Evolution Commons^™

A Geometric Morphometric Analysis Of Acetabular Shape Variation Across Bat Families, Jordan L. Huff

Electronic Theses and Dissertations

Bats are the only mammals capable of powered flight, and research is concentrated on this adaptation. Their non-flight locomotion has received comparatively little attention. Previous studies show that non-flight locomotor behaviors vary across families. Members of Pteropodidae are efficient climbers but cannot effectively walk, whereas Phyllostomidae and Vespertilionidae are better at terrestrial locomotion but show reduced arboreal capabilities. The non-flight locomotion of Hipposideridae and Rhinolophidae is less understood, although rhinolophids exhibit limited terrestrial locomotion. This study examined whether differences in locomotor behavior are associated with variation in acetabular morphology. A geometric morphometric analysis of acetabular shape was conducted across multiple …

Systematics Of Disk-Winged Bats (Thyroptera), Courtney L. Klumpp

Capstone Showcase

This thesis investigates the evolutionary relationships among disk-winged bats in the genus Thyroptera, a small group of Neotropical bats known for the adhesive suction disks on their wings and feet that allow them to roost inside tightly rolled leaves. The distinctive morphology and behavior of these bats have not been extensively documented, and their phylogenetic relationships remain only partially resolved. The goal of this research is to better understand how these species are related to one another and to determine whether the five recognized species of Thyroptera form a single monophyletic group. To address this question, morphological and genetic …

Morphology Of Smallmouth Bass (Micropterus Dolomieu) In Arkansas, Robert Laroche

Biological Sciences Undergraduate Honors Theses

The Smallmouth Bass, Micropterus dolomieu, is one of the most important game fishes in Arkansas. Three distinct lineages are recognized from different river basins: the Northern, Neosho, and Ouachita Smallmouth Bass. Understanding the biodiversity within this species complex inhabiting different water bodies in Arkansas is important for effective management of the fisheries resource and to guide conservation efforts. But current data on distribution of distinct forms are insufficient to guide management. The primary goals of the study presented here was to quantify morphological characteristics to identify distinct lineages of Smallmouth Bass, and to determine their specific locations within Arkansas streams …

Diversification Of Avifauna In The Darién Highland Region: Ecological Niche Modeling, Phylogeography And Morphology To Explore Speciation In The Montane Species Myadestes Coloratus, Chlorospingus Tacarcunae And Margarornis Bellulus., Jorge L. Garzon Vasquez Mrs

Theses and Dissertations

Montane regions in the Neotropics are hotspots of endemism and biodiversity, yet their species are especially vulnerable to the impacts of climate change and geographic isolation. This thesis investigates the evolutionary and ecological dynamics of three bird species endemic to the Darién Highlands of eastern Panama: Myadestes coloratus, Chlorospingus tacarcunae, and Margarornis bellulus. Through an integrative approach combining ecological niche modeling, morphometric analysis, and genomic data from ultraconserved elements (UCEs) and mitochondrial DNA, the study explores the historical biogeography, current distribution patterns, population structure, and phenotypic differentiation of these montane taxa. Ecological niche models revealed that suitable habitat …

Analyzing Head Morphology Trends With Increasing Population Density In A Jamaican Lizard Species, Lillian Durand

2024 Fall Honors Capstone Projects - Archive

Anolis lizards are model organisms for studying natural selection and evolutionary processes. One trait that is hypothesized to be advantageous for males is head size, as larger heads lead to stronger bite forces and increased likelihood in outcompeting other males for mates. To better understand how linked head size and intraspecific competition are, the head morphology of male A. lineatopus was analyzed among Jamaican populations with varying levels of population density. Population densities were determined using standardized plot surveys and mark resight models. Head dimensions and body condition for individual lizards were measured at each site. My study found that …

The Descent Of Anolis: Assemblages, Convergence, And Ecomorphological Evolution, Christopher G. Anderson

Biology ETDs

The evolutionary outcomes we observe in modern organisms, particularly associations between phenotypes and environments, have been and remain an invaluable tool in interpreting the biological phenomena that shape our world. In the following chapters, I leverage a comprehensive phylogenetic and morphological dataset for 351 species comprising a diverse group of arboreal lizards, the Anolis clade, to explore how communities and morphologies evolve. First, I characterized patterns among coexisting lineages of Anolis to reveal a general pattern of phylogenetic relatedness among lineages comprising assemblages and identify differences attributable to a biogeographic variable. Then I examined the morphological consequences associated with the …

Factors That Influence Small Mammal Long Bone Morphology: An Analysis Of The Femora, Tibiae, And Humeri Of The Eastern Gray Squirrel (Sciurus Carolinensis), Tyler Everette Blake

