Neotropical Biogeography Research Articles

The role of biogeographical barriers on the historical dynamics of passerine birds with a circum-Amazonian distribution.

Common distributional patterns have provided the foundations of our knowledge of Neotropical biogeography. A distinctive pattern is the "circum-Amazonian distribution", which surrounds Amazonia across the forested lowlands south and east of the basin, the Andean foothills, the Venezuelan Coastal Range, and the Tepuis. The underlying evolutionary and biogeographical mechanisms responsible for this widespread pattern of avian distribution have yet to be elucidated. Here, we test the effects of biogeographical barriers in four species in the passerine family Thamnophilidae by performing comparative demographic analyses of genome-scale data. Specifically, we used flanking regions of ultraconserved regions to estimate population historical parameters and genealogical trees and tested demographic models reflecting contrasting biogeographical scenarios explaining the circum-Amazonian distribution. We found that taxa with circum-Amazonian distribution have at least two main phylogeographical clusters: (1) Andes, often extending into Central America and the Tepuis; and (2) the remaining of their distribution. These clusters are connected through corridors along the Chaco-Cerrado and southeastern Amazonia, allowing gene flow between Andean and eastern South American populations. Demographic histories are consistent with Pleistocene climatic fluctuations having a strong influence on the diversification history of circum-Amazonian taxa, Refugia played a crucial role, enabling both phenotypic and genetic differentiation, yet maintaining substantial interconnectedness to keep considerable levels of gene flow during different dry/cool and warm/humid periods. Additionally, steep environmental gradients appear to play a critical role in maintaining both genetic and phenotypic structure.

The Miocene wetland of western Amazonia and its role in Neotropical biogeography

AbstractIn the Miocene (23–5 Ma), a large wetland known as the Pebas System characterized western Amazonia. During the Middle Miocene Climatic Optimum (c. 17–15 Ma), this system reached its maximum extent and was episodically connected to the Caribbean Sea, while receiving sediment input from the Andes in the west, and the craton (continental core) in the east. Towards the late Miocene (c. 10 Ma) the wetland transitioned into a fluvial-dominated system. In biogeographic models, the Pebas System is often considered in two contexts: one describing the system as a cradle of speciation for aquatic or semi-aquatic taxa such as reptiles, molluscs and ostracods, and the other describing the system as a barrier for dispersal and gene flow for amphibians and terrestrial taxa such as plants, insects and mammals. Here we highlight a third scenario in which the Pebas System is a permeable biogeographical system. This model is inspired by the geological record of the mid-Miocene wetland, which indicates that sediment deposition was cyclic and controlled by orbital forcing and sea-level change, with environmental conditions repeatedly altered. This dynamic landscape favoured biotic exchange at the interface of (1) aquatic and terrestrial, (2) brackish and freshwater and (3) eutrophic to oligotrophic conditions. In addition, the intermittent connections between western Amazonia and the Caribbean Sea, the Andes and eastern Amazonia favoured two-way migrations. Therefore, biotic exchange and adaptation was probably the norm, not the exception, in the Pebas System. The myriad of environmental conditions contributed to the Miocene Amazonian wetland system being one of the most species-rich systems in geological history.

Unravelling distribution patterns of Neotropical lianas: an analysis of endemicity of tribe Bignonieae (Bignoniaceae)

AbstractAreas of endemism characterize geographical regions by their unique biotas, providing the basis for studies on the ecological and historical drivers of these biologically distinct units. Tribe Bignonieae (Bignoniaceae) are a highly diverse clade of lianas distributed throughout the Neotropics, representing an excellent model for studying the drivers of species diversity and distribution patterns in this region. We used a dataset representing 98% of the diversity of Bignonieae and 21 170 unique locality records to perform an analysis of endemicity using NDM/VNDM. We recovered areas of endemism distributed across the Neotropics, including a higher number of areas at coarser spatial scales. Although overlapping and nested patterns of endemism were common and the spatial congruence with the individual units of previous regionalization schemes was low, the patterns of endemism recovered were in general agreement with those documented for other taxa. Our findings are generally consistent with key Neotropical biogeographical hypotheses. These results highlight the importance of studying detailed distribution patterns of selected taxa for an improved understanding of Neotropical biogeography.

Solving the cryptic diversity of the genus Manerebia Staudinger in northern Peru: description of new species and considerations on the biogeographical role of the Huancabamba Deflection (Nymphalidae: Satyrinae: Pronophilina).

