French Guiana, Apatou, Crevette river, one female (holotype), deposited in the MNHN, J. Chevalier & P. Gallier coll., 30/VI/2017. Apatou, Crevette river, four females (paratypes), deposited in the EYPC, EY0094, J. Chevalier & P. Gallier coll., 30/VI/2017.

The specific name refers to the ethnic group Aluku, living in the area where the new species was found.

Total length ranging from 20.4 to 21.5 mm (20.9 mm in total length for female holotype; see morphometric values after the description). Coloration reddish brown, with carapace, chelicerae, pedipalps and legs marked with darker spots. Tergites brownish with confluent reddish yellow spots, on the sides and the middle of tergites, forming a yellowish longitudinal median stripe. Posterior half of ventral side of segments I to IV yellowish, without spots. Body and appendages almost smooth, shiny; chela weakly granulated, dorso-internal carina inconspicuous; ventral posterior spinoid granulations on metasomal segment V. Pectines of female holotype and paratypes with 5–6 to 6–6 teeth; male unknown. Trichobothrial pattern of type C neobothriotaxic ‘majorante’.

Coloration. General coloration reddish brown. Carapace reddish yellow, marked with brownish variegated spots around the ocular tubercle and on the anterior and posterior edges of the carapace; ocular tubercle darker, almost black. Tergites brownish with confluent reddish yellow spots, on the sides and the middle of tergites, forming a yellowish longitudinal median stripe. Venter and sternites yellowish; sternum yellowish with darker spots on the middle and anterior edge; genital opercle yellowish; pectines pale yellow. Metasomal segments reddish yellow, marked with variegated brownish spots on lateral and dorsal sides of segments I to V and on ventral side of segments IV and V; posterior half of ventral side of segments I to IV yellowish, without spots. Vesicle reddish yellow with basis of aculeus blackish and tip of aculeus reddish. Chelicerae yellowish, with variegated dark brown spots; fingers reddish yellow; teeth reddish. Pedipalps reddish yellow, with longitudinal dark brown spots. Legs yellowish, intensely marked with brownish spots.

Carapace acarinate, shiny, and almost smooth, with only some minute granulations on lateral edges; furrows shallow; anterior edge emarginate. Tergites acarinate, shiny, and almost smooth. Sternum pentagonal, wider than long. Pectinal tooth count 6–6 in female holotype (5–6 to 6–6 in females paratypes), fulcra absent. Sternites smooth and shiny, VII acarinate; spiracles rounded in shape. Only metasomal segments IV and V longer than wide; metasomal tegument almost lustrous, without granulation, and with a few punctations; segment V with posterior spinoid granulation ventrally; carinae on segments I-V vestigial or absent; only dorso-lateral carinae are weakly marked on segments I to IV. Pedipalp femur with dorsal internal, dorsal external and ventral internal carinae moderately marked, internal face weakly granular, other faces smooth; patella smooth, with vestigial carinae; chela weakly granulated, almost smooth, with dorso-internal carina weakly marked; dentate margins on fixed and movable fingers with six rows of granules. Chelicerae with dentition typical of the family Chactidae (Vachon, 1963), and with dense setation ventrally and internally. Trichobothriotaxy of type C; neobothriotaxic ‘majorante’ (Vachon, 1974). Morphometric values (in mm) of the female holotype. Total length including telson, 20.9. Carapace: length, 3.2; anterior width, 1.9; posterior width, 3.2. Mesosoma length, 7.2. Metasomal segments. I: length, 1.3; width, 2.0; II: length, 1.3; width, 1.7; III: length, 1.4; width, 1.5; IV: length, 1.7; width, 1.4; V: length, 2.6; width, 1.2; depth, 1.2. Telson: length, 2.2; width, 1.1; depth, 0.8. Pedipalp: femur length, 1.5, width, 0.9; patella length, 2.1, width, 1.0; chela length, 4.6, width, 2.1, depth, 1.7; movable finger length, 2.3.

Auyantepuia aluku sp. n. can be readily distinguished from other species of the genus Auyantepuia and, in particular, from the three species occurring in the northern part of French Guiana and Suriname, by the following main features:

– A. laurae Ythier, 2015 (described from Saut Sabbat, Mana): (i) smaller size (27.5 to 28.2 mm in total length for A. laurae), (ii) tergites with confluent reddish yellow spots forming a yellowish longitudinal median stripe (no stripe in A. laurae), (iii) posterior half of ventral side of segments I to IV yellowish, without spots (ventral side of segments I to III entirely yellowish, without spots in A. laurae).

– A. gaillardi Lourenço, 1983 (described from Saint-Laurent-du-Maroni): (i) smaller size (26.9 mm in total length for the female of A. gaillardi), (ii) carapace, tergites, chelicerae, pedipalps and legs marked with darker spots (uniform coloration without darker spots in A. gaillardi), (iii) posterior half of ventral side of segments I to IV yellowish, without spots (all segments uniformly reddish in A. gaillardi).

– A. surinamensis Lourenço & Duhem, 2010 (described from Albina/Moengo, Suriname): (i) tergites with confluent reddish yellow spots forming a yellowish longitudinal median stripe (no stripe in A. surinamensis), (ii) posterior half of ventral side of segments I to IV yellowish, without spots (all segments reddish uniformly and intensely marked with brownish spots in A. surinamensis).