Article

Evolution in the High Andes: The Phylogenetics of Muscisaxicola Ground-Tyrants

July 2000
Molecular Phylogenetics and Evolution 15(3):369-80

July 2000
15(3):369-80

DOI:10.1006/mpev.1999.0774

Source
PubMed

Authors:

Phylogenetic relationships within the genus Muscisaxicola, a primarily Andean group of tyrant-flycatchers, were studied using complete sequences of the mitochondrial genes COII and ND3. Relationships among Muscisaxicola species were found to differ substantially from those of previous views, suggesting convergence in traditional avian taxonomic characters within the genus. The 11 species of large, gray, "typical" Muscisaxicola flycatchers (including M. grisea, newly restored to species status) formed a distinct clade, consisting of two major groups: a clade of 6 species breeding primarily in the central Andes and a clade of 5 species breeding primarily in the southern Andes. The other 2 species traditionally placed in this genus, M. fluviatilis, an Amazonian species, and M. maculirostris, were both rather divergent genetically from the typical species, although M. maculirostris may be the sister taxon to the typical clade. The patterns of sympatry exhibited by Muscisaxicola species in the high Andes appear to be the consequence of speciation and secondary contact within regions of the Andes, rather than a result of dispersal between regions. Diversification of the typical Muscisaxicola species appears to have occurred during the middle and late Pleistocene, suggesting generally that taxa of the high Andes and Patagonia may have been greatly influenced by mid-to-late Pleistocene events. There were likely several independent developments of migration within this genus, but migration is probably ancestral in the southern clade, with subsequent loss of migration in two taxa.

Ancestral State Reconstruction of Migration: Multistate Analysis Reveals Rapid Changes in New World Orioles (Icterus SPP)

Article

Apr 2007

During the past century, numerous theoretical articles explored the evolution of seasonal migration in birds; many of these focused on environmental or social conditions that may have led to the origin of migration. More recent work has focused not on the origin of migration, but on changes in migratory behavior that have occurred in modern species and their immediate ancestors. We used a novel approach, a multistate ancestral state reconstruction of migration, to examine patterns of migratory evolution in the New World orioles (Icterus spp.). Both the multistate and binary reconstructions indicated repeated gains in migration. However, the multistate method revealed details of how migration may be gained that the standard binary-state reconstructions would not have shown. Our maximum-likelihood reconstruction, using branch lengths based on a molecular phylogeny, suggested multiple instances of rapid gain of migration. Furthermore, we found that every migratory species' migration type differed from that of its closest relatives. Surprisingly, no partially migratory species was closely related to a fully migratory species. These novel patterns involving gain of migration demonstrate the utility of multistate ancestral reconstruction for examining changes in migratory behavior in closely related birds. Reconstrucción de Estados Ancestrales de la Migración: Análisis con Múltiples Estados de Carácter Revelan Cambios Rápidos en los Orioles del Nuevo Mundo (Icterus spp.)

Rapid expansion and diversification into new niche space by fluvicoline flycatchers

Article

Jan 2018

The fluvicoline New World flycatchers (Subfamily Fluvicolinae, family Tyrannidae) inhabit a broad range of forest and non-forest habitats in all parts of the New World. Using a densely sampled phylogeny we depict the diversification and expansion of this group in time and space. We provide evidence that a shift in foraging behaviour allowed the group to rapidly expand in a wide range of tropical and subtropical habitats in South America. The results support that four main clades expanded into and specialized to distinct habitats and climates (closed to open, and warm to cold), respectively, and subsequently underwent vicariant speciation within their respective ecoregions. The group soon reached a significant species diversity over virtually all of South and North America, and with parallel trajectories of speciation slow-down in all four clades. The genus Muscisaxicola is an exception, as it invaded the most inhospitable and barren environments in the Andes where they underwent rapid diversification in the Plio-Pleistocene.

Unraveling the diversification history of grasshoppers belonging to the "Trimerotropis pallidipennis" (Oedipodinae: Acrididae) species group: A hotspot of biodiversity in the Central Andes

Article

Full-text available

Sep 2017

The Andean Mountain range has been recognized as one of the biodiversity hotspots of the world. The proposed mechanisms for such species diversification, among others, are due to the elevation processes occurring during the Miocene and the intensive glacial action during the Pleistocene. In this study we investigated the diversification history of the grasshopper Trimerotropis pallidipennis species complex which shows a particularly wide latitudinal and altitudinal distribution range across the northern, central and southern Andes in South America. Many genetic lineages of this complex have been so far discovered, making it an excellent model to investigate the role of the central Andes Mountains together with climatic fluctuations as drivers of speciation. Phylogenetics, biogeographic and molecular clock analyses using a multi-locus dataset revealed that in Peru there are at least two, and possibly four genetic lineages. Two different stocks originated from a common ancestor from North/Central America—would have dispersed toward southern latitudes favored by the closure of the Panama Isthmus giving rise to two lineages, the coastal and mountain lineages, which still coexist in Peru (i.e., T. pallidipennis and T. andeana ). Subsequent vicariant and dispersal events continued the differentiation process, giving rise to three to six genetic lineages (i.e., clades) detected in this study, which were geographically restricted to locations dispersed over the central Andes Mountains in South America. Our results provide another interesting example of “island diversification” motored by the topography plus unstable climatic conditions during the Pleistocene, pointing out the presence of a hotspot of diversification in the Andean region of Peru.

Pleistocene climate oscillations and habitat connectivity contributed to avian beta-diversity in the megadiverse Colombian Paramo ecosystems

Article

Oct 2021
J BIOGEOGR

Aim The role of evolutionary history in shaping the patterns of species distributions is generally explored at coarse spatial extents. However, at small spatial extents, the combined effects of history and ecological processes on local diversity has received less attention. We test the relative importance of historical and ecological factors on the spatial distribution of bird taxonomic (TβD) and phylogenetic (PβD) β‐diversity on Paramo ecosystems. Location South‐western Colombia. Taxon Andean bird species. Methods Using point occurrence data for 175 bird species recorded in 11 Paramos, we calculated TβD and PβD. We used a lineage through time plot to evaluate the association between bird species richness and the time of Andean uplift and Quaternary climatic oscillations. To capture range dynamics associated with past climate oscillations, we delimited paramos using connectivity matrices based on four distance criteria (i.e. paramos connected at 20, 25, 35 and 55 km apart) to compute Moran's eigenvectors maps. Then, we evaluated the relative importance of altitude, past climatic oscillations, current climate and connectivity on the spatial distribution of avian TβD and PβD. Results Two‐thirds of the bird species in the paramos are recent and emerged after the late Miocene/early Pliocene. The average TβD was four times higher than the average PβD indicating that paramo assemblages harbour distinct, but closely related, species. We found that distribution of β‐diversity had a spatial structure resulting in two groups of paramos – one in the north of our study area containing four paramos and other in the south with seven paramos. This spatial structure together with past climate conditions explained the variation of both TβD and PβD. Main conclusions Our results are consistent with the hypothesis that patterns of β‐diversity reflect the complex history of Andean region including mountain uplift and climatic oscillations in the Pleistocene. We demonstrated that the integration of different facets of β‐diversity into a community ecology framework provides new insights about the historical and ecological factors responsible for generating the patterns of species distribution.

A revised classification of the fluvicoline tyrant flycatchers (Passeriformes, Tyrannidae, Fluvicolinae)

Article

Mar 2020

A new classification is proposed for the subfamily Fluvicolinae in the New World Flycatchers (Tyrannidae), based on the results of a previously published phylogeny including more than 90% of the species. In this classification we propose one new family level name (Ochthoecini) and one new generic name (Scotomyias). We also resurrect three genera (Heteroxolmis, Pyrope and Nengetus) and subsume five (Tumbezia, Lathrotriccus, Polioxolmis, Neoxolmis and Myiotheretes) into other genera to align the classification with the current understanding of phylogenetic relationships in Fluvicolinae.

Molecular phylogenetics and biogeography of the Neotropical redstarts (Myioborus; Aves, Parulinae)

Article

Full-text available

Dec 2005
MOL PHYLOGENET EVOL

Jorge L Pérez-Emán

Montane areas in the Neotropics are characterized by high diversity and endemism of birds and other groups. The avian genus Myioborus (Parulinae) is a group of insectivorous warblers, characteristic of cloud forests, that represents one of the few Parulinae genera (New World warblers) that has radiated substantially in South America. The genus is distributed throughout most montane regions from the southwestern United States to northern Argentina. Here, I use mitochondrial sequences from the cytochrome b, ND2, and ND3 genes to present the first hypothesis of phylogenetic relationship among all Myioborus species level taxa. Phylogenetic reconstructions based on maximum parsimony, maximum likelihood, and Bayesian methods produced similar results and suggest a northern origin for the genus Myioborus with subsequent colonization of the Neotropical Montane Region. The lower-montane species, M. miniatus, is the sister taxon to a clade in which all taxa occupy upper-montane habitats. These "highland" taxa diverged early in the history of the genus and produced two well-defined monophyletic lineages, a Central-northern Andean clade formed by M. albifrons, M. ornatus, and M. melanocephalus, and a Pantepui (table-mountains of southern Venezuela, northern Brazil, and western Guyana) clade consisting of M. castaneocapillus, M. albifacies, and M. cardonai, and probably M. pariae. M. brunniceps, M. flavivertex, and M. torquatus were included in this upper-montane clade but without clear relationships to other taxa. Lack of resolution of nodes defining the upper-montane species clade is likely to result from a period of rapid diversification mediated by geological and climatic events during the Late Pliocene. These results suggest that an interplay of dispersal and vicariance has shaped the current biogeographic patterns of Myioborus.

Phylogeny and biogeography of a large radiation of Andean lizards (Iguania, Stenocercus)

Article

Jul 2007

Omar Torres-Carvajal

With 61 species occurring mostly in the Andes and adjacent lowland areas, Stenocercus lizards represent one of the most widespread and well-represented Andean vertebrate groups. Phylogenetic relationships among species of Stenocercus are inferred using different datasets based on mitochondrial DNA sequence data of 35 species and morphological data of 59 species. Among morphological data, polymorphic and meristic/morphometric characters are coded under the frequency parsimony and gap-weighting methods, respectively, and the accuracy of these methods is tested. When both types of characters are included, the resulting tree topology is more similar to the topologies obtained from analyses of DNA sequence data than those topologies obtained after exclusion of one or both types of characters. The phylogenetic hypotheses inferred including 59 species of Stenocercus (dataset 1) and excluding those species for which DNA data were not available (dataset 2) are generally congruent with each other, as well as with previously published hypotheses. The most parsimonious tree obtained from analysis of dataset 2 is used in a dispersal-vicariance analysis to infer ancestral areas and major biogeographical events. Species of Stenocercus are divided into two major clades. Clade A has diversified mostly in the central Andes, with a few species in the northern Andes and one species in the southern Andes. Clade B is more widespread, with species in the northern, central, and southern Andes, as well as in the Atlantic lowlands and Amazon basin. The most recent common ancestor of Stenocercus is inferred to have occurred in the eastern cordillera of the central Andes. Given morphological similarity and altitudinal distribution of some species nested in a northern-Andes clade, as well as the relatively recent uplift of this Andean region, it is possible that species in this clade have diverged as recently as the mid-Pliocene.

Phylogeny and biogeography of the New World siskins and goldfinches: Rapid, recent diversification in the Central Andes

Article

Full-text available

Mar 2015
MOL PHYLOGENET EVOL

Animal Migration: An Overview of One of Nature's Great Spectacles

Article

Full-text available

Nov 2021

The twenty-first century has witnessed an explosion in research on animal migration, in large part due to a technological revolution in tracking and remote-sensing technologies, along with advances in genomics and integrative biology. We now have access to unprecedented amounts of data on when, where, and how animals migrate across various continents and oceans. Among the important advancements, recent studies have uncovered a surprising level of variation in migratory trajectories at the species and population levels with implications for both speciation and the conservation of migratory populations. At the organismal level, studies linking molecular and physiological mechanisms to traits that support migration have revealed a remarkable amount of seasonal flexibility in many migratory animals. Advancements in the theory for why animals migrate have resulted in promising new directions for empirical studies. We provide an overview of the current state of knowledge and promising future avenues of study. Expected final online publication date for the Annual Review of Ecology, Evolution, and Systematics, Volume 52 is November 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Rugged relief and climate promote isolation and divergence between two neotropical cold‐associated birds

Article

Aug 2021

The role of historical factors in establishing patterns of diversity in tropical mountains is of interest to understand the buildup of megadiverse biotas. In these regions, the historical processes of range fragmentation and contraction followed by dispersal are thought to be mediated by the interplay between rugged relief (complex topography) and climate fluctuations and likely explain most of the dynamics of diversification in plants and animals. Although empirical studies addressing the interaction between climate and topography have provided invaluable insights into population divergence and speciation patterns in tropical montane organisms, a more detailed and robust test of such processes in an explicit spatio-temporal framework is still lacking. Consequently, our ability to gain insights into historical range shifts over time and the genomic footprint left by them is limited. Here we used niche modeling and subgenomic population-level datasets to explore the evolution of two species of warbling finches (genus Microspingus) disjunctly distributed across the Montane Atlantic Forest, a Neotropical region with complex geological and environmental histories. Population structure inferences suggest a scenario of three genetically differentiated populations, which are congruent with both geography and phenotypic variation. Demographic simulations support asynchronous isolation of these populations as recently as ∼40 kya, relatively stable population sizes over recent time, and past gene flow subsequent to divergence. Throughout the last 800 ky, niche models predicted extensive expansion into lowland areas with increasing overlap of species distributions during glacial periods, with prominent retractions and isolation into higher altitudes during interglacials, which are in line with signs of introgression of currently isolated populations. These results support a dual role of cyclical climatic changes: population divergence and persistence in mountain tops during warm periods followed by periods of expansion and admixture in lower elevations during cold periods. Our results underscore the role of the interplay between landscape and climate as an important mechanism in the evolution of the Neotropical montane biota. This article is protected by copyright. All rights reserved

Bird migration within the Neotropics

Article

Jul 2020

Although the migration ecology of birds breeding in the Neotropics is still poorly studied relative to that of their counterparts breeding at north-temperate latitudes, studies conducted over the last 2 decades have revealed that migration in the Neotropics is much more common and diverse than previously thought. These studies have identified dozens of species that migrate latitudinally within South America, altitudinally within various mountain ranges, to and between Caribbean islands, and longitudinally across diverse ecosystems such as the Amazon rainforest. Advances in miniaturized tracking technologies, enormous citizen science databases, and powerful analytical approaches provide an unprecedented ability to detect and evaluate temporally and spatially fine-scale patterns, greatly facilitating the study of migratory patterns across tropical regions. We argue that a renewed effort in research on short- and long-distance bird migration within the Neotropics will allow (1) comparative studies that identify the emergent properties of migratory behavior, (2) identification of the convergent or unique mechanistic drivers of migration across diverse ecological settings, (3) formulation of effective conservation and management plans for migratory Neotropical birds, and (4) predictions about how migratory birds will respond to large-scale climatic changes within the Neotropics. Here, we review the current state of knowledge on Neotropical bird migration, with a focus on South America. We specifically examine similarities and differences in the observed migratory patterns of birds that breed in the Nearctic compared to the Neotropics and highlight key future research questions.

