Skip to main content

Graduate Students

Samuel Kwame Lumor

PhD Student (2022 – to present)

I grew up near the Volta River at Kpong in the Eastern Region of Ghana. The Volta River is home to diverse fish species, most of these species I have encountered while throwing hooks and catching some fish in that part of the river and other streams in the area. I am very fascinated by aquatic life and its conservation. Prior to BYU, I received my undergraduate education in Biological Sciences at Kwame Nkrumah University of Science and Technology(KNUST), Kumasi, Ghana. I also have a Master of Philosophy in Educational Innovations and Leadership Science from the same university. For my PhD, I will be working on developing fish aquaculture systems in Ghana, including the possible use of the African bony tongue fish (Heterotis niloticus). My goal is to use this approach to help conserve this and other endangered species in Ghana. Finally, I hope to employ eDNA approaches to understand current distribution patterns of some of the most threatened species.

Alli Duffy

DUFFY_Department website BIO.jpg
PhD Student (2017-present)

My focal research areas are evolutionary ecology, animal behavior, and sensory ecology. Prior to BYU, I received my B.Sc. in Biological Sciences from North Carolina State University and M.Sc. in Entomology from Purdue University. My M.Sc. thesis investigated variation in volatile and tactile chemical communication in a group of sympatric beetles. For my PhD research at BYU I will mainly focus on the sensory ecology of Brachyrhaphis fishes in Costa Rica and Panama. I am investigating chemical recognition and how predator detection varies across populations that occur in different selective environments. I will also explore Brachyrhaphis foraging behavior and their potential to sequester and/or metabolize toxins from their diet.

Research Gate
Google Scholar Citations

Ellie (Mary-Elise) Nielsen

MS Student, (2020-present)

I am from Salt Lake City, UT and completed my BS in Biology from BYU prior to my graduate studies. I am broadly interested in topics in evolutionary and behavioral ecology, but am particularly interested in understanding how polymorphisms emerge in populations and the forces that change and maintain such traits. My masters thesis aims to capture and describe variation in livebearing fish species from northern Costa Rica, using geometric morphometric approaches.

Maddie Nate

Masters student (2020-present)

Lab Alumni

Trevor Williams, PhD

PhD Student (2015 - 2022)

My interests are focused on the processes that generate diversity, both species diversity (community ecology and biogeography) and genetic diversity (phylogeography and population genetics). For my PhD I am researching the interface between phylogeography and community ecology. Specifically, I'm trying to answer how historical events have influenced modern day community assembly. I'm doing this by using phylogeography to understand how species dispersed in response to climate driven changes in habitat, such as the rise and fall of Lake Bonneville or sea level change in Costa Rica. By showing how past events have influenced community assembly scientists can get a full understanding of the processes that influence species diversity and be equipped to conserve that diversity. I'm also interested in how theoretical ecology and population genetics can be integrated to test hypotheses of community assembly. To investigate this integration I'm trying to adapt population genetics approaches to see if we can untangle the processes that govern community assembly in meta-communities.

Kaitlyn Golden, MS

MS Student (2018-2020)

My research interest centers in evolutionary ecology, specifically life history evolution. I did my undergraduate and master's degree work at BYU. My thesis project focused on how predation environments affect life history when there are physical constraints. A lot of my research has used the study species Alfaro cultratus from the family Poeciliidae. My thesis showed that there is no difference in the life history of populations of Alfaro cultratus that co-occur with predators and those that are only found with non-piscivorous fishes, possibly due to their constrained morphology.

Andrea Roth Monzón, PhD

PhD Student (2013 - 2019)

I am broadly interested in evolutionary ecology, animal behavior, and phylogenetics. Prior to coming to BYU, I completed both my BS and MS at the Universidad Nacional Autónoma de México where I worked almost exclusively with herps. My PhD research at BYU focuses on understanding character displacement when more than two species are interacting. I am working with four species of livebearing fishes in the genus Poeciliopsis that occur in western Mexico. My project is anchored in measuring the results of a natural experiment wherein different combinations of these species have persisted over time. I will also conduct a set of field and laboratory experiments, including some using video animation, to determine how these closely related species are able to co-exist.

Kandace Hugentobler, MS

Kandace new.jpg
MS Student (2013 - 2016)

My interests center around sexual selection, animal behavior, and science education. My thesis project focused on female anal fin pigmentation in Brachyrhaphis fishes.Brachyrhaphis are part of the family Poeciliidae whose individuals are classified by external male genitalia and live-bearing females. In this genus, males of most species have a distinct pigmentation along their gonopodium (genitalia) and females appear to have pigmentation in the same shape and color along their anal fin, which is the corresponding location to the male gonopodium. I have conducted behavioral tests as well as geometric morphometric studies to ascertain the similarity of pigmentation shape between males and females. Hugentobler, K. and J. B. Johnson. 2018. Anal fin pigmentation in Brachyrhaphis fishes is not used for sexual mimicry. PLoS One.

