scholarly journals Combining morphology and population genetic analysis uncover species delimitation in the widespread African tree genus Santiria (Burseraceae)

Phytotaxa ◽  
2017 ◽  
Vol 321 (2) ◽  
pp. 166 ◽  
Author(s):  
DAVY U. IKABANGA ◽  
TARIQ STÉVART ◽  
K. GUILLAUME KOFFI ◽  
FRANCK KAMENI MONTHÉ ◽  
ELIE C. NZIGOU DOUBINDOU ◽  
...  
Keyword(s):  
Dna Sequences ◽  
Species Delimitation ◽  
Nuclear Dna ◽  
Central Africa ◽  
Taxonomic Revision ◽  
Biological Species ◽  
Morphological Data ◽  
Biological Species Concept ◽  
Population Genetic Analysis ◽  
Genetic Clusters

Taxonomic classification based on morphology alone can prove difficult. This is the case of the polymorphic forest tree species Santiria trimera in Africa, whose classification has remained controversial for over a century. Studies combining chloroplast and nuclear DNA sequences show the existence of several phylogenetic clades in this taxon, with some occurring in sympatry in western Central Africa suggesting the existence of at least two species. By combining genetic and morphological markers, we aim to assess the species delimitation in the Santiria species complex. Morphological trait (trunk, leaflet, flower and fruit characteristics) analysis using 223 standing individuals and 103 herbarium samples were combined with genetic analyses using 479 individuals genotyped at eight microsatellite markers. Genetic clusters were identified using Bayesian assignment in order to delimit species following the Biological Species Concept and to identify distinctive characters from morphometric analyses in retrospect. Three genetic clusters were identified and found to occur in sympatry. The type of inflorescence and the colour of unripe fruit were the most discriminant morphological traits among those genetic clusters, while many quantitative traits showed overlapping distributions between genetic clusters and explain the difficulty encountered by previous botanists to resolve the taxonomy of Santiria. The combination of genetic and morphological data suggests the presence of three species within the taxon Santiria trimera from western Central Africa. This work should guide a taxonomic revision within the genus Santiria in Africa.

scholarly journals Taxonomy and Species Delimitation in Cyanobacteria

2021 ◽  
Author(s):  
Alessio Papini ◽  
Sara Falsini ◽  
Tiruha Habte Karssa
Keyword(s):  
Dna Sequences ◽  
Species Delimitation ◽  
Species Concept ◽  
Cell Structure ◽  
Ultrastructural Level ◽  
Biological Species ◽  
Botanical Nomenclature ◽  
Biological Species Concept ◽  
Theoretical Point ◽  
Main Concept

Cyanobacteria are prokaryotes whose taxonomy follows the same rules of a code (the International Botanical Nomenclature Code, IBNC) built for eukaryotic photosynthetic organisms. Hence, names of cyanobacteria follow the same rules and are assigned to biological entities (species) that should correspond to eukaryotic species. The main difficulty in the current situation is that the species concept in eukaryotes is based theoretically mainly on the biological species concept, that is centered on genetic exchange through sexual reproduction or lack of them. However, as shown, this difference is important from a theoretical point of view, but also in eukaryotes, the boundaries between different species are very rarely checked experimentally by direct observation of sexual barriers and hybridization events. The main concept for species delimitation is hence that related to morphology and, more recently and always in relation to morphology, DNA sequences. The introduction of distances obtained from matrixes of aligned sequences in the framework of a barcoding project provides a quantitative interpretation of species delimitation in relation to genetic distance that can be used both in eukaryotes and prokaryotes. However, the introduction of quantitative criteria needs the definition of distance thresholds to identify the boundaries between different species and, for doing that, it is necessary to test the distance thresholds in models of traditionally defined and recognized species. An alternative approach may be the comparison of the molecular distance (quantitative approach) to data about the capability of strains/species to exchange genetic information. Unfortunately data about this last question is still scarce. The adoption of molecular criteria to check species boundaries based on morphological characters has proved particularly challenging in cyanobacteria: a known example is provided. In conclusion, the only possible approach appears to be the association of molecular data to the increase of available data about the cell structure and the variation thereof in different physiological situations, particularly at the ultrastructural level. A further necessity is the check of the typus for a large number of cyanobacteria species, often based on old basionyms. In many of these cases the typus is often a drawing and more rarely a herbarium specimen or a microscope slide. In many cases an epitypification or a neotypification appears to be necessary.

