skip to main content


Title: Molecular systematics of the Amazonian endemic genus Hylexetastes (Aves: Dendrocolaptidae): taxonomic and conservation implications

Hylexetasteswoodcreepers are endemic to theterra firmeforests of the Amazon basin. Currently, most taxonomic sources recognize two species ofHylexetastes(H. perrotiiandH. stresemanni), each divided into three subspecies. Some authors maintain that theH. perrotiisubspecies should be elevated to full species status. In particular,Hylexetastes perrotii brigidaiis endemic to the eastern Amazon, the second Amazonian area of endemism (Xingu) most affected by deforestation and habitat degradation. Consequently, the taxonomic status ofH. p. brigidaiis of particular concern for conservation. Thus far, only morphological characters have been evaluated for the taxonomic delimitation of species and subspecies ofHylexetastes. We present a molecular phylogenetic analysis of all subspecies to help delimitHylexetastesinterspecific limits. Fragments of two mitochondrial (CytbandND2) and three nuclear genes (FGB5, G3PDHandMUSK) from 57Hylexetastesspecimens were sequenced. An ecological niche model was estimated to describe more accurately the potential distributions of taxa and to evaluate their vulnerability to ongoing deforestation. Phylogenetic analyses support the paraphyly of the polytypicH. perrotiias currently delimited and the elevation ofHylexetastes perrotii uniformisto full species rank, as well as the presence of three evolutionary significant units (ESUs) within this newly delimited species, including one grouping allH. p. brigidaispecimens. Alternatively, under lineage‐based species concepts, our results support at least five evolutionary species inHylexetastes:H. stresemanni,H. undulatus,H. perrotii,H. uniformisandH. brigidai. Each of these taxa andESUs are distributed in different interfluvial areas of the Amazon basin, which have different degrees of disturbance. Because they occupy the most heavily impacted region among allHylexetastesESUs, regular assessments of the conservation statuses ofH. p. brigidaiand bothH. uniformisESUs are paramount.

 
more » « less
NSF-PAR ID:
10081810
Author(s) / Creator(s):
 ;  ;  ;  ;  ;  ;  ;  
Publisher / Repository:
Wiley-Blackwell
Date Published:
Journal Name:
Ibis
Volume:
162
Issue:
1
ISSN:
0019-1019
Page Range / eLocation ID:
p. 119-136
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
More Like this
  1. Abstract Aim

    To test the importance of alternative diversification drivers and biogeographical processes for the evolution of Amazonian upland forest birds through a densely sampled analysis of diversification of the endemic Amazonian genusRhegmatorhinaat multiple taxonomic and temporal scales.

    Location

    Amazonia.

    Taxon

    Antbirds (Thamnophilidae).

    Methods

    We sequenced four mtDNAand nuclear gene regions of 120 individuals from 50 localities representing all recognized species and subspecies of the genus. We performed molecular phylogenetic analyses using both gene tree and species tree methods, molecular dating analysis and estimated population demographic history and gene flow.

    Results

    Dense sampling throughout the distribution ofRhegmatorhinarevealed that the main Amazonian rivers delimit the geographic distribution of taxa as inferred from mtDNAlineages. Molecular phylogenetic analyses resulted in a strongly supported phylogenetic hypothesis for the genus, with two main clades currently separated by the Madeira River. Molecular dating analysis indicated diversification during the Quaternary. Reconstruction of recent demographic history of populations revealed a trend for population expansion in eastern Amazonia and stability in the west. Estimates of gene flow corroborate the possibility that migration after divergence had some influence on the current patterns of diversity.

