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Systematics and the Phenotypic Evolution of Papuan Microhylid Frogs.

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Title:Systematics and the Phenotypic Evolution of Papuan Microhylid Frogs.
Authors:Rivera, Julio A.
Contributors:Zoology (department)
adaptive radiation
locomotor performance
microhylid frogs
Date Issued:Aug 2017
Publisher:University of Hawaiʻi at Mānoa
Abstract:Understanding how biodiversity is generated is a central task of evolutionary
biology. Many studies have established that natural selection or stochastic processes, like
population fragmentation via biogeographic barriers, play a major role in generating
biodiversity. However, much less attention has been paid to how these processes interact.
A promising group in which to study the generation of biodiversity is the Asterophyinae
frogs of Paupa New Guinea. Recently, it has been discovered that this is a hyper-diverse
group of frogs, both in species number and ecological habit. Field workers have proposed
five different ecological types based on where they are found: tree, shrub, ground, semiaquatic,
and subterranean. However, no formal evolutionary or ecological studies have
yet been conducted. Here, I explore adaptive and stochastic processes in the
Asterophryine frogs by first constructing a time-calibrated phylogeny of the clade to
determine the intergeneric relationships and ecological evolution of the group. I then
investigate the morphological and performance evolution of 28 species with over 500
individuals to determine if these phenotypes are evolving in response to natural selection
to microhabitat. I find that ecological novelty arose early in the group’s history and is
tied to the rise of the Central Mountains of New Guinea. It also appears that
amalgamation of offshore land masses onto New Guinea lead to bursts of species
divergence but less so to ecological transitions. Furthermore, I find that the species have
evolved specialized morphologies that match microhabitat-use, providing support for the
reality of “ecomorphs”. These morphologies are also convergent so that species of the
same ecomorph evolved similar morphologies, independent of phylogenetic relationships.
Last, I find that performance capabilities in terms of jumping, climbing and swimming
differ between ecomorphs and these differences are imparted by specialized
morphologies. This correspondence between ecology, morphology, and performance
capabilities independent of phylogeny, provides strong evidence that selection is an
important force in the phenotypic diversification of the lineage. Overall, I demonstrate
that the phenotypic diversity seen in the Asterophryinae is driven by selection to
microhabitat. Therefore, both adaptive and biogeographic processes were needed to
generate the great diversity seen in the Asterophryinae today.
Description:Ph.D. Thesis. University of Hawaiʻi at Mānoa 2017.
Rights:All UHM dissertations and theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission from the copyright owner.
Appears in Collections: Ph.D. - Zoology

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