DESCRIPTION: Holotype female. Length 12.8 mm; width: 3 mm. Form moderately sized, elongate, subcylindrical. Integument dark brown, lighter brown on legs and last eight antennomeres; clothed with recumbent white, ochraceous and dark brown pubescence. Head: Front trapezoidal, narrower toward base, sides elevated and carinate; clypeus depressed medially and separated from the front by a oblique furrow, deeper at sides, with median line extending from clypeus to vertex; depressed longitudinally between antennal tubercles and vertex; eyes with lower lobes 1.6× longer than genae, upper lobes same width as base of scape and separated by 3.4× its width; pubescence whitish, moderately dense, not obscuring integument; antennae 0.8× body length; antennal formula (proportion) based on length of third segment: scape = 0.55, II = 0.22, IV = 0.66, V = 0.61, VI = 0.5, VII = 0.38, VIII = 0.36, IX = 0.33, X = 0.3, XI = 0.3; antennomeres clothed with erect, long brown setae, denser on basal segments, becoming scarce toward apical segments and semierect, short pale pubescence from antennomere VI to XI. Thorax: Pronotum 1.2× as long as broad; base 1.05× wider than apex; sides widely rounded at middle, base strongly constricted and apex slightly constricted; apex and base depressed transversally; disc strongly convex, with midline evident, depressed on basal half; with a low obtuse tubercle each side of midline at base of apical half and slightly prominent callus behind each tubercle; punctures very small, contiguous, dense, giving integument an areolate appearance, except slightly bigger and deeper setiferous punctures; disc with a middle transverse band of dark brown pubescence, which crosses the tubers and extends to both sides; backward and contiguous to the band, a middle area of golden pubescence, which extends to the basal depression and is wider anteriorly, an oblique fascia on each side of bright whitish pubescence; rest of pronotum with whitish, less dense pubescence and gold hairs interspersed. Prosternum with apical half glabrous, smooth, and with blunt transverse fold extending from one side to the other, basal half with fine, dense punctation, giving integument an areolate appearance, and whitish pubescence not obscuring integument; procoxal process very narrow, curved, with apex expanded, forming horizontal subrectangular plate; procoxal cavities closed behind by moderately broad, smooth, glabrous ridge extending nearly to stridulatory plate of mesonotum; mesosternum with whitish pubescence and mesocoxal process narrow, 0.2× width of coxa; metasternum convex, inclined anteriorly, almost glabrous, smooth at base and the rest superficially punctured, with whitish pubescence anteriorly and laterally. Scutellum subrectangular, convex, with sides depressed medially, angles of apex moderately prominent, pale brown with margins dark brown, clothed with whitish pubescence. Elytra: 2.2× as long as wide; nearly parallel sided, feebly impressed at middle; apices rounded; with three areas of whitish pubescence: a narrow band contiguous to base, elongate semicircular fasciae extending from behind humeri to elytral half, medially nearly reaching sutural margin and becoming narrower posteriorly; apical fourth with appressed pubescence, front margin oblique on each side; golden pubescent between basal band and semicircular fasciae; area between semicircular fasciae and apical fourth dark brown pubescent with widely dispersed erect setae. Abdomen: with scattered setae; last sternite with apices rounded and middle feebly emarginate. Legs: with femora clavate, profemora enlarged nearly from base with pedicel of meso- and metafemora almost as long as clavate portion, clothed with erect, sparse, long setae; tibial setae more abundant and longer than femoral setae, protibiae curved with meso- and metatibiae straight.
TYPE MATERIAL: Holotype female, MEXICO: Veracruz: Municipio de San Andrés Tuxtla, Estación Biológica de los Tuxtlas, 480 m, El Vigía, 1.VII.1986, P. Sinaca, CNIN 06180.
DIAGNOSIS: This species can be distinguished from A. tubericollis Bates, 1885, by the pronotal shape and the pubescent pattern of elytra. In A. santossilvai the anterior pronotal depression slopes gradually from the tubercles toward the apex and is deeper at the middle and superficial toward the sides, making the sides of the pronotum more widely rounded. In A. tubericollis, the anterior pronotal depression slopes abruptly from the tubercles to its lower part, covering the entire apical quarter; from the middle to the sides it is equally deep, making the sides of the pronotum more rounded. In A. santossilvai the whitish semicircular median fascia on the elytra is elongate, not reaching the sutural margin, it becomes narrow posteriorly; appressed pubescence on the apical fourth with front margin oblique on each side. In A. tubericollis, the semicircular median fascia is short but reaches the elytral suture, forming an X, and the appressed pubescence on the apical fourth has its front margin curved.
ETYMOLOGY: We dedicate this species to Antonio Santos Silva (MZSP) in recognition of his helpful demeanor and his many contributions to our knowledge of the Neotropical Cerambycidae.