Conservative plumage masks extraordinary phylogenetic diversity in the Grallaria rufula (Rufous Antpitta) complex of the humid Andes

Article

Full-text available

Jun 2020

The Grallaria rufula complex is currently considered to consist of 2 species, G. rufula (Rufous Antpitta) and G. blakei (Chestnut Antpitta). However, it has been suggested that the complex, populations of which occur in humid montane forests from Venezuela to Bolivia, comprises a suite of vocally distinct yet morphologically cryptic species. We sequenced nuclear and mitochondrial DNA for 80 individuals from across the distribution of the complex to determine the extent of genetic variation between and within described taxa. Our results revealed 18 geographically coherent clades separated by substantial genetic divergence: 14 within rufula, 3 within blakei, and 1 corresponding to G. rufocinerea (Bicolored Antpitta), a species with distinctive plumage found to be nested within the complex. Neither G. rufula nor G. blakei as presently defined was monophyletic. Although 6 of the 7 recognized subspecies of G. rufula were monophyletic, several subspecies contained substantial genetic differentiation. Genetic variation was largely partitioned across recognized geographic barriers, especially across deep river valleys in Peru and Colombia. Coalescent modeling identified 17 of the 18 clades as significantly differentiated lineages, whereas analyses of vocalizations delineated 16 biological species within the complex. The G. rufula complex seems unusually diverse even among birds of the humid Andes, a prime location for cryptic speciation; however, the extent to which other dispersal-limited Andean species groups exhibit similar degrees of cryptic differentiation awaits further study.

Systematics and Taxonomy of Tonatia saurophila Koopman & Williams, 1951 (Chiroptera, Phyllostomidae)

Article

Full-text available

Feb 2020

The Stripe-headed Round-eared bat, Tonatia saurophila, includes three subspecies: Tonatia saurophila saurophila (known only from subfossil records in Jamaica), Tonatia saurophila bakeri (distributed from southeastern Mexico to northern Colombia, Venezuela west and north of the Cordillera de Mérida, and northwestern Ecuador), and Tonatia saurophila maresi (distributed in Venezuela east and south of the Cordillera de Mérida, the Guianas, Trinidad and Tobago, northeastern Brazil, and along the upper Amazon basin in Colombia, Ecuador, Peru, and Bolivia). The last two subspecies are an attractive example to test predictions about the historical role of the Andes in mammalian diversification. Based on morphological descriptions, morphometric analyses, and phylogenetic reconstruction using the mitochondrial gene Cyt-b and the nuclear exon RAG2, this study evaluates the intraspecific relationships within Tonatia saurophila and the taxonomic status of the taxon. The three subspecies of T. saurophila are recognizable as full species: Tonatia bakeri, Tonatia maresi, and Tonatia saurophila. The latter is restricted to its type locality and possibly is extinct. Tonatia bakeri, in addition to being larger than T. maresi, is morphologically distinguishable by possessing an acute apex at the posterior edge of the skull, a well-developed clinoid process, and relatively robust mandibular condyles, and by lacking a diastema between the canine and the first lower premolar. The genetic distance between T. bakeri and T. maresi is 7.65%. Mateo Basantes, Nicolás Tinoco, Paúl M. Velazco, Melinda J. Hofmann, Miguel E. Rodríguez-Posada, M. Alejandra Camacho.

Incongruence between mitochondrial DNA, nuclear DNA and non-molecular data in the avian genus Motacilla: implications for estimates of species phylogenies

Article

Full-text available

Oct 2019

We used the mitochondrial control region and ND2 and ATP8+6 genes (c. 2900 bp), an intron in the CHD1Z gene on the Z-chromosome (c. 550 bp) and non-molecular (mainly morphological) data to reconstruct the phylogeny of nearly all of the least-inclusive nominal taxa in the avian genus Motacilla (wagtails). All three data sets are incongruent, although the mitochondrial DNA tree deviates most. We propose that, in wagtails, the CHD1Z tree conforms better than the mitochondrial DNA tree with the taxon phylogeny. We argue that the mitochondrial DNA tree has been affected by introgressive hybridisation, possibly also by lineage sorting. We suggest that introgression and successive fixation of foreign mitochondrial DNA may be a common phenomenon in recently diverged taxa, where reproductive isolating barriers are generally incomplete, and stress that this will lead to permanent incongruence between gene trees and species trees. Our results highlight the importance of using multiple independent data sets in phylogeny reconstructions. However, a review of the literature published in the past seven years reveals that virtually all avian phylogenies in that time period are based only on mitochondrial sequences. We argue against indiscriminately combining independent data sets, especially if the number of informative sites differs markedly between the data sets, as is the case in the present study.

Geographic distribution analysis of the genus Xenodacnis (Birds: Thraupidae) using ecological niche modeling

Article

Full-text available

Sep 2019

Juan Manuel Aguilar

Xenodacnis is a monotypic thraupid genus restricted to the tropical high Andes of Peru and Ecuador. Its only species, X. parina has a large discontinuous distribution from central Ecuador to southern Peru. To date, three subspecies are recognized, all separated by geographical barriers that clouded promote allopatric events. The taxonomic affinities of the Ecuadorian population have not been assessed since its discovery in the 1970s at the Cajas National Park in Azuay province. I studied the environmental affinities between the distribution of the described subspecies and the Ecuadorian population bias ecological niche modeling. I found a distinctive ecological niche in the distribution of each of the analyzed populations and also for the southern Arequipa population. These different environmental niche conditions come apart by deep Andean valleys playing a role as geographical barriers for the isolation of these populations that need further taxonomic analysis.

Neotropical Ornithology: Then and Now

Article

Jul 2003

François Vuilleumier

The conquering of North America: dated phylogenetic and biogeographic inference of migratory behavior in bee hummingbirds

Article

Full-text available

Jun 2017
BMC EVOL BIOL

Background: Geographical and temporal patterns of diversification in bee hummingbirds (Mellisugini) were assessed with respect to the evolution of migration, critical for colonization of North America. We generated a dated multilocus phylogeny of the Mellisugini based on a dense sampling using Bayesian inference, maximum- likelihood and maximum parsimony methods, and reconstructed the ancestral states of distributional areas in a Bayesian framework and migratory behavior using maximum parsimony, maximum-likelihood and re-rooting methods. Results: All phylogenetic analyses confirmed monophyly of the Mellisugini and the inclusion of Atthis, Calothorax, Doricha, Eulidia, Mellisuga, Microstilbon, Myrmia, Tilmatura, and Thaumastura. Mellisugini consists of two clades: (1) South American species (including Tilmatura dupontii), and (2) species distributed in North and Central America and the Caribbean islands. The second clade consists of four subclades: Mexican (Calothorax, Doricha) and Caribbean (Archilochus, Calliphlox, Mellisuga) sheartails, Calypte, and Selasphorus (incl. Atthis). Coalescent-based dating places the origin of the Mellisugini in the mid-to-late Miocene, with crown ages of most subclades in the early Pliocene, and subsequent species splits in the Pleistocene. Bee hummingbirds reached western North America by the end of the Miocene and the ancestral mellisuginid (bee hummingbirds) was reconstructed as sedentary, with four independent gains of migratory behavior during the evolution of the Mellisugini. Conclusions: Early colonization of North America and subsequent evolution of migration best explained biogeographic and diversification patterns within the Mellisugini. The repeated evolution of long-distance migration by different lineages was critical for the colonization of North America, contributing to the radiation of bee hummingbirds. Comparative phylogeography is needed to test whether the repeated evolution of migration resulted from northward expansion of southern sedentary populations.

Long-Distance Range Expansion and Rapid Adjustment of Migration in a Newly Established Population of Barn Swallows Breeding in Argentina

Article

Mar 2017
CURR BIOL

When bird populations spread, long-distance pioneering populations are often backfilled by a more slowly advancing front [1-3]. The Barn Swallow Hirundo rustica, a globally distributed passerine [4, 5], expanded its breeding range an exceptional 7,000 km when it began breeding 35 years ago in its regular wintering range in Argentina [6], subsequently expanding over 500 km from its starting point [7-11]. Trans-hemispheric breeding attempts have occurred previously in related swallows [12-14], but only this colonization has lasted. Comparative studies of birds show a remarkable diversity in patterns of change in migratory habits [15-21], and these Argentine-breeding swallows might retain ancestral patterns, breeding in Argentina but returning to North America for the austral winter. Feather isotopes from these birds are consistent with the alternative possibility that they migrate no farther than northern South America [22]. Because isotopic patterns cannot definitively distinguish these alternatives, we pursued a solar geolocator study [23, 24] to do so. Data from nine tagged birds show conclusively that Barn Swallows breeding in Argentina have rapidly changed their movements to migrate no farther north in austral winter than northern South America. The phenology of the annual cycles of molt, migration, and breeding for these Argentine-breeding swallows have all shifted by about 6 months, and we suggest that stimulatory day lengths and the proliferation of nesting substrates facilitated their colonization.

Phylogeny and diversification of the cloud forest Morpho sulkowskyi group (Lepidoptera, Nymphalidae) in the evolving Andes

Article

Nov 2016

The monophyletic Morpho sulkowskyi butterfly group, endemic of Andean cloud forests, was studied to test the respective contributions of Mio-Pliocene intense uplift period and Pleistocene glacial cycles on Andean biodiversity. We sampled nine taxa covering the whole geographical range of the group. Two mitochondrial and two nuclear genes were analysed using a Bayesian method. We established a dated phylogeny of the group using a relaxed clock method and a wide-outgroup approach. To discriminate between two hypotheses, we used a biogeographical probabilistic method. Results suggest that the ancestor of the M. sulkowskyi group originated during the Middle–Late Miocene uplift of the Eastern Cordillera in northern Peru. Biogeographical inference suggests that the M. sulkowskyi and Morpho lympharis clades diverged in the northern Peruvian Andes. The subsequent divergences, from the Late Miocene to the Late Pliocene, should have resulted from a dispersal towards the Northern Andes (M. sulkowskyi clade), after the closure of the West Andean Portal separating the Central and Northern Andes, and a southwards dispersal along the Peruvian and Bolivian Eastern Cordilleras (M. lympharis clade). Only a few divergences occurred at the very end of the Pliocene or during the Pleistocene, a period when the more recent uplifts interfered with Pleistocene glacial cycles.

Understanding the evolutionary history of a high Andean endemic: the Ecuadorian hillstar ( Oreotrochilus chimborazo )

Article

Full-text available

Mar 2016

Geographic isolation has been proposed as the factor driving subspecific diversity of the Ecuadorian hillstar (Oreotrochilus chimborazo), a highland species restricted to the naturally fragmented paramos of Ecuador and southern Colombia. Current taxonomy recognizes three subspecies: O. c. chimborazo (from the Chimborazo volcano), O. c. soderstromi (from the Quilotoa volcano), and O. c. jamesonii (along the paramos of Ecuador and southern Colombia). To understand the origin of this morphological diversity, we explored the genetic variation along the species range based on analyses of two mitochondrial genes (ND2 and ND4), and one nuclear intron (MUSK). Subspecies O. c. soderstromi was not included in the analysis, as it was not registered at or around its type locality, the Quilotoa volcano. Instead, only O. c. jamesonii was encountered in that area. We found no evidence of genetic structure corresponding to subspecies or physiographic units, aside from some inconclusive evidence in putatively isolated populations. Ecological niche modeling predicted continuous and homogeneous environmental space between the two volcanos, and field expeditions showed evidence of a potential contact zone between O. c. jamesonii and O. c. chimborazo. Also, our data suggest that the only specimen described as O. c. soderstromi may have been an intergrade. We discuss our results in the light of possible range shifts in the past, resulting from climatic fluctuations around the Pleistocene–Holocene transition.El aislamiento geográfico ha sido propuesto como el factor más importante en la generación de diversidad subespecífica en la estrellita ecuatoriana (Oreotrochilus chimborazo), un ave de los altos Andes restringida a los páramos naturalmente fragmentados de Ecuador y el sur de Colombia. La taxonomía actual reconoce tres subespecies: O. c. chimborazo (en el volcán Chimborazo), O. c. soderstromi (en el volcán Quilotoa) y O. c. jamesonii (a lo largo de los páramos de Ecuador y el sur de Colombia). Con el fin de comprender el origen de esta diversidad morfológica, exploramos la variación genética a lo largo del rango de la especie con base en los análisis de dos genes mitocondriales (ND2 y ND4) y un intrón nuclear (MUSK). La subespecie O. c. soderstromi no fue incluida en el análisis, porque no se registraron individuos de este taxón en su localidad tipo, el volcán Quilotoa, donde solo confirmamos la presencia de O. c. jamesonii. No encontramos evidencia de estructura genética correspondiente a las subespecies o a unidades fisiográficas de páramo, a excepción de una posible estructuración genética probablemente debida a poblaciones presumiblemente aisladas. Análisis de modelamiento de nicho ecológico predijeron que el espacio ambiental entre los dos volcanes es continuo y homogéneo, mientras que los resultados de expediciones de campo sugieren la existencia de una zona de contacto entre O. c. jamesonii y O. c. chimborazo. Además, nuestros datos apoyan la idea de que el único espécimen descrito como O. c. soderstromi puede ser un híbrido. Discutimos nuestros resultados en el contexto de posibles cambios de rango de distribución en el pasado, como resultado de las fluctuaciones climáticas que se dieron en el periodo de transición entre el Pleistoceno y el Holoceno.

