Arboriticus, Borges & Abegg & Paladini & 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 : 523-525

Arboriticus gen. nov. Borges and Bertani

( Figs 1 –88)

Eupalaestrus : Mello-Leitão, 1923: 221, figs 104, 105; Pérez-Miles, 1992: 34; Bertani, 2001: 283, figs 19, 56, 57 (in part: E. spinosissimus ); Bücherl, 1947: 298, 1 plate (in part, E. tarsicrassus ).

Type species: Arboriticus celsoi Borges & Bertani gen. nov. sp. nov.

Species included: Arboriticus celsoi Borges & Bertani gen. nov. n. sp, A. tarsicrassus ( Bücherl, 1947) gen. nov. comb. nov., A. spinosissimus ( Mello-Leitão, 1923) gen. nov. comb. nov., A. petropolis Borges & Bertani gen. nov. sp. nov., A. minor Borges & Bertani gen. nov. sp. nov., A. giganteus Borges & Bertani gen. nov. sp. nov., A. maculatus Borges, Abegg & Bertani gen. nov. sp. nov.

Diagnosis: Males of most species (except A. giganteus gen. nov. sp. nov.) resemble Parvicarina Galleti-Lima, Hamilton, Borges & Guadanucci by having the male palpal bulb embolus without accessory prolateral keels and with PI, PS, R (most species) (Figs 63–65) and A weakly developed. From Parvicarina , they can be distinguished by having a straight or slightly curved metatarsus I and the PI without denticles. Males of A. giganteus gen. nov. sp. nov. resemble those of Lasiodora Koch , Lasiocyano Galleti-Lima, Hamilton, Borges & Guadanucci , Vitalius Lucas, Silva Junior & Bertani , Pterinopelma Pocock , Tekoapora Galleti-Lima, Hamilton, Borges & Guadanucci , and Crypsidromus Ausserer by having the palpal bulb with a SA keel (Figs 48–50). They differ from the first by the absence of stridulating setae, from the other genera above by the tibia of leg IV slightly incrassate ( Fig. 59 ), and presence of a shield of spiniform setae on retrolateral coxa III, as well as spiniform setae on basal prolateral coxae II, III, and IV. Females, except those of A. maculatus gen. nov. sp. nov., resemble those of Cotztetlana Mendoza by the presence of incrassate tibia and metatarsus IV covered both with stiff setae (Fig. 60). From Cotztetlana , they can be distinguished by the spiniform setae mainly on prolateral and retrolateral coxae II–IV (Fig. 58). Arboriticus maculatus gen. nov. sp. nov. female resembles those of Nhandu Lucas and some Vitalius species by lacking stridulatory setae on the coxae in conjunction with short spermathecae with stalks as wide as spermathecae bulbs and the area between them very sclerotized (Fig. 71). They can be distinguished by the general light brown color with pinkish setae on legs and abdomen, in addition to the presence of black dots on leg and palp segments (Fig. 79).

Etymology. The generic name is a composition of the Latin word arbor (= tree) and the suffix “ticus” (= belonging to) meaning ‘which belongs to trees”, due to arboreal habits of its species. The gender is masculine.

