Theses and Dissertations

Date of Award

12-1-2024

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Biology

First Advisor

Kathryn E. Perez

Second Advisor

Matthew Terry

Third Advisor

Frederic Zaidan

Abstract

The springsnail genus Pyrgulopsis is one of the most diverse groups of freshwater gastropods in North America (Hershler, 2014), with many species displaying high levels of endemism (Hurt, 2003). This study attempts to circumscribe three putative species of springsnails: Pyrgulopsis serrata, Pyrgulopsis marcida, and a newly identified clade, referred to as Lineage C, from the Ruby Lake National Wildlife Refuge, Nevada, USA and nearby springs. Using an integrative taxonomic approach, we combined morphological, anatomical, and molecular data to examine species boundaries and evolutionary relationships.

Many lines of evidence were considered to determine species boundaries. Phylogenetic analysis of the mitochondrial cytochrome oxidase I (COI) gene supported the distinctiveness of Lineage C, forming a well-supported monophyletic clade sister to P. sterilis and separate from P. serrata and P. marcida. However, pairwise genetic distances (p-distances) between Lineage C and the other species ranged from 2.1% to 2.6%, which is below the expected “DNA barcoding” threshold for Pyrgulopsis. The combined morphological and anatomical results, with differences in shell morphology and radular structure, suggest that Lineage C represents a distinct species. These data also support P. marcida and P. serrata as distinct species.

The findings of this study have important implications for the conservation of these springsnails, which are highly vulnerable due to their restricted ranges and dependency on groundwater-fed habitats. The integrative approach employed here, combining genetic and morphological data, underscores the importance of multi-faceted taxonomic studies in understanding biodiversity and informing conservation efforts.

Comments

Copyright 2024 Trenton Meadows. https://proquest.com/docview/3153338581

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