A new fossil wood of Detarioideae from the Boa Vista Basin, Upper Oligocene (Northeast Brazil): Comparisons with living and fossil Leguminosae Subfamilies. Paleoclimate and biogeography inferences for the Leguminosae story

Abstract

A new genus and species of Leguminosae wood has been discovered and described from the Upper Oligocene in Northeast Brazil. The well-preserved tissues and unique diagnostic characters allowed for its assignment to Goniorrhachisinoxylon sergioarchangelskii nov. gen. et sp. (Detarioideae). Leguminosae woods have a rich fossil record, and in order to establish this new genus and species, detailed comparisons were made among the living subfamilies Cercidoideae, Detarioideae, Duparquetioideae, Dialioideae, and Caesalpinioideae, and a revision of the generic diagnoses of caesalpiniod fossil woods (except the Mimosoid clade) was conducted. By examining the presence of some wood characters and using modern related forms, it was inferred that seasonal (possibly monsoonal) palaeoclimatic conditions existed in Northeast Brazil at the end of the Oligocene. This new record from the Boa Vista Basin can contribute to our understanding of the origin and distribution of some members of the Leguminosae.