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R. Terry Chesser

Publications and source records attributed to R. Terry Chesser.

36 records · Page 2Linked to original sources
USGS2015

A further note on the scientific name of Bullocks’ Oriole

Chesser (2013) intended to introduce a justified emendation to Icterus bullockii under Article 32.5.1 of the Code (ICZN 1999), because the name honors both William Bullock, Sr., and William Bullock, Jr. However, the correction bullockorum is "incorrect" and therefore is an unjustified emendation (Article 33.2.3). Under the assumption that the name Bullock was latinized (cf. Article 31.1.1) to Bullockius (bullocki– + the nominative case ending –us) and therefore that the name bullockii comprises the stem bullocki– + the genitive case ending –i, the justified correction bullockiorum is required.

Zootaxa↗
USGS2015

Morphological divergence in a continental adaptive radiation: South American ovenbirds of the genus Cinclodes

Cinclodes is an ecologically diverse genus of South American passerine birds and represents a case of continental adaptive radiation along multiple axes. We investigated morphological diversification in Cinclodes using a comprehensive set of morphometric measurements of study skins. Principal component analysis identified 2 primary axes of morphological variation: one describing body size and a second capturing differences in wing-tip shape and toe length. Phylogenetic analyses of the first principal component suggest an early divergence of Cinclodes into 2 main clades characterized by large and small body sizes. We suggest that 2 morphological outliers within these main clades ( C. antarcticus and C. palliatus ) may be cases of island gigantism and that a third ( C. patagonicus ) may reflect ecological character displacement. Despite its ecological and physiological diversity, the genus Cinclodes does not appear to show morphological diversity beyond what is typical of other avian genera.

The Auk↗
USGS2014

Ecological change on California's Channel Islands from the Pleistocene to the Anthropocene

Historical ecology is becoming an important focus in conservation biology and offers a promising tool to help guide ecosystem management. Here, we integrate data from multiple disciplines to illuminate the past, present, and future of biodiversity on California's Channel Islands, an archipelago that has undergone a wide range of land-use and ecological changes. Our analysis spans approximately 20,000 years, from before human occupation and through Native American hunter–gatherers, commercial ranchers and fishers, the US military, and other land managers. We demonstrate how long-term, interdisciplinary research provides insight into conservation decisions, such as setting ecosystem restoration goals, preserving rare and endemic taxa, and reducing the impacts of climate change on natural and cultural resources. We illustrate the importance of historical perspectives for understanding modern patterns and ecological change and present an approach that can be applied generally in conservation management planning.

California↗
USGS2014

Fifty-fifth supplement to the American Ornithologists' Union Check-list of North American Birds

This is the 14th supplement since publication of the 7th edition of the Check-list of North American Birds (American Ornithologists' Union [AOU] 1998). It summarizes decisions made between May 15, 2013, and May 15, 2014, by the AOU's Committee on Classification and Nomenclature - North and Middle America. The Committee has continued to operate in the manner outlined in the 42nd Supplement (AOU 2000).

The Auk↗
USGS2013

On the correct name of Icterus bullockii (Passeriformes: Icteridae)

William Bullock was an Englishman who owned the Egyptian Hall (also known as the London Museum or Bullock’s Museum) at Piccadilly in London, a museum opened in 1812 to display his collection of antiquities, artifacts, and natural history specimens. Following the sale of Bullock’s collection in 1819, the Egyptian Hall served as an exhibition space. Bullock and his son, William Bullock, Jr., both enthusiastic naturalists, travelled in Mexico in 1822–1823, spending some six months together collecting natural history specimens and other artifacts for exhibition and investigating mining and other business opportunities (Costeloe 2006). The elder Bullock returned to London with the collections in 1823, but his son, while ostensibly managing the silver mine his father had purchased in Temascaltepec, outside of Mexico City, continued to travel in Mexico and collect specimens, often in the company of German naturalist Ferdinand Deppe (Costeloe 2006). William Bullock, Sr., meanwhile prepared the Mexican collection for exhibition at the Egyptian Hall. Twin exhibitions on ancient and modern Mexico opened, with much fanfare, in April 1824, and were a great success, remaining open until September 1825 (Costeloe 2006). Afterwards, the contents of the exhibitions were dispersed via auction, but not before Bullock had made the bird specimens available to English naturalist William Swainson for “recording this portion of his discoveries” (Swainson 1827: 365).

