why does the yellow-eyed ensatina have yellow eyes? batesian mimicry of pacific newts (genus taricha) by the salamander ensatina eschscholtzii xanthoptica.color patterns commonly vary geographically within species, but it is rare that such variation corresponds with divergent antipredator strategies. the polymorphic salamander ensatina eschscholtzii, however, may represent such a case. in this species, most subspecies are cryptically colored, whereas e. e. xanthoptica, the yellow eyed ensatina, is hypothesized to be an aposematic mimic of highly toxic pacific newts (genus taricha). to test the mimicry hypothesis, we conducted feeding trials using ...200818248632
comparative and phylogenetic perspectives of the cleavage process in tailed amphibians.the order caudata includes about 660 species and displays a variety of important developmental traits such as cleavage pattern and egg size. however, the cleavage process of tailed amphibians has never been analyzed within a phylogenetic framework. we use published data on the embryos of 36 species concerning the character of the third cleavage furrow (latitudinal, longitudinal or variable) and the magnitude of synchronous cleavage period (up to 3-4 synchronous cell divisions in the animal hemis ...201525180466
molecular systematics of plethodon and aneides (caudata: plethodontidae: plethodontini): phylogenetic analysis of an old and rapid radiation.the closely related salamander genera plethodon and aneides (plethodontidae) differ in morphology, behavior, and ecology. although the systematics of these taxa has been the focus of much study, many details remain unresolved. to generate an hypothesis for the relationships among these taxa, i sequenced a segment of the mitochondrial protein-coding gene nd4 and portions of mitochondrial trnas. taxa sampled were 5 species of aneides, 7 species of western plethodon, and 13 species of eastern pleth ...200111161754
strong selection against hybrids at a hybrid zone in the ensatina ring species complex and its evolutionary implications.the analysis of interactions between lineages at varying levels of genetic divergence can provide insights into the process of speciation through the accumulation of incompatible mutations. ring species, and especially the ensatina eschscholtzii system exemplify this approach. the plethodontid salamanders e. eschscholtzii xanthoptica and e. eschscholtzii platensis hybridize in the central sierran foothills of california. we compared the genetic structure across two transects (southern and northe ...200516050109
genetic leakage after adaptive and nonadaptive divergence in the ensatina eschscholtzii ring species.the salamander ensatina eschscholtzii is an example of a ring species in which extant intermediate stages of terminal forms have a nearly continuous range, offering replicated interactions at several stages of divergence. we employ a greatly expanded allozyme database and individual-based analyses to separate the effects of divergence time and gene flow to evaluate how gradual divergence of populations around the ring contributes to the development of reproductive isolation. despite the high deg ...200919453728
early development of ensatina eschscholtzii: an amphibian with a large, yolky egg.comparative analyses between amphibians, concentrating on the cellular mechanisms of morphogenesis, reveal a large variability in the early developmental processes that were thought to be conserved during evolution. increased egg size is one factor that could have a strong effect on early developmental processes such as cleavage pattern and gastrulation. salamanders of the family plethodontidae are particularly appropriate for such comparative studies because the species have eggs of varying siz ...201020849648
predictors for reproductive isolation in a ring species complex following genetic and ecological divergence.reproductive isolation (ri) is widely accepted as an important "check point" in the diversification process, since it defines irreversible evolutionary trajectories. much less consensus exists about the processes that might drive ri. here, we employ a formal quantitative analysis of genetic interactions at several stages of divergence within the ring species complex ensatina eschscholtzii in order to assess the relative contribution of genetic and ecological divergence for the development of ri.201121733173
asymmetric reproductive isolation between terminal forms of the salamander ring species ensatina eschscholtzii revealed by fine-scale genetic analysis of a hybrid zone.ring species, exemplified by salamanders of the ensatina eschscholtzii complex, represent a special window into the speciation process because they allow the history of species formation to be traced back in time through the geographically differentiated forms connecting the two terminal forms of the ring. of particular interest is the nature and extent of reproductive isolation between the geographically terminal forms, in this case e. e. eschscholtzii and e. e. klauberi. previous studies have ...201121859447
montane refugia predict population genetic structure in the large-blotched ensatina salamander.understanding the biotic consequences of pleistocene range shifts and fragmentation remains a fundamental goal in historical biogeography and evolutionary biology. here, we combine species distribution models (sdm) from the present and two late quaternary time periods with multilocus genetic data (mitochondrial dna and microsatellites) to evaluate the effect of climate-induced habitat shifts on population genetic structure in the large-blotched ensatina (ensatina eschscholtzii klauberi), a pleth ...201323379992
dynamics and thermal sensitivity of ballistic and non-ballistic feeding in salamanders.low temperature reduces the performance of muscle-powered movements, but in movements powered by elastic recoil mechanisms, this effect can be mitigated and performance can be increased. to better understand the morphological basis of high performance and thermal robustness of elastically powered movements, we compared feeding dynamics at a range of temperatures (5-25°c) in two species of terrestrial plethodontid salamanders, plethodon metcalfi and ensatina eschscholtzii, which differ in tongue ...201626612894
