Download or read book Phylogeography Evolution and Population Genetics of the Salamanders Pseudobranchus in the Southeastern United States written by Fu-Guo Robert Liu and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This difference is tied to the greater population bottlenecking and extinction within P. axanthus due to interglacial marine flooding since the late Miocene, as well as to the faster sorting times for the mitochondrial DNA. Estimates of the ages and of the effective female population sizes (Nf) for both species show that P. striatus is at least 2.5 times older than P. axanthus despite their similar Nf. This age difference is linked to the more recent divergence of the phylogeographic groups within P. axanthus, again as a result of its greater lineage extinction due to interglacial marine flooding since the late Miocene.
Download or read book Phylogeography Evolution and Conservation in Forest associated Pacific Northwest Salamanders written by R. Steven Wagner and published by . This book was released on 2000 with total page 580 pages. Available in PDF, EPUB and Kindle. Book excerpt: Phylogeographic studies of six Pacific Northwest forest-associated salamanders provide insight into historical and contemporary processes on population genetic structure. Among Larch Mountain Salamanders (Plethodon larselli), cytochrome b mitochondrial (mtDNA) sequences (381 bp) and random amplified polymorphic DNA (RAPDs; 34 loci) supported separate Management Units for northern and southern populations (12 populations, N 184 individuals) as delineated by the Columbia River. Southern populations exhibited significantly reduced expected heterozygosity at RAPD loci, which may be a consequence of a founder event or bottleneck. Similarly, significant population structure was found in Oregon Slender Salamanders (Batrachoseps wrighti). Cytochrome b sequences (744 bp) revealed two historical lineages among 22 populations (N = 339 individuals). RAPD markers further differentiated mid-range populations. Therefore, overlapping Management Units are warranted for northern-most, mid-range, and southern-most populations. Phylogenetic relationships, taxonomic identity, and population differentiation was examined among four morphologically conserved Torrent Salamanders species (Family Rhyacotritonidae). Analysis of three mitochondrial genes (cytochrome b, 16S, and 12S ribosomal RNA) indicated each species represented a well-supported monophyletic group. Results agreed with allozyme data (Good et. al. 1987, Good and Wake 1992) suggesting three groups of Torrent Salamanders (Rhyacotriton variegatus, R. cascadae, and the ancestor of R. olympicus and R. kezeri) diverged during the Miocene. A more recent divergence appears to have occurred between R. olympicus and R. kezeri during the late Pliocene/early Pleistocene. Populations within R. variegatus appear to be as diverged as R. olympicus and R. kezeri, supporting conservation unit designation within R. variegatus. MtDNA 16S ribosomal RNA sequences and allozymes (5 loci) identified Cascade and Southern Torrent Salamanders recently discovered in the Central Oregon Cascades. Results indicate a range extension for both species and suggest the Middle Fork of the Willamette River may provide a geographic barrier to dispersal. Phylogenetic analyses of Southern Torrent Salamanders (72 localities) based upon cytochrome b sequences revealed three divergent clades (north coast, Oregon, and California) that coincide with possible geographic barriers to dispersal. Merging mtDNA results with previous allozyme studies provides support for an Evolutionary Significant Unit for the California dade and separate Management Units for the north coast and Oregon clades.
Download or read book Dissertation Abstracts International written by and published by . This book was released on 2006 with total page 848 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Biology of Plethodontid Salamanders written by Richard C. Bruce and published by Springer Science & Business Media. This book was released on 2000-04-30 with total page 506 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume offers a state-of-the-art overview of plethodontid salamanders. Readers will find the best current understanding of many aspects of the evolution, systematics, development, morphology, life history, ecology, and field methodology of these animals.