Differentiation of the Akodon mollis Species Group (Rodentia: Cricetidae: Sigmodontinae) in the Andes of Peru.

Article

Jan 2012

Lucia Alejandra Luna Wong

The mechanisms responsible for the species composition of montane biotas remain poorly understood. Parapatric and allopatric speciation, in the forms of the Ecological Gradients and Montane Vicariance hypotheses respectively, have been suggested to explain the diversification of Andean fauna. This dissertation reviews the possible role of these mechanisms in the speciation of mammals in Andean habitats. The soft grass mouse, Akodon mollis, was chosen as the test organism because of its wide elevational and latitudinal range. A. mollis inhabits the Andean mountains of North and Central Peru, and the Andes of Ecuador; however, this work focuses exclusively on Peruvian populations. Geometric morphometrics and environmental analyses revealed that despite the wide elevational range of these mice, their skull morphology does not vary consistently across elevation except for a sharp change at the treeline (the edge of the p??ramo/puna, ~4000m). Partial least squares and multivariate multiple regression analyses showed a significant association between skull shape and environment. The most important variables were associated with temperature, and these almost perfectly correlated with elevation. Nevertheless, a clear association between morphology and elevation was not found. Phylogenetic analyses of the mitochondrial Cytochrome b gene showed spatial structuring of A. mollis populations. Deeper lineages at the southern limit of the species coincide with the oldest part of the Andes, while shallower clades were found in the more recent northern Andes. An unambiguous test of the Ecological Gradient hypothesis was not possible; however, Montane Vicariance was suggested in two instances where mice at similar elevations on different mountains were closely related. Geographic distance did not explain patterns of genetic variation in Andean populations. Finally, AMOVA suggested differentiation between populations at higher southern elevations (>3500) and lower northern elevations (

Avian Diversification in the Andes: Understanding Endemism Patterns and Historical Biogeography

Thesis

Full-text available

Jan 2011

Esther Quintero

The Andes, along with the Amazon and Atlantic forests, harbor the richest avifauna in the world with roughly one third of all the world’s species of birds. Many biogeographical studies have sought to explain the origin and diversification of Andean taxa. However, because of the Andes’ extensive latitudinal span and complexity, there is no one single cause of origin or of diversification that can explain the diversity found in them. Along the Andes, multiple biogeographic patterns of disjunction between highland and lowland sister-groups have been linked to Andean uplift. For example, Ribas et al. (2007) provided evidence that the spatio-temporal diversification in the monophyletic parrot genus Pionus is causally linked to Andean tectonic and palaeoclimate change through vicariance. Thus, if the Andes uplift is responsible for some of the patterns of montanelowland disjunctions, it may be one of the mechanisms underlying the taxonomic assembly of the Andean montane avifauna. In this dissertation I explored whether the origin and diversification of three groups of Andean birds—the exclusively Andean parrot genera Hapalopsittaca, the subclade of mangoes containing Doryfera, Schistes, and Colibri, and the ovenbirds of the tribe Thripophagini—can be linked to Earth history. The results show that the origin of these Andean taxa can be explained through vicariance from their lowland sister-groups, mediated by the uplift of the Andes. Thus, this thesis proposes that geological events are directly responsible for originating diversity throughout montane environments. Once in the Andes, the diversification of these montane taxa can be explained by events such as the tectonic evolution of the Andes—which created canyons and valleys that may have caused the vicariance of continuous populations—as well as by the climatic oscillation of the Pleistocene, which caused altitudinal shifts, expansion, and contraction of the montane vegetation belts during the climatic oscillations of the Pleistocene. In summary a significant part of the temporal patterns of origins and diversification of the three groups of birds included in this study can be linked to Earth history, both in terms of the tectonic history of the Andes and of the climatic events of the Pleistocene.

Neotropical bird evolution and 100 years of the enduring ideas of Frank M. Chapman

Article

Full-text available

Mar 2016
BIOL J LINN SOC

The processes of bird diversification in South America have long been a focus of evolutionary biologists and this paper partly acts as an introduction to a selection of such work published in the Biological Journal of the Linnean Society and collated into a Virtual Issue (http://wileyonlinelibrary.com/bij/neotropical-bird-evolution). At the beginning of the 20th century, Frank M. Chapman, curator of birds at the American Museum of Natural History, conducted a series of expeditions in Colombia and Ecuador to ‘discover the geographic origins of South American bird-life’. The expeditions produced almost 30 000 specimens, obtained in a sampling scheme aimed at revealing the geographical and elevational distributions of birds. Chapman proposed a series of ideas about the evolutionary origins of the tropical Andean avifauna. Despite being nearly 100 years old, Chapman's evolutionary hypotheses on the role of the appearance of new environments and geographical barriers on speciation, have an enduring influence. With the development of molecular methods and tools for the study of the mechanisms and timing of speciation events, Chapman's hypotheses have seen a revival in the recent scientific literature. Recent work has provided support for some of Chapman's hypotheses, but has also revealed greatly complex processes of biotic differentiation in the Neotropics. What is remarkable is that with means that today seem precarious, Chapman envisioned evolutionary processes at a continental scale that remain valid, in fields that currently advance at an accelerated rhythm and soon render older ideas obsolete.

Cryptic speciation in the Lesser Elaenia Elaenia chiriquensis (Aves: Passeriformes: Tyrannidae)

Article

Full-text available

Oct 2015

Tyrant-flycatchers (Tyrannidae) are a taxonomically confusing bird group containing a large degree of cryptic diversity that has only recently begun to be unraveled through the application of acoustic and molecular methods. We investigated all three subspecies of the Lesser Elaenia, Elaenia chiriquensis Lawrence, across their range using sound recordings as well as nuclear and mitochondrial markers. We show that two of the three subspecies, the nominate race from southern Central America and the widespread South American subspecies E. c. albivertex Pelzeln, have undergone very low levels of vocal and molecular differentiation across their fragmented range. In contrast, the isolated taxon E. c. brachyptera Ber-lepsch, endemic to the western and also, as recently shown, eastern slopes of the northern Andes, is phylogenetically and vocally distinct from other Lesser Elaenias, indicating that it constitutes a separate biological species.

Species delimitation in the Andean grasshopper genus Orotettix Ronderos & Carbonell (Orthoptera: Melanoplinae): An integrative approach combining morphological, molecular and biogeographical data

Article

Full-text available

Aug 2015

The reciprocal illumination nature of integrative taxonomy through hypothesis testing, corroboration and revision is a powerful tool for species delimitation as more than one source has to support the hypothesis of a new species. In this study, we applied an integrative taxonomy approach combining molecular and morphological data sets with distributional patterns to examine the level of differentiation between and within the grasshopper Orotettix species. Orotettix was described based on five valid species distributed in the Andes of Peru. In our study, initially a molecular‐based hypothesis was postulated and tested against morphological data and geographical patterns of distribution. Results from molecular and morphological analyses showed agreement among the species delimitation in Orotettix, and were also consistent with the geographical distribution. The analyses allowed us to delimit five new species for the genus ( O. lunatus sp. nov., O . astreptos sp. nov., O. colcaensis sp. nov., O . paucartambensis sp. nov. and O . dichrous sp. nov.) from the Eastern and Western Cordilleras of Peru. We also provide critical knowledge on the phylogenetic relationships and distribution of the genus and conduct a revision of Orotettix. © 2015 The Linnean Society of London

Diversification in Andean tit-tyrants (Aves, Tyrannidae)

Article

Aug 2012

Shane DuBay

The role of geological history, topography, and environmental heterogeneity in the diversification of an endemic Andean radiation : the Metallura hummingbirds

Article

Aug 2012

Phred M. Benham

Aportes sobre la distribución, comportamiento y biología del cerquero amarillo, Atlapetes citrinellus (Aves: Emberizidae)

Research

Full-text available

Apr 2015

Atlapetes citrinellus es una especie endémica de la parte más austral de las Yungas de Argentina. En este estudio investigamos la distribución altitudinal y latitudinal y la abundancia relativa de la especie, y aportamos información novedosa sobre su biología, como su presencia en bandadas mixtas de aves, nidificación y la realización de desplazamientos. Para ello, revisamos la información publicada, los registros de colecciones ornitológicas, registros de captura y anillado, y observaciones propias. La especie posee una abundancia variable que aumenta en sentido latitudinal desde los 23°S, donde es rara, hacia el extremo sur de las Yungas, en la provincia de Tucumán (26°S), llegando su distribución hasta los 28°S en Capayán, en el sur de la provincia de Catamarca. Es en el piso de vegetación del Bosque Montano de Tucumán donde la especie alcanza su mayor abundancia. Cría principalmente entre 1200 y 1800 m de altura en el Bosque Montano, entre noviembre y marzo. Describimos 4 nidos, construidos a baja altura entre 0,7 a 1,9 m del suelo, en microambientes con alta densidad de vegetación alrededor del nido. Las puestas fueron de 2 a 3 huevos, de color crema con puntos y manchitas castañas claras y oscuras más abundantes en el polo obtuso. Esta especie realiza movimientos estacionales altitudinales. Parte de las poblaciones desciende entre mayo y octubre hasta los pedemontes, donde es un miembro regular en bandadas mixtas invernales de aves. Datos provenientes de recapturas de 28 ejemplares anillados mostraron fidelidad al sitio de cría e invernada, desplazamientos altitudinales luego de nidificar y una longevidad de al menos 5 años.

Distribución y biología del Cerquero amarillo Atlapetes citrinellus (Aves: Emberizidae)

Article

Full-text available

Jan 2014

Resumen — Atlapetes citrinellus es una especie endémica de la parte más austral de las Yungas de Argentina. En este estudio investigamos la distribución altitudinal y latitudinal y la abundancia relativa de la especie, y aportamos información novedosa sobre su biología, como su presencia en bandadas mixtas de aves, nidificación y la realización de desplazamien-tos. Para ello, revisamos la información publicada, los registros de colecciones ornitológicas, registros de captura y anillado, y observaciones propias. La especie posee una abundancia variable que aumenta en sentido latitudinal desde los 23°S, donde es rara, hacia el extremo sur de las Yungas, en la provincia de Tucumán (26°S), llegando su distribución hasta los 28°S en Capayán, en el sur de la provincia de Catamarca. Es en el piso de vegetación del Bosque Montano de Tucumán donde la especie alcanza su mayor abundancia. Cría principalmente entre 1200 y 1800 m de altura en el Bosque Montano, entre noviembre y marzo. Descri-bimos 4 nidos, construidos a baja altura entre 0,7 a 1,9 m del suelo, en microambientes con alta densidad de vegetación alrededor del nido. Las puestas fueron de 2 a 3 huevos, de color crema con puntos y manchitas castañas claras y oscuras más abundantes en el polo obtuso. Esta especie realiza movimientos estacionales altitudinales. Parte de las poblaciones desciende entre mayo y octubre hasta los pedemontes, donde es un miembro regular en bandadas mixtas invernales de aves. Datos provenientes de recapturas de 28 ejemplares anillados mostraron fidelidad al sitio de cría e invernada, desplazamientos altitudinales luego de nidificar y una longevidad de al menos 5 años. Abstract — " Contributions to the distribution, behavior and biology of the Yellow

Rampant polyphyly indicates cryptic diversity in a clade of Neotropical flycatchers (Aves: Tyrannidae)

Article

Full-text available

Apr 2013
BIOL J LINN SOC

Polyphyletic arrangements in DNA phylogenies are often indicators of cryptic species diversity masked by erroneous taxonomic treatments that are frequently based on morphological data. Although mitochondrial (mt)DNA polyphyly is detected relatively rarely in phylogenetic studies, it has recently been found in a variety of tyrant-flycatcher (Tyrannidae) groups. In the present study, we provide a DNA phylogeny for a mitochondrial and a nuclear locus with a complete species sampling in Zimmerius flycatchers, showing that the genus is characterized by multiple mtDNA polyphyly. Based on phylogenetic and life-history information, we suggest the elevation of a number of taxa to species status, leading to a doubling of Zimmerius species-level diversity compared to taxonomic treatments conducted before 2001. © 2013 The Linnean Society of London, Biological Journal of the Linnean Society, 2013, ●●, ●●–●●.