Theses, Dissertations and Capstones

The goal of this study is to examine the effect of urbanization and latitude on bone morphology, specifically limb length and bone density among gray squirrels endemic to the eastern United States. This study’s hypotheses are as follows: gray squirrels occupying lower latitudes will have larger body sizes and longer limbs relative to body size than those at higher latitudes following Bergmann’s and Allen’s rules. Further, squirrels in urban habitats will have greater bone density than those in rural habitats. Results show moderate correlation between body mass and respective proxies and latitude following Bergmann’s rule. Weak correlations were found between …

Geometric Morphometric Analysis Of Modern Viperid Vertebrae Facilitates Identification Of Fossil Specimens, Lance D. Jessee

Electronic Theses and Dissertations

Snake vertebrae are common in the fossil record, whereas cranial remains are generally fragile and rare. Consequently, vertebrae are the most commonly studied fossil element of snakes. However, identification of snake vertebrae can be problematic due to extensive variation. This study utilizes 2-D geometric morphometrics and canonical variates analysis to 1) reveal variation between genera and species and 2) classify vertebrae of modern and fossil eastern North American Agkistrodon and Crotalus. The results show that vertebrae of Agkistrodon and Crotalus can reliably be classified to genus and species using these methods. Based on the statistical analyses, four of the …

Morphological Trait Evolution In Solanum (Solanaceae): Evolutionary Lability Of Key Taxonomic Characters, Rebecca Hilgenhof, Edeline Gagnon, Sandra Knapp, Xavier Aubriot, Eric Tepe, Lynn Bohs, Leandro Giacomin, Yuri Gouvea, Andres Orejuela, Christopher T. Martine, Clara Ines Orozco, Iris E. Peralta, Tina Sarkinen

Faculty Journal Articles

Solanum is one of the world's largest and economically most important plant genera, including 1245 currently accepted species and several major and minor crops (e.g., tomato, potato, brinjal eggplant, scarlet eggplant, Gboma eggplant, lulo, and pepino). Here we provide an overview of the evolution of 25 key morphological traits for the major and minor clades of this giant genus based on stochastic mapping using a well-sampled recently published phylogeny of Solanum. The most evolutionarily labile traits (showing >100 transitions across the genus) relate to plant structure (growth form and sympodial unit structure), herbivore defence (glandular trichomes), pollination (corolla shape …

Halodash: The Deep And Shallow History Of Aquatic Life's Passages Between Marine And Freshwater Habitats, Eric T. Schultz, Lisa Park Boush

EEB Articles

This series of papers highlights research into how biological exchanges between salty and freshwater habitats have transformed the biosphere. Life in the ocean and in freshwaters have long been intertwined; multiple major branches of the tree of life originated in the oceans and then adapted to and diversified in freshwaters. Similar exchanges continue to this day, including some species that continually migrate between marine and fresh waters. The series addresses key themes of transitions, transformations, and current threats with a series of questions: When did major colonizations of fresh waters happen? What physiographic changes facilitated transitions? What organismal characteristics facilitate …

Cryptic Hybridization In The Temperate Bamboos: Is Pleioblastus Simonii A Species Of Hybrid Origin?, Morgan Brown

Theses

Japanese river bamboo (Pleioblastus simonii, ‘medake,’‘kawadake’) is an ecologically important species of temperate bamboo native to Japan. This species is widely known and historically important in Japanese rural farm life. Based on morphological data, Japanese river bamboo is classified in Pleioblastus section Medakea (Poaceae: Bambusoideae) along with five other Japanese species, which are collectively considered to represent a phylogenetically distinct lineage. However, recent studies suggest that Japanese river bamboo may have arisen as a result of previously undetected hybridization (i.e., cryptic hybridization), while also calling into question the diversity of section Medakea. The role of hybridization in natural plant populations …

Morphological Variation And Community Science In Orthoptera, Amy Byerly

Electronic Theses and Dissertations

Patterns of morphological divergence across species’ ranges provide insight into local adaptation and speciation. Here, we compare phenotypic divergence among 4,221 crickets from 337 populations of two related species of field cricket, Gryllus firmus and G. pennsylvanicus and their hybrids. We find that these species differ across their geographic range in key morphological traits, such as body size and ovipositor length, and we directly compare phenotype with genotype for a subset of crickets demonstrating nuclear genetic introgression, phenotypic intermediacy of hybrids, and essentially unidirectional mitochondrial introgression. We discuss how these morphological traits relate to life history differences between the species. …

Getting To The Root Cause: The Genetic Underpinnings Of Root System Architecture And Rhizodeposition In Sorghum, Farren Smith

Graduate Theses, Dissertations, and Problem Reports (ETD)