Download or read book Phylogeographic and Phylogenetic Exploration of Plethodon Plethodontidae Caudata Salamanders in the Pacific Northwest written by and published by . This book was released on 2009 with total page 99 pages. Available in PDF, EPUB and Kindle. Book excerpt: Genetic studies of amphibians often reveal substantial population structure due to either historical demographics from changing climate and geographic features over varying timeframes. Eight species of terrestrial salamanders (Family: Plethodontidae, Genus: Plethodon) reside in forests of the Pacific Northwest (PNW). Plethodon vehiculum is the most widespread and abundant terrestrial salamander in the PNW yet evolutionary studies are lacking. Using mitochondrial DNA (mtDNA) sequence data (D-loop and cytb) questions regarding the phylogeography of P. vehiculum and phylogenetics of western Plethodons are explored. Two major clades were defined in P. vehiculum, a southern clade in the Klamath-Siskiyou region and a northern clade ranging from northern Oregon to British Columbia using parsimony and maximum likelihood trees and a haplotype network. High divergence levels between the north and south clades are observed warranting further investigation into the southern clade's unique evolutionary trajectory. The northern populations were not highly differentiated with high levels of haplotype sharing, not common in other terrestrial salamander species. A large recent range expansion or high habitat connectivity for these salamanders is suggested. The Columbia River did not act as barrier to dispersal in this species, however, Vancouver Island and the population of Washington's Olympic Peninsula revealed unique haplotypes only to those areas, due to the presence of geographic barriers to dispersal and/or multiple glacial refugia. The D-loop and cytb provided evidence for recent range expansion in the northern clade. This was the first study to incorporate all western Plethodon salamanders in a phylogenetic study. Parsimony and maximum likelihood methods offered strong support for recognized relationships among western Plethodons, however relationships between the major groups remain unhighly supported. Lack of genetic diversity in the mtDNA cytb gene in P. vehiculum is highly inconsistent with other Plethodon salamanders and highlights the importance of understanding mtDNA evolution in ectotherms. Divergence measures were used to estimate divergence times among species, dating all speciation before the Pleistocene glaciations. The southern OR clade of P. vehiculum was dated to have been separated from the northern clade at the start of the Pleistocene. The deep phylogeographic break here justifies the possibility of reclassification of the southern clade.
Download or read book Western Plethodon Salamanders as a Model System in Phylogeography written by Tara Anne Pelletier and published by . This book was released on 2015 with total page 226 pages. Available in PDF, EPUB and Kindle. Book excerpt: Plethodon salamanders are fully terrestrial, lungless salamanders found in forested areas throughout North America. My dissertation focuses on five of these salamander species located in the Pacific Northwest (PNW). The PNW has a complex geologic history including events such as volcanism and repeated glaciations. This complexity makes studying biodiversity patterns informative as to what evolutionary processes shape current population and species structure. The five species that are the focus of my dissertation are used to learn about Plethodon salamanders in general, but because these salamanders are at different stages of divergence within and among species, they can further be used to explore methods in phylogeography, which help us better understand the process of evolution. First, I explore demographic model selection using genetic data in P. idahoensis (Chapter 2). The best demographic model for this species is one with population divergence, expansion, and migration. Furthermore, the evaluation of Approximate Bayesian computation techniques highlights the complexities of this method for model selection in phylogeography.
Download or read book The Historical and Ecological Biogeography of the Eastern Red Backed Salamander Plethodon Cinereus written by Brian P. Waldron and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Patterns in the distributions of species result from numerous ecological and evolutionary processes, including competitive interactions, evolved physiological tolerances, and the historical environmental fluctuations that have caused ranges to shift, expand, or contract over long time periods. For some groups of species, these processes have resulted in an elaborate diversification of traits. For other groups, however, such as woodland salamanders (genus Plethodon), closely related species may be phenotypically similar or even identical. It is less clear what drives the formation of such species, whether and how they maintain their identities and interact after initial divergence, and how such similar species might have evolved ecologically in subtle ways to differentially utilize the landscape. The Eastern Red-backed Salamander (Plethodon cinereus) is a small, fully terrestrial woodland salamander