Zootaxa↗
USGS2012

Hybridization among Arctic white-headed gulls (Larus spp.) obscures the genetic legacy of the Pleistocene

We studied the influence of glacial oscillations on the genetic structure of seven species of white-headed gull that breed at high latitudes ( Larus argentatus, L. canus, L. glaucescens, L. glaucoides, L. hyperboreus, L. schistisagus, and L. thayeri ). We evaluated localities hypothesized as ice-free areas or glacial refugia in other Arctic vertebrates using molecular data from 11 microsatellite loci, mitochondrial DNA (mtDNA) control region, and six nuclear introns for 32 populations across the Holarctic. Moderate levels of genetic structure were observed for microsatellites ( F ST = 0.129), introns ( Φ ST = 0.185), and mtDNA control region ( Φ ST = 0.461), with among-group variation maximized when populations were grouped based on subspecific classification. Two haplotype and at least two allele groups were observed across all loci. However, no haplotype/allele group was composed solely of individuals of a single species, a pattern consistent with recent divergence. Furthermore, northernmost populations were not well differentiated and among-group variation was maximized when L. argentatus and L. hyberboreus populations were grouped by locality rather than species, indicating recent hybridization. Four populations are located in putative Pleistocene glacial refugia and had larger t estimates than the other 28 populations. However, we were unable to substantiate these putative refugia using coalescent theory, as all populations had genetic signatures of stability based on mtDNA. The extent of haplotype and allele sharing among Arctic white-headed gull species is noteworthy. Studies of other Arctic taxa have generally revealed species-specific clusters as well as genetic structure within species, usually correlated with geography. Aspects of white-headed gull behavioral biology, such as colonization ability and propensity to hybridize, as well as their recent evolutionary history, have likely played a large role in the limited genetic structure observed.

Ecology and Evolution↗
USGS2012

Isleria, a new genus of antwren (Aves: Passeriformes: Thamnophilidae)

A comprehensive molecular phylogenetic analysis of the family Thamnophilidae indicated that the genus Myrmotherula is not monophyletic. The clade composed of M. guttata and M. hauxwelli is only distantly related to other members of the genus and should be removed from Myrmotherula. The phenotypic distinctiveness of the clade argues against merging it with its sister group Thamnomanes and no generic name is available for the guttata-hauxwelli clade. Consequently, we describe the genus Isleria for these two species, and designate Myrmothera guttata as its type species.

Zootaxa↗
USGS2011

Lineage diversification and morphological evolution in a large-scale continental radiation: The neotropical ovenbirds and woodcreepers (Aves: Furnariidae)

Patterns of diversification in species-rich clades provide insight into the processes that generate biological diversity. We tested different models of lineage and phenotypic diversification in an exceptional continental radiation, the ovenbird family Furnariidae, using the most complete species-level phylogenetic hypothesis produced to date for a major avian clade (97% of 293 species). We found that the Furnariidae exhibit nearly constant rates of lineage accumulation but show evidence of constrained morphological evolution. This pattern of sustained high rates of speciation despite limitations on phenotypic evolution contrasts with the results of most previous studies of evolutionary radiations, which have found a pattern of decelerating diversity-dependent lineage accumulation coupled with decelerating or constrained phenotypic evolution. Our results suggest that lineage accumulation in tropical continental radiations may not be as limited by ecological opportunities as in temperate or island radiations. More studies examining patterns of both lineage and phenotypic diversification are needed to understand the often complex tempo and mode of evolutionary radiations on continents.

Evolution↗
USGS2011

No population genetic structure in a widespread aquatic songbird from the Neotropics

Neotropical lowland organisms often show marked population genetic structure, suggesting restricted migration among populations. However, most phylogeographic studies have focused on species inhabiting humid forest interior. Little attention has been devoted to the study of species with ecologies conducive to dispersal, such as those of more open and variable environments associated with watercourses. Using mtDNA sequences, we examined patterns of genetic variation in a widely distributed Neotropical songbird of aquatic environments, the Yellow-hooded Blackbird (Icteridae, Chrysomus icterocephalus ). In contrast to many forest species, Yellow-hooded Blackbirds showed no detectable genetic structure across their range, which includes lowland populations on both sides of the Andes, much of northeastern South America, Amazonia, as well as a phenotypically distinct highland population in Colombia. A coalescent-based analysis of the species indicated that its effective population size has increased considerably, suggesting a range expansion. Our results support the hypothesis that species occurring in open habitats and tracking temporally dynamic environments should show increased dispersal propensities (hence gene flow) relative to species from closed and more stable environments. The phenotypic and behavioral variation among populations of our study species appears to have arisen recently and perhaps in the face of gene flow.