Phylogeny, diversity, and species delimitation of the North American Round-Nosed Minnows (Teleostei: Dionda), as inferred from mitochondrial and nuclear DNA sequences

2012 ◽  
Vol 62 (1) ◽  
pp. 427-446 ◽  
Author(s):  
Susana Schönhuth ◽  
David M. Hillis ◽  
David A. Neely ◽  
Lourdes Lozano-Vilano ◽  
Anabel Perdices ◽  
...  
Keyword(s):  
Dna Sequences ◽  
North American ◽  
Species Delimitation ◽  
Nuclear Dna ◽  
The North

Steinernema khuongin. sp. (Panagrolaimomorpha, Steinernematidae), a new entomopathogenic nematode species from Florida, USA

2018 ◽  
Vol 93 (2) ◽  
pp. 226-241 ◽  
Author(s):  
S.P. Stock ◽  
R. Campos-Herrera ◽  
F.E. El-Borai ◽  
L.W. Duncan
Keyword(s):  
New Species ◽  
Sequence Data ◽  
Novel Species ◽  
Entomopathogenic Nematode ◽  
Biological Species ◽  
Morphological Data ◽  
Biological Species Concept ◽  
The Novel ◽  
Ecological Data ◽  
Cross Hybridization

AbstractIn this study, molecular (ribosomal sequence data), morphological and cross-hybridization properties were used to identify a newSteinernemasp. from Florida, USA. Molecular and morphological data provided evidence for placing the novel species into Clade V, or the ‘glaseri-group’ ofSteinernemaspp. Within this clade, analysis of sequence data of the rDNA genes, 28S and internal transcribed spacer (ITS), depicted the novel species as a distinctive entity and closely related toS. glaseriandS. cubanum.Additionally, cross-hybridization assays showed that the new species is unable to interbreed with either of the latter two species, reinforcing its uniqueness from a biological species concept standpoint. Key morphological diagnostic characters forS. khuongin. sp. include the mean morphometric features of the third-stage infective juveniles: total body length (average: 1066 μm), tail length (average: 65 μm), location of the excretory pore (average: 80.5 μm) and the values ofc(average: 16.4),D% (average: 60.5),E% (average: 126) andH% (average: 46.6). Additionally, males can be differentiated fromS. glaseriandS. cubanumby the values of several ratios:D% (average: 68),E% (average: 323) and SW% (average: 120). The natural distribution of this species in Florida encompasses both natural areas and citrus groves, primarily in shallow groundwater ecoregions designated as ‘flatwoods’. The morphological, molecular, phylogenetic and ecological data associated with this nematode support its identity as a new species in theS. glaseri-group.

Phylogeny and higher classification of the scale insects (Hemiptera: Sternorrhyncha: Coccoidea)*

Zootaxa ◽  
2007 ◽  
Vol 1668 (1) ◽  
pp. 413-425 ◽  
Author(s):  
P. J. GULLAN ◽  
L. G. COOK
Keyword(s):  
Dna Sequences ◽  
Phylogenetic Trees ◽  
Nuclear Dna ◽  
Sister Group ◽  
Scale Insect ◽  
Scale Insects ◽  
Morphological Data ◽  
Adult Males ◽  
Plant Feeding ◽  
Phylogenetic Studies

The superfamily Coccoidea contains nearly 8000 species of plant-feeding hemipterans comprising up to 32 families divided traditionally into two informal groups, the archaeococcoids and the neococcoids. The neococcoids form a monophyletic group supported by both morphological and genetic data. In contrast, the monophyly of the archaeococcoids is uncertain and the higher level ranks within it have been controversial, particularly since the late Professor Jan Koteja introduced his multi-family classification for scale insects in 1974. Recent phylogenetic studies using molecular and morphological data support the recognition of up to 15 extant families of archaeococcoids, including 11 families for the former Margarodidae sensu lato, vindicating Koteja’s views. Archaeococcoids are represented better in the fossil record than neococcoids, and have an adequate record through the Tertiary and Cretaceous but almost no putative coccoid fossils are known from earlier. In contrast, the sister group of the scale insects (Aphidoidea) has a more informative Jurassic and Triassic record. Relationships among most scale insect families are unresolved in phylogenetic trees based on nuclear DNA sequences, and most nodes in trees based on morphological data, including those from adult males, are poorly supported. Within the neococcoids, the Eriococcidae is not monophyletic and the monophyly of the Coccidae and Diaspididae may be compromised by the current family-level recognition of a few species-poor autapomorphic groups.