notable for its wide distribution and high phylogeographic diversity in the eastern United States and southeastern Canada. Most of its current distribution, however, was covered by ice sheets at the end of the Pleistocene, suggesting recent and rapid post-glacial expansion. It is not yet clear how P. cinereus colonized these landscapes, and what ecological characteristics made P. cinereus so successful in its range expansion compared to other species. Some studies comparing narrowly-distributed montane Plethodon to their lowland counterparts have suggested a combination of physiological specialization and competitive superiority of montane species relative to generalist lowland species such as P. cinereus, but it is unknown if this asymmetry applies to sets of lowland species outside of montane systems. In this dissertation, I explore the biogeography of woodland salamanders, with special attention to P. cinereus, at ecological and evolutionary time scales to uncover the processes that shape genetic diversity and species distributions. Chapters 1 and 2 concern the historical biogeography and evolution of P. cinereus, while Chapters 3 and 4 compare the habitat use of P. cinereus to two of its more broadly distributed relatives, the Northern Ravine Salamander (P. electromorphus) and the Southern Ravine Salamander (P. richmondi), to test if they have diverged ecologically, including multiple ecological scales. In Chapter 1, I used next-generation DNA sequencing to explore the phylogeographic structure and demographic history of P. cinereus, using the species as a model for the formation of incipient lineages of Plethodon. I identified several groups that diverged within the Pleistocene, yet I also found numerous and sometimes extensive regions of admixture between groups, suggesting a model of range fragmentation and fusion during incipient species formation. In Chapter 2, I focus on the most recent post-glacial expansion of P. cinereus, using DNA sequencing from range-wide samples to uncover the origins and routes of colonization. Results generally supported a southeastern coastal origin that expanded northward, westward into the Great Lakes region, and then a novel colonization route southward back into unglaciated areas. In Chapter 3, I used ecological niche modeling to test if niche differentiation between P. cinereus, P. electromorphus, and P. richmondi explains their broad distributional patterns. All species had estimated niches that were more different than expected by chance, and historical habitat suitability has fluctuated dramatically in the Holocene epoch, although I did not find strong evidence that climatic or topographic variables differentiated occurrences of P. cinereus and P. electromorphus within their overlapping distribution. Finally, in Chapter 4, I explore microhabitat differentiation between P. cinereus and P. electromorphus where they occur and interact at fine spatial scales. Plethodon cinereus greatly outnumbered P. electromorphus, and P. electromorphus used cooler, wetter microhabitats that were also occupied by P. cinereus, with no evidence for a negative correlation in their occupancies or abundances. Taken together, my work suggests that current distributions, including patterns within and between species, are shaped by historical range expansion and contractions, as well as subtle differences in habitat use at multiple spatial scales.
Download or read book Phylogenetic History Morphological Parallelism and Speciation in a Complex of Appalachian Salamanders genus Desmognathus written by Nathan D. Jackson and published by . This book was released on 2005 with total page 128 pages. Available in PDF, EPUB and Kindle. Book excerpt: Understanding the mechanisms that generate shared morphologies across closely related taxa is important when identifying distinct evolutionary lineages using morphological characters. Desmognathus salamanders are an ideal group for testing hypotheses concerning the correlation between morphological similarity and genetic exchange within and among nominal species due to a pattern of high discordance between the two. Phylogeographic hypotheses are tested for populations of the D. quadramaculatus species complex throughout southern Appalachia by combining phylogenetic and population genetic methods with geographical information. Phylogenetic and phylogeographic inferences are then assessed in conjunction with morphological characteristics that have traditionally diagnosed taxonomic entities to understand the genetic basis of shared morphology in this complex, and to assess species boundaries. A history of fragmentation followed by range expansion is suggested as a recurrent pattern that has shaped the current population structure within this complex. The current taxonomy is found to unite populations that share similar morphologies due to parallel evolution rather than ancestry. We suggest revisions in taxonomy that will better reflect the evolutionary history of these lineages. Appreciation of the hidden genetic variation and homoplasious morphological variation often present in and among salamander species can foster the implementation of more appropriate methods for detecting and recognizing the complex history of these organisms.