Patterns of diversification in the high Andean Ponderacris grasshoppers (Orthoptera: Acrididae: Melanoplinae)

Article

Apr 2013
SYST ENTOMOL

The Andes, the world's longest mountain chain, harbours great taxonomic and ecological diversity. Despite their young age, the tropical Andes are highly diverse due to recent geological uplift. Speciation either followed the orogeny closely or occurred after the Andean uplift, as a result of subsequent climatic changes. Different scenarios have been proposed to explain the diversification of high Andean taxa. The Melanoplinae grasshopper Ponderacris Ronderos & Cigliano is endemic to the eastern slopes of the Andes of Peru and Bolivia, mostly distributed between 1000 and 4000 m above sea level. Diversification in several montane habitats of Bolivia and Peru allows tests via cladistic analysis of distinct possible geographic modes of speciation. Eight species are recognized, with three described here as new with revised diagnostic morphological characters provided: Ponderacris carlcarbonellisp.n.,P. chulumaniensissp.n. and P. amboroensissp.n. Cladistic analyses of 15 species (8 ingroup and 7 outgroup) and 38 morphological characters, under equal and implied weighting, confirm the monophyly of Ponderacris. Characters from the external morphology and colour pattern provided less phylogenetic information than did the male abdominal terminalia and phallic complex. Species distributed in the Peruvian Andes constituted a monophyletic group, whereas those from the Bolivian Andes formed a basal paraphyletic grade. Dispersal–vicariance analysis resulted in one ancestral distribution reconstruction indicating that the most recent common ancestor was distributed in the Lower Montane Yungas of Bolivia. Eleven dispersal and one vicariant events are postulated, with a South-to-North speciation pattern coincident with progressive Andean uplift. Vicariance could relate to fragmentation of montane forest during the dry intervals of the late Cenozoic. From the Bolivian area, ancestral Peruvian Ponderacris may have dispersed northward, coinciding with the rise of the Andes. Ten of 11 dispersal events occurred at terminal taxa and are likely to be recent. However, diversification of Ponderacris cannot be explained solely by the South-to-North speciation hypothesis, but may also include both vicariance and dispersal across barriers influenced by Pleistocene climatic cycles.

Why northern hemisphere waders did not colonise the south

Chapter

Jan 2013

Ken Kraaijeveld

While much of the (avi)fauna of the southern hemisphere is unique, most of the water-, shore- and seabirds have close ties with the northern hemisphere. Some of the latter are closely related to species breeding further north, while others only visit the southern hemisphere as non-breeders. This is not surprising. Waterbirds are highly mobile and many species can disperse over very long distances. However, within the waterbirds, there is a puzzling bias in the taxonomic distribution of species that breed in the southern hemisphere versus those that only visit during the non-breeding season. The majority of waterbird groups have breeding representatives on both hemispheres. For example, we find breeding ducks, cranes, herons and gulls in both the southern and the northern hemisphere. Only a small number of high-latitude taxa, such as penguins and diving petrels in the Antarctic and divers and alcids in the Arctic are restricted to one hemisphere. The major exception to this pattern are waders. Many waders of the genera Calidris, Tringa, Pluvialis, Limosa and others visit the southern hemisphere each year in large numbers. None of these has established breeding populations in the south. The reason for their remarkable absence as breeders is the topic of this chapter.

Primer registro reproductivo y cuidado parental de la dormilona chica (Muscisaxicola maculirostris) en el norte de los Andes

Article

Full-text available

Oct 2021

Los estudios de la reproducción de las aves pueden contribuir al conocimiento en campos como ecología, evolución, fisiología, sistemática y conservación. Además, en especies de amplia distribución, la información de diferentes poblaciones puede contribuir al entendimiento de los patrones de variación en sus rasgos reproductivos a diferentes escalas. La dormilona chica (Muscisaxicola maculirostris), tiene la distribución más amplia de su género en los Andes y las poblaciones aisladas del norte, en Colombia, son consideradas bajo amenaza por la rápida reducción de su hábitat. Como parte del inicio de un programa participativo de monitoreo poblacional para la especie, documentamos en el desierto de La Candelaria (Boyacá) el primer registro de anidación para M. m. niceforoi, con medidas de nido, huevo y desarrollo de polluelo, además de observaciones de cuidado biparental. Con esta contribución, queremos aportar al conocimiento de la historia natural de la especie como primer paso para continuar estudiando su biología reproductiva y estado poblacional e incentivar a seguir documentando aspectos de la historia natural de aves neotropicales, que permitan implementar medidas de conservación para especies amenazadas teniendo en cuenta aspectos de su historia de vida.

A revised classification of the Xolmiini (Aves: Tyrannidae: Fluvicolinae), including a new genus for Muscisaxicola fluviatilis

Article

May 2020

Systematics, Evolution, and Biogeography of the South American Ovenbird Genus Cinclodes

Article

Jul 2004

R. Terry Chesser

Phylogenetic relationships within the genus Cinclodes, a group of South American furnariids, were studied using complete sequences of the mitochondrial genes COII and ND3. The 13 species of Cinclodes formed a monophyletic group consisting of three major lineages: (1) the southeastern Brazilian isolate C. pabsti, which was sister to the rest of the genus; (2) a clade of five primarily Patagonian or central Argentine highlands species; and (3) a clade of seven primarily north-central Andean or Pacific species. Biogeographic structure in the Patagonian-Andean taxa was consistent with the deep Patagonian and north-central Andean division previously noted in the similarly distributed genus Muscisaxicola. Evolutionary relationships among Cinclodes species were partially consistent with expectations based on plumage, behavior, and ecology. The phenotypically distinctive C. antarcticus was found to be sister to the widespread C. fuscus in the primarily Patagonian-Argentine clade, and the distinctive C. palliatus to be sister to C. atacamensis in the high Andean-Pacific clade. The central Argentine isolates C. comechingonus and C. olrogi formed a clade with C. oustaleti (olrogi sister to oustaleti, and comechingonus sister to those two) within the Patagonian-Argentine clade. The Pacific marine specialists C. nigrofumosus and C. taczanowskii were sisters within the Andean-Pacific clade and were distantly related to the southern maritime species C. antarcticus. Thus, marine ecological specialization apparently evolved twice within Cinclodes; behavioral and ecological data also support the nonhomology of the two character states. The two exclusively Pacific species were positionally apomorphic within the Andean-Pacific clade; ancestral area analysis indicated that the high Andes were the most likely area of origin for this clade, and that the Pacific coast was occupied secondarily.

Elevational Zonation and the Phylogenetic Relationships of the Henicorhina Wood-Wrens

Article

Jan 2006

The Henicorhina wood-wren complex consists of three taxonomic species. Two of these, the Gray-breasted Wood-Wren (Henicorhina leucophrys) and the White-breasted Wood-Wren (H. leucosticta), are widespread throughout Central America and northern South America, with leucophrys occurring at higher elevations in regions where both occur. A third, recently described, species—the Bar-winged Wood-Wren (H. leucoptera)—occurs only in several isolated cordilleras in southeastern Ecuador and northeastern Peru, where it replaces the Gray-breasted Wood-Wren at the highest elevations. We used mitochondrial DNA sequences to explore the phylo-genetic relationships among populations of these taxa and to draw inferences about the evolutionary origins of elevational zonation. We found substantial mitochondrial diversity within both leucophrys and leucosticta. Differentiation across the Andes in leucophrys was negligible, but populations from Central America and from northwestern Ecuador showed substantial differentiation. Three highly differentiated haplotype groups were also present in leucosticta, corresponding to populations in the eastern Andean lowlands, Central America, and the Chocó region of northwestern Ecuador; these populations may each warrant taxonomic species status. Bar-winged haplo-types nested within the mitochondrially diverse leucosticta group, where they were most closely allied to the geographically distant Chocó haplotypes. This leucoptera-leucosticta affinity is not consistent with previous inferences, based on plumage and behavioral similarities, that grouped leucoptera and leucophrys as sister species. These reconstructions refute the hypothesis that elevational zonation in this clade originated from in situ speciation along an elevational gradient, and instead highlight the role of complex changes in geographic distributions in fostering phylogenetic and ecological diversification. Reemplazos Altitudinales y Relaciones Filogenéticas en el Género Henicorhina (Troglodytidae)

Molecular Phylogenetic Relationships Among the Geositta Miners (Furnariidae) and Biogeographic Implications for Avian Speciation in Fuego-Patagonia

Article

Jan 2005

Pleistocene glacial cycles have often been hypothesized to provide vicariant mechanisms leading to allopatric speciation in a wide range of southern South American (Fuegian and Patagonian) avian taxa. Few of those biogeographic hypotheses, however, have been rigorously tested using phylogenetic analysis. We examined sequence variation in three mitochondrial gene fragments (cytochrome b, ND2, and ND3) to construct a molecular phylogeny for the South American genus Geositta (Furnariidae) and to test the interrelated hypotheses that Geositta cunicularia and G. antarctica are sister species that originated from a common ancestor while isolated in glacial refugia during Pleistocene glacial events in Fuego-Patagonia. Sequence data were obtained for all 10 currently recognized species of Geositta as well as Geobates poecilopterus and two outgroup taxa (Upucerthia ruficauda and Aphrastura spinicauda). We found levels of sequence divergence among Geositta species to be high, ranging from 7.4% to 16.3%. Our phylogenetic reconstructions clearly indicate relationships among Geositta species that differ considerably from those of traditional Geositta phylogeny. These data also strongly suggest that Geositta, as currently defined, is paraphyletic, with Geobates being embedded within Geositta. Our data do not support the hypothesized sister relationship between G. antarctica and G. cunicularia. Instead, they suggest that Geositta consists of two distinct clades, with antarctica and cunicularia falling into different clades. The high levels of sequence divergence among Geositta species, lack of a sister relationship between cunicularia and antarctica, and placement of Fuego-Patagonian antarctica into a clade consisting of two high-Andean (saxicolina and isabellina) and one coastal-west-slope (maritima) species demonstrate that the evolutionary history of Geositta is much older and far more complex than a simple model of allopatric speciation in glacial refugia would suggest. Filogenia Molecular del Género Geositta (Furnariidae) e Implicaciones Biogeográficas para la Especiación de la Aves en Tierra del Fuego y Patagonia

The flickering connectivity system of the north Andean páramos

Article

Full-text available

Jun 2019

Aim To quantify the effect of Pleistocene climate fluctuations on habitat connectivity across páramos in the Northern Andes. Location Northern Andes. Methods The unique páramos habitat underwent dynamic shifts in elevation in response to changing climate conditions during the Pleistocene. The lower boundary of the páramos is defined by the upper forest line, which is known to be highly responsive to temperature. Here, we reconstruct the extent and connectivity of páramos over the last 1 million years (Myr) by reconstructing the upper forest line from the long fossil pollen record of Funza09, Colombia, and applying it to spatial mapping on modern topographies across the Northern Andes for 752 time slices. Data provide an estimate of how often and for how long different elevations were occupied by páramos and estimate their connectivity to provide insights into the role of topography in biogeographical patterns of páramos. Results Our findings show that connectivity amongst páramos of the Northern Andes was highly dynamic, both within and across mountain ranges. Connectivity amongst páramos peaked during extreme glacial periods but intermediate cool stadials and mild interstadials dominated the climate system. These variable degrees of connectivity through time result in what we term the ‘flickering connectivity system’. We provide a visualization (video) to showcase this phenomenon. Patterns of connectivity in the Northern Andes contradict patterns observed in other mountain ranges of differing topographies. Main conclusions Pleistocene climate change was the driver of significant elevational and spatial shifts in páramos causing dynamic changes in habitat connectivity across and within all mountain ranges. Some generalities emerge, including the fact that connectivity was greatest during the most ephemeral of times. However, the timing, duration and degree of connectivity varied substantially among mountain ranges depending on their topographical configuration. The flickering connectivity system of the páramos uncovers the dynamic settings in which evolutionary radiations shaped the most diverse alpine biome on Earth.

Diversification mechanisms in the Andean grasshopper genus Orotettix (Orthoptera: Acrididae): Ecological niches and evolutionary history

Article

Mar 2018

The Andes harbour an outstanding taxonomic and ecological diversity, for which several mechanisms promoting diversification, including ecological gradients and allopatric speciation, have been cited. The grasshopper genus Orotettix is an informative but challenging group to study diversification mechanisms because species in the genus are morphologically very similar, have low vagility and display local endemism over a complex topography in the Central Andes. We conducted several tests using ecological niche overlap and predictions of geographical distributions of Orotettix species on a phylogenetic framework to disentangle their speciation patterns. A multilocus molecular phylogeny was generated for Orotettix. Niche similarity tests were performed and the degree of niche overlap was estimated between species. Ecological niche models were generated to assess the realized ecological niche and potential distribution. The phylogenetic signal between the phylogenetic relatedness and niche overlap, and geographical and the environmental distances were analysed. Our findings suggest that speciation was not restricted to a single period and that species origins might have coincided with glacial-interglacial cycles of the Pleistocene. Given that we only found cases of niche conservatism for Orotettix, we infer that allopatric speciation had the primary role in its diversification. No significant phylogenetic signal was found, probably due to an island-like radiation process.