intraspecific variation in the skin-associated microbiome of a terrestrial salamander.resident microbial communities living on amphibian skin can have significant effects on host health, yet the basic ecology of the host-microbiome relationship of many amphibian taxa is poorly understood. we characterized intraspecific variation in the skin microbiome of the salamander ensatina eschscholtzii xanthoptica, a subspecies composed of four genetically distinct populations distributed throughout the san francisco bay area and the sierra nevada mountains in california, usa. we found that ...201728466089
incipient species formation in salamanders of the ensatina complex.the ensatina eschscholtzii complex of plethodontid salamanders, a well-known "ring species," is thought to illustrate stages in the speciation process. early research, based on morphology and coloration, has been extended by the incorporation of studies of protein variation and mitochondrial dna sequences. the new data show that the complex includes a number of geographically and genetically distinct components that are at or near the species level. the complex is old and apparently has undergon ...19979223261
geographical variation in agonistic behaviour in a ring species of salamander, ensatina eschscholtzii.ensatina eschscholtzii is a plethodontid salamander with several geographical races distributed in a ring-like series throughout the coastal mountains and inland sierra nevada mountains of california. populations of these salamanders show genetic and morphological divergence, and in this study, we examined divergence in overt aggressive, passive aggressive/exploratory, avoidance and sensory behaviours in four populations. two of the populations represent a zone of secondary contact between coast ...19989642003
pronounced phylogeographic structure on a small spatial scale: geomorphological evolution and lineage history in the salamander ring species ensatina eschscholtzii in central coastal california.the salamander ensatina eschscholtzii is a classic example of a ring species, and has an intricate biogeographic history. within a part of the ring distribution, earlier work using allozymes disclosed high levels of genetic structure in central coastal california, where the subspecies oregonensis, xanthoptica, and eschscholtzii meet. we used mitochondrial cytochrome b sequences to further examine patterns of divergence in this area, including data from 155 localities (309 individuals). our focus ...200919026754
isolation and characterization of 15 polymorphic microsatellites in the plethodontid salamander ensatina eschscholtzii.we developed 15 new polymorphic microsatellites for the plethodontid salamander ensatina eschscholtzii. loci were isolated from a genomic library from ensatina eschscholtzii xanthoptica enriched for (aaag)(n) repetitive elements. the number of alleles per locus ranged from 4 to 20 (mean 9) in the sampled population. observed heterozygosity ranged from 0.37 to 1. none of the loci deviated from hardy-weinberg equilibrium or showed significant linkage disequilibrium after a bonferroni correction fo ...200921564807
modulation of prey-capture behavior in the plethodontid salamander ensatina eschscholtziithe hypothesis that salamander prey-capture behavior is highly stereotyped was tested in the plethodontid salamander ensatina eschscholtzii using high-speed videography and kinematic analysis of feedings on two types of prey (waxworms and termites). the results show that e. eschscholtzii is capable of modulating the timing and magnitude of tongue and jaw movements in response to prey type. feedings on waxworms, the larger prey, were characterized by shorter durations and higher velocities of ton ...19979319864
geographic variation in allozymes in a "ring species," the plethodontid salamander ensatina eschscholtzii of western north america.the ring species ensatina eschscholtzii (a plethodontid salamander) of western north america has a circle of subspecies surrounding the central valley of california which come into contact and are sympatric in southern california. we examined 26 proteins in 19 populations (maximum of 10 specimens per population) collected throughout the range in order to gain an understanding of the degree of differentiation in the group. allozymic differentiation is profound, with genetic distances in excess of ...198628556154
intraspecific sympatry in a "ring species," the plethodontid salamander ensatina eschscholtzii, in southern california. 198628556151
composition and structure of helminth communities of the salamanders, aneides lugubris, batrachoseps nigriventris, ensatina eschscholtzii (plethodontidae), and taricha torosa (salamandridae) from california.component helminth communities of aneides lugubris (n=31), batrachoseps nigriventris (n=63), ensatina eschscholtzii (n=30), and taricha torosa (n=68) from california were determined. the compound helminth community consisted of 1 species of cestode, bitegmen gerrhonoti and 6 species of nematodes, batracholandros salamandrae, cosmocercoides variabilis, falcaustra pretiosa, megalobatrachonema gigantica, oswaldocruzia pipiens, and rhabdias joaquinensis. the least diverse infracommunities were assoc ...19989576495
ring distributions leading to species formation: a global topographic analysis of geographic barriers associated with ring the mid 20th century, ernst mayr and theodosius dobzhansky championed the significance of circular overlaps or ring species as the perfect demonstration of speciation, yet in the over 50 years since, only a handful of such taxa are known. we developed a topographic model to evaluate whether the geographic barriers that favor processes leading to ring species are common or rare, and to predict where other candidate ring barriers might be found.201222410314
Displaying items 1 - 20 of 20