Plants are some of the most diverse organisms on earth, consisting of more than 350,000 different species. To understand the underlying processes that contributed to plant diversification, it is fundamental to identify the genetic and genomic components that facilitated various adaptations over evolutionary history. Most studies to date have focused on the underlying controls of above-ground traits such as grain and vegetation; however, little is known about the “hidden half” of plants. Root systems comprise half of the total plant structure and provide vital functions such as anchorage, resource acquisition, and storage of energy reserves. The execution of these key …

Testing For Character Displacement Between Two Abundant Stream Fishes, Amber Nations

Honors Theses

Character displacement is a pattern that can be used to explain differences between similar species in sympatric and allopatric situations. Gause’s Principle explains that a niche can only be occupied by one species at a time, so character displacement may be a way for similar species in the same habitat to shift resource use and compensate in order for the species to coexist. The Southeastern United States offers a unique opportunity to study this pattern because the diversity of freshwater fauna is quite high. However, the question of “How did this region become so diverse?” remains unanswered. One way for …

Molecular And Morphological Consequences Of Post-Glacial Contact Among Lineages Of Northern Short-Tailed Shrews (Blarina Brevicauda) In Eastern North America, Ellen Michels

All NMU Master's Theses

During the Pleistocene, advancing glacial ice fragmented populations of species, which restricted populations from expanding, ultimately inhibiting gene flow. As glaciers receded, expansion out of unglaciated-isolated areas was possible. In addition to glacial barriers, landscape features such as rivers and mountain ranges served as barriers to dispersal of populations during the Pleistocene, influencing the phylogeography of multiple species. Though divergence between multiple lineages is a common feature of North American mammal diversity, circumstances that affected the post-glacial expansion of structured diversity within regions are less well-documented. Northern short-tailed shrews (Blarina brevicauda) are restricted to eastern North America, yet …

The Homology Of Sarcopterygian Gills, Kyle Orr

Cal Poly Humboldt theses and projects

Vertebrate gills may be either external (protruding from the body surface) or internal (enclosed in a chamber). Among living amphibians, external gills are found in salamander larvae and neotenes, early frog larvae, and caecilian embryos; internal gills are found only in later-stage frog larvae. Evidence for internal gills has also been found in stem tetrapods, and amphibian-like external gills have been found in some fossil temnospondyls and anthracosaurs. Gill homology among these groups and life stages has long been questioned. To address this, scanning electron microscopy, vascular casting, and paraffin sectioning were utilized to study the morphology of gills and …

Multiple Connections Between Amazonia And Atlantic Forest Shaped The T Phylogenetic And Morphological Diversity Of Chiasmocleis Mehely, 1904 (Anura: Microhylidae: Gastrophryninae), Rafael O. De Sá, João Filipe Riva Tonini, Hannah Van Huss, Alex Long, Travis Cuddy, Mauricio C. Forlani, Pedro L.V. Peloso, Hussam Zaher, Célio F.B. Haddad

Biology Faculty Publications

Chiasmocleis is the most species-rich genus of Neotropical microhylids. Herein, we provide the first comprehensive multilocus phylogeny for the genus, including all but 3 of the 34 recognized species and multiple individuals per species. We discuss cryptic speciation, species discovery, patterns of morphological evolution, and provide a historical biogeographic analysis to account for the current distribution of the genus. Diversification of Chiasmocleis from other New World microhylids began during the Eocene, app. 40 mya, in forested areas, and current diversity seems to be a product of recurrent connections between the Atlantic Forest and Amazonia. Small-sized species evolved independently three times …

Shaping The Tools Of Battle : Sexual Selection, Contest Dynamics, And Weapon Divergence In The Asian Rhinoceros Beetle Trypoxylus Dichotomus, Jillian F. Del Sol

Graduate Student Theses, Dissertations, & Professional Papers

Exaggerated weapons of sexual selection often diverge more rapidly and dramatically than other body parts, suggesting that relevant agents of selection may be discernible in contemporary populations. I examined the ecology, reproductive behavior, and strength of sexual selection on horn length in five recently diverged beetle populations that differ in relative horn size. I show that mating system ecology differs between these locations and corresponds with the local strength of contemporary selection on horn length. Comparisons of ecological conditions and selection strength across populations offer a critical first step towards meaningfully linking mating system dynamics, selection patterns, and diversity in …

Confirming World-Wide Distribution Of An Agriculturally Important Lacewing, Chrysoperla Zastrowi Sillemi, Using Songs, Morphology, Mitochondrial Gene Sequencing, And Phylogenetic Reconstruction, Zoe Mandese

Honors Scholar Theses

The Chrysoperla carnea-group of green lacewings is a cryptic species complex. Species within the group are morphologically similar, yet isolated from one another via reproductive mating song. Chrysoperla zastrowi, a species within the carnea-group, is currently described with a distribution ranging from South Africa to the Middle East and India. However, recent collections of carnea-group lacewings from Guatemala and California were preliminarily identified as Chrysoperla zastrowi based upon similarities in their vibrational courtship songs. This analysis aims to place six specimens, collected by collaborators in Guatemala, Armenia, Iran, and California, into a pre-existing phylogeny of the …