Shifts in habitat suitability and the conservation status of the Endangered Andean cat Leopardus jacobita under climate change scenarios

Article

Jul 2017

Organisms adapted to life at high elevations are particularly threatened by climate change, which can cause them to become isolated on mountain tops, yet their responses may vary according to their position in the food chain and their ecological flexibility. Predicting the future distributions of such organisms requires fine-tuned species-specific models. Building on a previous ecological niche model, we explored shifts in the suitability of habitats for the Endangered Andean cat Leopardus jacobita , and assessed how these will be represented within existing protected areas in the future. Using a robust set of presence records and corrected climate surfaces, we applied the Maxent algorithm to model habitat suitability for this carnivore and for its preferred prey, the mountain viscacha Lagidium viscacia . Our predictions indicate that the areas climatically suitable for Andean cats could contract by up to 30% by 2080 under the most pessimistic scenario, with an overall upwards shift of 225 m and a polewards displacement of 98–180 km. The predicted range contraction was more pronounced in the species’ core range, in the Bolivian and Peruvian Andes, whereas suitable conditions may increase in the southern range in Patagonia. Bolivia and Peru are predicted to suffer the most marked decline in habitat representativeness within protected areas. The southern range appears to be less vulnerable to climate change, offering opportunities for the conservation of this genetically distinct population. We discuss the value and limitations of using species distribution modelling to assess changes in the potential distribution and conservation status of this and other Andean species.

Genetic population structure in an equatorial sparrow: Roles for culture and geography

Article

Mar 2017
J EVOLUTION BIOL

Female preference for local cultural traits has been proposed as a barrier to breeding among animal populations. As such, several studies have found correlations between male bird song dialects and population genetics over relatively large distances. To investigate if female choice for local dialects could act as a barrier to breeding between nearby and contiguous populations, we tested if variation in male song dialects explains genetic structure among eight populations of rufous-collared sparrows (Zonotrichia capensis) in Ecuador. Our study sites lay along a transect and adjacent study sites were separated by approximately 25km, an order of magnitude less than previously examined for this and most other species. This transect crossed an Andean ridge and through the Quijos River Valley, both of which may be barriers to gene flow. Using a variance partitioning approach, we show that song dialect is important in explaining population genetics, independent of the geographic variables: distance, the river valley, and the Andean Ridge. This result is consistent with the hypothesis that song acts as a barrier to breeding among populations in close proximity. In addition, songs of contiguous populations differed by the same degree or more than between two populations previously shown to exhibit female preference for local dialect, suggesting that birds from these populations would also breed preferentially with locals. As expected, all geographic variables (distance, the river valley, and the Andean Ridge) also predicted population genetic structure. Our results have important implications for the understanding if, and at what spatial scale, culture can affect population divergence. This article is protected by copyright. All rights reserved.

High-altitude peatland temporary pools in Bolivia house a high cladoceran diversity

Article

Dec 2007

We studied richness and composition of the cladoceran species in 61 temporary peat-pools (pools within high-altitude peatland mires) in the Cordillera del Tunari in Cochabamba (Bolivia) during one wet season. Of the 21 species collected, two were new to science and five were new records to Bolivia. Across all 61 pools, species richness per pool varied from 3–16 (mean = 8.3 + 2.8 SD). Rarefaction analysis revealed that more than 80% of all collected species was represented by a subsample of 25 pools. This is the first study to comprehensively present the cladoceran fauna of temporary peat-pools in the high Andes. The cladoceran diversity is comparable with many permanent systems in the region and other temporary pool systems around the world, and underlines the conservation value of these peatland systems (bofedales) for the aquatic biodiversity of South America.

Filogenia de lulo, tomate de árbol y sus parientes silvestres

Article

Full-text available

Nov 2009

Dentro de la familia Solanaceae, el género monofilético Solanum es el más grande y diverso. Dentro de este género, S. quitoense Lam. (lulo) y S. betaceum Cav. (tomate de árbol) representan dos de las especies más importantes de Solanáceas neotropicales para convertirse en cultivos prominentes en mercados locales y de exportación. S. quitoense y su pariente silvestre S. hirtum pertenecen al clado Leptostemomum del género Solanum, mientras que S. betaceum y su pariente silvestre S. unilobum pertenecen al clado Cyphomandra del mismo género. En estudios filogenéticos previos se ha reportado que el clado Leptostemomum y el Cyphomandra podrían formar un clado hermano al de Papa (que agrupa a S. lycopersicum y S. tuberosum entre otras especies); alternativamente, estos tres clados formarían una politomía al interior del género. Con el propósito de clarificar las relaciones entre los clados del género Solanum y contribuir con el entendimiento de su proceso de divergencia, el presente estudio utilizó secuencias de marcadores COSII para conducir análisis filogenéticos y de datación. Los resultados obtenidos soportan la hipótesis que indica que Leptostemomum y Cyphomandra forman un subclado hermano al clado Papa. Adicionalmente, éstos sugieren que la divergencia entre los pares S. hirtum y S. quitoense, y S. unilobum y S. betaceum ocurrió hace aproximadamente un millón y 450 mil años respectivamente, periodos que coinciden con eventos de cambio climático a los que se les ha atribuido la diversificación de varios clados andinos.

Neotropical Ornithology: Then and Now

Article

Jul 2003
AUK

François Vuilleumier

Divergent timing and patterns of species accumulation in lowland and highland Neotropical birds

Article

Apr 2006
EVOLUTION

Jason T. Weir

Abstract Late Pliocene and Pleistocene climatic instability has been invoked to explain the buildup of Neotropical biodiversity, although other theories date Neotropical diversification to earlier periods. If these climatic fluctuations drove Neotropical diversification, then a large proportion of species should date to this period and faunas should exhibit accelerated rates of speciation. However, the unique role of recent climatic fluctuations in promoting diversification could be rejected if late Pliocene and Pleistocene rates declined. To test these temporal predictions, dateable molecular phylogenies for 27 avian taxa were used to contrast the timing and rates of diversification in lowland and highland Neotropical faunas. Trends in diversification rates were analyzed in two ways. First, rates within taxa were analyzed for increasing or decreasing speciation rates through time. There was a significant trend within lowland taxa towards decreasing speciation rates, but no significant trend was observed within most highland taxa. Second, fauna wide diversification rates through time were estimated during one-million-year intervals by combining rates across taxa. In the lowlands, rates were highest during the late Miocene and then decreased towards the present. The decline in rates observed both within taxa and for the fauna as a whole probably resulted from density dependent cladogenesis. In the highlands, faunawide rates did not vary greatly before the Pleistocene but did increase significantly during the last one million years of the Pleistocene following the onset of severe glacial cycles in the Andes. These contrasting patterns of species accumulation suggest that lowland and highland regions were affected differently by recent climatic fluctuations. Evidently, habitat alterations associated with global climate change were not enough to promote an increase in the rate of diversification in lowland faunas. In contrast, direct fragmentation of habitats by glaciers and severe altitudinal migration of montane vegetation zones during climatic cycles may have resulted in the late Pleistocene increase in highland diversification rates. This increase resulted in a fauna with one third of its species dating to the last one million years.

The mixed success of Mimosoideae clades invading into Australia

Article

Jan 2012

Kyle W Tomlinson

Mimosoideae are a dominant plant clade in Australia with more than 1000 taxa recognised. Most species belong to genus Acacia s.s. Mill. and evolved in Australia during the post-Gondwanan isolation. Very few species (<20) belong to genera that evolved outside Australia (Vachellia Wight & Arn., Senegalia Raf.; until quite recently both included under Acacia s.l.) and have subsequently invaded into Australia (Chapter 2). Most of these are descended from individuals that immigrated into Australia and New Guinea prior to European migrations (hereafter pre-colonial species), while a few were either accidentally or deliberately introduced by Europeans (hereafter colonial species). The relative abundance and distribution of the species varies significantly between early and later invaders: the later colonial invaders show wider or rapidly expanding distributions and superior dominance status in the communities where they are found (Table 3.1; Australian Biological Resources Study 2001; Kriticos et al. 2003). The early colonial species range from being (more usually) abundant to locally dominant, in some instances (Table 3.1). This suggests that either trait differences between the species have affected their relative performance under modern, post-colonial systems of native vegetation management, or that human activities have particularly favoured the spread of post-colonial species.

Invasion ecology of honeyeaters

Article

Jan 2012

Many conservationists argue that invasive species form one of the most important threats to ecosystems the world over, often spreading quickly through their new environments and jeopardising the conservation of native species. As such, it is important that reliable predictions can be made regarding the effects of new species on particular habitats. This book provides a critical appraisal of ecosystem theory using case studies of biological invasions in Australasia. Each chapter is built around a set of 11 central hypotheses from community ecology, which were mainly developed in North American or European contexts. The authors examine the hypotheses in the light of evidence from their particular species, testing their power in explaining the success or failure of invasion and accepting or rejecting each hypothesis as appropriate. The conclusions have far-reaching consequences for the utility of community ecology, suggesting a rejection of its predictive powers and a positive reappraisal of natural history.

Historical Biogeography of Neotropical Freshwater Fishes

Book

Full-text available

Mar 2011

The fish faunas of continental South and Central America constitute one of the greatest concentrations of aquatic diversity on Earth, consisting of about 10 percent of all living vertebrate species. Historical Biogeography of Neotropical Freshwater Fishes explores the evolutionary origins of this unique ecosystem. The chapters address central themes in the study of tropical biodiversity: why is the Amazon basin home to so many distinct evolutionary lineages? What roles do ecological specialization, speciation, and extinction play in the formation of regional assemblages? How do dispersal barriers contribute to isolation and diversification? Focusing on whole faunas rather than individual taxonomic groups, this volume shows that the area's high regional diversity is not the result of recent diversification in lowland tropical rainforests. Rather, it is the product of species accumulating over tens of millions of years and across a continental arena.

Patterns of partial avian migration in northern and southern temperate latitudes of the New World

Article

Full-text available

Mar 2012

We describe partial migration of passerine birds across temperate latitudes in the New World. Owing to lower climatic seasonality near the coast of North America, the proportion of partial migrants at high latitudes in North America should be lower when excluding coastal records. We detected a 10% decrease in the proportion of partially migratory species at high latitudes when excluding species recorded only coastally at those latitudes. We also expected a smaller proportion of partial migrants in inland North America compared with South America. However, at high latitudes (i.e. >39 degrees) we found a similar proportion of partially migratory species but a different taxonomic makeup between continents. Within the Tyrannidae (New World flycatchers), we evaluated the latitude at which species winter in North and South America. The mean latitude at which partially migratory New World flycatchers winter in temperate South America (30.3 degrees S, s.d. 5.6) is not significantly different from the mean latitude in inland North America (30.4 degrees N, s.d. 2.8). Partial migration of birds in the New World may be under different constraints, depending on factors such as habitat occupancy and distance of a population from the coast.

Reweaving the Tapestry: a Supertree of Birds

Article

Full-text available

Jun 2014

Our knowledge of the avian tree of life remains uncertain, particularly at deeper levels due to the rapid diversification early in their evolutionary history. They are the most abundant land vertebrate on the planet and have been of great historical interest to systematists. Birds are also economically and ecologically important and as a result are intensively studied, yet despite their importance and interest to humans around 13% of taxa currently on the endangered species list perhaps as a result of human activity. Despite all this no comprehensive phylogeny that includes both extinct and extant species currently exists. Here we present a species-level supertree, constructed using the Matrix Representation with Parsimony method, of Aves containing approximately two thirds of all species from nearly 1000 source phylogenies with a broad taxonomic coverage. The source data for the tree were collected and processed according to a strict protocol to ensure robust and accurate data handling. The resulting tree topology is largely consistent with molecular hypotheses of avian phylogeny. We identify areas that are in broad agreement with current views on avian systematics and also those that require further work. We also highlight the need for leaf-based support measures to enable the identification of rogue taxa in supertrees. This is a first attempt at a supertree of both extinct and extant birds, it is not intended to be utilised in an overhaul of avian systematics or as a basis for taxonomic re-classification but provides a strong basis on which to base further studies on macroevolution, conservation, biodiversity, comparative biology and character evolution, in particular the inclusion of fossils will allow the study of bird evolution and diversification throughout deep time.

Genetic divergence among populations of a tropical passerine, the streaked saltator (Saltator albicollis)

Article

Full-text available

Jan 1993

We analyzed mitochondrial-DNA (mtDNA) restriction-site variation in populations (subspecies) of the Streaked Saltator (Saltator albicollis) in Panama, Peru, and the Lesser Antilles. Genetic differentiation between populations (Panama vs. Peru, 0.035; Lesser Antilles vs. Panama/Peru, 0.063) greatly exceeded values reported for populations or subspecies within North American bird species (0.0028-0.0086), and was near the high end of the range reported for congeneric species of passerine birds (0.016-0.073). Nucleotide diversity within populations was similar to that reported for other species of passerines and did not differ markedly between mainland and island populations. Thus, founder effects and population bottlenecks associated with island colonization appear to have caused little, if any, loss of mtDNA nucleotide diversity. No significant mtDNA differentiation was observed between populations of named subspecies on mainland Panama (S. a. isthmicus) and the Pearl Islands (speratus), or between two subspecies in the Lesser Antilles (albicollis and guadelupensis). Saltator albicollis exhibits marked geographical genetic differentiation, as assayed by mtDNA polymorphism, but this bears little relationship to subspecies distinctions. Finally, the genetic data suggest that Antillean populations of Streaked Saltators should be distinguished at specific rank (S. albicollis), with continental forms referred to S. striatipectus.