scholarly journals When forms meet genes: revision of the scleractinian genera Micromussa and Homophyllia (Lobophylliidae) with a description of two new species and one new genus

2016 ◽  
Vol 85 (4) ◽  
pp. 387-422 ◽  
Author(s):  
Roberto Arrigoni ◽  
Francesca Benzoni ◽  
Danwei Huang ◽  
Hironobu Fukami ◽  
Chaolun Allen Chen ◽  
...  
Keyword(s):  
New Genus ◽  
Nuclear Dna ◽  
New Caledonia ◽  
Sequence Data ◽  
Intergenic Spacer ◽  
Taxonomic Revision ◽  
Its Region ◽  
Distinct Species ◽  
Morphological Data ◽  
Eastern Australia

The scleractinian family Lobophylliidae is undergoing a major taxonomic revision thanks to the combination of molecular and morphological data. In this study, we investigate the evolutionary relationships and the macro- and micromorphology of six nominal coral species belonging to two of the nine molecular clades of the Lobophylliidae, clades A and B, and of Symphyllia wilsoni, a lobophylliid species analyzed from a molecular point of view for the first time. Sequence data from mitochondrial DNA (COI and the intergenic spacer between COI and l-rRNA), and nuclear DNA (histone H3 and ITS region) are used to generate robust molecular phylogenies and a median-joining haplotype network. Molecular results are strongly in agreement with detailed observations of gross- and fine-scale morphology of skeletons, leading to the formal revision of the genera Micromussa and Homophyllia and the description of two newly discovered zooxanthellate shallow-water species, Micromussa pacifica sp. nov. Benzoni & Arrigoni and Micromussa indiana sp. nov. Benzoni & Arrigoni, and a new genus, Australophyllia gen. nov. Benzoni & Arrigoni. In particular, Acanthastrea lordhowensis and Montastraea multipunctata are moved into Micromussa, A. hillae is synonymized with A. bowerbanki and is transferred to Homophyllia, and a revised diagnosis for both genera is provided. Micromussa pacifica sp. nov. is described from the Gambier Islands with its distribution spanning New Caledonia and eastern Australia. Despite a superficial resemblance with Homophyllia australis, it has distinctive macroand micromorphological septal features. Micromussa indiana sp. nov., previously identified as M. amakusensis, is here described from the Gulf of Aden and the southern Red Sea as a distinct species that is genetically separated from M. amakusensis and is morphologically distinct from the latter due to its smaller corallite size and lower number of septa. Finally, molecular trees show that S. wilsoni is closely related, but molecularly separated from clades A and B, and, also based on a unique combination of corallite and sub-corallite characters, the species is moved into Australophyllia gen. nov. These findings confirm the need for using both genetic and morphological datasets for the ongoing taxonomic revision of scleractinian corals.

Description of a new genus and two new species of killifish (Cyprinodontiformes: Nothobranchiidae) from West Africa, with a discussion of the taxonomic status of Aphyosemion maeseni Poll, 1941

Zootaxa ◽  
2009 ◽  
Vol 2294 (1) ◽  
pp. 1-22 ◽  
Author(s):  
RAINER SONNENBERG ◽  
ECKHARD BUSCH
Keyword(s):  
New Species ◽  
Dna Sequences ◽  
New Genus ◽  
Nuclear Dna ◽  
Taxonomic Status ◽  
Morphological Characters ◽  
Color Pattern ◽  
Monophyletic Group ◽  
Morphological Data ◽  
Adult Males

The phylogeny of the West African genus Archiaphyosemion was studied with mitochondrial and nuclear DNA sequences. The results of the combined dataset presented here did not support a monophyletic group. After the exclusion of the type species of the genus, A. guineense, the remaining species form a well-supported monophyletic group. Based on these molecular results and supported by morphological data, we suggest a new name for this group, Nimbapanchax, new genus. Additionally, based on a recent collection in Guinea, two new Nimbapanchax species were described. The taxon Nimbapanchax leucopterygius, new species, is described for a nothobranchiid fish formerly misidentified as Archiaphyosemion maeseni (Poll, 1941). Nimbapanchax melanopterygius, new species, is described from the Mount Nimba region in southeastern Guinea. Both new Nimbapanchax species are clearly distinguished from their congeners by the coloration pattern of adult males. The results of the DNA data support the assumption based on color pattern and morphological characters that the new described species are sister taxa. The type of Aphyosemion maeseni Poll, 1941 was reexamined and transferred to the genus Epiplatys, a decision based on diagnostic morphological characters.

