01114nas a2200133   4500008004100000245009600041210006900137300001200206490000700218520067000225100001600895700001700911856005200928       2010                        eng d00aAntiquity and Evolution of Prosternal Horns in Baridine Weevils (Coleoptera: Curculionidae)0 aAntiquity and Evolution of Prosternal Horns in Baridine Weevils   a918-9260 v843 aAmong weevils of the subfamily Baridinae (548 extant genera and ca. 9,000 species), unique prosternal horns and associated sheaths have evolved independently multiple times. These structures are utilized in a unique form of male-male aggression in which males push, rather than overturn as in most other horned beetles, their
competitor. Herein we report the first fossils of male Baridinae  exhibiting such prosternal horns. Two males recovered from the middle Eocene Green River Formation in northwestern Colorado serve to provide a minimum age (at ca. 47 million years old) for both the origin of horns and its  associated form of male-male combat in Baridinae.1 aDavis, S.R.1 aEngel, M., S  uhttp://www.bioone.org/doi/full/10.1666/09-160.1