scholarly journals Morphological Species of Gloeandromyces (Ascomycota, Laboulbeniales) Evaluated Using Single-locus Species Delimitation Methods

2019 ◽  
Vol 3 (1) ◽  
pp. 19-34 ◽  
Author(s):  
D. Haelewaters ◽  
D.H. Pfister
2018 ◽  
Vol 18 (6) ◽  
pp. 1234-1246 ◽  
Author(s):  
Simon Dellicour ◽  
Jean-François Flot

2020 ◽  
Vol 34 (4) ◽  
pp. 420-431
Author(s):  
B. L. Rodrigues ◽  
L. A. Baton ◽  
P. H. F. Shimabukuro

2014 ◽  
Vol 5 (10) ◽  
pp. 1086-1094 ◽  
Author(s):  
Cuong Q. Tang ◽  
Aelys M. Humphreys ◽  
Diego Fontaneto ◽  
Timothy G. Barraclough

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Michael K. Young ◽  
Rebecca Smith ◽  
Kristine L. Pilgrim ◽  
Michael K. Schwartz

AbstractBeing able to associate an organism with a scientific name is fundamental to our understanding of its conservation status, ecology, and evolutionary history. Gastropods in the subfamily Physinae have been especially troublesome to identify because morphological variation can be unrelated to interspecific differences and there have been widespread introductions of an unknown number of species, which has led to a speculative taxonomy. To resolve uncertainty about species diversity in North America, we targeted an array of single-locus species delimitation methods at publically available specimens and new specimens collected from the Snake River basin, USA to generate species hypotheses, corroborated using nuclear analyses of the newly collected specimens. A total-evidence approach delineated 18 candidate species, revealing cryptic diversity within recognized taxa and a lack of support for other named taxa. Hypotheses regarding certain local endemics were confirmed, as were widespread introductions, including of an undescribed taxon likely belonging to a separate genus in southeastern Idaho for which the closest relatives are in southeast Asia. Overall, single-locus species delimitation was an effective first step toward understanding the diversity and distribution of species in Physinae and to guiding future investigation sampling and analyses of species hypotheses.


2020 ◽  
Author(s):  
J Buchanan ◽  
Giuseppe Zuccarello

© 2018 International Phycological Society. Many brown macroalgal species are difficult to identify because of limited morphological differentiation and/ or high levels of plasticity. Molecular methods for distinguishing species coupled with morphological examination have been useful in clarifying species status in many groups. Cystophora is a species-rich, morphologically complex brown algal genus that has been carefully monographed, and it is ideal for testing the utility of molecular markers for genetic species delimitation. We evaluated the utility of the cytochrome oxidase subunit 1 (COI) DNA-barcode marker, alone and in combination with nuclear-encoded internal transcribed spacer (ITS) rDNA, in delimiting species. We also used several methods to delimit putative genetic species. Our results showed that for consistent species delimitation and species delimitation that approximates morphological species, both markers in combination are necessary. Most species in the genus are morphologically recognizable and genetically distinct but neither COI nor combined COI-ITS data separate Cystophora congesta from Cystophora retroflexa or Cystophora distenta from Cystophora scalaris. We showed that morphological characters used to separate these two species pairs are highly variable among samples, with many intermediates. Thus, we concluded that these are not independent species and synonymize these species. Our data showed that this genus, while widespread, mostly conforms to a morphospecies concept.


2015 ◽  
Author(s):  
Santiago Herrera ◽  
Timothy M. Shank

Species delimitation is problematic in many taxa due to the difficulty of evaluating predictions from species delimitation hypotheses, which chiefly relay on subjective interpretations of morphological observations and/or DNA sequence data. This problem is exacerbated in recalcitrant taxa for which genetic resources are scarce and inadequate to resolve questions regarding evolutionary relationships and uniqueness. In this case study we demonstrate the empirical utility of restriction site associated DNA sequencing (RAD-seq) by unambiguously resolving phylogenetic relationships among recalcitrant octocoral taxa with divergences greater than 80 million years. We objectively infer robust species boundaries in the genusParagorgia, which contains some of the most important ecosystem engineers in the deep-sea, by testing alternative taxonomy-guided or unguided species delimitation hypotheses using the Bayes factors delimitation method (BFD*) with genome-wide single nucleotide polymorphism data. We present conclusive evidence rejecting the current morphological species delimitation model for the genusParagorgiaand indicating the presence of cryptic species boundaries associated with environmental variables. We argue that the suitability limits of RAD-seq for phylogenetic inferences in divergent taxa cannot be assessed in terms of absolute time, but depend on taxon-specific factors such as mutation rate, generation time and effective population size. We show that classic morphological taxonomy can greatly benefit from integrative approaches that provide objective tests to species delimitation hypothesis. Our results pave the way for addressing further questions in biogeography, species ranges, community ecology, population dynamics, conservation, and evolution in octocorals and other marine taxa.


2019 ◽  
Vol 10 ◽  
Author(s):  
Erich P. Hofmann ◽  
Kirsten E. Nicholson ◽  
Ileana R. Luque-Montes ◽  
Gunther Köhler ◽  
César A. Cerrato-Mendoza ◽  
...  

2020 ◽  
Author(s):  
J Buchanan ◽  
Giuseppe Zuccarello

© 2018 International Phycological Society. Many brown macroalgal species are difficult to identify because of limited morphological differentiation and/ or high levels of plasticity. Molecular methods for distinguishing species coupled with morphological examination have been useful in clarifying species status in many groups. Cystophora is a species-rich, morphologically complex brown algal genus that has been carefully monographed, and it is ideal for testing the utility of molecular markers for genetic species delimitation. We evaluated the utility of the cytochrome oxidase subunit 1 (COI) DNA-barcode marker, alone and in combination with nuclear-encoded internal transcribed spacer (ITS) rDNA, in delimiting species. We also used several methods to delimit putative genetic species. Our results showed that for consistent species delimitation and species delimitation that approximates morphological species, both markers in combination are necessary. Most species in the genus are morphologically recognizable and genetically distinct but neither COI nor combined COI-ITS data separate Cystophora congesta from Cystophora retroflexa or Cystophora distenta from Cystophora scalaris. We showed that morphological characters used to separate these two species pairs are highly variable among samples, with many intermediates. Thus, we concluded that these are not independent species and synonymize these species. Our data showed that this genus, while widespread, mostly conforms to a morphospecies concept.


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