scholarly journals Three, two, one! Revision of the long-bodied sphaerodorids (Sphaerodoridae, Annelida) and synonymization ofEphesiella,EphesiopsisandSphaerodorum

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5783 ◽  
Author(s):  
María Capa ◽  
Torkild Bakken ◽  
Karin Meißner ◽  
Arne Nygren
Keyword(s):  
Dna Sequences ◽  
Nuclear Dna ◽  
Sequence Data ◽  
Phylogenetic Analyses ◽  
Intraspecific Variability ◽  
Morphological Data ◽  
Nominal Species ◽  
Type Specimens ◽  
Diagnostic Features ◽  
28S Rdna Sequence

BackgroundLong-bodied sphaerodorids (Annelida, Sphaerodoridae) is the common name for members of the three closely and morphologically homogenous currently accepted genera of benthic marine bristle worms:Ephesiella,EphesiopsisandSphaerodorum. Members of this group share the presence of two dorsal and longitudinal rows of macrotubercles with terminal papillae, and two longitudinal rows of microtubercles, features that are unique among sphaerodorids. Genera are distinguished by the chaetae morphology. Members ofEphesiellaare characterised by having compound chaetae (except, sometimes, simple chaetae in the first chaetigers),Sphaerodorumbear only simple chaetae, andEphesiopsishave both compound and simple chaetae in all parapodia.MethodsMitochondrial (partial COI and 16S rDNA) and nuclear (partial 18S rDNA and 28S rDNA) sequence data of long-bodied sphaerodorids with compound and simple chaetae, and an outgroup of additional seven sphaerodorid species were analysed separately and in combination using Bayesian inference (BA), and Maximum Likelihood (ML) methods. Long-bodied sphaerodorids from around the world (including type specimens) were examined under a range of optical equipment in order to evaluate putative generic and specific diagnostic features, in addition to intraspecific variability.ResultsPhylogenetic analyses of mitochondrial and nuclear DNA sequences of specimens identified asEphesiellaandSphaerodorum,based on chaeta morphology, were performed.SphaerodorumandEphesiellawere recovered as paraphyletic and nested within each other. Revision of current nominal species diagnostic features are performed and discussed.DiscussionResults contradict current generic definitions. Recovery of paraphyletic compound and simple chaetae clades urge the synonymization of these two genera of long-bodied sphaerodorids. Morphological data also suggest the synonymization ofEphesiopsis.

scholarly journals Untangling systematics of the Paramacrobiotus areolatus species complex by an integrative redescription of the nominal species for the group, with multilocus phylogeny and species delineation in the genus Paramacrobiotus

2020 ◽  
Vol 188 (3) ◽  
pp. 694-716 ◽  
Author(s):  
Daniel Stec ◽  
Łukasz Krzywański ◽  
Krzysztof Zawierucha ◽  
Łukasz Michalczyk
Keyword(s):  
Dna Sequences ◽  
Integrative Taxonomy ◽  
Genetic Distances ◽  
Biological Species ◽  
Biological Species Concept ◽  
Nominal Species ◽  
Species Delineation ◽  
F1 Hybrid ◽  
Complex Species ◽  
History Of

Abstract Incomplete descriptions of nominal taxa are one of the most significant obstacles in modern taxonomy, including the taxonomy of Tardigrada. Another major problem in tardigrade systematics is the lack of tests for the reliability of genetic markers in species delineation. Here, we employ an integrative taxonomy approach to redescribe the nominal taxon for the P. areolatus complex, Paramacrobiotus areolatus. Moreover, we obtained multilocus DNA sequences for another 16 populations representing 9–12 Paramacrobiotus species collected from Europe, North America, Africa and Australia, enabling us to reconstruct the most extensive phylogeny of the genus to date. The identification of a pair of potentially cryptic dioecious P. areolatus complex species with divergent genetic distances in ITS2 (1.4%) and COI (13.8%) provided an opportunity to test the biological species concept for the first time in the history of tardigrade taxonomy. Intra- and interpopulation crosses did not differ in reproductive success in terms of F1 offspring. However, because of the low F1 family sizes, we were unfortunately unable to test F1 hybrid fertility. Although our results are only partially conclusive, they offer a baseline not only for further taxonomic and phylogenetic research on the areolatus complex, but also for studies on species delineation in tardigrades in general.

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.

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