Abstract
SummarySince its description, almost 100 years ago, the genus Dinizia has been treated as monospecific, comprising the single canopy-emergent species Dinizia excelsa Ducke which grows in non-flooded Amazonian forests of Guyana, Suriname and seven states of northern and central-western Brazil. Dinizia jueirana-facao G. P. Lewis & G. S. Siqueira, which grows in a restricted area of semi-deciduous Atlantic rain forest in Espírito Santo state, Brazil, is described as a new species in the genus. The new species is also a canopy-emergent of impressive stature. We provide descriptions for both species, a key to species identification, a distribution map and the new species is illustrated. Fossil leaves, inflorescences and fruit provide evidence for a Dinizia-like ancestor occurring in south-eastern North America during the Eocene. In contrast to D. excelsa where pollen is dispersed in tetrads, the pollen of D. jueirana-facao is shed in monads. D. jueirana-facao is considered critically endangered following IUCN conservation criteria, whereas D. excelsa is assessed to be of least concern. A lectotype is designated for D. excelsa.
Highlights
For almost 100 years the genus Dinizia has been treated as monospecific
The genus was first described by Ducke (1922) to accommodate the single species D. excelsa Ducke, a rain forest canopy-emergent of impressive stature
Burkart (1943) placed Dinizia in his tribe Mimozygantheae based on the similar imbricate sepals and indehiscent fruits of D. excelsa and Mimozyganthus carinatus (Griseb.) Burkart
Summary
For almost 100 years the genus Dinizia has been treated as monospecific. The genus was first described by Ducke (1922) to accommodate the single species D. excelsa Ducke, a rain forest canopy-emergent of impressive stature (some individuals over 60 m tall are recorded from the Brazilian Amazon). Burkart (1943) placed Dinizia in his tribe Mimozygantheae based on the similar imbricate sepals and indehiscent fruits of D. excelsa and Mimozyganthus carinatus (Griseb.) Burkart. Both species have a nectary in a distinct hypanthium (Ancibor 1969). Luckow et al (2003), based on molecular and morphological data, found Dinizia to be more closely related to caesalpinioid genera than to genera in the Mimosoideae This placement of the genus is supported by it having flowers with a hypanthium, a stylar groove, and imbricate petals, “characters either unusual or unknown among other mimosoids” (Luckow et al 2003). Fossils Fossil leaves of Duckeophyllum eocenicum Herendeen & Dilcher (1990), the co-occurring fossil inflorescence, Eomimosoidea plumosa Crepet & Dilcher (1977), and specimens of fossil pods, Eliasofructus catahoulensis Herendeen & Dilcher (1990) and E. claibornensis
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