Biology ETDs

Publication Date



Eighteen morphological features were measured for 103 species of insectivorous bats found throughout North America. These characters were standardized to a mean of zero and a standard deviation of unity. Using these morphological characters, thirty-one distinct faunas, ranging from a Boreal Forest fauna with three species to a Wet Tropical fauna with 50 species, were analyzed in an 18-dimensional mathematical hyperspace with the numerical taxonomic techniques of distance, correlation and principal components.

The results show that tropical faunas occupy a greater morphological hypervolume than temperate-zone faunas. Morphological packing is not greater in tropical faunas, and it appears that a limiting morphological similarity exists between species of insectivorous bats in North America. In the tropics, increased faunal morphological diversity is clearly related to utilization of an increasingly diverse set of resources.

The first major trend of variation through the faunal character hyperellipsoid is associated with size variance and this accounts for approximately 68% of the variability in all the faunas studied. The second and third major axes are associated with relative proportions of ear and wing elements and these factors account for an additional 13% and 5% of the total variability, respectively.

To relate faunal morphological structure to effects of the physical environment, eleven indices of faunal location, physiography, precipitation and temperature were statistically compared to eleven indices of phenetic structure for twenty-nine faunas. Morphological divergence is significantly related to increased precipitation, warmer, less fluctuating ambient temperatures and greater topographic relief. Morphological packing in a fauna is greater at higher altitudes and in areas of decreased precipitation.

These statistical models of community morphological structure are used to make limited ecological predictions.

Project Sponsors

Anna M. Jackson Award

Document Type


Degree Name


Level of Degree


Department Name

UNM Biology Department

First Committee Member (Chair)

James S. Findley

Second Committee Member

John W. Wilson

Third Committee Member


Fourth Committee Member

Michael Rosenzweig

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Biology Commons