UVM Theses and Dissertations
Format:
Print
Author:
McHugh, Anne
Dept./Program:
Biology
Year:
2014
Degree:
MS
Abstract:
Historical Biogeography is the study of the relationships of flora and fauna to the geologic history of land areas. I study the biogeography of the Caribbean utilizing spider phylogenetics. The Caribbean is a complex region comprised of over 700 islands with diverse geologic histories. There are several historical biogeographic hypotheses of how terrestrial fauna colonized these islands. The two main hypotheses are that terrestrial fauna colonized via GAARlandia (the Greater Antilles Aves Ridge landbridge) or via overwater dispersal. This debate between a vicariance and a dispersal mechanism is one that has been central to the field of biogeography since its inception.
In this thesis, I first provide an exploration of the past research done on biogeography, with a focus on evaluating the merits of various methods and gaps in our knowledge of Caribbean geology. The following two chapters present the biogeographic history of two separate spider lineages: Deinopis and Micrathena. Deinopis is the ogre-faced spider and is cosmotropical in distribution. It is a hypothesized poor dispersal and we found that its history likely mirrors that of the continental break-up of Gondwana. Micrathena is only found in the neotropics of the western hemisphere and is a morphologically diverse spiny orb-web weaving spider. We found that all Caribbean Micrathena are single-island endemics and that Micrathena has colonized the Caribbean four times likely utilizing GAARlandia.
Future research on both of these lineages focuses on expanding taxon sampling to increase confidence in the biogeographic hypotheses presented herein.
In this thesis, I first provide an exploration of the past research done on biogeography, with a focus on evaluating the merits of various methods and gaps in our knowledge of Caribbean geology. The following two chapters present the biogeographic history of two separate spider lineages: Deinopis and Micrathena. Deinopis is the ogre-faced spider and is cosmotropical in distribution. It is a hypothesized poor dispersal and we found that its history likely mirrors that of the continental break-up of Gondwana. Micrathena is only found in the neotropics of the western hemisphere and is a morphologically diverse spiny orb-web weaving spider. We found that all Caribbean Micrathena are single-island endemics and that Micrathena has colonized the Caribbean four times likely utilizing GAARlandia.
Future research on both of these lineages focuses on expanding taxon sampling to increase confidence in the biogeographic hypotheses presented herein.