The Huancabamba Deflection in the Andes of northern Peru and southern Ecuador is a pivotal area for Neotropical biogeography, where exceptional biodiversity coincides with high rates of endemism. These characteristics are well illustrated within the montane butterfly genus Manerebia Staudinger (Nymphalidae, Satyrinae). Here, six new, apparently endemic species, and two new subspecies, are described from this region: M. inducta Pyrcz Willmott n. sp., M. ronda Pyrcz Boyer, n. sp., M. ronda amplia Pyrcz Boyer, n. ssp., M. punku Pyrcz Farfn n. sp., M. huamanii Cerdea Pyrcz n. sp., M. placida Pyrcz Willmott n. sp., M. granatus Willmott, Radford Pyrcz n. sp. and M. prattorum udima Pyrcz Boyer, n. ssp. A total of 22 species of Manerebia is reported from the study region, as much as half the total number of species in this genus distributed throughout the tropical Andes. The alpha-taxonomy of Manerebia is particularly demanding, as colour patterns have apparently converged among different species making identification virtually impossible in some cases without comparison of their genitalia, which prove taxonomically and phylogenetically highly valuable. On the other hand, several species differ markedly in wing colour patterns and occur at different elevations but have identical genitalia. Furthermore, our data show that DNA barcoding is only partly viable as an alpha-taxonomic tool, as some markedly different species of Manerebia, in terms of external morphology and ecological preferences, are genetically not separable using only COI markers. On the other hand, several species barely differing morphologically are identified based on barcode. Barcodes of 26 species, including 18 from the northern Andes, are studied here, showing strong differences within some taxa previously considered conspecific based on morphological characters, suggesting that their taxonomic status needs to be re-evaluated. In particular, M. trimaculata and the widely distributed polytypic M. inderena may be highly variable species or complexes of several species. A total of 16 species are found north of the Chamaya valley in southern Ecuador and extreme northern Peru, compared to 14 species south of it in northern Peru. The faunal (Jaccard) similarity coefficient of the two adjacent regions is low (0.3), reflecting the role of the Huancabamba Deflection as a biogeographical barrier.

Whiptail lizard lineage delimitation and population expansion as windows into the history of Amazonian open ecosystems

Historical variations in climate and landscape configuration are the main aspects known to generate and maintain diversity. Taxa associated with open habitats within broader forest contexts are often overlooked in studies of Neotropical biogeography. We investigated the evolutionary and demographic history of lizards in the Cnemidophorus lemniscatus species group, which encompasses three described species – one unisexual and two bisexuals – restricted to open environments in Amazonia. We also explored the geographic ecology of the group using critical ecophysiological traits as proxies for sensitivity or resilience to environmental change. To that end, we delimited the main lineages within the group, estimated their divergence times, and asked if these lineages have experienced changes in effective population size. We recovered six lineages, three of which correspond to C. cryptus, C. lemniscatus, and C. gramivagus, and three yet unnamed species. We recovered divergence events during the Late Miocene and signs of recent population expansion for at least one of the species (the parthenogenetic C. cryptus). This pattern corroborates the ancient emergence of the Amazonian open areas, followed by a high and recent dynamism during the Pleistocene. Conserved traits related to high thermal tolerance and broad thermal tolerance ranges likely facilitated niche tracking and establishment in open ecosystems during Pleistocene climatic fluctuations. Our results bring insights regarding how these species might be influenced, and even favoured, by human-induced environmental changes in the contemporary timescale.

Historical biogeography of Vochysiaceae reveals an unexpected perspective of plant evolution in the Neotropics.

Despite the fast pace of exploration of the patterns and processes influencing Neotropical plant hyperdiversity, the taxa explored are mostly from large groups that are widely distributed, morphologically diverse, or economically important. Vochysiaceae is an example of an undersampled taxon, providing an excellent system for investigating Neotropical biogeography. We present a phylogenomics-based hypothesis of species relationships in Vochysiaceae to investigate its evolutionary history through space and time. We inferred a phylogeny for 122 species from Vochysiaceae and seven other families of Myrtales. Fossils from four myrtalean families were used to estimate the divergence times within Vochysiaceae. Historical biogeography was estimated using ancestral range probabilities and stochastic mapping. Monophyly of all genera was supported except for Qualea, which was split by Ruizterania into two clades. Vochysiaceae originated ~100 mya, splitting into an Afrotropical and a Neotropical lineage ~50 mya, and its ancestral range is in the area currently occupied by the Cerrado. The most recent common ancestor of Vochysiaceae + Myrtaceae had a West Gondwanan distribution, supporting a South American + African ancestral range of Vochysiaceae. On a global scale, geographic range reduction was the principal biogeographic event. At a finer scale, initial range reduction was also important and the Cerrado region was the most ancestral area with multiple colonization events to the Amazon, Central America, and the Atlantic Forest. Colonization events occurred from open areas to forest vegetation, an unusual finding regarding the evolution of plants in the Neotropics.