Development of the high Andean p??ramo flora and vegetation

Article

Full-text available

Jan 1986

Evolutionary Genetics of the Andean Lizard Genus Pholidobolus (Sauria: Gymnophthalmidae): Phylogeny, Biogeography, and a Comparison of Tree Construction Techniques

Article

Full-text available

Jun 1985

David Hillis

Electrophoretic examination of the products of 29 gene loci in the five species of Pholidobolus and three species of Proctoporus largely substantiates the taxonomic arrangement that was based on earlier morphological work. The electrophoretic data are used to construct a phylogeny of the species and the morphological data are reanalyzed for comparison; these data sets are largely consistent. The hypothesized phylogeny places Ph. affinis as the sister species to the other Pholidobolus, Ph. macbrydei as the sister species to the remaining taxa, and the two populations referred to Ph. prefrontalis as the sister species to Ph. montium plus Ph. annectens. Because of the small size of the genus Pholidobolus and the concomitant small number of possible phylogenetic hypotheses, comparisons among various methods of constructing phylogenetic trees from electrophoretic data are facilitated. All 105 possible bifurcating unrooted trees were examined for each of 13 goodness-of-fit statistics; three similar trees were consistently favored by all criteria. If outgroup rooting is used, the most favored of these trees is identical to the most parsimonious cladogram. However, with midpoint rooting, almost all phylogenetic information is lost and the resulting tree is identical to the UPGMA phenogram. The midpoint-rooting option of distance trees reinvokes an assumption (equal rates of change) that the distance methods are supposed to avoid. This assumption is clearly not met for the genus Pholidobolus. Biogeographic analysis of the species of Pholidobolus with respect to the hypothesized phylogeny of the genus reveals that no contact zones of this parapatric complex involve two sister species. This emphasizes the need for phylogenetic reconstruction as the first step in the examination of speciation mechanisms. This finding also suggests that competing species, rather than geographic barriers, may at times serve to isolate differentiating populations.

QUATERNARY GEOLOGY/GEOMORPHOLOGY: Back

Article

Full-text available

Jan 2006

Hendy, M. D. and D. Penny. A framework for the quantitative study of evolutionary trees. Syst. Zool

Article

Full-text available

Dec 1989
Syst Zool

A direct method for calculating expected data from an evolutionary model for two state characters is described. The method uses four vectors p, q, r and s. p and q are the probabilities of a character change on the 2n − 3 edges of a tree T (n is the number of taxa). r and s are properties of the data, are independent of any tree and have 2n−1 entries. For a given tree T, and with specified probabilities (p or q), we determine r, then s, the expected probabilities of each of the 2n−1 possible partitions of taxa. For any tree T the relationship can be inverted. This allows the probabilities of change on the tree, p and q, to be estimated directly from observed data (r or s). These relationships have been used to analyse the behaviour of tree building algorithms under conditions when there are sufficient data. (This is when the tree does not change as more data are collected, i.e., convergence to a single tree.) With equal rates of evolution (i.e., with a molecular clock), we show that for n = 4 taxa, parsimony will always converge to the correct tree, but we give examples with n = 5 where parsimony will converge on an incorrect tree, even for equal rates of evolution. A further example with n = 6 shows convergence to an incorrect tree with equal but arbitrarily small rates of change. We interpret a basic difficulty with parsimony as ‘long edges attract.’ If there are additional taxa that intersect long edges on the tree, then this effect can be reduced. Some distance methods may also converge to an incorrect tree.

The Importance of Recent Ice Ages in Speciation: A Failed Paradigm

Article

Full-text available

Sep 1997
SCIENCE

Late Pleistocene glaciations have been ascribed a dominant role in sculpting present-day diversity and distributions of North American vertebrates. Molecular comparisons of recently diverged sister species now permit a test of this assertion. The Late Pleistocene Origins model predicts a mitochondrial DNA divergence value of less than 0.5 percent for avian sister species of Late Pleistocene origin. Instead, the average mitochondrial DNA sequence divergence for 35 such songbird species pairs is 5.1 percent, which exceeds the predicted value by a factor of 10. Molecular data suggest a relatively protracted history of speciation events among North American songbirds over the past 5 million years.

Evaluation of the maximum likelihood estimate of the evolutionary tree topologies from DNA sequence data, and the branching order in Hominoidea

Article

Full-text available

Aug 1989

A maximum likelihood method for inferring evolutionary trees from DNA sequence data was developed by Felsenstein (1981). In evaluating the extent to which the maximum likelihood tree is a significantly better representation of the true tree, it is important to estimate the variance of the difference between log likelihood of different tree topologies. Bootstrap resampling can be used for this purpose (Hasegawa et al. 1988; Hasegawa and Kishino 1989), but it imposes a great computation burden. To overcome this difficulty, we developed a new method for estimating the variance by expressing it explicitly.The method was applied to DNA sequence data from primates in order to evaluate the maximum likelihood branching order among Hominoidea. It was shown that, although the orangutan is convincingly placed as an outgroup of a human and African apes clade, the branching order among human, chimpanzee, and gorilla cannot be determined confidently from the DNA sequence data presently available when the evolutionary rate constancy is not assumed.

Dispersal-Vicariance Analysis: A New Approach to the Quantification of Historical Biogeography

Article

Full-text available

Mar 1997

Fredrik Ronquist

Quantification in historical biogeography has usually been based on the search for a single branching relationship among areas of endemism. Unlike organisms, however, areas rarely have a unique hierarchical history. Dispersal barriers appear and disappear and may have different effects on different species. As a result, the biota of an area may consist of several components with separate histories, each of which may be reticulate rather than branching. In an attempt to address these problems, I present a new biogeographic method, dispersal–vicariance analysis, which reconstructs the ancestral distributions in a given phylogeny without any prior assumptions about the form of area relationships. A three-dimensional step matrix based on a simple biogeographic model is used in the reconstruction. Speciation is assumed to subdivide the ranges of widespread species into vicariant components; the optimal ancestral distributions are those that minimize the number of implied dispersal and extinction events. Exact algorithms that find the optimal reconstruction(s) are described. In addition to their use in taxon biogeography, the inferred distribution histories of individual groups serve as a basis for the study of general patterns in historical biogeography, particularly if the relative age of the nodes in the source cladograms is known.

Ancient DNA and island endemics

Article

Full-text available

Jul 1996

mtDNA PHYLOGENY OF ANDEAN MICE: A TEST OF DIVERSIFICATION ACROSS ECOLOGICAL GRADIENTS

Article

Feb 1992
EVOLUTION

Parapatric speciation across sharp ecological gradients is an alternative to the more usual allopatric model as both a general explanation of organismal diversification and as an explicit statement regarding differentiation of tropical forest biotas (Endler, 1977, 1982a, 1982b). The relevance of this model to species of small mammals distributed across a 3,000 meter gradient on the eastern flank of the Peruvian Andes is examined here by phylogenetic analysis of comparative mitochondrial DNA sequences, relying on both freshly collected samples and extracts taken from skins preserved in museum collections. These analyses falsify the applicability of the gradient model in this case. Moreover, the phylogenetic approach employed here provides an explicit test of the feasibility of the gradient model for any other taxon, either plant or animal, of the lowland Amazonian forest.

Evolutionary genetics of the Andean lizard genus Pholidobolus (Sauria: Gymnophthalmidae): phylogeny, biogeography, and a comparison of tree construction techniques

Article

Jan 1985
Syst Zool

DM HILLIS

A phylogeny of the thirty-three genera in the Empidonax assemblage of tyrant flycatchers

Article

Jan 1986

W.E. Lanyon

A classification of the tyrant flycatchers (Tyrannidae)

Article

Jan 1977

M.A. Traylor

Catalogue of birds of the Americas

Article

Jan 1918

The distribution of bird-life in Ecuador

Article

Jan 1926

F.M. Chapman

The distribution of bird-life in Colombia

Article

Jan 1917

F.M. Chapman

Elevational Correlates of Speciation and Intraspecific Geographic Variation in Plumage in Andean Forest Birds

Article

Jul 1985

Gary R. Graves

Intraspecific variation in plumage was used to test the null hypotheses that geographic variation in 280 species of elevationally restricted Andean forest birds is independent of elevation and is not a function of patchy geographic distribution. Both null hypotheses were rejected. At most taxonomic levels, geographic variation in plumage was correlated positively with both the mean of its elevational distribution and the size of its geographic range. Vertical amplitude of elevational distribution was not a significant predictor of geographic variation in plumage in most taxa. Independent of these elevational correlates, patchily distributed species showed significantly more geographic variation than continuously distributed species. These results show that geographic variation and presumably ongoing speciation phenomena are greater at higher elevations. The decreased species richness at high elevations may be attributable to a higher rate of extinction from catastrophic disturbance as well as to ecological factors that limit sympatry in newly formed species.

Molecular Genetic Divergence between Avian Sibling Species: King and Clapper Rails, Long-Billed and Short-Billed Dowitchers, Boat-Tailed and Great-Tailed Grackles, and Tufted and Black-Crested Titmice

Article

Jul 1988
AUK

Surveys of electrophoretic variation in proteins, and restriction site variation in mitochondrial DNA (mtDNA), were conducted to assess the resolving power of these molecular genetic techniques to distinguish four pairs of avian sibling taxa. Samples of rails (Rallus elegans and R. longirostris), dowitchers (Limnodromus scolopaceus and L. griseus), grackles (Quiscalus major and Q. mexicanus), and titmice (Parus bicolor bicolor and P. b. atricristatus) were assayed for allozymes encoded by 34-37 nuclear loci, and for an average of 77 mtDNA restriction sites per individual by 19 endonucleases. MtDNA's of the two rail species showed large-scale size polymorphism and individual heteroplasmy, the first such findings of these molecular features in an avian species. Genetic distances based on allozyme comparisons were small for all assayed taxa (Nei's D ≤ 0.063). The mtDNA assays offered consistently greater resolving power, providing at least five fixed restriction site differences for samples of any taxon pair. The Long-billed and Short-billed dowitchers were especially divergent, differing by at least 24 assayed mtDNA restriction sites and an estimated nucleotide sequence divergence of p = 0.082. We compared these results to previous reports of genetic distances within and among closely related bird species. The mtDNA divergence among dowitchers is near the high end of the scale of such estimates for avian congeners. The mtDNA distances between the pairs of rails (p = 0.006), titmice (p = 0.004), and grackles (p = 0.016) were typical for extremely closely related species, and overlap maximum values reported for some avian conspecifics.

Nidificación de Hirundo rustica erythrogaster (Boddaert) en la Argentina (Aves, Hirundinidae)

Article

Jan 1983

M.M. Martínez

Evolution into the Andes: Molecular evidence for species relationships in the genus Leptopogon

Article

Jan 1994
AUK

The Limits of Amino Acid Sequence Data in Angiosperm Phylogenetic Reconstruction

Article

Jul 1988

Kåre Gunnar Bremer

Amino acid sequence data are available for ribulose biphosphate carboxylase, plastocyanin, cytochrome c, and ferredoxin for a number of angiosperm families. Cladistic analysis of the data, including evaluation of all equally or almost equally parsimonious cladograms, shows that much homoplasy (parallelisms and reversals) is present and that few or no well supported monophyletic groups of families can be demonstrated. In one analysis of nine angiosperm families and 40 variable amino acid positions from three proteins, the most parsimonious cladograms were 151 steps long and contained 63 parallelisms and reversals (consistency index = 0.583). In another analysis of six families and 53 variable amino acid positions from four proteins, the most parsimonious cladogram was 161 steps long and contained 50 parallelisms and reversals (consistency index = 0.689). Single changes in both data matrices could yield most parsimonious cladograms with quite different topologies and without common monophyletic groups. Presently, amino acid sequence data are not comprehensive enough for phylogenetic reconstruction among angiosperms. More informative positions are needed, either from sequencing longer parts of the proteins or from sequencing more proteins from the same taxa.

Chilean Bird Distribution

Article

May 1970

Martin L. Cody

The results of bird censuses from 13 Chilean habitats are presented. Any one habitat supports a slighly higher bird species diversity than structurally similar habitats in North America and Australia. The bird species turnover between habitats in the same locale, in contrast to other temperate areas, is very low--an island characteristic. Turnover between geographically distinct habitats within Chile is comparable to that between adjacent habitats in North America. Chilean birds exhibit wide habitat tolerance in narrow geographic areas, whcih is attributed to a slow development rate of this bird fauna. Character convergence, where similarities in appearance have evolved to faciliate interspecific aggression and aggregation, is a byproduct of this type of distribution.

