Publication Date

2019

Document Type

Dissertation/Thesis

First Advisor

Samonds, Karen E.

Degree Name

M.S. (Master of Science)

Legacy Department

Department of Biological Sciences

Abstract

Macronycteris bats are morphologically conservative between species but demonstrate intraspecific morphological variation between geographic locations and sexes. Two of the four living species of Macronycteris are found on Madagascar, where they are broadly distributed and demonstrate a trend in body size correlated with the latitudinal precipitation cline on the western side of the island. The presence of an extinct species, M. besaoaka, from Anhjohibe Cave in northern Madagascar suggests that Macronycteris was once more diverse, at least with respect to morphology. Since its description, taxonomic and phylogenetic revisions have reshaped our understanding of this genus. On Madagascar, these include the discovery of a new cryptic species, M. cryptovalorona, and two genetic clades within M. commersoni. Furthermore, recent augmentation of museum collections has permitted deeper investigation into morphological trends within the genus, and new subfossil bat deposits have been discovered in the submerged caves of Tsimanampesotse National Park in southwestern Madagascar. Herein, I investigate the validity of M. besaoka and assess the Tsimanampesotse subfossil community through nonparametric multivariate methods.

My results suggest that M. besaoka is morphologically distinct from modern species, though this difference is statistically smaller as compared to that observed between sexes in living M. commersoni and is primarily a difference in size rather than shape. The subfossil specimens referred to as M. besaoka likely attainted their large size through adaptation to a more mesic environment compared to modern conditions. This study also examines Macronycteris subfossils from two deposits in Mitoho Cave in southwestern Madagascar which document the local community from ≥ 8,000 years BP to the present. This study has determined that the Macronycteris community of Mitoho Cave has undergone significant changes in craniodental shape, but not size, and that these changes have occurred recently. Moreover, these subfossils are not statistically similar in shape to any modern population on Madagascar. These results cannot confirm the influence of bioclimatic conditions on size for Macronycteris spp. but do indicate recent disruption of the Mitoho Cave bat community and the existence of a previously undescribed morphotype.

Extent

147 pages

Language

eng

Publisher

Northern Illinois University

Rights Statement

In Copyright

Rights Statement 2

NIU theses are protected by copyright. They may be viewed from Huskie Commons for any purpose, but reproduction or distribution in any format is prohibited without the written permission of the authors.

Media Type

Text

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