scholarly journals In-depth investigation of the species problem and taxonomic status of marbled crayfish, the first asexual decapod crustacean

2018 ◽  
Author(s):  
Günter Vogt ◽  
Nathan J. Dorn ◽  
Michael Pfeiffer ◽  
Chris Lukhaup ◽  
Bronwyn W. Williams ◽  
...  
Keyword(s):  
Meta Analysis ◽  
Decapod Crustacean ◽  
Taxonomic Status ◽  
Morphological Characters ◽  
Published Data ◽  
Parent Species ◽  
Natural Habitats ◽  
Separate Species ◽  
Procambarus Fallax ◽  
Marbled Crayfish

ABSTRACTThe marbled crayfish is the only obligately parthenogenetic decapod crustacean and a novel research model and invasive animal on three continents. It is regarded either as a parthenogenetic form of slough crayfish Procambarus fallax or as a separate species named Procambarus virginalis. In order to investigate the species question of this unusual crayfish in detail we have identified the similarities and differences in morphology, life history, genetics, behaviour, ecology and biogeography between marbled crayfish and its most likely parent species P. fallax. We have investigated specimens from natural habitats, laboratory colonies and museum collections and performed a meta-analysis of our data and published data. Our COI based molecular tree with 27 Cambaridae confirms closest relationship of marbled crayfish with P. fallax. Marbled crayfish and P. fallax are similar with respect to morphological characters, coloration and body proportions, but differ considerably with respect to body size, fertility and longevity. The mitochondrial genes of both crayfish are similar, but ploidy level and haploid genome size are markedly different. Both crayfish are eurytopic and have two major annual recruitment periods, but marbled crayfish show different population structure and higher invasiveness. Marbled crayfish occur in tropical to cold temperate habitats of the old world, but P. fallax is confined to subtropical and warm-temperate habitats of the southeastern USA. Cross-breeding experiments with both crayfish revealed reproductive isolation. The application of the Evolutionary Genetic Species Concept for asexuals to all available data supports raising marbled crayfish from “forma” to species rank. A determination key is provided to discriminate Procambarus virginalis, the first asexual decapod species, from its parent species P. fallax.

scholarly journals Taxonomy of dark- and white-barked birches related to Betula pendula and B. pubescens (Betulaceae) in Ukraine based on both morphological traits and DNA markers

2019 ◽  
Vol 191 (1) ◽  
pp. 142-154 ◽  
Author(s):  
Andrii Tarieiev ◽  
Igor Olshanskyi ◽  
Oliver Gailing ◽  
Konstantin V Krutovsky
Keyword(s):  
Morphological Traits ◽  
Molecular Genetic ◽  
Taxonomic Status ◽  
Morphological Characters ◽  
Betula Pubescens ◽  
Internal Transcribed Spacers ◽  
Published Data ◽  
Nucleotide Polymorphisms ◽  
Separate Species ◽  
Molecular Genetic Data

Abstract Distribution, taxonomy, nomenclature and molecular genetic data are presented for two closely related pairs of birch taxa: (1) dark-barked Betula pubescens var. sibakademica (Baran.) Kuzeneva (basionym B. sibakademica Baranov) and white-barked B. pubescens var. pubescens, and (2) dark-barked B. kotulae Zaverucha = B. pendula var. obscura (Kotula ex Fiek) Olšavská (basionym B. obscura Kotula ex Fiek, heterotypic synonym B. kotulae) and white-barked B. pendula, respectively. Using published data and sequences obtained in this study, it was found that, although these pairs can be distinguished not only by morphological characters but also by two diagnostic single nucleotide polymorphisms (SNPs) in the internal transcribed spacers ITS1 and ITS2, no sequence differences within each pair were detected. These results suggest that the colour of the bark cannot be used as a taxonomic trait at the species level, and the dark-barked birches within each pair should not be treated as separate species or varieties, but as forms, respectively. Therefore, we reassessed the taxonomic status of B. sibakademica and B. kotulae using morphological traits and molecular genetic markers and suggest that B. pubescens f. sibakademica (Baranov) Tarieiev comb. nov. and B. pendula f. obscura (Kotula ex Fiek) Tarieiev comb. nov. should be used for them, respectively. Betula pubescens f. sibakademica was described in Ukraine for the first time.