Phylogenetic inference in section Archerythroxylum informs taxonomy, biogeography, and the domestication of coca (Erythroxylum species).

This investigation establishes the first DNA-sequence-based phylogenetic hypothesis of species relationships in the coca family (Erythroxylaceae) and presents its implications for the intrageneric taxonomy and neotropical biogeography of Erythroxylum. We also identify the closest wild relatives and evolutionary relationships of the cultivated coca taxa. We focused our phylogenomic inference on the largest taxonomic section in the genus Erythroxylum (Archerythroxylum O.E.Schulz) using concatenation and gene tree reconciliation methods from hybridization-based target capture of 427 genes. We show that neotropical Erythroxylum are monophyletic within the paleotropical lineages, yet Archerythroxylum and all of the other taxonomic sections from which we sampled multiple species lack monophyly. We mapped phytogeographic states onto the tree and found some concordance between these regions and clades. The wild species E. gracilipes and E. cataractarum are most closely related to the cultivated E. coca and E. novogranatense, but relationships within this "coca" clade remain equivocal. Our results point to the difficulty of morphology-based intrageneric classification in this clade and highlight the importance of integrative taxonomy in future systematic revisions. We can confidently identify E. gracilipes and E. cataractarum as the closest wild relatives of the coca taxa, but understanding the domestication history of this crop will require more thorough phylogeographic analysis.

The hidden anatomy of paranasal sinuses reveals biogeographically distinct morphotypes in the nine-banded armadillo (Dasypus novemcinctus).

BackgroundWith their Pan-American distribution, long-nosed armadillos (genus Dasypus) constitute an understudied model for Neotropical biogeography. This genus currently comprises seven recognized species, the nine-banded armadillo (D. novemcinctus) having the widest distribution ranging from Northern Argentina to the South-Eastern US. With their broad diversity of habitats, nine-banded armadillos provide a useful model to explore the effects of climatic and biogeographic events on morphological diversity at a continental scale.MethodsBased on a sample of 136 skulls of Dasypus spp. belonging to six species, including 112 specimens identified as D. novemcinctus, we studied the diversity and pattern of variation of paranasal cavities, which were reconstructed virtually using µCT-scanning or observed through bone transparency.ResultsOur qualitative analyses of paranasal sinuses and recesses successfully retrieved a taxonomic differentiation between the traditional species D. kappleri, D. pilosus and D. novemcinctus but failed to recover diagnostic features between the disputed and morphologically similar D. septemcinctus and D. hybridus. Most interestingly, the high variation detected in our large sample of D. novemcinctus showed a clear geographical patterning, with the recognition of three well-separated morphotypes: one ranging from North and Central America and parts of northern South America west of the Andes, one distributed across the Amazonian Basin and central South America, and one restricted to the Guiana Shield.DiscussionThe question as to whether these paranasal morphotypes may represent previously unrecognized species is to be evaluated through a thorough revision of the Dasypus species complex integrating molecular and morphological data. Remarkably, our recognition of a distinct morphotype in the Guiana Shield area is congruent with the recent discovery of a divergent mitogenomic lineage in French Guiana. The inflation of the second medialmost pair of caudal frontal sinuses constitutes an unexpected morphological diagnostic feature for this potentially distinct species. Our results demonstrate the benefits of studying overlooked internal morphological structures in supposedly cryptic species revealed by molecular data. It also illustrates the under-exploited potential of the highly variable paranasal sinuses of armadillos for systematic studies.

Phylogeny, classification, and fruit evolution of the species-rich Neotropical bellflowers (Campanulaceae: Lobelioideae).

