Relative Contributions of Ecological and Spatial Factors to Genetic Variation Among Hyporheic Populations of Lirceolus spp. Across Central and Southwest Texas




Pustka, Lucas

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Understanding mechanisms of local adaption is key for the conservation of biological diversity. However, disentangling why organisms vary across geographical space can be a complex task, this is especially true for groundwater obligate organisms who reside in a habitat that can be dynamic through space and time. I examined the groundwater obligate asellid isopod genus Lirceolus across central Texas combining morphology and population genomic data to address questions about population structure, connectivity, and to see if nominal taxonomy comports with genomic data. There have been six species of Lirceolus historically identified within the state of Texas (L. bisetus, L. cocytus, L. hardeni, L nidulus, L. pilus, L. smithii) but their status, and the location of range boundaries is unknown. I discovered deep divergences within the genus Lirceolus, suggesting a long evolutionary history with distinct lineages that do not clearly correspond to the nominal taxonomy. I separated individuals into four groups for further analysis. Overall, nominal taxonomy, geography, specific conductance and minimum 30-year temperature were all identified as significant variables explaining genomic variation within separate groups, but these predictors were generally colinear and hard to disentangle. While nominal taxonomy was found to be a significant predictor of genomic variation within our separate groups, our initial genomic assembly revealed seven lineages of Lirceolus hardeni and two lineages of Lirceolus pilus. These findings call to attention the need for further exploration of Lirceolus spp. across this range to understand how they are genetically structured within hyporheic populations.



hyporheic, Lirceolus, genomic variation, Biology


Pustka, L. (2023). Relative contributions of ecological and spatial factors to genetic variation among hyporheic populations of Lirceolus spp. across Central and Southwest Texas (Unpublished thesis). Texas State University, San Marcos, Texas.


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