The Mechanism Of Biotremor Production In The Veiled Chameleon (Chamaeleo Calyptratus), Samuel Tegge

Masters Theses & Specialist Projects

Vibratory communication has evolved in numerous animal groups, including insects, spiders, fishes, mammals, and was recently discovered in veiled chameleons (Chamaeleo calyptratus). I examined the mechanism by which C. calyptratus produce these biotremors. Muscle activity data were gathered during simulated anti-predator responses via electromyography (EMG) with simultaneous recordings of biotremor production using an accelerometer. I correlated EMG data with the accelerometer data to implicate the muscles responsible for the production of the biotremors. Mixed-effect linear regression models described the mechanism, and a model selection framework determined which model fit the data best. I then used an analysis of variance to …

Tityus Ythieri Lourenço, 2007 Is A Synonym Of Tityus Magnimanus Pocock, 1897 (Scorpiones: Buthidae): A Combined Approach Using Morphology, Hybridization Experiments, Chromosomes, And Mitochondrial Dna, František Kovařík, František Šťáhlavský, Tereza Kořínková, Jiří Král, Tom Van Der Ende

Euscorpius

Diagnostic morphological differences to distinguish between two scorpion species, Tityus ythieri Lourenço, 2007 and T. magnimanus Pocock, 1897 do not exist; moreover, the two easily hybridize to produce fertile offspring. Therefore, we suggest that T. ythieri is a synonym of T. magnimanus. This conclusion is further supported by (1) very similar distribution of relative sizes of chromosome bivalents in both species, (2) regular pairing of homologous chromosomes in meiosis of their hybrids, and (3) identical sequences of mitochondrial DNA (COI) markers.

Phenotypic Plasticity Of Oral Jaw Dentition In Archosargus Probatocephalus, Cynthia E. Worcester

Masters Theses & Specialist Projects

Phenotypic plasticity, the capacity of a single genotype to exhibit variable phenotypes in different environments, is common in many species. A sample of wild caught Archosargus probatocephalus, also known as sheepshead, from Florida was randomly divided into two treatment groups: one group was fed soft prey, Mercenaria sp. muscle tissue, and the other group was fed hard prey, Mercenaria sp. in the shell, for 365 days. It was hypothesized that the sheepshead fed hard prey would have a thicker tooth enamel layer containing more calcium, and therefore be stronger than the tooth enamel layer of those fed soft prey …

Phenotypic Plasticity Of Rattlesnake Trophic Morphology, Matthew Thomas Smith

Graduate Theses and Dissertations

The trophic morphology of gape-limited predators constrains the shape and size of prey items they can ingest. Trophic morphology consists of any morphological feature that is involved in the handling and ingestion of food. Diet has a profound effect on the morphology of many gape-limited predators. Identifying how prey type and resource level affect the morphology of different populations is an essential step in understanding the mechanisms contributing to patterns of morphological diversity. Species interactions (Chapter 1) induce plasticity in morphology that can lead to increased fitness, morphological divergence, and eventually speciation.

In Chapter 2, a laboratory study tested the …

Homoploid Hybrid Speciation In A Rare Endemic Castilleja From Idaho (Castilleja Christii, Orobanchaceae), Danielle Leigh Clay

Boise State University Theses and Dissertations

Evidence to support the origins of a putative hybrid species with certainty must be determined using several lines of evidence: the presence of genetic additivity of parental marker alleles in a putative hybrid species, along with ecological or niche separation. Novel or transgressive morphological traits obtained through chromosomal rearrangements during hybridization may facilitate niche separation of the hybrid species from progenitor habitats. These evolutionary processes together enforce reproductive isolation and promote an independent evolutionary trajectory in hybrid species. By studying these evolutionary processes in putative hybrid species, researchers may identify hybrid species with confidence.

We employed multiple lines of evidence …

Determining The Composition Of The Dwelling Tubes Of Antarctic Pterobranchs, Lukasz J. Sewera

Honors Projects

Pterobranchs are a group of marine invertebrates within the Hemichordata, which share characteristics with both chordates and echinoderms.  Pterobranchs live in colonies of secreted tubes, coenicia, which are composed of a gelatinous material of unknown composition.  Visually, the tubes appear similar to the tunic of tunicates, a group of invertebrates within the Chordata. The nonproteinaceous tunic of tunicates is composed of cellulose, which is unusual.  The goal of this study was to determine the composition of the pterobranch coenicium. Some aspects of pterobranch phylogeny are still unclear even after multiple molecular and morphological studies.  Identification of any new shared characteristics …