Recent Topics Posters
Gilberto, Ocampo .
Insights into the evolutionary relationships within the Secundiflorae clade (Miconieae, Melastomataceae).
Tribe Miconieae (Melastomataceae) comprises 18 genera with ca. 1800 species distributed in the New World tropics. Generic circumscription in the tribe is problematic and several genera are not monophyletic (e.g., Clidemia, Leandra, Miconia, Ossaea). However, tribal level phylogenetic studies show that a number of clades are statistically supported and have distinctive morphological traits. This is the case for the Secundiflorae clade, a group of taxa circumscribed in Leandra sect. Secundiflorae Cogn. and Ossaea sect. Diclemia Cogn. The ca. 30 spp. in this group are distributed from southern Mexico to northern South America. Species of the Secundiflorae clade usually have scorpioid inflorescences and ovoid seeds with U-type anticlinal walls and par-conical periclinal walls. This preliminary study of the 18 spp. in the Secundiflorae clade (including species of both sections) analyzed a combined data matrix of chloroplast (ndhF and psbK-psbI intergenic spacer) and nuclear (ITS) DNA sequences. Bayesian analysis recovered L. subulata, an epiphytic taxon, as an early divergent species within the clade, although with no support. The clade formed by the remaining species is strongly supported, but the relationships among them are not. Divergence times analysis showed that the most recent common ancestor of the Secundiflorae clade is ca. 12 million years. Dispersal-vicariance analysis using S-DIVA showed that the clade is of Andean origin, that most of the internal nodes had a northern Andean ancestral range, and that the distribution of the species of the Secundiflorae clade can be explained by dispersal events. Ecological niche modeling using Maxent was applied to some sympatric, close-related species. The results show that they have divergent niches that could support species delimitation. Additional taxon sampling and the use of other molecular markers are in order to improve nodal support.
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1 - California Academy of Sciences, Department of Botany, 55 Music Concourse Drive, Golden Gate Park, San Francisco, CA, 94118, USA
Ecological niche modeling
Presentation Type: Recent Topics Poster
Location: Hall A/Convention Center
Date: Monday, August 2nd, 2010
Time: 5:30 PM