Molecular Phylogenetics and Evolution↗
USGS2010

Long-term isolation of a highly mobile seabird on the Galapagos

The Galapagos Islands are renowned for their high degree of endemism. Marine taxa inhabiting the archipelago might be expected to be an exception, because of their utilization of pelagic habitats—the dispersal barrier for terrestrial taxa—as foraging grounds. Magnificent frigatebirds ( Fregata magnificens ) have a highly vagile lifestyle and wide geographical distribution around the South and Central American coasts. Given the potentially high levels of gene flow among populations, the species provides a good test of the effectiveness of the Galapagos ecosystem in isolating populations of highly dispersive marine species. We studied patterns of genetic (mitochondrial DNA, microsatellites and nuclear introns) and morphological variation across the distribution of magnificent frigatebirds. Concordant with predictions from life-history traits, we found signatures of extensive gene flow over most of the range, even across the Isthmus of Panama, which is a major barrier to gene flow in other tropical seabirds. In contrast, individuals from the Galapagos were strongly differentiated from all conspecifics, and have probably been isolated for several hundred thousand years. Our finding is a powerful testimony to the evolutionary uniqueness of the taxa inhabiting the Galapagos archipelago and its associated marine ecosystems.

Galapagos Islands↗
USGS2010

Testing founder effect speciation: Divergence population genetics of the Spoonbills Platalea regia and Pl. minor (Threskiornithidae, Aves)

Although founder effect speciation has been a popular theoretical model for the speciation of geographically isolated taxa, its empirical importance has remained difficult to evaluate due to the intractability of past demography, which in a founder effect speciation scenario would involve a speciational bottleneck in the emergent species and the complete cessation of gene flow following divergence. Using regression-weighted approximate Bayesian computation, we tested the validity of these two fundamental conditions of founder effect speciation in a pair of sister species with disjunct distributions: the royal spoonbill Platalea regia in Australasia and the black-faced spoonbill Pl. minor in eastern Asia. When compared with genetic polymorphism observed at 20 nuclear loci in the two species, simulations showed that the founder effect speciation model had an extremely low posterior probability (1.55 × 10 -8 ) of producing the extant genetic pattern. In contrast, speciation models that allowed for postdivergence gene flow were much more probable (posterior probabilities were 0.37 and 0.50 for the bottleneck with gene flow and the gene flow models, respectively) and postdivergence gene flow persisted for a considerable period of time (more than 80% of the divergence history in both models) following initial divergence (median = 197,000 generations, 95% credible interval [CI]: 50,000-478,000, for the bottleneck with gene flow model; and 186,000 generations, 95% CI: 45,000-477,000, for the gene flow model). Furthermore, the estimated population size reduction in Pl. regia to 7,000 individuals (median, 95% CI: 487-12,000, according to the bottleneck with gene flow model) was unlikely to have been severe enough to be considered a bottleneck. Therefore, these results do not support founder effect speciation in Pl. regia but indicate instead that the divergence between Pl. regia and Pl. minor was probably driven by selection despite continuous gene flow. In this light, we discuss the potential importance of evolutionarily labile traits with significant fitness consequences, such as migratory behavior and habitat preference, in facilitating divergence of the spoonbills.

Molecular Biology and Evolution↗
USGS2010

Polyphyly of Campylorhamphus , and description of a new genus for C. pucherani (Dendrocolaptinae)

We investigated the phylogenetic relationships of Campylorhamphus pucherani using DNA sequences from three mitochondrial genes and a nuclear intron, as well as 84 morphological characters from the skeleton, the integument, and the musculature. The molecular phylogeny indicated that C. pucherani is not part of Campylorhamphus ; instead, it is the sister species to Drymornis bridgesii , in a clade that also contains Lepidocolaptes . The morphological phylogeny also placed C. pucherani in a clade that contains Drymornis and Lepidocolaptes . Using a morphometric analysis of size and shape diversity, we demonstrated that the inclusion of C. pucherani in Drymornis would create an excessively heterogeneous genus compared with other dendrocolaptine genera. Because no generic name is available for C. pucherani , we describe the new genus Drymotoxeres for this species.

