Fruits and wood of Parinari from the early Miocene of Panama and the fossil record of Chrysobalanaceae.

PREMISE OF THE STUDY: Chrysobalanaceae are woody plants with over 500 species in 20 genera. They are among the most common trees in tropical forests, but a sparse fossil record has limited our ability to test evolutionary and biogeographic hypotheses, and several previous reports of Chrysobalanaceae megafossils are doubtful. METHODS: We prepared fossil endocarps and wood collected from the lower Miocene beds along the Panama Canal using the cellulose acetate peel technique and examined them using light microscopy. We compared the fossil endocarps with previously published fossils and with fruits from herbarium specimens. We compared the fossil wood with photographs and descriptions of extant species. KEY RESULTS: Parinari endocarps can be distinguished from other genera within Chrysobalanaceae by a suite of features, i.e., thick wall, a secondary septum, seminal cavities lined with dense, woolly trichomes, and two ovate to lingulate basal germination plugs. Fossil endocarps from the Cucaracha, Culebra, and La Boca Formations confirm that Parinari was present in the neotropics by the early Miocene. CONCLUSIONS: The earliest unequivocal evidence of crown-group Chrysobalanaceae is late Oligocene-early Miocene, and the genus Parinari was distinct by at least 19 million years ago. Parinari and other Chrysobalanaceae likely reached the neotropics via long-distance dispersal rather than vicariance. The presence of Parinari in the Cucaracha flora supports the interpretation of a riparian, moist tropical forest environment. Parinari was probably a canopy-dominant tree in the Cucaracha forest and took advantage of the local megafauna for seed dispersal.

Comparative leaf morphological analysis of 20 species of Chrysobalanaceae / Morfologia foliar comparativa de 20 espécies de Chrysobalanaceae

Morphological studies focusing on vegetative traits are useful in identifying species when fertile material is not available. The aim of this study was to assess the application of comparative leaf morphology to identify species of the Chrysobalanaceae family. The morphological observations were made with a stereomicroscope. We used the diaphanization technique for viewing venation details. It is shown the descriptions of the leaf morphology, illustrations and an identification key for 20 species from genera Couepia, Licania and Parinari (Chrysobalanaceae) occurring in the Adolpho Ducke Forest Reserve, Manaus, AM, Brazil. The key was constructed using the DELTA (DEscription Language for TAxonomy) software. Leaf traits such as the presence of intersecondary venation and the type of insertion of secondary veins were recorded for each species. These morphological leaf traits are reliable for identifying species of Chrysobalanaceae.

Estudos morfológicos com foco em caracteres vegetativos são úteis na identificação das espécies quando material fértil não está disponível. O objetivo deste estudo foi avaliar a aplicação da morfologia foliar comparativa na identificação de espécies da família Chrysobalanaceae. A caracterização morfológica foi realizada com observação em estereomicroscópio. Foi utilizada a técnica de diafanização para visualização de detalhes da venação. São apresentadas descrições da morfologia foliar, ilustrações e uma chave de identificação de 20 espécies dos gêneros Couepia, Licania e Parinari (Chrysobalanaceae) que ocorrem na Reserva Florestal Adolpho Ducke, Manaus, AM, Brasil. A chave de identificação foi construída com uso do programa DELTA (DEscription Language for TAxonomy). Caracteres foliares como a presença de nervuras intersecundárias e o tipo de inserção das nervuras secundárias foram registrados para cada espécie. Essas características foliares são confiáveis para a identificação de espécies de Chrysobalanaceae.

Comparison between the anatomical and morphological structure of leaf blades and foliar domatia in the ant-plant Hirtella physophora (Chrysobalanaceae).

BACKGROUND AND AIMS: Myrmecophytes, or ant-plants, are characterized by their ability to shelter colonies of some ant species in hollow structures, or ant-domatia, that are often formed by hypertrophy of the internal tissue at specific locations (i.e. trunk, branches, thorns and leaf pouches). In Hirtella physophora (Chrysobalanaceae), the focal species of this study, the ant-domatia consist of leaf pouches formed when the leaf rolls over onto itself to create two spheres at the base of the blade. METHODS: The morphological and anatomical changes through which foliar ant-domatia developed from the laminas are studied for the first time by using fresh and fixed mature leaves from the same H. physophora individuals. KEY RESULTS: Ant-domatia were characterized by larger extra-floral nectaries, longer stomatal apertures and lower stomatal density. The anatomical structure of the domatia differed in the parenchymatous tissue where palisade and spongy parenchyma were indistinct; chloroplast density was lower and lignified sclerenchymal fibres were more numerous compared with the lamina. In addition, the domatia were thicker than the lamina, largely because the parenchymatous and epidermal cells were enlarged. CONCLUSIONS: Herein, the morphological and anatomical changes that permit foliar ant-domatia to be defined as a specialized leaf structure are highlighted. Similarities as well as structural modifications in the foliar ant-domatia compared with the lamina are discussed from botanical, functional and mutualistic points of view. These results are also important to understanding the reciprocal evolutionary changes in traits and, thus, the coevolutionary processes occurring in insect-plant mutualisms.