Philippine Journal of Science
142:(3) 159-168, Special Issue
ISSN 0031 - 7683
Preliminary phylogeny of the Astronieae (Melastomataceae) Based on Nuclear and Plastid DNA Sequence Data, with Comments on the Philippine Endemic Genus, Astrocalyx
Darin S. Penneys
Department of Botany, California Academy of Sciences
San Francisco, California 94118–4503, U.S.A.
ABSTRACT
The Astronieae (Melastomataceae) are a paleotropical tribe of trees and shrubs. It comprises about 150 species in four genera: Astrocalyx, Astronia, Astronidium, and Beccarianthus. Neither the monophyly of the tribe nor its constituent genera have been adequately tested in a phylogenetic context. Historical classifications have assigned differing complements of genera to the Astronieae, and have varied in their circumscriptions of Astronia and Astronidium, with the latter sometimes regarded as a synonym of the former. To test tribal- and genus-level monophyly in the group, 19 samples from three genera of Astronieae and 15 outgroup species from two related tribes were sequenced for nrITS and plastid rbcL. DNA sequence data were analyzed with maximum likelihood and Bayesian methods in individual and combined datasets comprising up to 2276 base pairs and 38 terminals. The analyses indicate that the Astronieae, Astronia, Astronidium, and Beccarianthus are each monophyletic. No material was available for Astrocalyx. Analyses that include a much wider sample of genic regions and correctly identified specimens from throughout the range of the tribe are desirable to confirm these preliminary conclusions, especially in consideration of the relatively weak distinction between Astronia and Astronidium.
INTRODUCTION
The tribe Astronieae (Decne.) Triana (Melastomataceae Juss.) comprises four genera of trees and shrubs: Astrocalyx Merr., Astronia Blume, Astronidium A. Gray, and Beccarianthus Cogn. (Van Vliet 1981, Maxwell & Veldkamp 1990a, b, Figures 1 and 2). With nearly 150 species, the Astronieae are distributed from French Polynesia to the Mariana Islands, Vanuatu, Malesia (especially the Philippines), Taiwan, and the Andaman and Nicobar Islands. Most species have very limited ranges, often being restricted to a single island or mountain range. They are typically found in forests that lack a pronounced dry season, from sea level to 2700 meters in elevation.. . . . . . . . read more
