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Species delimitation

James Starrett, Shahan Derkarabetian, Marshal Hedin, Robert W Bryson, John E McCormack, Brant C Faircloth
Arachnida is an ancient, diverse, and ecologically important animal group that contains a number of species of interest for medical, agricultural, and engineering applications. Despite their importance, many aspects of the arachnid tree of life remain unresolved, hindering comparative approaches to arachnid biology. Biologists have made considerable efforts to resolve the arachnid phylogeny; yet, limited and challenging morphological characters, as well as a dearth of genetic resources, have hindered progress...
October 21, 2016: Molecular Ecology Resources
Nhu Nguyen, Else C Vellinga, Thomas D Bruns, Peter Kennedy
The genus Suillus represents one of the most recognizable groups of mushrooms in conifer forests throughout the Northern Hemisphere. Although for decades the genus has been relatively well defined morphologically, previous molecular phylogenetic assessments have provided important yet preliminary insights into its evolutionary history. Here we present the first large-scale phylogenetic study of the boundaries of each species in the genus Suillus based on the most current internal transcribed spacer (ITS) barcode sequences available in public databases, as well as sequencing of 224 vouchered specimens and cultures, 15 of which were type specimens from North America...
October 19, 2016: Mycologia
Xianghua Wang, Seppo Huhtinen, Karen Hansen
Species limits in the small genus Geopyxis are debatable because of problems with interpreting the few phenotypic features and poor documentation of types. To clarify species boundaries and diversity, we studied the morphology of 74 specimens of Geopyxis from the Northern Hemisphere, including five types, and sequenced four loci for 57 representatives: the nuc rDNA ITS1-5.8S-ITS2 (ITS), D1-D2 domains of nuc 28S rDNA (28S), translation elongation factor (tef1), and (or) part of the second largest subunit of the RNA polymerase II (rpb2) (5-7 region)...
October 19, 2016: Mycologia
Paul M Hime, Scott Hotaling, Richard E Grewelle, Eric M O'Neill, S Randal Voss, H Bradley Shaffer, David W Weisrock
Perhaps the most important recent advance in species delimitation has been the development of model-based approaches to objectively diagnose species diversity from genetic data. Additionally, the growing accessibility of next-generation sequence datasets provides powerful insights into genome-wide patterns of divergence during speciation. However, applying complex models to large datasets is time consuming and computationally costly, requiring careful consideration of the influence of both individual and population sampling, as well as the number and informativeness of loci on species delimitation conclusions...
October 17, 2016: Molecular Ecology
Benjamin E Carter, Juan Larraín, Alžběta Manukjanová, Blanka Shaw, A Jonathan Shaw, Jochen Heinrichs, Peter de Lange, Monica Suleiman, Louis Thouvenot, Matt von Konrat
Frullania subgenus Microfrullania is a clade of ca. 15 liverwort species occurring in Australasia, Malesia, and southern South America. We used combined nuclear and chloroplast sequence data from 265 ingroup accessions to test species circumscriptions and estimate the biogeographic history of the subgenus. With dense infra-specific sampling, we document an important role of long-distance dispersal in establishing phylogeographic patterns of extant species. At deeper time scales, a combination of phylogenetic analyses, divergence time estimation and ancestral range estimation were used to reject vicariance and to document the role of long-distance dispersal in explaining the evolution and biogeography of the clade across the southern Hemisphere...
October 13, 2016: Molecular Phylogenetics and Evolution
Sereina Rutschmann, Harald Detering, Sabrina Simon, David H Funk, Jean-Luc Gattolliat, Samantha J Hughes, Pedro M Raposeiro, Rob DeSalle, Michel Sartori, Michael T Monaghan
The study of processes driving diversification requires a fully sampled and well resolved phylogeny. Multilocus approaches to the study of recent diversification provide a powerful means to study the evolutionary process, but their application remains restricted because multiple unlinked loci with suitable variation for phylogenetic or coalescent analysis are not available for most non-model taxa. Here we identify novel, putative single-copy nuclear DNA (nDNA) phylogenetic markers to study the colonization and diversification of an aquatic insect species complex, Cloeon dipterum L...
October 11, 2016: Molecular Phylogenetics and Evolution
Steven D Leavitt, Theodore L Esslinger, Pradeep K Divakar, Ana Crespo, H Thorsten Lumbsch
Molecular data provide unprecedented insight into diversity of lichenized fungi, although morphologically cryptic species-level lineages circumscribed from sequence data often remain undescribed even in well-studies groups. Using diagnostic characters from DNA sequence data and support from the multispecies coalescent model, we formally describe a total of eleven new species and resurrect two others in the hyperdiverse lichen-forming fungal family Parmeliaceae. These include: four in the genus Melanelixia - M...
