Fossil galls (zoocecids) from the Upper Miocene of La Cerdaña (Lérida, Spain)

Abstract

Upper Miocene strata of the La Cerdaña basin, Spain, have provided diverse flora of leaf remains assignable to the Magnoliidae, Hamamelididae, Dilleniidae, Rosidae and the Asteridae. Thirteen different types of fossil galls were identified on representatives of all these subclasses except for the Asteridae. The galls are two-dimensional impressions on the leaves and can be attributed to the following gall-inducing arthropods based on their similarity with modern galls: Acari, Eriophyoidea— Aceria nervisequa on Fagus gussonii, Eriophyies vilarrubiae on Quercus drymeja, Artacris macrorhynchus on Acer pyrenaicum, an undetermined species on Persea, Zelkova zelkovaefolia and Acer pyrenaicum; Diptera, Cecidomyiidae— Mikiola pontensis on Fagus pristina, Contarinia? on Quercus drymeja; Hymenoptera, Cynipidae— Neuroterus sp. on Quercus hispanica. The fossil gall collection studied here from La Cerdaña, Spain, confirms that an arthropod gall-inducing fauna was already well established in the Miocene. Gall-inducer interaction is reported for the first time for all the fossil plants mentioned. The host plant record for two cecidogenous taxa is expanded, and two taxa of parasitized plants as well as two new plant/animal associations are mentioned for the first time.