Arboriticus celsoi 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 : 525-529

publication ID	https://doi.org/10.11646/zootaxa.5679.4.4
publication LSID	lsid:zoobank.org:pub:FBAE6047-FC82-4A66-9FF7-80F9DC768E4E
persistent identifier	https://treatment.plazi.org/id/03EC1C29-FFE2-FF82-FF7A-FA4E6A8AFDD1
treatment provided by	Plazi
scientific name	Arboriticus celsoi Borges and Bertani
status	gen. nov.

Treatment

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

( Figs 1 View FIGURE 1 –14, 74–76, 81, 85)

Gen. sp. 4; Bertani, 2023:14–15, 19, 23

Diagnosis. Males resemble those of A. maculatus gen. nov. sp. nov. by the reduced male palpal bulb keels (Figs 4–6) in conjunction with the metatarsus I touching the apex of the retrolateral process when flexed. They can be distinguished from those of A. maculatus gen. nov. sp. nov. by the very reduced bulb keels PS, PI, A, lacking the R keel (Figs 4–6) and the longer than wide sternum (Fig. 3). Females resemble those of A. spinosissimus gen. nov. comb. nov., A. giganteus gen. nov. sp. nov., and A. tarsicrassus gen. nov. comb. nov. by the incrassate metatarsus IV with stiff setae (Fig. 76). They can be distinguished from those of A. giganteus gen. nov. sp. nov. and A. tarsicrassus gen. nov. comb. nov. by having the spermathecae stalk width equal to the not sub-spherical bulb (Fig. 12). From A. spinosissimus gen. nov. comb. nov., they can be distinguished by the retrolateral ventral area of maxillae lacking spiniform setae.

Type material. Holotype male from Brazil, state of Minas Gerais, Juiz de Fora (21º44’23.10” S, 43º17’30.69” W), C. Rios col., February 2015, MZUSP 78856 View Materials GoogleMaps ; Paratype female, same data ( MZUSP 78857 View Materials ) GoogleMaps ; Paratype male from Brazil, state of Rio de Janeiro, Guapimirim, Serra dos Órgãos, Estrada do Garrafão [22º28’S, 42º59’W] 730 m a.s.l., A. C. Caparelli, 03 March 2003, MNRJ 12945 View Materials GoogleMaps .

Other material examined. BRAZIL: Rio de Janeiro: Itatiaia, Parque Nacional do Itatiaia [22º25’ S, 44º36’ W], 1 male, V. M. Ghirotto col., I.2017, (CAD 1652), 4 females, same collection data, ( CAD 1648, CAD 1649, CAD 1650, CAD 1651); same location, 2 males, W. Moeller col., 13.III.2022, ( CAD 1277, CAD 1278) GoogleMaps .

Etymology. The specific name is a patronym in honor of the Brazilian biologist Celso Rios who collected the types.

Description. Holotype male ( Figs 2 View FIGURES 2 –9) MZUSP 78856. Carapace 12.22 long, 10.71 wide, chelicerae 3.62. Legs (femur, patella, tibia, metatarsus, tarsus, total): I: 11.90, 5.93, 9.46, 9.88, 6.70, 43.87. II: 10.85, 5.44, 8.18, 8.99, 6.08, 39.54. III: 9.86, 4.61, 7.59, 8.98, 5.26, 36.30. IV: 12.04, 5.29, 10.92, 12.88, 5.93, 47.06. Palp: 7.36, 4.12, 6.52, –, 3.11, 21.11. Midwidths: femora I–V = 2.03, 2.06, 2.77, 2.31, palp = 1.52; patellae I–IV = 2.22, 2.12, 2.28, 2.30, palp = 1.81; tibiae I–IV = 1.87, 1.67, 1.78, 1.80, palp = 2.04; metatarsi I–IV = 1.21, 1.20, 1.30, 1.50; tarsi I–IV = 1.14, 1.14, 1.17, 1.14, palp = 1.76. Abdomen 13.15 long, 8.01 wide. Spinnerets: PMS, 1.47 long, 0.69 wide, 0.27 apart; PLS, 2.42 basal, 1.67 middle, 2.20 distal; midwidths 1.27, 1.14, 0.82, respectively.