Phylogenetic Inference From Restriction Endonuclease Cleavage Site Maps with Particular Reference to the Evolution of Humans and the Apes

Article

Mar 1983

Alan R. Templeton

The estimation procedure utilizes a compatibility analysis between enzyme data sets of the most parsimonious trees constructed from the restriction enzyme. Next, a non-parametric test is given for comparing alternative phylogenies. A 2nd non-parametric test is developed for testing the molecular clock hypothesis. To illustrate the power of these procedures, data derived from the mitochondrial DNA and globin DNA of man and the apes are analyzed. Although previous analyses of these data led to the speculation that 10 times more information would be required to resolve the evolutionary relationships between man with chimps and gorillas, this algorithm resolved these relationships at the 5% level of significance. The molecular clock hypothesis was rejected at the 1% level. The implications of this phylogenetic inference when coupled with other types of data lead to the conclusion that knuckle-walking - not bipedalism - is the evolutionary novelty in mode of locomotion in the primates and that many other hominid features are primitive whereas their African ape counterparts are derived.-from Author

Phylogeny and Classification of New World Suboscine Passerine Birds (Passeriformes: Oligomyodi: Tyrannides)

Article

Jan 1985

During the past century the classifications of the suboscine passerine birds have included the following groups, as in Wetmore (1960): Superfamily Furnarioidea- Dendrocolaptidae, Furnariidae, Formicariidae, Conopophagidae, Rhinocryptidae; and Superfamily Tyrannoidea-Cotingidae, Pipridae, Tyrannidae, Oxyruncidae, Phytotomidae, Pittidae, Acanthisittidae, Philepittidae. DNA-DNA hybridization data and congruent morphological characters show that a revision of this arrangement is indicated, as follows: (1) Woodcreepers (Dendrocolaptinae) and ovenbirds (Furnariinae) are subfamilies of the Furnariidae. (2) The Formicariidae of Wetmore (1960) is a diphyletic assemblage divisible into ground antbirds (Formicariidae), which are closely related to the gnateaters (Conopophagidae) and tapaculos (Rhinocryptidae), and typical antbirds (Thamnophilidae), which diverged from the lineage leading to the furnariids, formicariids, conopophagids, and rhinocryptids before these groups diverged from one another. (3) The Tyrannoidea includes only the New World taxa of Wetmore (1960). Pittidae is the sister group of the Eurylaimidae, and the New Zealand wrens (Acanthisittidae) are descendants of the oldest known branch in the suboscine phylogeny (Sibley et al. 1982). Affinities of the Philepittidae are uncertain, but the family is presumed to belong to the Old World suboscine infraorder Eurylaimides. (4) The Tyrannidae of Wetmore (1960) is divided into the Mionectidae, which consists of several genera previously thought to be tyrannids, and the Tyrannidae, which includes the Tyranninae, Tityrinae, Cotinginae, and Piprinae. (5) The Tyranninae includes most of the genera of tyrant flycatchers. (6) The Tityrinae (becards, tityras, Schiffornis) is the sister group of the Tyranninae. (7) The Cotinginae includes the cotingas, plantcutters (Phytotoma), and the Sharpbill (Oxyruncus) (Sibley et al. 1 984). (8) The Piprinae includes the manakins, except Schiffornis which, tentatively, is the descendant of an early branch from the tityrine lineage. /// Durante el siglo pasado la clasificación de aves passeriformes suboscines ha incluído, tal como aparece en Wetmore (1960), los siguientes grupos: Superfamilia Furnarioidea-Dendrocolaptidae, Furnariidae, Formicariidae, Conopophagidae, Rhinocryptidae; y Superfamilia Tyrannoidea-Cotingidae, Pipridae, Tyrannidae, Oxyruncidae, Phytotomidae, Pittidae, Acanthisittidae, Philepittidae. Datos de hibridación de ADN-ADN y caracteres morfológicos congruentes muestran que sería necesaria una revisión de este arreglo de la siguiente manera: (1) Los trepadores (Dendrocolaptinae) y horneros (Furnariinae) son subfamilias de los Furnariidae. (2) El Formicariidae de Wetmore (1960) es una union de dos filos ("diphyletic") divisible entre los hormigueros terrestres (Formicariidae), (que están cercanamente relacionados con las perlitas (Conopophagidae) y los tapaculos (Rhinocryptidae) y típicos hormigueros (Thamnophilidae) que se apartaron del linaje que formó a los furnariidos, formicariidos, conopophagidos y rhinocryptidos, antes de que esos grupos se separasen entre si. (3) El Tyrannoidea incluye únicamente la taxa de Wetmore (1960) para el Nuevo Mundo. Pittidae es el grupo hermano ("sister group") de los Eurylaimidae, y los salta paredes (Acanthisittidae) de Nueva Zelanda son descendientes de la rama más antigua conocida en la filogenía de los suboscines (Sibley et al. 1982). Son inciertas las afinidades de los Philepittidae, pero se presume que la familia pertenece al infraorden suboscine Eurylaimides del Viejo Mundo. (4) El Tyrannidae de Wetmore (1960) se divide en Mionectidae, formado por varios géneros previamente considerados como tyrannidos y la Tyrannidae, que incluye Tyranninae, Tityrinae, Cotinginae y Piprinae. (5) El Tyranninae incluye a la mayoría de los géneros de atrapa moscas tiranos. (6) El Tityrinae (cabezones, rechinadores, Schiffornis) es el grupo hermano del Tyranninae. (7) El Cotinginae incluye las cotingas, los cortaplantas (Phytotoma), y los picoafilados (Oxyruncus) (Sibley et al. 1984). (8) El Piprinae incluye las matracas, excepto Schiffornis, el cual es considerado tentativamente descendiente de una rama más antigua del linaje de los tityrines.

Origin, Evolution, and Status of the Avifauna of Andean Wetlands

Article

Jan 1985

Jon Fjeldså

The distribution of Andean wetland habitats in the Pleistocene and present is reviewed and considered in relation to the known distribution of waterbirds. Analysis based on suture zones, disjunctions, core areas for endemic taxa, and phylogenetic relationships suggests evolutionary processes closely tied to events in the Pleistocene. The distributions of species that prefer barren habitats suggest a center of origin in the glacial Lake Michín on the Bolivian Altiplano. Other glacial refugia that gave rise to new taxa were Lake Atacama in Chile, Lake Junín in Peru, and the large lakes that previously were present in the Bogotá area, Colombia. Semi-open refugia along the Andean slopes had slight evolutionary significance. The inhabitants of Andean marsh habitats are generally poorly differentiated, morphologically, from lowland counterparts, and most probably they immigrated to the area in postglacial time. The colonization of the Andes was almost unidirectional, from the southern lowlands, which has resulted in a strong northward reduction of taxa adapted to barren habitats. The previous lakes of the Bogotá area received propagules from other directions, including from North America, but the many marsh birds in this area have not shown adaptive shifts in response to vacant niches in barren habitats. /// Se revee la distribución de los habitats pantanosos de los Andes tanto durante el pleistoceno como en la actualidad y se los considera en relación con la distribución conocidas de aves acuáticas. Análisis basados en zonas de sutura, disjunción, áreas centrales para grupos taxonómicos endémicos y relaciones filogenéticas, sugieren procesos de evolución cercanamente relacionados con sucesos del pleistoceno. La distribución de especies que prefieren habitats estériles hace suponer que el lago glacial Michín, en el altiplano boliviano, ha sido el centro de origen (de las mismas). Otros refugios glaciales, como el lago de Atacama en Chile, la laguna de Junín en Perú y los grandes lagos que se encontraban anteriormente en el área de Bogotá, Colombia, también brindaron origen a nuevos grupos taxonómicos. Refugios semidescubiertos en las laderas de los Andes tienen escaso significado a nivel de evolución. Los habitantes de los habitats pantanosos andinos generalmente presentan pocas diferencias morfológicas respecto a sus contrapartes en las tierras bajas, y probablemente han emigrado hacia el área luego de la época glacial. La colonización de los Andes fue casi unidireccional desde las tierras bajas del sur, lo cual ha determinado que hacia el norte se de una marcada disminución de taxa adaptada a los ambientes estériles. Los lagos que existían anteriormente en el área de Bogotá habían sido colonizados desde otras direcciones, incluyendo América del Norte, pero muchas de las aves acuáticas de esta area no muestran cambios adaptativos con respecto a los nichos vacantes en los habitats estériles.

Evolution, Weighting, and Phylogenetic Utility of Mitochondrial Gene Sequences and a Compilation of Conserved Polymerase Chain Reaction Primers

Article

Nov 1994
ANN ENTOMOL SOC AM

Evolution, weighting, and phylogenetic utility of mitochondrial gene sequences and a compilation of conserved polymerase chain reaction primers. C SIMON, F FRATI, A BECKENBACH, B CRESPI, H LIU, P

Examining Two Standard Assumptions of Ancestral Reconstructions: Repeated Loss of Dichromatism in Dabbling Ducks (Anatini)

Article

Oct 1997

Kevin Omland

Although phylogenetic reconstruction of ancestral character states is becoming an increasingly common technique for studying evolution, few researchers have assessed the reliability of these reconstructions. Here I test for congruence between a phylogenetic reconstruction and a widely accepted scenario based on independent lines of evidence. I used Livezey's (1991) phylogeny to reconstruct ancestral states of plumage dichromatism in dabbling ducks (Anatini). Character state mapping reconstructs monochromatic ancestors for the genus A,rns as well as most of its main clades. This reconstruction differs strongly from the widely accepted scenario of speciation and plumage evolution in the group (e.g., Delacour and Mayr 1945; Sibley 1957). This incongruence may occur because two standard assumptions of character state reconstruction are probably not met in this case. Violating either of these two assumptions would be a source of error sufficient to create misleading reconstructions. The first assumption that probably does not apply to ducks is that terminal taxa, in this case species, are monophyletic, Many of the widespread dichromatic species of ducks may be paraphyletic and ancestral to isolated monochromatic species. Three lines of evidence support this scenario: population-level phylogenies, biogeography, and vestigial plumage patterns. The second assumption that probably does not apply to duck plumage color is that gains and losses of character states are equally likely. Four lines of evidence suggest that dichromatic plumage might be lost more easily than gained: weak female preferences for bright male plumage, biases toward the loss of sexually dichromatic characters, biases toward the loss of complex characters, and repeated loss of dichromatism in other groups of birds. These seven lines of evidence support the accepted scenario that widespread dichromatic species repeatedly budded off isolated monochromatic species. Drift and genetic biases probably caused the easy loss of dichromatism in ducks and other birds during peripatric speciation. In order to recover the accepted scenario using Livezey's tree, losses of dichromatism must be five times more likely than gains. The results of this study caution against the uncritical use of unordered parsimony as the sole criterion for inferring ancestral states, Detailed population-level sampling is needed and altered transformation weighting may be warranted in ducks and in many other groups and character types with similar attributes.

Ecology versus History as Determinants of Patchy and Insular Distributions in High Andean Birds

Article

Jan 1980

Molecular Systematics of the Rhinocryptid Genus Pteroptochos

Article

May 1999

R. Terry Chesser

Relationships within the rhinocryptid ge- nus Pteroptochos (huet-huets and turca) were,investi- gated,using complete,sequences,of the mitochondrial genes,COB and ND3. Phylogenetic analysis of multi- ple individuals per taxon revealed that P. castaneus, P. tarn& and P. megapodius,constitute separate line- ages, with P. castaneus and P. turnii as sister taxa, and P. megapodius,sister to these. Bootstrap support,for these results was,strong (79-100%). Sequence diver- gence between species was high, ranging from 6.1% between,P. castaneus,and P. tarnii to 7.6% between P. castaneus,and P. megapodius.,High genetic diver- gence,between,P. castaneus,and P. tarnii is consistent with,plumage,and,vocal,differences,between,these taxa, and they appear to be separate species under both biological and phylogenetic,species concepts. The Bi’o- Bio River, a proposed dispersal barrier to P. tarnii, may be ineffective in limiting gene flow in this species, east of its confluence,with the Laja River. Key words: Chile, huet-huet, Nothofagus forest,

Thomas Coke: Apostle of Methodism. By John Vickers. Nashville: Abingdon Press, 1969. xiv + 394 pp. $14.50

Article

Jun 1971

Warren Thomas Smith

Dispersal-Vicariance Analysis: A New Approach to the Quantification of Historical Biogeography

Article

Nov 1996

Fredrik Ronquist

Quantification in historical biogeography has usually been based on the search for a single branching relationship among areas of endemism. Unlike organisms, however, areas rarely have a unique hierarchical history. Dispersal barriers appear and disappear and may have different effects on different species. As a result, the biota of an area may consist of several components with separate histories, each of which may be reticulate rather than branching. In an attempt to address these problems, I present a new biogeographic method, dispersal-vicariance analysis, which reconstructs the ancestral distributions in a given phylogeny without any prior assumptions about the form of area relationships. A three-dimensional step matrix based on a simple biogeographic model is used in the reconstruction. Speciation is assumed to subdivide the ranges of widespread species into vicariant components; the optimal ancestral distributions are those that minimize the number of implied dispersal and extinction events. Exact algorithms that find the optimal reconstruction(s) are described. In addition to their use in taxon biogeography, the inferred distribution histories of individual groups serve as a basis for the study of general patterns in historical biogeography, particularly if the relative age of the nodes in the source cladograms is known.

Speciation in Amazonian Forest Birds

Article

Jürgen Haffer

Molecular Systematics of the Scaled Quail Complex (Genus Callipepla)

Article

Apr 1998

We obtained 1,040 bp of sequence from the mitochondrial DNA (mtDNA) genes cytochrome b (cyt b; 736 bp) and NADH-subunit 2 (ND2; 304 bp) to address phylo- genetic relationships among the four species in the Scaled Quail complex. California Quail (Callipepla californica) and Gambel's Quail (C. gambelii) were sister taxa, whereas the rela- tionships of the Elegant Quail (C. douglasii) and Scaled Quail (C. squamata) were unclear; they might be sister species, or Elegant Quail might be the sister to California plus Gambel's quails. A third, less-likely alternative predicts a contemporaneous origin of Elegant Quail, Scaled Quail, and the ancestor of California and Gambel's quail. The latter phylogenetic hy- pothesis, however, matches Hubbard's (1973) biogeographic model. Irrespective of which biogeographic hypothesis is correct, calibration of mtDNA genetic distances suggests that the speciation events are much older than the late Pleistocene dates given by Hubbard. Cal- ibration of the rate of mtDNA (cyt b, ND2) evolution based on dating of fossil remains of the extinct species Cyrtonyx cooki suggested a rate of 2% per million years. Northern Bobwhite (Colinus virginianus), Mountain Quail (Oreortyx pictus), and Montezuma Quail (Cyrtonyx montezumae) were successively more distantly related to the Scaled Quail complex. Phylo- genetic trees derived from allozymes (Gutierrez et al. 1983) and mtDNA sequences were topologically identical, suggesting that both types of gene trees recover the species tree. Re-

Sequence and gene organization of the chicken mitochondrial genome

Article

Jan 1990

Molecular Phylogenetics of the Genus Piranga: Implications for Biogeography and the Evolution of Morphology and Behavior

Article

Jul 1998

Kevin J Burns

Species in the genus Piranga vary in degree of sexual dimorphism, plumage coloration, morphology, song, migratory patterns, and geographic distribution. To study these aspects of Piranga biology in an evolutionary context, I constructed a phylogeny for this genus using cytochrome-b sequence data. Parsimony and maximum-likelihood analyses of DNA data reveal three possible phylogenies for species in this genus. All three trees iden- tify a clade containing P. rubriceps, P. leucoptera, and P. erythrocephala and a clade containing P. rubra, P. ludoviciana, P. olivacea, P. bidentata, and P. fiava. The trees differ in the placement of P. roseogularis. Morphology, song, and plumage data did not agree with these phylogenies. Levels of sequence divergence and the phylogeny of haplotypes are consistent with the idea that P. fiava as currently described contains more than one evolutionary unit. Mapping the evolution of seasonal migration onto the DNA trees indicates that migration evolved once within Piranga. Received 15 November 1996, accepted 20 November 1997.

