Abstract Detail


Koenemann, Daniel [1].

Speciation in the New World Tropics: Species Boundaries in the Plant Genus Triplaris (Polygonaceae).

The Amazon Rainforest is in danger of losing its biodiversity due to resource use and changing weather patterns. It is important that the flora and fauna of the Amazon be documented in order that they might be preserved for the future. The tree genus Triplaris is native throughout the Neotropics, but has a center of diversity in the western section of the Amazon basin. Some of the species in the genus are geographically widespread and morphologically diverse, suggesting that they are, in fact, multiple, unrecognized species rather than single widespread species. I used molecular phylogenetics and morphological clustering (principal component analysis and normal mixture modeling) as evidence of divergence between individuals, in order to better estimate the number of species in the genus Triplaris. I hypothesized that, if a single widespread species was composed of multiple, unrecognized species, that I would observe consistent clustering at the sub-species level, each cluster corresponding to one of the unrecognized species. The molecular phylogenies showed that, for two species, Triplaris americana and Triplaris melaenodendron, geographically distinct populations formed sub-species clades. In Triplaris melaenodendron, principal component analysis showed morphological clustering corresponding to those same genetic sub-groups. In Triplaris americana, the clustering was more indicative of source-sink population dynamics. The normal mixture modeling inferred two morphological groups in Triplaris melaenodendron and three in Triplaris americana. In Triplaris americana, the groups were distinguished by elevation and geographic location. These initial results point toward the presence of unrecognized species in Triplaris americana and Triplaris melaenodendron.

1 - 9434 Rhode Island Avenue, College Park, MD, 20740, United States

South America
Species Complex.

Presentation Type: Oral Paper
Session: SYS4, Systematics IV: Monocots part B to Rosids part A
Location: Virtual/Virtual
Date: Thursday, July 30th, 2020
Time: 1:45 PM
Number: SYS4006
Abstract ID:164
Candidate for Awards:None

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