The tribe Eustylini was named for the first time by Jean-Baptiste Henri Lacordaire in 1863, although, when first named, the tribe (Groupe Eustylides, p.205) only contained three genera: Aptolemus (currently in Naupactini), Brachystylus, and Eustylus.
In 1986 the Eustylini contained most of its current genera, mostly due to revised taxonomic placements made by Guillermo Kuschel. The latest additions were made by Franz in 2012 by transferring former members of other tribes including Geonemini, Phyllobiini, and Tanymecini.
The type species of some genera (Compsus, Diaprepes, Eustylus, Exorides, and Exophthalmus) were redescribed by Franz. Most species of Eustylini are only known from their original descriptions.
Description
A diagnosis for the tribe was offered by Girón 2020:
Medium to large weevils (approx. 10–25 mm); scale coverage highly variable in presence, density and coloration; iridescent scales, erect setae or waxy secretions are frequently present; surface smooth and even or strongly sculptured and irregular; head (including rostrum) subrectangular, nearly as long or longer than wide; eyes small to mid-sized, slightly dorsally positioned; frons usually as wide as or narrower than interantennal distance, often bearing median fovea; rostrum nearly parallel-sided or broadened apically; dorsal surface of rostrum with variable elevations or depressions, including longitudinal carinae or oblique fossae; antennal scrobe generally fully visible in dorsal view; nasal plate usually well developed, either depressed, flat or elevated regarding surface of rostrum; anterior margin of prothorax in lateral view straight, seldom slightly sinuate, never forming conspicuous postocular lobe; postocular setae may be present, if so, forming a fringe instead of a tuft; elytral shoulders usually well-developed, absent in Brachyomus, reduced in some Compsus and Exorides; tubercles and apical projections may be present on elytra; femora usually not toothed (except in some Eustylus).
—J.C. Girón, Status of knowledge of the broad-nosed weevils of Colombia (Coleoptera, Curculionidae, Entiminae).
1234Wibmer, G. J.; O’Brien, C. W. (1986). "Annotated checklist of the weevils (Curculionidae sensu lato) of South America (Coleoptera: Curculionoidea)". Memoirs of the American Entomological Institute. 39: 1–563.
↑O’Brien, C.W.; Wibmer, G.J. (1982). "Annotated checklist of the weevils (Curculionidae sensu lato) of North America, Central America, and the West Indies (Coleoptera: Curculionoidea)". Memoirs of the American Entomological Institute. 34: 1–382.