• The species-rich Neotropical genera Centropogon, Burmeistera, and Siphocampylus represent more than half of the ∼1200 species in the subfamily Lobelioideae (Campanulaceae). They exhibit remarkable morphological variation in floral morphology and habit. Limited taxon sampling and phylogenetic resolution, however, obscures our understanding of relationships between and within these genera and underscores our uncertainty of the systematic value of fruit type as a major diagnostic character.• We inferred a phylogeny from five plastid DNA regions (rpl32-trnL, ndhF-rpl32, rps16-trnK, trnG-trnG-trns, rbcL) using maximum-likelihood and Bayesian inference. Ancestral character reconstructions were applied to infer patterns of fruit evolution.• Our results demonstrate that the majority of species in the genera Centropogon, Burmeistera, and Siphocampylus together form a primarily mainland Neotropical clade, collectively termed the "centropogonids." Caribbean Siphocampylus, however, group with other Caribbean lobelioid species. We find high support for the monophyly of Burmeistera and the polyphyly of Centropogon and mainland Siphocampylus. The ancestral fruit type of the centropogonids is a capsule; berries have evolved independently multiple times.• Our plastid phylogeny greatly improves the phylogenetic resolution within Neotropical Lobelioideae and highlights the need for taxonomic revisions in the subfamily. Inference of ancestral character states identifies a dynamic pattern of fruit evolution within the centropogonids, emphasizing the difficulty of diagnosing broad taxonomic groups on the basis of fruit type. Finally, we identify that the centropogonids, Lysipomia, and Lobelia section Tupa form a Pan-Andean radiation with broad habitat diversity. This clade is a prime candidate for investigations of Neotropical biogeography and morphological evolution.

IBS Doctoral Dissertation Award

ISSN 1948-6596 Announcements IBS Doctoral Dissertation Award Since 2013, the IBS makes a periodic award for the best doctoral dissertation, as judged from thesis abstracts submitted to Frontiers of Biogeography by an Early Career Researcher (up to 2 years after graduation from a PhD program). The Early Career Committee and Frontiers of Biogeography editors evaluate all thesis abs- tracts submitted for publication in Frontiers of Biogeography following the journal’s usual peer- review process; authors should state their interest to be considered for the award in their cover let- ter. The recipient of the award will be invited to present their thesis research at the biennial Early Career Conference and will receive a commemo- rative plate and monetary award to subsidize tra- vel expenses to the Early Career Conference. We are pleased to announce that the reci- pient of the 2013 Doctoral Dissertation Award has been Matthew Iacchei, from the Department of Oceanography, School of Ocean and Earth Science and Technology, University of Hawai‘i at Mānoa (Honolulu, USA), for his PhD entitled “Population genetic and phylogenetic insights into the phyllo- somal odyssey.” An honourable mention was granted to Dr. Jesse Morris from the Department of Geography, Kansas State University (USA), for his PhD synopsis “Using lake sediment records to reconstruct bark beetle disturbances in western North America .” More information about the IBS awards can be found at: http://www.biogeography.org/html/ About%20IBS/awards.html. Leticia Ochoa-Ochoa IBS Student-at-large If you want to announce a meeting, event or job offer that could be of interest for (some) bio- geographers, or you want to make a call for manuscripts or talks, please contact us at ibs@mncn.csic.es and frontiersofbiogeography@gmail.com. upcoming events IBS Special Meeting on the Geography of Species Associations 15–17 November 2013 – Montreal, Canada International Statistical Ecology Conference http://ibsmontreal.webs.com/ 28 June–4 July 2014 – Montpellier, France http://isec2014.sciencesconf.org/ IBS Early Career Conference 2014 7–11 January 2014 – Canberra, Australia 7th International Conference of the IBS http://www.biogeography.org/ January 2015 – Bayreuth, Germany http://www.biogeography.org/ 3rd Meeting of the Network for Neotropical Biogeography January 2014 – Bogota, Colombia http://nnb.myspecies.info/ To post jobs, advertisements, or other announcements please contact the Frontiers of Biogeography editoral office (frontiersofbiogeography@googlemail.com). Advertisements are $50 per quarter page for professional or institutional positions. Announcements are free to members for vacancies in their lab. All advertisements and announcements also appear at no additional cost on the IBS facebook pa- ge (in abbreviated form) and on the IBS Blog (in long, or longer form). frontiers of biogeography 5.3, 2013 — © 2013 the authors; journal compilation © 2013 The International Biogeography Society

Phylogeography of Neotropical trees

Special issue editorial. Freely available on the publisher's website - access full text via the Official URL link.