    Main Conclusions

    Based on broad‐scale sampling, a clarification of taxonomic boundaries, and strongly supported phylogenetic relationships, we confirm that, first, mitochondrial lineages within this upland forest Amazonian bird genus agree with spatial patterns known for decades based on phenotypes, and second, that most lineages are geographically delimited by the large Amazonian rivers. The association between past demographic changes related to palaeoclimatic cycles and the historically varying strength and size of rivers as barriers to dispersal may be the path to the answer to the long‐standing question of identifying the main drivers of Amazonian diversification.

     
    more » « less
  2. Abstract

    The systematics of the enigmatic and rather uncommon species ofSeaHayward andCybdelisBoisduval is assessed through morphological and molecular analyses. The aim of this paper is three‐fold: (i) to ascertain the phylogenetic position ofSeaandCybdelisin Biblidinae; (ii) to determine the evolutionary relationships among species ofSeaandCybdelis; and (iii) to review the taxonomy ofSeaandCybdelis. The result of the molecular analysis recoversSeasister toCybdelis, and this clade sister to Eubagina (sensu Lamas,), rendering Epicaliina (sensu Lamas,) paraphyletic. A new tribe, Cybdelinitrib.n.is erected to includeSeaandCybdelis; the other genera formerly included in Epicaliina (sensu Lamas,),EunicaHübner andSeveniaKoçak are assigned to Eunicinitrib.rest., and the remaining genera of Biblidinae to other previously recognized tribes, similar to those implicitly proposed by Wahlberget al. (). The morphological analysis recovers similar results and the following relationships among species ofCybdelis:C. phaesyla(Hübner) (C. bolivianaSalvin (C. mnasylusDoubleday (C. petronitaBurmeisterstat.rest.+C. thrasyllaC. Felder & R. Felderstat.rest.))).SeaandCybdelisare recognized as distinct genera; a new subspecies,S. sophronia jenkinsiDias, Siewert & Freitasssp.n., distributed from Venezuela to Bolivia along the Andes eastern foothills, is described; andC. petronitaandC. thrasyllaare accepted as valid species. Lectotypes forC. boliviana,C. peruvianaStaudinger,C. mnasylus, C. thrasylla,C. petronitaandC. mnasylusvar.meridionalisHall and a neotype forVanessa sophroniaGodart are designated. Additionally, dichotomous keys and distribution maps to all taxa are provided; male genitalia and hypandria are illustrated for all species; generic characters of the head, labial palpi and legs are illustrated; immature stages of some species also are figured.

    The published work has been registered on ZooBank:http://zoobank.org/urn:lsid:zoobank.org:pub:D8EBB649‐5E9D‐4218‐B1F1‐7A69DA775FD0.

     
    more » « less
  3. Abstract

    Nylanderia(Emery) is one of the world's most diverse ant genera, with 123 described species worldwide and hundreds more undescribed. Fifteen globetrotting or invasive species have widespread distributions and are often encountered outside their native ranges. A molecular approach to understanding the evolutionary history and to revision ofNylanderiataxonomy is needed because historical efforts based on morphology have proven insufficient to define major lineages and delimit species boundaries, especially where adventive species are concerned. To address these problems, we generated the first genus‐wide genomic dataset ofNylanderiausing ultraconserved elements (UCEs) to resolve the phylogeny of major lineages, determine the age and origin of the genus, and describe global biogeographical patterns. Sampling from seven biogeographical regions revealed a Southeast Asian origin ofNylanderiain the mid‐Eocene and four distinct biogeographical clades in the Nearctic, the Neotropics, the Afrotropics/Malagasy region, and Australasia. The Nearctic and Neotropical clades are distantly related, indicating two separate dispersal events to the Americas between the late Oligocene and early Miocene. We also addressed the problem of misidentification that has characterized species‐level taxonomy inNylanderiaas a result of limited morphological variation in the worker caste by evaluating the integrity of species boundaries in six of the most widespreadNylanderiaspecies. We sampled across ranges of species in theN. bourbonicacomplex (N. bourbonica(Forel) + N. vaga(Forel)), theN. fulvacomplex (N. fulva(Mayr) + N. pubens(Forel)), and theN. guatemalensiscomplex (N. guatemalensis(Forel) + N. steinheili(Forel)) to clarify their phylogenetic placement. Deep splits within these complexes suggest that some species names – specificallyN. bourbonicaandN. guatemalensis– each are applied to multiple cryptic species. In exhaustively samplingNylanderiadiversity in the West Indies, a ‘hot spot’ for invasive taxa, we found five adventive species among 22 in the region; many remain morphologically indistinguishable from one another, despite being distantly related. We stress that overcoming the taxonomic impediment through the use of molecular phylogeny and revisionary study is essential for conservation and invasive species management.