Download or read book Phylogeography and Range Limit Evolution in the Cumberland Plateau Salamander Plethodon Kentucki written by Emily F. Watts and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Gene flow and geography are critically influential factors in shaping the genetic history of a species. Gene flow can have beneficial effects on a population that may allow for new adaptations to occur, such as increasing genetic variation. However, gene flow may also result in negative consequences for populations if their fitness is decreased through the introduction of non-optimized traits or through selection resulting in a reduction of locally adapted individuals. Asymmetrical gene flow can even prevent local adaptation in edge populations when gene flow from central populations adapted to central conditions swamps locally adapted populations. This phenomenon can prevent a species from expanding its range, as it is unable to adapt to local conditions at the range edges. Thus, patterns of gene flow can determine the extent to which gene flow slows or promotes adaptation. Gene flow can also create problems for the inference of species relationships, because it is a source of gene tree-species tree discordance. While speciation is commonly modeled as a finite event, divergence is a process. Even after divergence, hybridization is common, and neglecting to account for it can lead to incorrect species tree inference. Nonetheless, the development of species tree inference methods that account for gene flow remains in its infancy. Even with the addition of more loci from genomic-scale data, gene flow misleads phylogenetic reconstruction. Thus, it is vital to account for gene flow with phylogenetic networks when inferring species relationships. This dissertation examines the role of gene flow in constraining adaptation in the Cumberland Plateau Salamander, Plethodon kentucki, a cryptic species with respect to the sympatric Northern Slimy Salamander, Plethodon glutinosus. After its description in 1983 by Highton and MacGregor using allozyme data, its taxonomic status was unclear, as the authors reported extreme levels of genetic differentiation for a single species with a narrow distribution, and follow-up studies found patterns of genetic variation that were discordant with the allozyme data. In chapter 1, I describe genetic variation within P. kentucki and conclude it is best recognized as a single species with substantial genetic structure within its limited distribution. In chapter 2, I describe the heterogeneity of the landscape within the range of P. kentucki. I also quantify the genetic connectivity across the range of P. kentucki and describe how the two interact to maintain the range of P. kentucki. I also test a novel theory about how different types of range edges impact adaptation at the periphery of a species’ range. This dissertation also examines the role of gene flow in confounding phylogenetic inference using two prominent phylogenetic network methods. In chapter 3, I use computer modeling to examine how these two methods perform under varying degrees of gene flow and population history, as well as how they perform under two different datasets. This dissertation explores the role of gene flow, or lack thereof, in maintaining species boundaries, inhibiting range expansion, and confounding the inference of species relationships.
Download or read book Speciation Phylogeography and Gene Flow in Giant Salamanders Dicamptodon written by Craig A. Steele and published by . This book was released on 2006 with total page 137 pages. Available in PDF, EPUB and Kindle. Book excerpt: Giant salamanders of the genus Dicamptodon occur in the Pacific Northwest of North America. The variety of geographic distributions and life history traits displayed among this genus provide opportunities to test hypotheses concerning regional biogeography, effects of Pleistocene glaciation, comparative phylogeography, and patterns of gene flow. A genus-level phylogeny was constructed to test competing biogeographic hypotheses concerning the disjunct distribution of the Idaho giant salamander (D. aterrimus ), and a Pleistocene speciation hypothesis for the Cope's giant salamander (D. copei). Results indicate speciation and distribution of D. aterrimus is attributable to the orogeny of the Cascade Mountains rather than recent inland dispersal and that D. copei is distantly related to other coastal species and likely originated much earlier than the Pleistocene. Patterns of intraspecific variation were examined for the widespread Pacific giant salamander (D. tenebrosus) and hypotheses concerning the location and number of Pleistocene refugia were tested. Results indicate that D. tenebrosus was restricted to two Pleistocene refugia, one in the Columbia River valley and another in the Klamath-Siskiyou Mountains, and has recently expanded northward from these refugia into its current distribution. Phylogeographic patterns for D. copei were compared to that of the codistributed Van Dyke's salamander (Plethodon vandykei). Results reveal that sympatric populations displayed identical phylogeographic topologies, suggesting shared evolutionary histories, but topologies were ultimately incongruent due to several highly divergent allopatric populations of D. copei. Comparative patterns of genetic population structure were examined for sympatric populations of D. tenebrosus and D. copei. Results indicate that the metamorphosing species, D. tenebrosus, displayed a lack of population structure while the non-metamorphosing species, D. copei, displayed a larger degree of population structure. These results help explain the phylogeographic patterns presented for each species. The large distribution and post-glacial expansion by D. tenebrosus was facilitated by its high dispersal ability while the low dispersal ability of D. copei lead to a small and fragmented geographic range and greater phylogeographic structure within its range. These results suggest that understanding life history variation on a local scale can lead to a better understanding of the mechanistic underpinnings of species' distributions in general.