Molecular systematics and historical biogeography of tree boas (Corallus spp.)

Inferring the evolutionary and biogeographic history of taxa occurring in a particular region is one way to determine the processes by which the biodiversity of that region originated. Tree boas of the genus Corallus are an ancient clade and occur throughout Central and South America and the Lesser Antilles, making it an excellent group for investigating Neotropical biogeography. Using sequenced portions of two mitochondrial and three nuclear loci for individuals of all recognized species of Corallus, we infer phylogenetic relationships, present the first molecular analysis of the phylogenetic placement of the enigmatic C. cropanii, develop a time-calibrated phylogeny, and explore the biogeographic history of the genus. We found that Corallus diversified within mainland South America, via over-water dispersals to the Lesser Antilles and Central America, and via the traditionally recognized Panamanian land bridge. Divergence time estimates reject the South American Caribbean-Track as a general biogeographic model for Corallus and implicate a role for events during the Oligocene and Miocene in diversification such as marine incursions and the uplift of the Andes. Our findings also suggest that recognition of the island endemic species, C. grenadensis and C. cookii, is questionable as they are nested within the widely distributed species, C. hortulanus. Our results highlight the importance of using widespread taxa when forming and testing biogeographic hypotheses in complex regions and further illustrate the difficulty of forming broadly applicable hypotheses regarding patterns of diversification in the Neotropical region.

Conference program and abstracts. International Biogeography Society 6th Biennial Meeting – 9-13 January 2013, Miami, Florida, USA

Proceedings of the Sixth biennial conference of the International Biogeography Society, an international and interdisciplinary society contributing to the advancement of all studies of the geography of nature. Held at Miami, Florida, USA, 9 – 13 January 2013.Abstracts include:(i) the Opening, MacArthur & Wilson Award and Alfred Russel Award Plenary Lectures;(ii) four symposia entitled "Island Biogeography: New Syntheses", "Beyond Bergmann: New perspectives on the biogeography of traits", "The Convergence of Conservation Paleontology and Biogeography" and "Predicting species and biodiversity in a warmer world: are we doing a good job?";(iii) oral presentations from contributed papers on Phylogeography, Marine Biogeography, Biogeography of the Anthropocene, Hot Topics in biogeography, Island Biogeography, Neotropical Biogeography, Global Change Biogeography, Historical and Paleo-biogeography, Conservation Biogeography and Global-Scale Biogeography; and(iv) contributions presented as posters on Phylogeography, Geospatial techniques and land cover, Biodiversity gradients and macroecology, Biogeography of traits, Island Biogeography, Neotropical Biogeography, Conservation Biogeography, Disturbance and Disease Biogeography, Climate Change Biogeography and Historical and Paleo-Biogeography.

Evolutionary history of bulldog bats (genusNoctilio): recent diversification and the role of the Caribbean in Neotropical biogeography

We present phylogenetic relationships and phylogeographic patterns of the two species of bulldog bats, genus Noctilio. Using a comprehensive sampling of 118 individuals throughout the species distribution, we investigated the distribution of molecular variation in one nuclear and two mitochondrial markers. Phylogenetic trees do not recover Noctilio albiventris as a monophyletic group and point to three similar-age intraspecific genetic lineages, suggesting cryptic diversity in this taxon. These lineages correspond to the subspecies previously proposed, and are strongly associated with major river basins in South America. Analyses also suggest a very recent origin for the fishing bat Noctilio leporinus, which probably originates from N. albiventris, with a population expansion corresponding to its invasion in South America. Based on our analysis, the speciation event was dated in the Pleistocene epoch and seems to be associated with the variation of the sea level in the Caribbean islands. The present work indicates how phylogeographic studies support the identification of independent evolutionary lineages, driving new systematic/taxonomic investigations, while at the same time shed light on the role of the Caribbean in shaping Neotropical bat fauna diversity.