Spencer Ingley, PhD

PhD Student (2011 - 2015)
Current postion: Assistant Profess, BYU Hawaii
email website

While at BYU I focused on the ecology, behavior, and evolution of the Central American livebearing fish genus Brachyrhaphis. This work was funded primarily by the National Science Foundation and the National Geographic Society. Brachyrhaphis is a small group of fishes native to lower Central America (Panama, Costa Rica, and Nicaragua), and are an excellent system for studying adaptation and speciation and different stages of divergence. Using a combination of field collections, field studies, and controlled behavioral experiments, I showed that natural selection acts in similar ways to drive repeated trait evolution at different stages of speciation. I published several papers from my PhD work, including this one:

Ingley, S. J. and J. B. Johnson. 2014. Animal personality as a driver of reproductive isolation. Trends in Ecology and Evolution 29:369-371.

I completed my PhD at BYU in 2015. I completed a National Science Foundation Postdoctoral fellow working at UNC Chapel Hill in the Pfennig Laboratory, and in the Herpetology unit at the North Carolina Museum of Natural History. My postdoctoral research focused on the mechanisms that underpin context depending mate choice in spadefoot toads. I am also conducting collections based research to determine the role of hybridization in niche width expansion in spadefoots. I am currently an Assistant Professor of Biology at Brigham Young University, Hawaii in Laie, Hawaii.

Justin Bagley, PhD

Justin pic.jpg
PhD Student (2008 - 2014)
Current position: Postdoc, CNPq Science Without Borders (Brazil)
email website

I am an evolutionary biologist interested in addressing a range of questions about the origin and maintenance of biodiversity. These questions motivate a research program that is broad yet focused on explaining the ecology and biodiversity of Neotropical and temperate freshwater fishes and lizards. While conducting my Ph.D. at BYU, I used comparative phylogeography and coalescent-based species delimitation to illuminate patterns and processes of evolutionary diversification in the Central American freshwater fish assemblage. Here is a representative publication:

Bagley, J. C. and J. B. Johnson. 2014. Phylogeography of the lower Central American Neotropics: diversification between two continents and between two seas. Biological Reviews 89(4):767-790. doi: 10.1111/brv.12076.

Currently, I am a Young Talent Fellow postdoc in Brazil's CNPq Science Without Borders program, where I am using multilocus and Rad-seq (Next-Generation Sequencing) comparative phylogeography and community phylogenetics to test hypotheses about the historical and ecological mechanisms underlying freshwater fish genetic diversity and community composition in the Brazilian Cerrado.

Florencia Breitman, PhD

Perito Moreno Glaciar, Patagonia- Field trip.jpg
Postdoctoral Fellow (2014)

I completed my Ph.D. work with Mariana Morando at Centro Nacional Patagonico in Argentina as part of the NSF-PIRE Patagonia project housed at BYU. My postdoctoral work at BYU focused on understanding the genetic and morphological evolutionary patterns of Liolaemus lizards from Patagonia, with the main goal of using phylogeographic and morphological results to delineate conservation areas in the region. I also worked with Dr. Jerald B. Johnson and his Ph.D. student Justin C. Bagley on projects that examined the evolutionary history of freshwater fishes from Central America and endangered North American Chinook salmon, with the objective of reconstructing population histories within these species. I left BYU to accept a position as a Young Talent Postdoctoral Fellow in Brazil's CNPq Science Without Borders Program.

Peter Unmack, PhD


Postdoctoral Fellow (2006 - 2010)
Current position: Research Fellow, University of Canberra (Australia)
email website

I joined the NSF-funded Patagonia Project as a postdoc in 2006. While at BYU I worked extensively on molecular systematics and phylogeography of freshwater fishes, including the catfishes of southern Argentina and Chile, several species of Australian fishes, and desert fishes of western North America. We have published several papers on this work, including this example from our Patagonia efforts.

Unmack, P. J., J. P. Barriga, M. A. Battini, E. Habit, and J. B. Johnson. 2012. Phylogeography of the catfish Hatcheria macraei reveals a negligible role of contemporary drainage divides in structuring populations. Molecular Ecology 21(4):942-959. doi: 10.1111/j.1365-294X.2011.05408.x

I am currently a research fellow at the University of Canberra’s Institute for Applied Ecology where I am continuing my work into the biogeography, ecology, systematics, and conservation of freshwater fishes. You can visit my webpage to see my various projects and publications.