Confidence Limits on Phylogenies: An Approach Using the Bootstrap

Article

Jul 1985
EVOLUTION

Joseph Felsenstein

The recently-developed statistical method known as the "bootstrap" can be used to place confidence intervals on phylogenies. It involves resampling points from one's own data, with replacement, to create a series of bootstrap samples of the same size as the original data. Each of these is analyzed, and the variation among the resulting estimates taken to indicate the size of the error involved in making estimates from the original data, In the case of phylogenies, it is argued that the proper method of resampling is to keep all of the original species while sampling characters with replacement, under the assumption that the characters have been independently drawn by the systematist and have evolved independently. Majority-rule consensus trees can be used to construct a phylogeny showing all of the inferred monophyletic groups that occurred in a majority of the bootstrap samples. If a group shows up 95% of the time or more, the evidence for it is taken to be statistically significant. Existing computer programs can be used to analyze different bootstrap samples by using weights on the characters, the weight of a character being how many times it was drawn in bootstrap sampling. When all characters are perfectly compatible, as envisioned by Hennig, bootstrap sampling becomes unnecessary; the bootstrap method would show significant evidence for a group if it is defined by three or more characters.

mtDNA Phylogeny of Andean Mice: A Test of Diversification Across Ecological Gradients

Article

Feb 1992
EVOLUTION

Pleistocene Speciation in Birds living in the High Andes

Article

Sep 1969

FRAN|[Ccedil]|OIS VUILLEUMIER

THE South American Andes were brought to their present height by the final uplift phases of the late Pliocene and the Pleistocene1–6 and an alpine-like vegetation (locally called páramo or puna7–14) developed in the terrain thus produced. It follows that the evolution of the associated páramo-puna fauna by multiple speciation in situ should have taken place mostly or entirely during the Quaternary, so that the occurrence of speciation within this fauna should be a convenient guide to the possible rate of speciation in the Pleistocene.

Migration in South America: an overview of the austral system

Article

Sep 1994
BIRD CONSERV INT

R. Terry Chesser

Austral migrants are species that breed in temperate areas of South America and migrate north, towards or into Amazonia, for the southern winter. Migrations among these species are the most extensive of Southern Hemisphere migrations, and the austral system represents a third major migration system, in the sense that the term has been applied to Northern Hemisphere temperate-tropical migration. The geography of South America greatly influences the austral system. Lack of east-west geographical barriers and the shape of the continent promote a pattern of partially overlapping breeding and wintering ranges. The suboscine family Tyrannidae, the tyrant-flycatchers, is the largest group of austral migrants, with other major families including Emberizidae, Anatidae, Furnariidae, Accipitridae and Hirundinidae. Tyrant-flycatchers constitute more than one-half of the passerine austral migrants and roughly one-third of total austral migrants, a taxonomic domination seen in no other global migration system. Parallels exist, however, between austral migration and the Nearctic and Palearctic systems. Many of the same families, including Hirundinidae, Anatidae and Charadriidae, exhibit similarly high degrees of migratory behavi-our in each system. Passerine migration in the austral system is similar in numbers to that of the Nearctic-Neotropical system, but species migrate shorter distances and breed in more open and scrubby habitats. Possible differences in year-round resource availability between South American and North American temperate forests, in addition to differing availability of these habitats, may contribute to the low numbers of forest-dwelling austral migrants.

Branch Support and Tree Stability

Article

Sep 1994
CLADISTICS

Kåre Gunnar Bremer

Abstract— Branch support is quantified as the extra length needed to lose a branch in the consensus of near-most-parsimonious trees. This approach is based solely on the original data, as opposed to the data perturbation used in the bootstrap procedure. If trees have been generated by Farris's successive approximations approach to character weighting, branch support should be examined in terms of weighted extra length needed to lose a branch. The sum of all branch support values over the tree divided by the length of the most parsimonious tree[s] provides a new index, the total support index. This index is a measure of tree stability in terms of supported resolutions, which is of prime importance in cladistic analysis.

Glacial history of Southernmost South America

Article

Jun 1976

J.H. Mercer

In southernmost South America, an incomplete radiometrically dated glacial chronology has been obtained by KAr dating for the interval 3.5-1 MY ago, and a more detailed chronology by C-14 dating for the last 25,000 years, with some older minimal ages. The first major glaciation was about 3.5 MY ago during the middle Pliocene. Little is yet known about glacial fluctuations during the interval 3.5-2.1 MY ago. Between 2.1 and 1 MY ago many glaciations occurred, probably including the greatest of late Cenozoic time which took place after 1.2 MY and, according to inconclusive evidence, before 1 MY ago. The Patagonian Gravel in its type area is mid-Pliocene to early Pleistocene glacial outwash that accumulated from the first to the greatest glaciations. During the late Pleistocene several glaciations occurred, but only the most recent has been radiometrically dated. During the last glaciation the glaciers were most extensive before 56,000 BP. Successively smaller advances that culminated about 19,500 BP and, probably, about 13,000 BP were separated by an interstade when glaciers shrank by more than half. The glaciers receded rapidly after 13,000 BP and were within their present borders by 11,000 BP; they remained so during the European Younger Dryas Stade 11,000-10,000 BP. Neoglacial regional readvances culminated 4600-4200 BP, probably 2700-2000 BP, and during the last three centuries; most glaciers reached their Neoglacial maxima during the first episode. Between readvances, the glaciers shrank within their present borders.

Quaternary glaciations of the southern Andes

Article

Dec 1990
QUATERNARY SCI REV

The southern Andes comprise the southernmost portion of the Andean Cordillera, beginning at the edge of the Puna Altiplano (lat.27°S) and ending at Isla de los Estados (lat.55°S). The late Cainozoic glacial record of these mountains spans the interval from the Late Miocene to the present and is one of the most complete to be found anywhere in the world. This has arisen for several reasons: (i) the conterminous mountain ice cap extended to the piedmont zone on both flanks of the range, where the sedimentary and morphological record has been well preserved; (ii) periodic volcanism, mainly from monogenetic fissure eruptions of basalt east of the range and from central tephra-producing cones along the mountain crest, has provided opportunity for the preservation and radiometric dating of interbedded glacial deposits; (iii) a tectonically-induced interval of stream incision in the Mid Pleistocene and simultaneous uplift has preserved glacial sediments on interfluves; (iv) in the Chilean lakes region west of the mountains, Late Quaternary glaciers terminated in a well-vegetated landscape, thus creating scope for radiocarbon dating of interbedded and incorporated organic materials; consequently, the last glaciation in the Llanquihue area of Chile is one of the best dated sequences in South America; thus the ‘Llanquihue’ Glaciation is proposed as the South American equivalent of the ‘Wisconsin’ and ‘Weichsel’ glaciations of North America and north west Europe respectively.

Biogeographic, ecological, and evolutionary aspects of South American austral migration, with special reference to the family Tyrannidae /

Article

Includes Vita. Thesis (Ph. D.)--Louisiana State University, Baton Rouge, 1995. Includes bibliographical references (p. 297-320) Photocopy.

The Birds of South Africa

Article

R. L

Improving the Accuracy of Phylogenetic Estimation by Combining Different Methods

Article

Sep 1993

Junhyong Kim

Three methods of phylogenetic tree estimation, UPGMA clustering (UP), maximum parsimony (MP), and neighbor joining (NJ), were used to estimate trees from a large simulation study of 5,400 eight-taxon data sets. The data sets represented nine evolutionary models and 20 tree topologies. The agreement of the trees estimated by the three methods was highly correlated (0.71) with the average agreement with the true tree from which the data sets had been generated. A simple index is proposed for the agreement of different estimation methods that can serve as a measure of the reliability of the joint estimate. This index was coupled with an unbiased character weighting procedure to increase the accuracy of estimation. Accuracy was increased by an average of 24% by use of this procedure in 47 of 61 data sets examined.

Non-Allopatric Speciation in Animals

Article

Sep 1980
Syst Zool

Non-allopatric speciation in animals. Syst. Zool., 29:254–271.—Major recent challenges to the view that animal speciation is usually allopatric are reviewed, and are found unconvincing, either because of their theoretical implausibility or because of insufficient evidence. Special attention is given to the theory of stasipatric speciation, and to purported cases, especially in tephritid fruit flies, of sympatric speciation associated with a shift to a new host. Stasipatric speciation is unlikely under population genetic theory; moreover, chromosome rearrangements probably seldom facilitate speciation. In the tephritid genus Rhagoletis, the archetypal case of sympatric speciation, there is little or no evidence of genetic divergence or of sympatric speciation. The conditions under which host-associated sympatric speciation might occur are so exacting as to be met by very few species.

Chelex 100 as a Medium for Simple Extraction of DNA for PCR-Based Typing from Forensic Material

Article

May 1991

Procedures utilizing Chelex 100 chelating resin have been developed for extracting DNA from forensic-type samples for use with the PCR. The procedures are simple, rapid, involve no organic solvents and do not require multiple tube transfers for most types of samples. The extraction of DNA from semen and very small bloodstains using Chelex 100 is as efficient or more efficient than using proteinase K and phenol-chloroform extraction. DNA extracted from bloodstains seems less prone to contain PCR inhibitors when prepared by this method. The Chelex method has been used with amplification and typing at the HLA DQ alpha locus to obtain the DQ alpha genotypes of many different types of samples, including whole blood, bloodstains, seminal stains, buccal swabs, hair and post-coital samples. The results of a concordance study are presented in which the DQ alpha genotypes of 84 samples prepared using Chelex or using conventional phenol-chloroform extraction are compared. The genotypes obtained using the two different extraction methods were identical for all samples tested.

Sequence and gene organization of the chicken mitochondrial genome *1A novel gene order in higher vertebrates

Article

May 1990

The 16,775 base-pair mitochondrial genome of the white Leghorn chicken has been cloned and sequenced. The avian genome encodes the same set of genes (13 proteins, 2 rRNAs and 22 tRNAs) as do other vertebrate mitochondrial DNAs and is organized in a very similar economical fashion. There are very few intergenic nucleotides and several instances of overlaps between protein or tRNA genes. The protein genes are highly similar to their mammalian and amphibian counterparts and are translated according to the same variant genetic code. Despite these highly conserved features, the chicken mitochondrial genome displays two distinctive characteristics. First, it exhibits a novel gene order, the contiguous tRNA(Glu) and ND6 genes are located immediately adjacent to the displacement loop region of the molecule, just ahead of the contiguous tRNA(Pro), tRNA(Thr) and cytochrome b genes, which border the displacement loop region in other vertebrate mitochondrial genomes. This unusual gene order is conserved among the galliform birds. Second, a light-strand replication origin, equivalent to the conserved sequence found between the tRNA(Cys) and tRNA(Asn) genes in all vertebrate mitochondrial genomes sequenced thus far, is absent in the chicken genome. These observations indicate that galliform mitochondrial genomes departed from their mammalian and amphibian counterparts during the course of evolution of vertebrate species. These unexpected characteristics represent useful markers for investigating phylogenetic relationships at a higher taxonomic level.

Calibration of Mitochondrial DNA evolution in Gees

Article

Feb 1987

Mitochondrial DNA was purified from five American species of geese representing the genera Anser and Branta, which have fossil records. The results of electrophoretic comparisons of about 75 fragments per individual produced by 14 restriction enzymes imply that the mean extent of sequence divergence between species of Anser and Branta is about 9%. Fossil evidence suggests that these two groups of geese had a common ancestor 4-5 million years ago. Thus, the mean rate of sequence divergence in goose mitochondrial DNA is not far from 2% per million years, the value in mammals.

Evidence from molecular systematic for decreased avian diversification in the Pleistocene Epoch

Article

Jul 1995

Pleistocene glaciations have been suggested as major events influencing speciation rates in vertebrates. Avian paleontological studies suggest that most extant species evolved in the Pleistocene Epoch and that species' durations decreased through the Pleistocene because of heightened speciation rates. Molecular systematic studies provide another data base for testing these predictions. In particular, rates of diversification can be determined from molecular phylogenetic trees. For example, an increasing rate of speciation (but constant extinction) requires shorter intervals between successive speciation events on a phylogenetic tree. Examination of the cumulative distribution of reconstructed speciation events in mtDNA phylogenies of 11 avian genera, however, reveals longer intervals between successive speciation events as the present time is approached, suggesting a decrease in net diversification rate through the Pleistocene Epoch. Thus, molecular systematic studies do not indicate a pulse of Pleistocene diversification in passerine birds but suggest, instead, that diversification rates were lower in the Pleistocene than for the preceding period. Documented habitat shifts likely led to the decreased rate of diversification, although from molecular evidence we cannot discern whether speciation rates decreased or extinction rates increased.

Evolution in the High Andes: The Phylogenetics of Muscisaxicola Ground-Tyrants

Abstract

No full-text available

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