Fossil flower of Salacia lombardii sp. nov. (Salacioideae-Celastraceae) preserved in amber from Simojovel de Allende, Mexico

Abstract A new fossil flower preserved in amber from Miocene sediments of Simojovel de Allende, Mexico, is described and recognized as a new member of Celastraceae. This fossil flower is bisexual, with a 5-merous perianth and extrastaminal disk, furthermore the presence of two stamens inserted in the inside surface of a pentagonal disk and ovoid pistil constitute characters that allows its inclusion in Salacia (Salacioideae). This is a new extinct taxon and represents a Salacia species with a mosaic of characters today present in different extant species distributed along the Paleo and Neotropic. The presence of Salacia ca. 23–15 My in southern Mexico can be explained through the Boreotropical Flora Hypothesis, a proposal supported by the Paleogene fossil record of Celastraceae in high latitude North America. The neobotanical data suggest that the Salacioideae was derived from an independent Old World Celastraceae lineage, and subsequently diversified in the New World. Fossil and extant plant evidence support the importance of fossil plants collected in low latitude North America and highlight the relevance of paleobotanical studies in challenging biogeographical hypothesis.