The Auk↗
USGS2010

Pseudasthenes , a new genus of ovenbird (Aves: Passeriformes: Furnariidae)

Phylogenetic analysis of the family Furnariidae (Aves: Passeriformes) indicates that the genus Asthenes is polyphyletic, consisting of two groups that are not sister taxa. Pseudasthenes , a new genus of ovenbird, is described for one of these groups. The four species included in the new genus, formerly placed in Asthenes , are P. humicola , P. patagonica , P. steinbachi , and P. cactorum .

Zootaxa↗
USGS2010

Molecular phylogeny of the spoonbills (Aves: Threskiornithidae) based on mitochondrial DNA

Spoonbills (genus Platalea ) are a small group of wading birds, generally considered to constitute the subfamily Plataleinae (Aves: Threskiornithidae). We reconstructed phylogenetic relationships among the six species of spoonbills using variation in sequences of the mitochondrial genes ND2 and cytochrome b (total 1796 bp). Topologies of phylogenetic trees reconstructed using maximum likelihood, maximum parsimony, and Bayesian analyses were virtually identical and supported monophyly of the spoonbills. Most relationships within Platalea received strong support: P. minor and P. regia were closely related sister species, P. leucorodia was sister to the minor-regia clade, and P. alba was sister to the minor-regia-leucorodia clade. Relationships of P. flavipes and P. ajaja were less well resolved: these species either formed a clade that was sister to the four-species clade, or were successive sisters to this clade. This phylogeny is consistent with ideas of relatedness derived from spoonbill morphology. Our limited sampling of the Threskiornithinae (ibises), the putative sister group to the spoonbills, indicated that this group is paraphyletic, in agreement with previous molecular data; this suggests that separation of the Threskiornithidae into subfamilies Plataleinae and Threskiornithinae may not be warranted.

Zootaxa↗
USGS2009

[book review] Systematics and Taxonomy of Australian Birds -- Les Christidis and Walter E. Boles. Collingwood, VIC, Australia: CSIRO Publishing, 2008

Systematists argue that the importance of our work lies not only in the elucidation of evolutionary relationships, but also in the incorporation of evolutionary information into classifications and the use of these classifications by government agencies, nongovernmental organizations, professional scientists, and others interested in biodiversity. If this is true, and I think that it is, then synthetic publications that make our findings accessible to a wide audience, such as Christidis and Boles' new Systematics and Taxonomy of Australian Birds , may be among the most significant works that we publish.

Systematic Biology↗
USGS2009

Paraphyly of Cinclodes fuscus (Aves: Passeriformes: Furnariidae): Implications for taxonomy and biogeography

The Andes are a hotspot of global avian diversity, but studies on the historical diversification of Andean birds remain relatively scarce. Evolutionary studies on avian lineages with Andean–Patagonian distributions have focused on reconstructing species-level phylogenies, whereas no detailed phylogeographic studies on widespread species have been conducted. Here, we describe phylogeographic patterns in the Bar-winged Cinclodes ( Cinclodes fuscus ), a widespread and common species of ovenbird (Furnariidae) that breeds from Tierra del Fuego to the northern Andes. Traditionally, C. fuscus has been considered a single species composed of nine subspecies, but its long and narrow range suggests the possibility of considerable genetic variation among populations. Sequences of two mitochondrial genes revealed three discrete and geographically coherent groups of C. fuscus , occupying the southern, central, and northern Andes. Surprisingly, phylogenetic analyses indicated that these groups were more closely related to other species of Cinclodes than to each other. Relationships of the southern and northern C. fuscus clades to other species of Cinclodes were straightforward; in combination with available information on plumage, behavioral, and vocal variation, this suggests that each should be recognized as a distinct biological species. The central Andean group was paraphyletic with respect to C. oustaleti , and relationships among these taxa and C. olrogi were poorly resolved. We suggest that the central Andean C. fuscus should also be considered a different species, pending new information to clarify species limits in this group. These new phylogenetic data, along with recently developed methods, allowed us to review the biogeography of the genus, confirming southern South America and the central Andes as important areas for the diversification of these birds.

Molecular Phylogenetics and Evolution↗