Date of Award

2024

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Biological Sciences

Committee Chair

Matthew Niemiller

Committee Member

Paul Wolf

Committee Member

Aron Katz

Research Advisor

Matthew Niemiller

Subject(s)

Invertebrates--Adaptation--Appalachian region, Collembola--Geographical distribution, Biospeleology

Abstract

Caves offer a unique opportunity to study the ecology and evolution of life in extreme environments, particularly with respect to understanding patterns of diversity. Most cave-obligate species are dispersal limited and have restricted ranges, often endemic to a single or a few cave systems. However, a few species have particularly broad distributions suggesting that they either are not dispersal limited or perhaps represent a species complex of morphological similar but genetically distinct species. In this thesis, I explore morphological variation, phylogeography, and possibly cryptic diversity in Pseudosinella spinosa, a cave collembolan (springtail) that inhabits the Interior Low Plateau and Appalachian Valley & Ridge karst regions of the eastern United States. I conducted morphological and molecular analyses on over 50 individuals from 22 caves. I examined molecular diversity and conducted species delimitation analyses using two mitochondrial loci (16S and COI). I found support for two primary genetically distinct clades loosely breaking up their range into a northern and a southern clade. Various species delimitation approaches identified 3 to 28 potential unique lineages depending on the dataset (16S, COI, and concatenated 16S+COI). Moreover, morphological analysis revealed morphological variation in the species’ labial triangle supporting two morphologically distinct groups. In total, evidence suggests that P. spinosa is a species complex; however, species boundaries are still not well understood requiring additional sampling as well as morphological and molecular investigation.

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