The Taxonomic Status of Littorina Neglecta: A Comment to Grahame, Mill, Double and Hull

1993 ◽  
Vol 73 (1) ◽  
pp. 249-249 ◽  
Author(s):  
K. Johannesson ◽  
B. Johannesson
Keyword(s):  
Western Europe ◽  
Short Communication ◽  
Taxonomic Status ◽  
Morphological Characters ◽  
Littorina Saxatilis ◽  
Separate Species ◽  
Close Coupling ◽  
Allozyme Loci ◽  
North Western ◽  
High Shore

In a short communication Grahame et al. (1992) argue against our finding that Littorina neglecta Bean is an ecotype of Littorina saxatilis (Olivi) rather than a separate species (Johannesson & Johannesson, 1990b). Unfortunately, Grahame et al. (1992) have miss-represented our earlier paper, and we feel the need to refute their arguments.In populations from north-western Europe we studied morphological characters used to separate Littorina neglecta from L. saxatilis. We found that intermediate shapes were common and, furthermore, we found no close coupling among characters used to define L. neglecta (Johannesson & Johannesson, 1990a). We further analysed the genetic variation in five strongly polymorphic allozyme loci. In four loci we found a pattern that indicated that L. neglecta is not reproductively isolated from L. saxatilis. In the fifth locus, Aat-1, we found consistent differences between populations of L. neglecta (from the low shore) and L. saxatilis (from the high shore). Similar differences were observed between low and high shore populations in Sweden where, however, no snails of neglecta-type were present.

scholarly journals Phylogeographic reconstruction of the marbled crayfish origin

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Julian Gutekunst ◽  
Olena Maiakovska ◽  
Katharina Hanna ◽  
Panagiotis Provataris ◽  
Hannes Horn ◽  
...  
Keyword(s):  
Geographic Origin ◽  
Freshwater Crayfish ◽  
Parent Species ◽  
Parent Population ◽  
Diploid Parent ◽  
Phylogeographic Analysis ◽  
Procambarus Fallax ◽  
Important Intermediate ◽  
Crayfish Population ◽  
Marbled Crayfish

AbstractThe marbled crayfish (Procambarus virginalis) is a triploid and parthenogenetic freshwater crayfish species that has colonized diverse habitats around the world. Previous studies suggested that the clonal marbled crayfish population descended as recently as 25 years ago from a single specimen of P. fallax, the sexually reproducing parent species. However, the genetic, phylogeographic, and mechanistic origins of the species have remained enigmatic. We have now constructed a new genome assembly for P. virginalis to support a detailed phylogeographic analysis of the diploid parent species, Procambarus fallax. Our results strongly suggest that both parental haplotypes of P. virginalis were inherited from the Everglades subpopulation of P. fallax. Comprehensive whole-genome sequencing also detected triploid specimens in the same subpopulation, which either represent evolutionarily important intermediate genotypes or independent parthenogenetic lineages arising among the sexual parent population. Our findings thus clarify the geographic origin of the marbled crayfish and identify potential mechanisms of parthenogenetic speciation.

Taxonomic status and distribution of the critically endangered Christmas Island spleenwort (Asplenium listeri, Aspleniaceae): it is not as rare as we thought

2014 ◽  
Vol 27 (6) ◽  
pp. 372 ◽  
Author(s):  
Daniel J. Ohlsen ◽  
Leon R. Perrie ◽  
Lara D. Shepherd ◽  
Michael J. Bayly
Keyword(s):  
New Caledonia ◽  
Conservation Status ◽  
Taxonomic Status ◽  
Distinct Species ◽  
Morphological Characters ◽  
Geographic Range ◽  
Critically Endangered ◽  
Separate Species ◽  
Christmas Island ◽  
Chloroplast Haplotype

