Gerromorphan bugs in Early Cretaceous French amber (Insecta: Heteroptera): first representatives of Gerridae and their phylogenetic and palaeoecological implications
Résumé
Three specimens of gerromorphan bugs in Late Albian amber from south-west France are described. One is regarded as an incertae sedis within the Gerromorpha, the other two are assigned to Cretogerris albianus gen. et sp. nov., the oldest representative of the aquatic bug family Gerridae. The discovery confirms the great antiquity of the Gerridae, until now only inferred from an Early Cretaceous representative of the sister family Veliidae. The phylogenetic affinities of Cretogerris within the Gerridae are still rather uncertain, but this fossil taxon shows highly specialized body and leg structures that are very similar to those of the marine Halobatinae, suggesting that it was possibly a marine surface skater. The Gerridae and the Chresmodidae, another extinct group of Mesozoic surface skaters, were contemporaneous during at least the early Cenomanian. The discovery of these gerromorphan bugs in the Albian amber supports the hypothesis of a selective trap of a litter fauna, originating from a beach environment, for this resin.