Concordant Phylogeographies of 2 Malaria Vectors Attest to Common Spatial and Demographic Histories

The phylogeography of South American lineages is a topic of heated debate. Although a single process is unlikely to describe entire ecosystems, related species, which incur similar habitat limitations, can inform the history for a subsection of assemblages. We compared the phylogeographic patterns of the cytochrome oxidase I marker from Anopheles triannulatus (N = 72) and previous results for A. darlingi (N = 126) in a broad portion of their South American distributions. Both species share similar population subdivisions, with aggregations northeast of the Amazon River, in southern coastal Brazil and 2 regions in central Brazil. The average capital EF, Cyrillic(ST) between these groups was 0.39 for A. triannulatus. Populations northeast of the Amazon and in southeastern Brazil are generally reciprocally monophyletic to the remaining groups. Based on these initial analyses, we constructed the a priori hypothesis that the Amazon and regions of high declivity pose geographic barriers to dispersal in these taxa. Mantel tests confirmed that these areas block gene flow for more than 1000 km for both species. The efficacy of these impediments was tested using landscape genetics, which could not reject our a priori hypothesis but did reject simpler scenarios. Results form summary statistics and phylogenetics suggest that both lineages originated in central Amazonia (south of the Amazon River) during the late Pleistocene (579 000 years ago) and that they followed the same paths of expansion into their contemporary distributions. These results may have implications for other species sharing similar ecological limitations but probably are not applicable as a general paradigm of Neotropical biogeography.

Phylogeny and temporal diversification of Calomys (Rodentia, Sigmodontinae): Implications for the biogeography of an endemic genus of the open/dry biomes of South America

A thorough analysis of character evolution and biogeography of a group is only possible with a comprehensive sampling of its diversity. The sigmodontine genus Calomys is particularly interesting for the study of neotropical biogeography as it occurs exclusively in the dry and grassland biomes: Cerrado, Caatinga, Chaco, Pampas, Venezuelan Llanos, Puna, and a diversity of dry forests biomes. Although Brazil encompasses a large part of the geographic distribution of the genus and at least three endemic species, the last published phylogeny of Calomys included only two specimens (both representing the same species) from a single locality in this country. In the present paper we add complete cytochrome b sequences of Brazilian karyomorphs to previously published sequences in order to provide a phylogenetic hypothesis including most of the genus diversity. The main objectives of this study were to clarify taxonomic issues related to Brazilian karyomorphs and to study the diversification processes of the genus by analyzing its biogeography in combination with cladogenesis dates estimated with a molecular clock. The phylogeny indicates that at least six different species inhabit the Brazilian territory, one of them still undescribed. Date estimates indicate that two sequential basal splits, the first separating Andean from lowland species and the second isolating species north and south of the Amazonia, took place in the Pliocene between 3 and 4 Ma. A large-bodied and speciose clade of lowland species associated with dry forests and ecotones of the core Cerrado and Chaco areas with adjacent biomes diversified in the Pleistocene. This indicates the importance of safeguarding ecotones and the Cerrado at a time where this biome is being rapidly destroyed.

Historical biogeography and diversification within the Neotropical parrot genus Pionopsitta (Aves: Psittacidae)

AbstractAim We investigate spatial and temporal patterns of diversification within the Neotropical avifauna using the phylogenetic history of parrots traditionally belonging to the genus Pionopsitta Bonaparte 1854. This genus has long been of interest for those studying Neotropical biogeography and diversity, as it encompasses species that occur in most Neotropical forest areas of endemism.Location The Neotropical lowland forests in South and Central America.Methods Phylogenetic relationships were investigated for all species of the genus Pionopsitta and five other short‐tailed parrot genera using complete sequences of the mitochondrial genes cyt b and ND2 as well as 26 plumage characters. The resulting phylogeny was used to test the monophyly of the genus, investigate species limits, and as a framework for reconstructing their historical biogeography and patterns of diversification.Results We found that the genus Pionopsitta, as previously defined, is not monophyletic and thus the Chocó, Central American and Amazonian species will now have to be placed in the genus Gypopsitta. The molecular and morphological phylogenies are largely congruent, but disagree on the position of one of the Amazon basin taxa. Using molecular sequence data, we estimate that species within Gypopsitta diversified between 8.7 and 0.6 Ma, with the main divergences occurring between 3.3 and 6.4 Ma. These temporal results are compared to other taxa showing similar vicariance patterns.Main conclusions The results suggest that diversification in Gypopsitta was influenced mainly by geotectonic events, marine transgressions and river dynamics, whereas Quaternary glacial cycles of forest change seem to have played a minor role in the origination of the currently recognized species.