Description. Carapace longer than wide. Cephalic area moderately to noticeably raised, well-visible thoracic striae. Deep fovea, straight, slightly procurved or slightly recurved. Carapace covered with short, dense setae, bordered by short setae pointing out. Rastellum absent. Ocular tubercle wider than long.Anterior eye row procurved, posterior row recurved. Clypeus short. Maxillae with 115–302 cuspules. Lyra absent. Labium wider than long, with 77–147 cuspules. Shallow, flattened labium-sternal groove with two large sigilla. Sternum slightly longer (most species) or much longer than wide ( A. minor gen. nov. sp. nov.), covered with short setae. Posterior angle rounded, not separating coxae IV. Sigilla rounded or oval. Leg formula: IV, I, II, III (females and male of A. giganteus gen. nov. sp. nov.) or I=IV, II, III (most males and female of A. maculatus gen. nov. sp. nov.). Females with thickened tibia IV, especially at the distal end (except A. maculatus gen. nov. sp. nov.). Slightly thickened tibia IV in males of A. giganteus gen. nov. sp. nov. Females with metatarsus IV thickened at base (most species) or metatarsus IV unmodified ( A. maculatus gen. nov. sp. nov.). Both tibia IV and metatarsus IV of females covered with stiff setae in the basal half (most species) or setae unmodified ( A. maculatus gen. nov. sp. nov.). Clavate trichobothria on distal 2/3 of tarsi I–IV. Stridulatory apparatus absent. Spiniform setae on most prolateral and retrolateral surfaces of coxae of females (except A. maculatus gen. nov. sp. nov.) and male of A. giganteus gen. nov. sp. nov. A few spiniform setae on superior retrolateral maxilla of males (most species), sometimes on coxae I–IV of males ( A. minor gen. nov. sp. nov., A. maculatus gen. nov. sp. nov.) and female of A. maculatus gen. nov. sp. nov. Retrolateral face of femur IV scopulate. Tarsi I–IV fully scopulate. Metatarsi I–II fully scopulate (most species) or 2/3 scopulate ( A. minor gen. nov. sp. nov.), III 1/2 or 3/5, IV 1/6 to 1/4 distal scopulate. Scopula of metatarsus IV divided by a row of 1–4 setae, III undivided (most species) or divided by a row of sparse setae ( A. minor gen. nov. sp. nov.). Claws: a single claw lacking tooth on palp; STC with a single row of 2–9 small teeth on legs I–IV, bare on some legs in A. tarsicrassus gen. nov. comb. nov. and A. maculatus gen. nov. sp. nov. males. ITC absent. Type I urticating setae present, sometimes type III also present in males ( A. celsoi gen. nov. sp. nov.). Bulb pyriform, embolus slightly longer than tegulum length ( A. tarsicrassus gen. nov. comb. nov., A. minor gen. nov. sp. nov., A. giganteus gen. nov. sp. nov., A. maculatus gen. nov. sp. nov.) to twice tegulum length ( A. celsoi gen. nov. sp. nov., A. petropolis gen. nov. sp. nov.). Embolus slightly flattened at distal region (most species) or conical ( A. celsoi gen. nov. sp. nov.). Apex of embolus narrowing abruptly, forming a more or less straight distal portion ( A. tarsicrassus gen. nov. comb. nov., A. celsoi gen. nov. sp. nov., A. petropolis gen. nov. sp. nov., A. minor gen. nov. sp. nov., A. maculatus gen. nov. sp. nov.) or apex short and thick ( A. giganteus gen. nov. sp. nov.). Prolateral keels present, PS forming embolus edge distally. PI reduced ( A. tarsicrassus gen. nov. comb. nov., A. celsoi gen. nov. sp. nov., A. petropolis gen. nov. sp. nov., A. minor gen. nov. sp. nov.) or unmodified ( A. giganteus gen. nov. sp. nov., A. maculatus gen. nov. sp. nov.). A keel small (most species) or absent ( A. petropolis gen. nov. sp. nov.). R not pronounced (most species), sharp ( A. giganteus gen. nov. sp. nov.), or absent ( A. celsoi gen. nov. sp. nov.). SA absent (most species) or present ( A. giganteus gen. nov. sp. nov.). Bifid tibial spur with two roughly straight to slightly curved processes originating from a common base (most species) or reduced in size, convergent processes and thickened PP ( A. minor gen. nov. sp. nov.). Metatarsus I straight ( A. minor gen. nov. sp. nov. and A. petropolis gen. nov. sp. nov.) or curved at its base ( A. maculatus gen. nov. sp. nov., A. tarsicrassus gen. nov. comb. nov., A. giganteus gen. nov. sp. nov., A. celsoi gen. nov. sp. nov.); when folded touches the retrolateral process laterally (most species) or on process apex ( A. celsoi gen. nov. sp. nov.). Two short spermathecae separated by a short weakly sclerotized area (most species) or with heavily sclerotized short area ( A. maculatus gen. nov. sp. nov.). Uniform color pattern ranging from dark brown to nearly black (most species), or light brown with purple setae and dark spots on the legs ( A. maculatus gen. nov. sp. nov.).

Distribution. All species are endemic to the Brazilian Atlantic Forest, ranging from the state of São Paulo to the southern coast of the state of Bahia, across the states of Minas Gerais, Rio de Janeiro, and Espírito Santo, in Brazil. They can be found in both lowlands and highlands within this region, encompassing the coastal areas, islands, Serra do Mar, Vale do Paraíba, and Serra da Mantiqueira ( 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 59─60. Arboriticus giganteus gen. nov. sp. nov., habitus, dorsal. 59, holotype male. 60, paratype female.