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Abstract Detail

Systematics Section/ASPT

Kriebel, Ricardo [1], Michelangeli, Fabian [2].

Phylogenetic study of Conostegia demonstrates the utility of anatomical and continuous characters in the sytematics of the Melastomataceae.

Phylogenetic relationships of species in the genus Conostegia (Melastomataceae: Miconieae) were investigated using four chloroplast and two nuclear ribosomal spacers. Individual datasets as well as the combined phylogeny revealed a non monophyletic Conostegia but recovered three major clades. A survey of morphological, anatomical and morphometric characters resulted in 18 potentially useful ones to circumscribe Conostegia and its major clades. We reconstructed the ancestral states for these characters to shed light on their possible utility for clade circumscription. Of historical importance, the calyptra was reconstructed to have evolved three times with ambiguity at the base of the Conostegia clade. Floral organ multiplication appears to have evolved twice with one of these times possibly at the base of the Conostegia clade. The morphological study resulted in the discovery of floral anatomical and continuous characters seldom used in the systematics of the family. Two of the anatomical ones are an ovary stain around the ovules in two clades within Conostegia, and a style with a vascularized cylinder inside in another. A promising continuous character is the degree of style exertion beyond the stamens (herkogamy), which can be used to circumscribe one large clade with an independent origin in another. Leaf venation has been historically useful yet difficult to use in systematics because of its continuous nature. Of the three major clades identified within Conostegia, species in one clade have strongly plinerved leaves. A geometric morphometric analysis was conducted to quantify leaf venation and assess its utility to circumscribe this clade. Twelve landmarks were placed on 600 leaves from 40 species in the Conostegia clade. A Principal Components Analysis of the symmetric component of variation revealed separation in leaf venation supporting the plinerved clade. Broader taxonomic sampling revealed that the Conostegia clade is actually more closely related to two clades of Central American Clidemia than it is to the Caribbean clade, as previously suggested. Measurements of 600 seeds for 40 taxa show that species in the Conostegia clade with the exception of a well nested subclade have small seeds whereas taxa in the Caribbean clade have large seeds. This provides evidence for the current phylogenetic placement of the two Clidemia clades that also have small seeds in between the Caribbean clade and Conostegia. In summary, a well supported and densely sampled phylogeny of Conostegia has been reconstructed and several morphological characters not usually used in Melastomataceae systematics were discovered or reinterptreted.

Broader Impacts:

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1 - CUNY and The New York Botanical Garden, Biology, 2900 Southern Blvd, Bronx, NY, 10458, USA
2 - The New York Botanical Garden, Institute of Systematic Botany, 2900 Southern Blvd., Bronx, NY, 10458, USA


Presentation Type: Oral Paper:Papers for Sections
Session: 39
Location: Elmwood/Riverside Hilton
Date: Wednesday, July 31st, 2013
Time: 11:15 AM
Number: 39011
Abstract ID:584
Candidate for Awards:None

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