November 2016: Fungal Biology
Daniel Poveda-Martínez, Chrystian C Sosa, Katherine Chacón-Vargas, Víctor Hugo García-Merchán
Characidium is a Neotropical fish genus. Its distribution ranges from eastern Panama to northern Argentina, and it is an important component of the Neotropical ichthyofauna present in the major rivers of South America. We here provide an approximation to the dispersal and historical distributions of Characidium. The biogeographic history of five species of the genus was analyzed through nuclear RAG-2 and mitochondrial 16S genes and a time-calibrated phylogenetic analysis using three outgroup species. A biogeographical reconstruction was performed to estimate ancestral geographic ranges and infer the historical events that impacted the geographic distributions of Characidium species...
2016: PloS One
John-Erich Haight, Gary A Laursen, Jessie A Glaeser, D Lee Taylor
Fungal species with a broad distribution may exhibit considerable genetic variation over their geographic ranges. Variation may develop among populations based on geographic isolation, lack of migration, and genetic drift, though this genetic variation may not always be evident when examining phenotypic characters. Fomitopsis pinicola is an abundant saprotrophic fungus found on decaying logs throughout temperate regions of the Northern Hemisphere. Phylogenetic studies have addressed the relationship of F. pinicola to other wood-rotting fungi, but pan-continental variation within F...
September 2016: Mycologia
Zhaofu Yang, Jean-François Landry, Paul D N Hebert
Although members of the crambid subfamily Pyraustinae are frequently important crop pests, their identification is often difficult because many species lack conspicuous diagnostic morphological characters. DNA barcoding employs sequence diversity in a short standardized gene region to facilitate specimen identifications and species discovery. This study provides a DNA barcode reference library for North American pyraustines based upon the analysis of 1589 sequences recovered from 137 nominal species, 87% of the fauna...
2016: PloS One
Martina Réblová, Vit Hubka, Olle Thureborn, Johannes Lundberg, Therese Sallstedt, Mats Wedin, Magnus Ivarsson
Rock-inhabiting fungi harbour species-rich, poorly differentiated, extremophilic taxa of polyphyletic origin. Their closest relatives are often well-known species from various biotopes with significant pathogenic potential. Speleothems represent a unique rock-dwelling habitat, whose mycobiota are largely unexplored. Isolation of fungi from speleothem biofilm covering bare granite walls in the Kungsträdgården metro station in Stockholm yielded axenic cultures of two distinct black yeast morphotypes. Phylogenetic analyses of DNA sequences from six nuclear loci, ITS, nuc18S and nuc28S rDNA, rpb1, rpb2 and β-tubulin, support their placement in the Chaetothyriales (Ascomycota)...
2016: PloS One
Israel Estrada-Contreras, Miguel Equihua, Javier Laborde, Enrique Martínez Meyer, Lázaro R Sánchez-Velásquez
Climate change is recognized as an important threat to global biodiversity because it increases the risk of extinction of many species on the planet. Mexico is a megadiverse country and native tree species such as red cedar (Cedrela odorata) can be used to maintain forests while helping mitigate climate change, because it is considered a fast growing pioneer species with great economic potential in the forestry industry. In order to assess possible shifts in areas suitable for C. odorata plantations in Mexico with ecological niche models, we used the MaxLike algorithm, climate variables, the geo-referenced records of this species, three general circulation models and three scenarios of future emissions...
2016: PloS One
Adrián Nieto-Montes de Oca, Anthony J Barley, Rubi N Meza-Lázaro, Uri O García-Vázquez, Joan G Zamora-Abrego, Robert C Thomson, Adam D Leaché
Middle American knob-scaled lizards of the genus Xenosaurus are a unique radiation of viviparous species that are generally characterized by a flattened body shape and a crevice-dwelling ecology. Only eight species of Xenosaurus, one of them with five subspecies (X. grandis), have been formally described. However, species limits within Xenosaurus have never been examined using molecular data, and no complete phylogeny of the genus has been published. Here, we used ddRADseq data from all of the described and potentially undescribed taxa of Xenosaurus to investigate species limits, and to obtain a phylogenetic hypothesis for the genus...
