Allometopon Kertesz is a relatively uncommon genus most closely resembling small Sobarocephala and a few pale Hendelia, but the anterior fronto-orbital bristle is reclinate, there are no dorsal preapical tibial bristles, and the surstylus is usually larger and elaborately sculptured. All other clusiids with a reclinate anterior fronto-orbital have well-developed dorsal preapical bristles on both the mid and hind tibiae. Allometopon species are also smaller than most clusiids (often being less than 4.0 mm in length), and most species have a reduced postvertical bristle, a reflective and ventrally wide occiput, a posteriorly removed and reduced anterior dorsocentral, and a predominantly yellow body with a variable brown pattern (although some species have a predominantly brown notum).
Like genera in the Sobarocephalinae, Allometopon has retained a relatively “ancestral” morphology, strongly contrasting with the derived appearance of other extant clusiodine genera. Allometopon is, however, placed in the subfamily Clusiodinae along with these derived genera because it has the following characters that define the group: longitudinally segmented spermathecae; no ventrolateral lobes on the hypandrium; entirely reclinate fronto-orbitals; no presutural intra-alar bristle.
Allometopon is predominantly southeast Asian in distribution, but a few species also occur in Japan, Australia and the Seychelles. There are 14 described species in the genus, but there are also numerous undescribed species throughout the Indoaustralian Region. Because of its ambiguous basal position in the Clusiodinae and its possible relationship to the extinct genus Electroclusiodes Hennig, Allometopon is of special interest with regard to the evolutionary history and biogeography of the Clusiidae.
Fourteen species of Allometopon have been named but we are aware of numerous undescribed Oriental and Australasian species. Frey (1960) described two subgenera (Calometopon and Allometopon s.s.) for the five species known at the time, but these will likely prove to be of little phylogenetic value. A revision of this relatively small but diverse genus is currently being developed (Lonsdale, in manuscript).
North American species: None.