Download or read book Key to the Herpetofauna of the Continental United States and Canada written by Robert Powell and published by University Press of Kansas. This book was released on 2019-07-26 with total page 180 pages. Available in PDF, EPUB and Kindle. Book excerpt: This profusely illustrated comprehensive key for identifying amphibians and reptiles from the continental United States and Canada incorporates a wealth of scientific findings. Since the first edition was published in 1998 and the second in 2012, the number of currently recognized species of native amphibians and reptiles in the area covered by this key has increased from 545 to 634 to 685, and the number of established non-native species has increased from 39 to 58 to 67. The increase in native taxa reflects the dynamic nature of modern systematics and the use of new (especially molecular) techniques to elucidate relationships and redefine species boundaries. The increase in non-native species reflects the porosity of the North American borders when it comes to controlling animal imports. The key is easy to use and illustrated with outstanding line drawings that show details of color patterns and structures used for identification. To accommodate the additional taxa, the number of line drawings in this third edition has increased from 257 to 279 to 295. In addition, nine maps illustrate the distributions of species that have been recognized since the publication of maps in the most recent editions of the Peterson Field Guides to the reptiles and amphibians of eastern, central, and western North America. A large number of annotations detail current taxonomic ambiguities or disagreements and the literature cited has been expanded. Collectively these features enhance opportunities to teach and learn the classification and identification of amphibians and reptiles in the continental United States and Canada.
Download or read book Phylogeography and Genetic Diversity of the Seal Salamander Desmognathus Monticola written by Erin D. Casey and published by . This book was released on 2002 with total page 90 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Scientific and Standard English Names of Amphibians and Reptiles of North America North of Mexico written by Society for the Study of Amphibians and Reptiles. Committee on Standard English and Scientific Names and published by . This book was released on 2001 with total page 104 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Herpetology written by Laurie J. Vitt and published by Academic Press. This book was released on 2012-12-02 with total page 544 pages. Available in PDF, EPUB and Kindle. Book excerpt: Herpetology has always been one of the most exciting disciplines of zoology. During the past few years the field has continued to grow, yet it has been plagued by scarcity of comprehensive, up-to-date textbooks containing the most important developments. This timely book fills that void. Through skillful synthesis, the author summarizes the diversity in the biology of living amphibians and reptiles and describes the breadth of current herpetological research. Topics covered include the evolution, classification, development, reproduction, population, and environmental issues surrounding the study of amphibians and reptiles. Designed as an advanced undergraduate textbook, Herpetology is a valuable resource for students, practitioners, and interested amateurs alike. Provides an incisive survey and much needed update of the field Emphasizes the biological diversity among amphibians and reptiles Details the most recent research findings, citing ke
Download or read book Threatened Amphibians of the World written by S. N. Stuart and published by . This book was released on 2008 with total page 784 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Amphibians are facing an extinction crisis, but getting to the facts has been difficult. "Threatened Amphibians of the World" is a visual journey through the first-ever comprehensive assessment of the conservation status of the world's 6,000 known species of frogs, toads, salamanders, and caecilians. All 1,900 species known to be threatened with extinction are covered, including a description of threats to each species and an evaluation of conservation measures in place or needed. Each entry includes a photograph or illustration of the species where available, a distribution map, and detailed information on range, population and habitat and ecology. Introductory chapters present a detailed analysis of the results, complemented by a series of short essays written by many of the world's leading herpetologists. Appendices include annoted lists of lower risk species and a country-by-country listing of threatened amphibians."--pub. desc.
Download or read book Sperm Biology written by Scott S. Pitnick and published by Academic Press. This book was released on 2008-11-21 with total page 683 pages. Available in PDF, EPUB and Kindle. Book excerpt: Sperm Biology represents the first analysis of the evolutionary significance of sperm phenotypes and derived sperm traits and the possible selection pressures responsible for sperm-egg coevolution. An understanding of sperm evolution is fast developing and promises to shed light on many topics from basic reproductive biology to the evolutionary process itself as well as the sperm proteome, the sperm genome and the quantitative genetics of sperm. The Editors have identified 15 topics of current interest and biological significance to cover all aspects of this bizarre, fascinating and important subject. It comprises the most comprehensive and up-to-date review of the evolution of sperm and pointers for future research, written by experts in both sperm biology and evolutionary biology. The combination of evolution and sperm is a potent mix, and this is the definitive account. The first review survey of this emerging field Written by experts from a broad array of disciplines from the physiological and biomedical to the ecological and evolutionary Sheds light on the intricacies of reproduction and the coevolution of sperm, egg and reproductive behavior
Download or read book American Alligators written by Scott E. Henke and published by . This book was released on 2018-04 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
