsus, total): I: 11.57, 5.47, 10.15, 9.53, 6.51, 43.23. II: 10.52, 5.40, 8.77, 8.37, 5.67, 38.73. III: 9.53, 4.94, 7.62, 8.35, 5.14, 35.58. IV: 11.24, 5.01, 10.10, 12.07, 5.51, 43.93. Palp: 7.21, 3.86, 6.01, –, 2.43, 19.51. Midwidths: femora I–IV = 1.58, 1.48, 2.04, 1.62, palp = 1.04; patellae I–IV = 1.65, 1.71, 1.73, 1.72, palp = 1.66; tibiae I–IV = 1.41, 1.20, 1.27, 1.21, palp = 1.51; metatarsi I–IV = 1.08, 1.06, 1.09, 1.01; tarsi I–IV = 1.04, 1.05, 1.07, 1.03, palp = 1.16. Abdomen 11.13 long, 6.71 wide. Spinnerets: PMS, 1.51 long, 0.47 wide, 0.71 apart; PLS, 2.08 basal, 1.62 middle, 2.35 distal; midwidths 0.76, 0.73, 0.58, respectively.

Carapace ( Fig. 30 ): 1.08 longer than wide; cephalic area moderately raised. Fovea: Straight, 1.83 wide. Eyes and eye tubercle: Tubercle 0.77 high, 1.36 long, 1.83 wide. Clypeus 0.17 wide. Sizes and inter-distances: AME 0.53, ALE, 0.57, PME 0.37, PLE 0.57, AME–AME 0.36, AME–ALE 0.26, AME–PME 0.14, ALE–ALE 1.40, ALE–PME 0.45, PME–PME 0.97, PME–PLE 0.09, PLE–PLE 1.50, ALE–PLE 0.16, AME–PLE 0.43. Eye group 2.24 wide, 1.10 long. Maxillae: Length 3.66, width 2.12. Cuspules ca. 146 spread over ventral inner heel. Labium: 1.17 long, 2.35 wide, with ca. 77 cuspules spaced by ca. one diameter from each other on anterior third center (Fig. 31). Chelicerae. Basal segment with 11 teeth in row on promargin and denticles in basal area. Sternum: 5.28 long, 4.58 wide. Sigilla: ovals, less than a diameter from margin (Fig. 31).

Legs: formula I= IV II III. Length leg IV to I: 1.02. Scopula: Tarsi I – IV fully scopulate, IV with a row of sparse setae. Metatarsi I fully scopulate; II 4 /5, III 1 /2, IV 1 /4 distal scopulate. Metatarsus IV divided by row of 3–4 setae. Spination: palp: femur 0, patella p1, tibia p0-1-2; leg I: femur 0, patella 0, tibia v0-1-1ap, metatarsus v0-0-1ap; leg II: femur 0, patella 0, tibia v0-1-2ap; metatarsus v0-1-3ap; leg III: femur 0, patella 0, tibia v0-1-2ap, p0-1-0, metatarsus v0-2-4ap, p0-1-1, r0-0-1; leg IV: femur 0, patella 0, tibia v1-2-4(2ap), r0-0-1, metatarsus v17(4ap), p0-0-1. Spiniform setae: few spiniform setae on superior area of retrolateral maxillae, absent on the coxae. STC: a single row of 6–9 small teeth on legs I– IV. Urticating setae: Only type I present, position and length range: MA (size 0.33–0.41). Distribution of urticating setae on the abdomen dorsum unknown due to a large bald area .

Palp (Figs 32–34). Bulb pyriform, embolus almost twice longer than tegulum length, slightly flattened at distal region, apex narrowing abruptly, forming more or less straight distal portion. Prolateral keels present. PS forming embolus edge distally. PI reduced. A keel not visible. R present, not pronounced. SA absent. Bifid tibial spur (Figs 35–37) with two straight processes originating from common base, RP longest. A single, flattened, rhomboidal spine contiguous to the internal upper face of the RP and another on the internal face of the PP. Metatarsus I roughly straight, when folded touches the retrolateral side of the retrolateral process (Fig. 35).

Color pattern (in alcohol): Carapace and chelicerae brown. Legs light brown with some light brown long setae. Coxae of legs ventrally and sternum brown, covered with short light brown setae. Labium and maxillae brown. Abdomen dorsally and ventrally black with long light brown setae. Femora, patellae, tibiae and metatarsi of legs and palp with very discrete light stripes. Apex of leg and palp segments with very discrete whitish rings on apex.

Distribution. Known only from the type locality, Petropolis, in the mountainous region of the state of Rio de Janeiro, Brazil ( Fig. 1 ).

Figures

FIGURE 1. Map of Brazil showing geographic records of Arboriticus gen. nov. species. Dots represent type localities, squares additional localities, and triangles correspond to records of undetermined collected specimens, which are likely undescribed species.

FIGURES 30─37. Arboriticus petropolis gen. nov. sp. nov., holotype male. 30, carapace and chelicerae, dorsal. 31, sternum, labium, maxillae, and coxae, ventral. (32–34) right palp bulb. 32, retrolateral. 33, prolateral. 34, dorsal. (35─37) left tibial apophysis. 35, retrolateral. 36, prolateral. 37, ventral. Scale bar = 1 mm.