Abstract Niche Differentiation Among Malagasy Carnivorans
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ABSTRACT NICHE DIFFERENTIATION AMONG MALAGASY CARNIVORANS: AN ANALYSIS OF EVOLUTION IN A SPATIOTEMPORALLY ISOLATED CARNIVORAN CLADE (EUPLERIDAE: CARNIVORA) Michael C. Taylor, M. S. Department of Biological Sciences Northern Illinois University, 2016 Virginia L. Naples, Director To occupy an ecological niche, a carnivoran species must possess the necessary morphotype to consistently capture and process resources. In theory, two species would inevitably compete with one another if they occupied the same niche. Carnivoran diversity is related to niche differentiation, which can be facilitated spatially, temporally, or morphologically. Differences in diet preference and prey preference among carnivorans are effectively indicated by variations in craniodental morphology. Eupleridae is the sole carnivoran lineage in Madagascar and many of its species coexist in its eastern lowland rainforests and other ecoregions. This study described, in detail, the craniodental morphology of eight euplerid species. Ten craniodental characters were chosen that are functionally significant in dictating diet and prey preferences, which are means for morphological niche differentiation among carnivorans. The following hypotheses were tested: (1) there is no differences in craniodental morphology among the euplerid species; (2) there is no difference in pattern between the evolution of Eupleridae and the evolutions of Carnivora and Carnivoramorpha. Principal component analyses established seven different morphotypes among species, based on diet preference and prey preference. Only Galidia elegans and Galidictis fasciata occupied the same morphospace. Because they also occupy the same geographic range, they must vary temporally. Morphological niche differentiation characterizes the rest of the family. Some euplerids exhibit morphotypes that make them ecomorphs to species belonging to phylogenetically distinct carnivoran families absent in Madagascar. Results suggest an isolated carnivoran lineage prioritizes morphological niche differentiation over spatial or temporal variation. NORTHERN ILLINOIS UNIVERSITY DE KALB, ILLINOIS DECEMBER 2016 NICHE DIFFERENTIATION AMONG MALAGASY CARNIVORANS: AN ANALYSIS OF EVOLUTION IN A SPATIOTEMPORALLY ISOLATED CARNIVORAN CLADE (EUPLERIDAE: CARNIVORA) BY MICHAEL C. TAYLOR ©2016 Michael C. Taylor A THESIS SUBMITTED TO THE GRADUATE SCHOOL IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE MASTER OF SCIENCE DEPARTMENT OF BIOLOGICAL SCIENCES Thesis Director: Virginia L. Naples ACKNOWLEDGEMENTS First and foremost, I wish to thank Dr. Virginia Naples for her invaluable mentoring, enthusiasm, and counsel throughout this project. Never have I known someone with such contagious passion for their discipline and fervor for learning. Her encouragement and confidence in my abilities have helped me see this project to its completion and reach a high level of scientific excellence. Thank you to my committee members, Dr. Karen Samonds and Dr. Robert McAfee, for their review and support of this project. Thank you to Dr. John Flynn for graciously giving his time to a nervous and star-struck graduate student to offer his esteemed feedback on the project when it was still in its infancy. I would like to thank Dan and Leslie O’Brien for graciously housing me as I scoured the many museum collections far from home for rare euplerid specimens. Thank you to Tsiory and Aina for their friendship and assistance in collecting measurements of specimens not found here in the States. I also thank all of my Naples lab cohort, past and present. A special thank you to my parents, Robert and Gertrud Taylor, and my siblings Dave, Julie, Vanessa, Jon, Lu, Charles, and Phill for their incredible love and support throughout these rigorous years. Last but not least, thanks to all of the remarkable friends and truly special people who, from the moment they entered my life, have been nothing but caring, loyal, and a joy to be with. As I take a moment to reflect, I am privileged and proud to be finishing my degree, but it is the relationships I formed here, which are built to last, that are the true reward. DEDICATION I am dedicating this to my brother, Dave, and his wife Julie for their unflinching love and counsel throughout my years at NIU. It is because of them that all of this was possible. TABLE OF CONTENTS Page LIST OF TABLES .................................................................................................................. vi LIST OF FIGURES ................................................................................................................ vii Chapter 1. INTRODUCTION ...................................................................................................... 1 Eupleridae ......................................................................................................... 1 Carnivoran Craniodental Morphology and Diversity ....................................... 6 Carnivoran Niche Differentiation via Spatiotemporal Variation...................... 8 Carnivoran Niche Differentiation via Morphological Diversification ............. 8 Niche Differentiation as a Means of Analyzing Euplerid Evolution................ 10 Objectives ......................................................................................................... 11 2. METHODS ............................................................................................................. 12 Study Species ................................................................................................... 12 Raw Morphological Data Collection ................................................................ 14 Functionally Significant Characters ................................................................. 16 Statistical Analyses ........................................................................................... 16 3. RESULTS ................................................................................................................ 18 Descriptions of Species Craniodental Morphologies ....................................... 18 Cryptoprocta ferox ................................................................................. 18 v Chapter Page Fossa fossana ......................................................................................... 21 Eupleres goudotii and Eupleres major ................................................... 24 Galidia elegans ....................................................................................... 27 Galidictis fasciata and G. grandidieri .................................................... 30 Salanoia concolor ................................................................................... 34 Principal Component Analysis ......................................................................... 38 4. DISCUSSION ............................................................................................................ 43 Euplerid Morphologies and Current Morphological Diversity of the Family .. 43 Euplerid Pattern of Evolution ........................................................................... 46 Conclusions....................................................................................................... 48 Future Directions .............................................................................................. 48 BIBLIOGRAPHY ................................................................................................................ 50 APPENDIX: STUDY SPECIMENS...................................................................................... 54 LIST OF TABLES Table Page 1. Euplerid species values for functionally significant craniodental morphological characters .................................................................................................................... 13 2. SPSS output showing eigenvalues for principal components 1-9 with total variances explained by each component and cumulative percentages ....................................... 40 LIST OF FIGURES Figure 1. Known habitats and geographic ranges for the eight euplerid species involved in this analysis ........................................................................................................................ 3 2. Current phylogenetic tree of Eupleridae ..................................................................... 4 3. Phylogenetic tree of Carnivora, Carnivoramorpha, and Creodonta ........................... 5 4. Schematic showing variation of dentition among carnivorans with differing diets ... 7 5. Idealized evolutionary pathways ................................................................................ 11 6. Schematic depicting all the raw craniodental measurements ...................................... 15 7. Cryptoprocta ferox craniodental images ..................................................................... 20 8. Fossa fossana craniodental images ............................................................................. 22 9. Eupleres goudotii and Eupleres major craniodental images ...................................... 25 10. Galidia elegans craniodental images .......................................................................... 29 11. Galidictis fasciata and Galidictis grandidieri craniodental images ........................... 32 12. Salanoia concolor craniodental images ...................................................................... 35 13. Loading plot of the first principal component analysis (characters) .........................