Figs 5–6
Type material. Holotype: ♂ from Estação Científica Ferreira Penna [01°42'24"S, 51°27'34.3"W], Floresta Nacional de Caxiuanã, Melgaço, Pará, Brazil, 14.IV.2006, J.A.P. Barreiros leg. (MPEG 29052).
Etymology. Noun in apposition taken from type locality. The final -n is added in order to mimic phonetics of the name of the locality.
Diagnosis. The embolic disc (with long dPED of rounded tip, prolaterally projected and short vPED ventrally projected; Figs 4 C, 6C) and pattern of scales on the carapace of A. caxiuanan sp. nov. (Fig. 5 A) are similar to those of A. mysticetus sp. nov. (Figs 1 A, 2A, 2C). However, A. caxiuanan sp. nov. can be distinguished from this species in having RvTA with rounded tip (Fig. 6 D), and a straight RTA (Fig. 6 B), while A. mysticetus sp. nov. has triangular RvTA tip (Fig. 4 D) and the RTA with the tip prolaterally curved over the cymbium (Fig. 4 B). In addition, it also differs from A. mysticetus sp. nov. by the curved, proximal, dorso-prolateral projection of the cymbium (Fig. 6 B), and a retrolateral depression on cymbium wherein the RTA fits (Fig. 6 D).
Description. Male holotype (MPEG 29052). Total length: 2.43. Carapace with a longitudinal stripe of white scales on carapace and tufts of brown scales laterally (Fig. 5 A), 1.33 long, 0.93 wide and 0.65 high. Ocular quadrangle 0.65 long. Anterior eye row 0.99 wide, posterior 0.84 wide. Legs: unknown (I–II lost). Length of leg III 2.44 (0.80 + 0.80 + 0.84); IV unknown (0.74 + 0.87 + broken). Palp (Figs 6 A–D): femur with a shallow distal depression, where the proximal tegular lobe fits when the palp is flexed (Fig. 6 A); embolic filament short, about half the length of the straight, sclerotized portion (Fig. 6 C). Color in alcohol: thoracic area dark brown and cephalic area black; abdomen dorsally brown and variegated; ventrally pale; legs brown (Fig. 5 A–B).
Female. Unknown.
Distribution. Known only from the type locality (Brazil, Pará) (Fig. 29).