Asplenium listeri C.Chr. has been considered endemic to Christmas Island and is one of only two fern species listed as Critically Endangered under Australia’s Environment Protection and Biodiversity Conservation Act. Its status as a distinct species has been questioned because of morphological similarity to the widespread A. polyodon G.Forst., which also occurs on Christmas Island. Molecular analyses revealed that A. listeri and plants attributed to A. polyodon from coastal limestone in New Caledonia and Vanuatu share the same rbcL, trnL–trnF and rps4–trnS haplotype and that other samples of A. polyodon in Australia and the south-western Pacific belong to three separate molecular lineages. One of these lineages is formed by epiphytic A. polyodon from Christmas Island and has a chloroplast haplotype closely related to that of A. listeri, differing by four mutations. The A. listeri haplotype and each of the three A. polyodon lineages are associated with morphological characters and are all worthy of recognition as separate species. Asplenium listeri is here expanded to include limestone dwelling populations in the Pacific previously assigned to A. polyodon. This greatly extends the geographic range of A. listeri, and its conservation status should be revised accordingly. Application of correct names to all species in the A. polyodon complex requires further molecular sampling throughout its geographic range and clarification of how type material relates to each of the molecular groups.

Synonymize Arma chinensis as Arma custos based on morphological, molecular and geographical data

Zootaxa ◽  
2018 ◽  
Vol 4455 (1) ◽  
pp. 161 ◽  
Author(s):  
QING ZHAO ◽  
JIUFENG WEI ◽  
WENJUN BU ◽  
GUOQING LIU ◽  
HUFANG ZHANG
Keyword(s):  
Dna Barcoding ◽  
Taxonomic Status ◽  
Morphological Characters ◽  
Similar Species ◽  
Separate Species ◽  
Geographical Data ◽  
Additional Tool ◽  
New Synonym

Arma custos and A. chinensis have a very conspicuous difference in the shape of the pronotal humeral angle, but the genitalic morphological characters are ambiguous and difficult to recognize. The aim of this study was to analyze the taxonomic status of A. chinensis and A. custos based on morphological, molecular, and geographical evidence, and to determine whether DNA barcoding could be a useful additional tool for differentiating similar species. The results clearly demonstrate that A. custos and A. chinensis have not diverged into separate species. So, the following new synonym is proposed: Arma chinensis Fallou, 1881 = Arma custos (Fabricius, 1794) syn. nov.. The results also showed that DNA barcoding using the marker COI can resolve insect taxonomic problems.

On the status of the species of Acanthistius (Gill, 1862) (Percoidei) in the South-West Atlantic Ocean

Zootaxa ◽  
2008 ◽  
Vol 1813 (1) ◽  
pp. 51 ◽  
Author(s):  
ALEJO J. IRIGOYEN ◽  
LEOPOLDO CAVALERI GERHARDINGER ◽  
ALFREDO CARVALHO-FILHO
Keyword(s):  
Taxonomic Status ◽  
Morphological Characters ◽  
Museum Specimens ◽  
The South ◽  
Separate Species ◽  
Western Atlantic ◽  
South West ◽  
The Status ◽  
Diagnostic Key ◽  
Management And Conservation

We review the species of Acanthistius Gill (1862) (Osteichthyes, Percoidei) from the South-Western Atlantic, solving a discrepancy concerning the taxonomic status of Acanthistius brasilianus (Cuvier & Valenciennes 1828) and Acanthistius patachonicus (Jenyns 1842), and providing an objective diagnostic key for the two species. While Argentinean fishery biologists consider A. patachonicus to be a synonym of A. brasilianus, ichthyologists elsewhere regard them as separate species with different distributional ranges. Based on a literature review, examination of museum specimens and observation of live individuals in the field, we identified the sources of the dissent and concluded that A. brasilianus and A. patachonicus are separate species, differing in diagnostic morphological characters and distinctive color patterns and having slightly overlapping distributional ranges. Distinction between these two species has significant implications for management and conservation.