Phylogeny of the Neotropical Killifish Family Rivulidae (Cyprinodontiformes, Aplocheiloidei) Inferred from Mitochondrial DNA Sequences

Phylogenetic relationships of 70 taxa representing 68 species of the Neotropical killifish family Rivulidae were derived from analysis of 1516 nucleotides sampled from four different segments of the mitochondrial genome: 12S rRNA, 16S rRNA, cytochrome oxidase I, and cytochrome b. The basal bifurcation of Cynolebiatinae and Rivulinae (Costa, 1990a,b) is supported; however, Terranatos, Maratecoara, and Plesiolebias are rivulins, not cynolebiatins. These three genera, along with the other recognized annual rivulin genera, form a monophyletic clade. Austrofundulus, Rachovia, Renova, Terranatos, and 3 species of the genus Pterolebias, all from northeastern South America, form a monophyletic clade excluding other species of Pterolebias. Pterolebias as presently understood is clearly polyphyletic. Trigonectes and Moema are supported as sister groups but do not form a monophyletic group with the genera Neofundulus and Renova as previously proposed. The suite of adaptations necessary for an annual life history has clearly been lost several times in the course of rivulid evolution. Also revealed is a considerable increase in substitution rate in most annual lineages relative to the nonannual Rivulus species. The widespread and speciose genus Rivulus is paraphyletic, representing both basal and terminal clades within the Rivulidae. Previous hypotheses regarding the vicariant origin of Greater Antillean Rivulus species are supported. Most rivulid clades show considerable endemism; thus, detailed analysis of rivulid phylogeny and distribution will contribute robust hypotheses to the clarification of Neotropical biogeography.

Phylogeography of the bushmaster (Lachesis muta: Viperidae): implications for neotropical biogeography, systematics, and conservation

We used mitochondrial gene sequences to reconstruct phylogenetic relationships among subspecies of the bushmaster, Lachesis muta. These large vipers are widely distributed in lowland tropical forests in Central and South America, where three of four allopatric subspecies are separated by montane barriers. Our phylogeny indicates that the four subspecies belong to two clades, the Central American and South American lineages. We use published molecular studies of other taxa to estimate a ‘reptilian mtDNA rate’ and thus temporal boundaries for major lineage divergences in Lachesis. We estimate that the Central and South American forms diverged 18-6 Mya, perhaps due to the uplifting of the Andes, whereas the two Central American subspecies may have diverged 11-4 Mya with the uprising of the Cordillera de Talamanca that separates them today. South American bushmasters from the Amazon Basin and the Atlantic Forest are not strongly differentiated, perhaps due to episodic gene flow during the Pleistocene, when suitable habitat for this species was at times more continuous. Our results agree with previous evidence that genetic divergence among some neotropical vertebrates pre-dated Pleistocene forest fragmentation cycles and the appearance of the Panamanian Isthmus. Based on morphological, behavioral, and molecular evidence, we recognize three species of Lachesis. In addition to L. muta, the widespread South American form, the Central American forms are treated as distinct species (L. meknocephak and L. stenophrys), each deserving of special conservation status due to restricted distribution and habitat destruction.

Phylogeography of the bushmaster (Lachesis muta: Viperidae): implications for neotropical biogeography, systematics, and conservation

We used mitochondrial gene sequences to reconstruct phylogenetic relationships among subspecies of the bushmaster,Lachesis muta. These large vipers are widely distributed in lowland tropical forests in Central and South America, where three of four allopatric subspecies are separated by montane barriers. Our phylogeny indicates that the four subspecies belong to two clades, the Central American and South American lineages. We use published molecular studies of other taxa to estimate a «reptilian mtDNA rate» and thus temporal boundaries for major lineage divergences inLachesis. We estimate that the Central and South American forms diverged 18–6 Mya, perhaps due to the uplifting of the Andes, whereas the two Central American subspecies may have diverged 11–4 Mya with the uprising of the Cordillera de Talamanca that separates them today. South American bushmasters from the Amazon Basin and the Atlantic Forest are not strongly differentiated, perhaps due to episodic gene flow during the Pleistocene, when suitable habitat for this species was at times more continuous. Our results agree with previous evidence that genetic divergence among some neotropical vertebrates pre-dated Pleistocene forest fragmentation cycles and the appearance of the Panamanian Isthmus. Based on morphological, behavioral, and molecular evidence, we recognize three species ofLachesis. In addition toL. muta, the widespread South American form, the Central American forms are treated as distinct species (L. melanocephalaandL. stenophrys), each deserving of special conservation status due to restricted distribution and habitat destruction.