Carapace ( Fig. 2 View FIGURES 2 ): 1.14 longer than wide; cephalic area moderately raised. Fovea: Straight, 1.08 wide. Eyes and eye tubercle: Tubercle 0.60 high, 1.38 long, 2.46 wide. Clypeus 0.26 wide. Sizes and inter-distances: AME 0.42, ALE, 0.42, PME 0.24, PLE 0.34, AME–AME 0.26, AME–ALE 0.16, AME–PME 0.14, ALE–ALE 1.49, ALE–PME 0.32, PME–PME 1.03, PME–PLE 0.11, PLE–PLE 1.57, ALE–PLE 0.39, AME–PLE 0.44. Eye group 2.43 wide, 1.05 long. Maxillae: Length 3.81, width 1.98. Cuspules ca. 115 spread over ventral inner heel. Labium: 1.39 long, 1.64 wide, with ca. 133 cuspules spaced by ca. one diameter from each other on anterior third center (Fig. 3). Chelicerae: Basal segment with 9 teeth in row on promargin and denticles in basal area. Sternum: 5.79 long, 4.54 wide. Sigilla: first pair rounded, second and third ovals (Fig. 3).

Legs: formula I= IV II III. Length leg IV to I: 1.07. Scopula: Tarsi I – IV fully scopulated. Metatarsi I – II fully scopulated; III 1 /2, IV 1 /4 distal scopulated. Metatarsus IV divided by row of 1–2 setae. Spination: palp: femur 0, patella 0, tibia v0-0-1; leg I: femur p0-0-1; patella 0, tibia v0-1-0, p1-0-1, r0-0-1ap, metatarsus v0-0-1ap; leg II: femur p0-0-1, patella 0, tibia v0-1-2ap, p0-1-2, metatarsus v0-0-3ap; leg III: femur r0-0-1, patella 0, tibia v0- 2-2ap, p1-1-1, r1-1-1, metatarsus v0-3-4ap, p1-1-1, r0-1-1; leg IV: femur r0-0-1, patella 0, tibia v0-4-2ap, r1-1-1, metatarsus v19(4ap), p0-1-1, r0-1-1. Spiniform setae: absent on retrolateral and prolateral maxilla and coxa I, some conspicuous setae on superior, median, and inferior areas of retrolateral coxa II, none on prolateral area; several on superior and inferior areas of retrolateral coxa III, none on retrolateral coxa IV, few on prolateral superior and inferior areas of coxae III and IV. STC: single row of 4–7 small teeth on legs I– IV. Urticating setae: Type I: Position and range: LA, 0.45–0.62; LM, 0.52–0.55; MA, 0.40–0.60; MM, 0.66–0.70, MP, 0.36–0.53; type III: LM, 0.63–0.65, LP, 0.55–0.61, MM, 0.66–0.70. Distribution of setae on the abdomen dorsum as fig. 7 in Bertani & Guadanucci (2013) .

Palp (Figs 4–6). Bulb pyriform, embolus almost twice as long as tegulum length, conical, retrolateral area slightly convex, apex narrowing abruptly, forming more or less straight distal portion. Prolateral keels present. PS forming embolus edge distally. PI reduced. A keel short, directed prolaterally. R absent. SA absent.

Bifid tibial spur (Figs 7–9) with two straight processes originating from common base, RP longest and with slight curvature on distal portion. A single, flattened, rhomboidal spine contiguous to internal upper face of the RP and another on internal face of PP.

Metatarsus I curved at its basal third, when folded touches apex of retrolateral process (Fig. 7).

Color pattern (in alcohol): Carapace and chelicerae brown. Legs brown with some light brown long setae. Coxae of legs ventrally and sternum brown, covered with short light brown setae. Labium and maxillae reddish 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 discrete whitish rings.

Description. Paratype female ( Figs 10 View FIGURES 10 –14) MZUSP 78857. Carapace 15.36 long, 13.27 wide, chelicerae 9.30. Legs (femur, patella, tibia, metatarsus, tarsus, total): I: 11.34, 6.51, 8.57, 7.84, 5.87, 40.13. II: 10.41, 5.94, 7.25, 6.87, 5.15, 35.62. III: 9.34, 5.31, 6.91, 7.72, 4.81, 34.09. IV: 12.84, 6.07, 9.93, 12.39, 5.12, 46.35. Palp: 8.18, 4.85, 5.68, –, 5.81, 24.52. Midwidths: femora I–V = 1.68, 1.85, 2.45, 2.07, palp = 1.65; patellae I–IV = 2.13, 2.17, 2.68, 2.60, palp = 1.99; tibiae I–IV = 1.93, 2.03, 2.37, 2.68, palp = 1.96; metatarsi I–IV = 1.73, 1.76, 1.78, 2.92; tarsi I–IV = 1.65, 1.64, 1.62, 1.60, palp = 1.88. Abdomen 20.88 long, 15.60 wide. Spinnerets: PMS, 2.08 long, 1.19 wide, 2.04 apart; PLS, 3.32 basal, 2.65 middle, 3.42 distal; midwidths 1.63, 1.45, 1.11, respectively.

