Silvanidae, "silvan flat bark beetles", is a family of beetles in the superfamily Cucujoidea, consisting of 58 described genera and about 500 described species. The family is represented on all continents except Antarctica, and is most diverse at both the generic and species levels in the Old World tropics. Silvanids generally are small, brownish, flattened, pubescent and densely punctured beetles ranging from 1.2-15mm in length, and mostly with a 5-5-5 tarsal formula. They have short, strongly clubbed, to very elongate antennae, and frequently grooves or carinae on the head and/or pronotum. Many genera have the lateral margins of the pronotum dentate or denticulate. The family is divided unequally into two subfamilies: Brontinae and Silvaninae. The Brontinae, arranged in two tribes of 10 genera each, are larger, loosely jointed beetles with long antennae, an especially elongate scape, inverted male genitalia, and mandibular mycangia. Both brontine tribes have recently been reviewed at the genus level. The Silvaninae, which has not been divided into tribes, consists of 48 genera of mostly smaller beetles characterized by their closed procoxal cavities, mostly without mandibular mycangia, and non-inverted male genitalia. The largest genera are Telephanus, Psammoecus, and Cryptamorpha and the Old World silvanine genus Airaphilus. There have been a number of major taxonomic studies in the Silvanidae in recent decades, including Halstead, Sen Gupta and Pal, Pal, and Karner. Investigations into the phylogenetic relationships within the family and between the Silvanidae and other cucujoids are at the preliminary stages. A phylogenetic analysis of the "primitive" cucujoids using morphological characters of larvae and adults found a close relationship between the Silvanidae and Cucujidae. A molecular phylogenetic study primarily aimed at clarifying the status of the more "advanced" cucujoids nevertheless included exemplars of the basal taxa. It showed a close relationship between Passandridae and Silvanidae, and a more distant one with Cucujidae.
Biology and habitats
Although all silvanids seem to be primarily fungivorous, the habitat where the various taxa are found varies. Members of the tribe Brontini primarily are found under dead bark, although Brontoliota are found on the outside of dead wood lying on the ground in wet forests and Protodendrophagus occur under rocks in alpine areas of New Zealand. Brontini do not have lobed tarsomeres. Members of Telephanini usually occur on withered, pendant leaves, especially of Musaceae and Heliconiaceae. Telephanini usually have lobed tarsomeres. Silvaninae are found in subcortical habitats as well as in leaf-litter and soil. Two genera, Nepharis and Nepharinus, are inquilines of ants in Australia, and two species of Coccidotrophus and one of Eunausibius occur in the petioles of ant-plants in the American tropics, where they feed on honeydew produced by a mealybug. Ten genera are represented by species that have been moved widely through commerce and now have worldwide or nearly worldwide distributions The most economically important genus is Oryzaephilus, with two common stored productspest species, the sawtoothed grain beetle, and O. mercator, and several others that are sporadic pests Other economically important stored products pests include Ahasverus advena, Cathartus quadricollis, and Nausibius clavicornis.
