A brief introduction to the morphological species concept of Spirogyra and emanating problems

2015 ◽  
Vol 148 (1) ◽  
pp. 67-86 ◽  
Author(s):  
Michael Schagerl ◽  
Melanie Zwirn
Keyword(s):  
Species Concept ◽  
Morphological Species ◽  
Morphological Species Concept

Rhoicosphenia kloseri, a new isopolar Rhoicosphenia (Bacillariophyta) species from the Antarctic with comparison to other isopolar Rhoicosphenia

Phytotaxa ◽  
2016 ◽  
Vol 265 (1) ◽  
pp. 50 ◽  
Author(s):  
EVAN W. THOMAS ◽  
RYSZARD LIGOWSKI
Keyword(s):  
New Species ◽  
Species Concept ◽  
Morphological Diversity ◽  
Red Alga ◽  
South Shetland Islands ◽  
Species Discovery ◽  
Shetland Islands ◽  
Morphological Species ◽  
Morphological Species Concept ◽  
The Antarctic

Rhoicosphenia is a common diatom in both freshwater and marine ecosystems and the genus can be found on nearly every continent. Despite the fact that the genus is common, few new species have been reported from outside of Europe, Asia, and North America, and only one species has been previously described from the Antarctic. Further, most Rhoicosphenia are heteropolar in valve outline, asymmetrical to the transapical axis, while few taxa are isopolar. During investigations into the epiphytes on the red alga Georgiella confluens from the South Shetland Islands, a new marine, isopolar Rhoicosphenia was discovered and is herein described and documented with both light and scanning electron microscopy. Rhoicosphenia kloseri is isopolar, and in that regard similar to other isopolar taxa, such as R. genuflexa and R. pullus, but does not fit the morphological species concept of those taxa and is thus described as new. This new species discovery is following a trend of high rates of discovery of previously ignored morphological diversity within the genus Rhoicosphenia.

scholarly journals The genus Syrrhoe (Crustacea, Amphipoda, Synopiidae) from the North Atlantic

2019 ◽  
Vol 3 (1) ◽  
pp. 85-108
Author(s):  
Luisa Fuchs ◽  
Charles Oliver Coleman ◽  
Anne-Nina Lörz
Keyword(s):  
North Atlantic ◽  
Convex Space ◽  
Posterior Margin ◽  
Species Concept ◽  
The North ◽  
The North Atlantic ◽  
Morphological Species ◽  
Morphological Species Concept

Three species of the amphipod genusSyrrhoeare described from the North Atlantic. The differences between these species are primarily the patterns of serration of the posterior margins of pleonite 3 and urosomite 1 and 2:Syrrhoeaffinishas a wide convex space on the posterior margin between the epimeron 3 and the dorsal serration. InSyrrhoecrenulataandSyrrhoeanneheleneaesp. nov.there is only a small notch on the posterior margin of pleonite 3.Syrrhoeanneheleneaesp. nov., otherwise similar toS.crenulata, has an additional serration on the posterior margin of urosomite 1. The inter- and intraspecific distances analyzed from COI confirm the morphological species concept of North AtlanticSyrrhoe.

scholarly journals The Ganoderma weberianum-resinaceum lineage: multilocus phylogenetic analysis and morphology confirm G. mexicanum and G. parvulum in the Neotropics

MycoKeys ◽  
2019 ◽  
Vol 59 ◽  
pp. 95-131 ◽  
Author(s):  
Milay Cabarroi-Hernández ◽  
Alma Rosa Villalobos-Arámbula ◽  
Mabel Gisela Torres-Torres ◽  
Cony Decock ◽  
Laura Guzmán-Dávalos
Keyword(s):  
Phylogenetic Analysis ◽  
Phenotypic Plasticity ◽  
Geographical Distribution ◽  
Species Concept ◽  
Phylogenetic Species ◽  
Additional Species ◽  
Neotropical Species ◽  
Morphological Studies ◽  
Morphological Species ◽  
Morphological Species Concept