Carapace ( Fig. 10 View FIGURES 10 ): 1.15 longer than wide; cephalic area moderately raised. Fovea: Straight, 2.66 wide. Eyes and eye tubercle: Tubercle 0.87 high, 1.69 long, 2.98 wide. Clypeus 0.35 wide. Eye sizes and inter-distances: AME 0.53, ALE, 0.70, PME 0.45, PLE 0.53, AME–AME 0.37, AME–ALE 0.27, AME–PME 0.27, ALE–ALE 1.86, ALE–PME 0.41, PME–PME 1.48, PME–PLE 0.13, PLE–PLE 2.16, ALE–PLE 0.26, AME–PLE 0.74. Eye group 2.98 wide, 1.29 long. Maxillae: Length 5.12, width 3.19. Cuspules ca. 233 spread over ventral inner heel. Labium: 2.18 long, 2.95 wide, with ca. 101 cuspules spaced by ca. one diameter from each other on the anterior third center (Fig. 11). Chelicerae: Basal segment with 10 teeth on promargin and denticles on basal area. Sternum: 7.57 long, 5.76 wide. Sigilla: first pair rounded, second and third ovals, all less than one diameter from margin (Fig. 11).

Legs: formula IV I II III. Length leg IV to leg I: 1.15. Scopula: Tarsi I – IV fully scopulated. Metatarsi I – II fully scopulated; III 1 /2, IV 1 /5 distal scopulated. Metatarsus IV divided by row of 3–4 setae. Spination: palp: femur 0, patella 0, tibia v0-0-5(2ap), p0-1-1; leg I: femur p0-0-1; patella 0, tibia v0-0-2ap, metatarsus v0-0-1ap; leg II: femur 0, patella 0, tibia v0-0-2ap, p0-2-0, metatarsus v0-0-2ap; leg III: femur r0-0-1, patella 0, tibia v0-2-2ap, p0-1-1, r1-1- 1, metatarsus v0-2-4ap, p1-1-1, r0-1-1; leg IV: femur r0-0-1, patella 0, tibia v0-1-4(3ap), p0-0-1, r1-0-1, metatarsus v21(4ap), p0-1-1, r0-1-1. Spiniform setae: a few, in line on median prolateral maxilla, few on superior retrolateral maxilla; some, sparse, on superior and middle of prolateral coxa I, few on superior and inferior retrolateral coxa I, some, sparse on prolateral superior, middle and inferior coxa II, retrolateral coxa II almost fully covered with spiniform setae, prolateral coxa III with sparse spiniform setae on superior, middle and inferior areas, prolateral coxa III and prolateral coxa IV with black shield of spiniform setae (Figs 13–14). STC: single row of 4–7 small teeth on legs I– IV. Metatarsus IV incrassate, mainly on its basal portion, covered with stiff setae. Urticating setae: Only type I present, position and length range: LA, 0.20–0.21, LM, 0.21–0.23, LP, 0.22–0.25, MA, 0.18–0.21, MM, 0.40–0.45, MP, 0.29–0.33. Distribution of setae on the abdomen dorsum as fig. 5 in Bertani & Guadanucci (2013) .

Spermathecae: Two very short spermathecae separated by weakly sclerotized area, spermathecal stalk narrower on external side than short spermathecal bulb (Fig. 12).

Color pattern (in alcohol): Carapace and chelicerae dark brown. Legs dark 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 black with long light brown setae, ventrally light brown. Femora, patellae, tibiae and metatarsi of legs and palp with very discrete light stripes. Apex of leg and palp segments with whitish rings on apex.

Distribution. Forested environments of the Serra da Mantiqueira and Serra do Mar (state of Rio de Janeiro) and the Zona da Mata region (state of Minas Gerais), Southeastern Brazil ( Fig. 1 View FIGURE 1 ).