     
    more » « less
  4. Abstract

    The Cyclophyllidea is the most diverse order of tapeworms, encompassing species that infect all classes of terrestrial tetrapods including humans and domesticated animals. Available phylogenetic reconstructions based either on morphology or molecular data lack the resolution to allow scientists to either propose a solid taxonomy or infer evolutionary associations. Molecular markers available for the Cyclophyllidea mostly include ribosomalDNAand mitochondrial loci. In this study, we identified 3641 single‐copy nuclear coding loci by comparing the genomes ofHymenolepis microstoma,Echinococcus granulosusandTaenia solium. We designedRNAbaits based on the sequence ofH. microstoma, and applied target enrichment and Illumina sequencing to test the utility of those baits to recover loci useful for phylogenetic analyses. We capturedDNAfrom five species of tapeworms representing two families of cyclophyllideans. We obtained an average of 3284 (90%) of the targets from the test samples and then used captured sequences (2 181 361 bp in total; fragment size ranging from 301 to 6969 bp) to reconstruct a phylogeny for the five test species plus the three species for which genomic data are available. The results were consistent with the current consensus regarding cyclophyllidean relationships. To assess the potential for our method to yield informative genetic variation at intraspecific scales, we extracted 14 074 single nucleotide polymorphisms (SNPs) from alignments of fourArostrilepis macrocirrosaand twoA. cookiand successfully inferred their relationships. The results showed that our target gene tools yield data sets that provide robust inferences at a range of taxonomic scales in the Cyclophyllidea.

     
    more » « less
  5. Abstract

    The paleback darter,Etheostoma pallididorsum, is considered imperilled and has recently been petitioned for listing under the Endangered Species Act. Previous allozyme‐based studies found evidence of a small effective population size, warranting conservation concern. The objective of this study was to assess the population dynamics and the phylogeographical history of the paleback darter, using a multilocus microsatellite approach and mitochondrial DNA.

    The predictions of this study were that: paleback darter populations will exhibit low genetic diversity and minimal gene flow; population structure will correspond to the river systems from which the samples are derived; reservoir dams impounding the reaches between the Caddo and Ouachita rivers would serve as effective barriers to gene flow; and the Caddo and Ouachita rivers are reciprocally monophyletic.

    Microsatellite DNA loci revealed significant structure among sampled localities (globalFst= 0.17,P< 0.001), with evidence of two distinct populations representing the Caddo and Ouachita rivers. However, Bayesian phylogeographical analyses resulted in three distinct clades: Caddo River, Ouachita River, and Mazarn Creek. Divergence from the most recent ancestor shared among the river drainages was estimated at 60 Kya. Population genetic diversity was relatively low (He= 0.65; mean alleles per locus,A= 6.26), but was comparable with the population genetic diversity found in the close relatives slackwater darter,Etheostoma boschungi(He= 0.65;A= 6.74), and Tuscumbia darter,Etheostoma tuscumbia(He= 0.57;A= 5.53).

    These results have conservation implications for paleback darter populations and can be informative for other headwater specialist species. Like other headwater species with population structuring and relatively low genetic diversity, the persistence of paleback darter populations is likely to be tied to the persistence and connectivity of local breeding and non‐breeding habitat. These results do not raise conservation concern for a population decline; however, the restricted distribution and endemic status of the species still renders paleback darter populations vulnerable to extirpation or extinction.

     
    more » « less