Many species of Ganoderma exhibit a high phenotypic plasticity. Hence, particularly among them, the morphological species concept remains difficult to apply, resulting in a currently confused taxonomy; as a consequence, the geographical distribution range of many species also remains very uncertain. One of the areas with a strong uncertainty, as far as morphological species concept is concerned, is the Neotropics. It is common that names of species described from other regions, mainly from northern temperate areas, have been applied to Neotropical species. The aim of the present study was to determine which species might lay behind the G. weberianum complex in the Neotropics, using morphological studies and phylogenetic inferences based on both single (ITS) and multilocus (ITS, rpb2, and tef1-α) sequences. The results indicated that G. weberianumsensu Steyaert, which is the usually accepted concept for this taxon, was absent from the Neotropics. In this area, G. weberianumsensu Steyaert encompassed at least two phylogenetic species, which are tentatively, for the time being, identified as belonging to G. mexicanum and G. parvulum. These two species could be distinguished morphologically, notably by the ornamentation or its absence on their chlamydospores. The results also showed that additional species from the Neotropics might still exist, including, e.g., G. perzonatum, but their circumscription remains uncertain until now because of the paucity of material available. Furthermore, it was found that the current concept of G. resinaceum embraced a complex of species.

A taxonomic monograph of the fern genus Ctenitis (Dryopteridaceae) in South America

Phytotaxa ◽  
2018 ◽  
Vol 335 (1) ◽  
pp. 1
Author(s):  
RAQUEL STAUFFER VIVEROS ◽  
GERMINAL ROUHAN ◽  
ALEXANDRE SALINO
Keyword(s):  
South America ◽  
West Indies ◽  
Species Concept ◽  
The Other ◽  
South American ◽  
Field Observations ◽  
New Combinations ◽  
South American Species ◽  
Morphological Species ◽  
Morphological Species Concept

Based on collections of 45 Herbaria in addition to newly collected specimens and some field observations, a taxonomic treatment for South American Ctenitis is provided, a hundred years after Christensen’s monographs. Guided by morphological species concept, 26 taxa are recognized (23 species and three varieties). A key including all taxa is provided, and all species are fully morphologically described, with information on distribution and habitat. Brazil is the richest country with 22 taxa, of which 13 are endemic, restricted mainly to Atlantic Forest. Taxa occurring in the other South American countries are also widely distributed in Mesoamerica and West Indies, except C. megalastriformis, only known from Peru, and C. refulgens var. peruviana, recorded in Peru and Bolivia. We dealt with 163 names that apply to the South American species. In addition, we propose three new combinations, and designate 38 lectotypes and three neotypes.

scholarly journals Automated and Unbiased Image Analyses as Tools in Phenotypic Classification of Small-Spored Alternaria spp.

2005 ◽  
Vol 95 (9) ◽  
pp. 1021-1029 ◽  
Author(s):  
Birgitte Andersen ◽  
Michael E. Hansen ◽  
Jørn Smedsgaard
Keyword(s):  
Image Analysis ◽  
Species Concept ◽  
Toxin Production ◽  
Phenotypic Characters ◽  
Metabolite Profiles ◽  
Different Temperatures ◽  
Morphological Species ◽  
Morphological Species Concept ◽  
Image Analyses

For more than 25 years, controversy has surrounded the characterization and differentiation of small-spored Alternaria spp. And, therefore, the application of names of several species that are involved in the pathology of diseases related to host-specific toxin production. The name A. alternata often has been broadly applied to various morphologically and chemically distinct groups of isolates from different hosts. The purpose of this study was to develop and evaluate automated and unbiased image analysis systems that will analyze different phenotypic characters and facilitate testing and application of the morphological species concept in Alternaria taxonomy. Host-specific toxin-producing Alternaria isolates assigned to five morpho-species were compared with representative isolates of morphologically distinct A. alternata. Combined results of growth rates at different temperatures, colony morphology, and metabolite profiles were found to be useful in characterization and differentiation of small-spored Alternaria spp. when standardized conditions are applied and representative isolates employed for comparison.

Species and speciation.

