Published online by Cambridge University Press: 31 May 2012
Insect mines have been reported in several fossil leaf specimens (Brooks 1955; Freeman 1965; Lewis 1969; Opler 1973; Hickey and Hodges 1975; Crane and Jarzembowski 1980). These fossils represent useful records for the study of insect-host evolutionary history. Opler (1973) and Hickey and Hodges (1975) compared fossil Ieaf mines with those caused by extant insect species in homologous host species and concluded that specific insect-host associations have persisted for as long as 50 million years. We report here the presence of leaf mines in a Miocene specimen of Mahonia reticulata (MacGinitie) Brown (Berberidaceae). It is unclear whether a comparable insect species is associated with extant Nearctic Mahonia Nuttall.