October 5, 2016: Molecular Phylogenetics and Evolution
Jorge M Lobo
Experimental information on the roles played by climatic factors in determining the ecology and distribution of insect species is scarce. This has stimulated the increasing use of the climatic characteristics of the localities in which the species are observed to derive predictions under different climatic scenarios (the so called species-distribution models or SDMs). This text reviews the main limitations of these correlative models when they are applied to organisms, such as insects, that are characterized by a high degree of collector bias and incompleteness...
October 2016: Current Opinion in Insect Science
Shinri Tomioka, Tomohiko Kondoh, Waka Sato-Okoshi, Katsutoshi Ito, Keiichi Kakui, Hiroshi Kajihara
Capitella teleta Blake et al., 2009 is an opportunistic capitellid originally described from Massachusetts (USA), but also reported from the Mediterranean, NW Atlantic, and North Pacific, including Japan. This putatively wide distribution had not been tested with DNA sequence data; intraspecific variation in morphological characters diagnostic for the species had not been assessed with specimens from non-type localities, and the species status of the Japanese population(s) was uncertain. We examined the morphology and mitochondrial COI (cytochrome c oxidase subunit I) gene sequences of Capitella specimens from two localities (Ainan and Gamo) in Japan...
October 2016: Zoological Science
Ying Wang, Qing-Song Zhou, Hui-Jie Qiao, Ai-Bing Zhang, Fang Yu, Xu-Bo Wang, Chao-Dong Zhu, Yan-Zhou Zhang
With the recent development of molecular approaches to species delimitation, a growing number of cryptic species have been discovered in what had previously been thought to be single morpho-species. Molecular methods, such as DNA barcoding, have greatly enhanced our knowledge of taxonomy, but taxonomy remains incomplete and needs a formal species nomenclature and description to facilitate its use in other scientific fields. A previous study using DNA barcoding, geometric morphometrics and mating tests revealed at least two cryptic species in the Encyrtus sasakii complex...
October 4, 2016: Scientific Reports
Quanjun Hu, Huichao Peng, Hao Bi, Zhiqiang Lu, Dongshi Wan, Qian Wang, Kangshan Mao
Interspecific hybridization and introgression can lead to partial genetic homogenization at certain neutral loci between morphologically distinct species and may obscure the species delimitation using nuclear genes. In this study, we investigated this phenomenon through population genetic survey of two alpine plants (Gentiana siphonantha and G. straminea) in the Qinghai-Tibet Plateau, where the distributions of two species are partly overlapped. We identified two clusters of chloroplast DNA haplotypes which correspond to the two species, and three clusters of ITS ribotypes...
September 30, 2016: Scientific Reports
Luciana Ghermandi, Natacha A Beletzky, Mónica I de Torres Curth, Facundo J Oddi
The overlapping zone between urbanization and wildland vegetation, known as the wildland urban interface (WUI), is often at high risk of wildfire. Human activities increase the likelihood of wildfires, which can have disastrous consequences for property and land use, and can pose a serious threat to lives. Fire hazard assessments depend strongly on the spatial scale of analysis. We assessed the fire hazard in a WUI area of a Patagonian city by working at three scales: landscape, community and species. Fire is a complex phenomenon, so we used a large number of variables that correlate a priori with the fire hazard...
December 1, 2016: Journal of Environmental Management
Rocío Ana González-Vaquero, Arturo Roig-Alsina, Laurence Packer
Special care is needed in the delimitation and identification of halictid bee species, which are renowned for being morphologically monotonous. Corynura Spinola and Halictillus Moure (Halictidae: Augochlorini) contain species that are key elements in southern South American ecosystems. These bees are very difficult to identify due to close morphological similarity among species and high sexual dimorphism. We analyzed 170 barcode-compliant COI sequences from 19 species. DNA barcodes were useful to confirm gender associations and to detect two new cryptic species...
October 2016: Genome Génome / Conseil National de Recherches Canada
Herinandrianina N Andriananjamanantsoa, Shannon Engberg, Edward E Louis, Luc Brouillet
Angraecum is the largest genus of subtribe Angraecinae (Orchidaceae) with about 221 species. Madagascar is the center of the diversity for the genus with ca. 142 species, of which 90% are endemic. The great morphological diversity associated with species diversification in the genus on the island of Madagascar offers valuable insights for macroevolutionary studies. Phylogenies of the Angraecinae have been published but a lack of taxon and character sampling and their limited taxonomic resolution limit their uses for macroevolutionary studies...
2016: PloS One
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