2022 ◽  
pp. 7-8
Author(s):  
Richard A. I. Drew ◽  
Meredith C. Romig
Keyword(s):  
New Species ◽  
Natural Selection ◽  
Dna Sequences ◽  
Species Concept ◽  
Natural Habitat ◽  
Biological Species ◽  
Biological Species Concept ◽  
Similar Species ◽  
Host Fruit ◽  
Morphological Species

Abstract This chapter discusses two species models, which are diametrically opposed. The first, often called the 'biological species concept', defines species in terms of 'reproductive isolation', convinced that species arise when subsets of a population are split off and remain geographically isolated over evolutionary time. If and when such new species are reunited with their founder population, interbreeding does not occur, or if it does, infertile progeny result. Hence, from the biological species concept, natural selection is a primary agent of change and directly selects for new species. In this sense, species are the direct products of natural selection and they are therefore 'adaptive devices'. When applying this species concept, it has been impossible to separate some sibling species of fruit flies in the genus Bactrocera where distinct morphological species can be similar in molecular analyses of certain DNA sequences, while similar species morphologically are distinct in the same molecular characters. A radically different model, the 'recognition concept of species', relies heavily on a knowledge of species ecology and behaviour, particularly in their natural habitat. The principal points in this concept are given. In contrast to the now-outdated biological species concept that leads one to depend on laboratory-based research to define species, the recognition concept requires workers to undertake extensive field research in the habitat of the taxon under investigation. In translating this approach to research in the insect family Tephritidae, particularly the Dacinae, some 35 years of field surveys have been undertaken throughout the Indian subcontinent, South-east Asia and the South Pacific region. These surveys included trapping using male lure traps and host fruit collections of commercial/edible fruits. The results of this work have included the provision of specimens of almost all known species for morphological descriptions (c.800 species), material for male pheromone chemistry, and data on host fruit relationships and biogeographical studies.

Biosystematic studies in the genus Pholiota, stirps Adiposa

1977 ◽  
Vol 55 (9) ◽  
pp. 1167-1180 ◽  
Author(s):  
Ellen R. Farr ◽  
Orson K. Miller Jr. ◽  
David F. Farr
Keyword(s):  
Species Concept ◽  
Spore Size ◽  
Mating Compatibility ◽  
Morphological Species ◽  
Composite Description

A study of the morphology and mating compatibility of a number of collections of Pholiota, stirps Adiposa A. H. Smith & Hesler, demonstrated that a species concept based upon interbreeding populations was broader than that of the morphological species currently recognized in the group. Pholiota abietis A. H. Smith & Hesler, P. connata A. H. Smith & Hesler, P. limonella (Pk.) Sacc, P. squarroso-adiposa Lange, and P. subvelutipes A. H. Smith & Hesler can be accommodated in the composite description of the eight interbreeding collections studied. Of these names, P. limonella has nomenclatural priority. Pholiota aurivella (Fr.) Kummer was found to be distinguished from P. limonella only by spore size.

Systematics and evolution of Nepenthes

2018 ◽  
Author(s):  
Charles Clarke ◽  
Jan Schlauer ◽  
Jonathan Moran ◽  
Alastair Robinson
Keyword(s):  
Southeast Asia ◽  
Analytical Methods ◽  
Best Practice ◽  
Species Concept ◽  
Reticulate Evolution ◽  
Ecological Information ◽  
Plastid Genomes ◽  
The Status ◽  
Species Descriptions ◽  
Adequate Research

Nepenthes is a genus of 130-160 species, almost half of which were described after 2001. The recent, rapid increase in species descriptions has been driven by application of a less rigorous species concept by botanists, taxonomic inflation, and discoveries of new taxa during explorations of remote parts of Southeast Asia. Many recently published species descriptions of Nepenthes are based entirely upon qualitative morphological information and are not supported by adequate research. Accordingly, the status of many Nepenthes taxa is contested. Evolution within the genus is not well understood, because nuclear and maternally inherited plastid genomes cannot resolve relationships between many species, particularly those that evolved recently through introgression or reticulate evolution. Improvement in our understanding of the systematics and evolution of Nepenthes requires the adoption of ‘best practice’ collection and preservation methods, and the application of quantitative analytical methods for morphological, genetic, and ecological information.

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