Rachael Remington, PhD


Visiting PhD Student (2010)

The goal of my Ph.D. research was to investigate the ecology and evolution of turbid water adaptations in freshwater fishes. While at BYU, I continued my study of turbid water trait evolution in the genus Hybognathus using morphometrics and molecular markers. Hybognathus is an ideal group to study trait evolution because the group is monophyletic and inhabits a range of aquatic environments. I found that fishes living in turbid environments possess traits that have recently and independently evolved, such as small eyes, small optic lobes and large olfactory lobes of the brain. Additionally, I investigated feeding success and growth of Great Plains cyprinids (e.g., Notropis bairdi, N. stramineus and N. boops) from turbid to clear water habitats. My ecological research was conducted in aquaria and artificial stream mesocosms at the University of Oklahoma Biological Station.

Jared Lee, PhD

MS Student (2007 - 2009)
Current position: Assistant Professor, Georgia Military College

My research at BYU focused on testing biogeographic boundaries developed from community composition data. My thesis examined whether or not boundaries between fish ecoregions in lower Central America could be predicted using single-species phylogeography. I examinded the phylogeography of the livebearing fish Poecilia gillii to test these ideas. The results from my thesis can be found in this paper.

Lee, J. B. and J. B. Johnson. 2009. Biogeography of the livebearing fish Poecilia gillii in Costa Rica: are phylogeographic breaks congruent with fish community boundaries? Molecular Ecology 18: 4088-4101.

My general interests in biology include molecular systematics, genomics, conservation, and science education. My taxonomic leanings and experience favor work on fish, amphibians, reptiles, and mammals. After leaving BYU, I went on to earn a Ph.D. in Genetics at the University of Georgia with Rodney Mauricio. I am currently an Assistant Professor of Biology at Georgia Military College.

Laura Scott, MS

MS Student (2007 - 2009)

My thesis centered on character displacement of poeciliid fish from Mexico. The study focused on three attributes to better understand this phenomenon: morphology, life history strategies, and behavior. Findings from this work are found in this publication.

Scott, L. E. and J. B. Johnson. 2010. Does sympatry predict life history and morphological diversification in the Mexican livebearing fish Poeciliopsis baenschi? Biological Journal of the Linnean Society 100:608-618.

Additionally, while at BYU I worked with the NSF-funded Patagonia Biodiversity Project as a field studies program coordinator to provide opportunities for students to participate in international research. After completing my master's degree at BYU, I was hired at Utah Valley University as an education outreach coordinator.

Carissa Jones, DVM

MS Student (2005 - 2007)
Current position: Resident, Vanderbilt University

My thesis examined how cycles of high and low sea levels associated with glacial and interglacial periods over the last five million years impacted spatial and temporal patterns of genetic diversity within Xenophallus umbratilis, a livebearing freshwater fish of Costa Rica. This is the primary manuscript that came from my project.

Jones, C. P. and J. B. Johnson. 2009. Phylogeography of the livebearer Xenophallus umbratilis (Teleostei: Poeciliidae): glacial cycles and sea level change predict diversification of a freshwater tropical fish. Molecular Ecology 18: 1640-1653.

After graduating from BYU, I went on to work for a cancer pharmaceutical. I am currently pursuing a career in laboratory animal medicine. I completed my doctorate in veterinary medicine (DVM) in 2014 from Oregon State University and veterinary residency at Vanderbilt University Medical School in 2015. I have accepted a faculty appointment at Vanderbilt, which will begin the summer of 2016.

José Jaime Zúñiga-Vega, PhD

Postdoctoral Fellow (2005 - 2006)
Current position: Associate Professor, Universidad Nacional Autónoma de México (UNAM)

My main research interests are population dynamics and evolution of life histories, particularly in fishes, amphibians and reptiles. However, I am also getting interested in conservation, phylogeography, and population genetics. The questions that I worked on at BYU dealt with the role of mortality in the evolution of life history strategies, understanding the evolutionary drivers of superfetation in poeciliid fishes, and the consequences of temporal and spatial variation in the demographic behavior of natural populations. Here's an example of the papers I published.

Zúñiga-Vega, J. J., D. N. Reznick, and J. B. Johnson. 2007. Habitat predicts reproductive superfetation and morphology in the livebearing fish Poeciliopsis turrubarensis. Oikos 116:995-1005.

I left BYU in 2006 for a faculty position. I am currently an Associate Professor with the Facultad de Ciencias, Universidad Nacional Autónoma de México in México City where I advise several of my own students. However, I still maintain a very active collaboration with Jerry Johnson and his lab group.