Morphological characterization and genotyping of the marbled crayfish and new evidence on its origin

Zootaxa ◽  
2018 ◽  
Vol 4524 (3) ◽  
pp. 329 ◽  
Author(s):  
GÜNTER VOGT ◽  
CHRIS LUKHAUP ◽  
BRONWYN W. WILLIAMS ◽  
MICHAEL PFEIFFER ◽  
NATHAN J. DORN ◽  
...  
Keyword(s):  
Morphological Characters ◽  
Morphological Characterization ◽  
Procambarus Fallax ◽  
Union County ◽  
Laboratory Populations ◽  
Gene Coi ◽  
Southern Georgia ◽  
Marbled Crayfish ◽  
New Evidence ◽  
Different Sources

The obligately parthenogenetic marbled crayfish, Procambarus virginalis, is the first formally described asexual species of the Crustacea Decapoda. It is a triploid descendant of the sexually reproducing slough crayfish, Procambarus fallax. Here we describe the morphology of cultured and wild marbled crayfish of wide size ranges in detail and photodocument all taxonomically relevant characters. Some morphological traits and coloration showed considerable variation within populations despite the monoclonal nature of marbled crayfish. There were also significant differences between wild and laboratory populations with respect to body proportions, coloration and spination. Comparison with Procambarus fallax revealed no qualitative morphological characters that unambiguously identify the marbled crayfish. Analysis of the mitochondrial cytochrome c oxidase subunit I gene (COI) and nuclear microsatellites of marbled crayfish and Procambarus fallax from different sources indicated that the tri-allelic microsatellite PclG-02 is better suitable than COI to identify the marbled crayfish. A respective identification key is provided. The COI and microsatellites of Procambarus fallax from different areas of Florida and southern Georgia suggest that the parents of the first marbled crayfish may have come from northern Union County, northern Florida. 

scholarly journals The marbled crayfish as a paradigm for saltational speciation by autopolyploidy and parthenogenesis in animals

2015 ◽  
Author(s):  
Günter Vogt ◽  
Cassandra Falckenhayn ◽  
Anne Schrimpf ◽  
Katharina Schmid ◽  
Katharina Hanna ◽  
...  
Keyword(s):  
Taxonomic Status ◽  
Parentage Analysis ◽  
Freshwater Ecosystems ◽  
Future Evolution ◽  
Procambarus Fallax ◽  
Flow Cytometric ◽  
Dna Contents ◽  
Saltational Evolution ◽  
Nuclear Microsatellite ◽  
Marbled Crayfish

AbstractThe parthenogenetic all-female marbled crayfish is a novel research model and potent invader of freshwater ecosystems. It is a triploid descendant of the sexually reproducing slough crayfish, Procambarus fallax, but its taxonomic status has remained unsettled. By cross-breeding experiments and parentage analysis we show here that marbled crayfish and P. fallax are reproductively separated. Both crayfish copulate readily, suggesting that the reproductive barrier is set at the cytogenetic rather than the behavioural level. Analysis of complete mitochondrial genomes of marbled crayfish from laboratory lineages and wild populations demonstrates genetic identity and indicates a single origin. Flow cytometric comparison of DNA contents of haemocytes and analysis of nuclear microsatellite loci confirm triploidy and suggest autopolyploidization as its cause. Global DNA methylation is significantly reduced in marbled crayfish implying the involvement of molecular epigenetic mechanisms in its origination. Morphologically, both crayfish are very similar but growth and fecundity are considerably larger in marbled crayfish, making it a different animal with superior fitness. These data and the high probability of a divergent future evolution of the marbled crayfish and P. fallax clusters suggest that marbled crayfish should be considered as an independent asexual species. Our findings also establish the P. fallax-marbled crayfish pair as a novel paradigm for rare chromosomal speciation by autopolyploidy and parthenogenesis in animals and for saltational evolution in general.

Morphological and physiological (i.e., upper lethal temperatures) comparisons between Notropis cornutus (Mitchell) and Notropis chrysocephalus (Rafinesque) from the Grand River, Ontario

1980 ◽  
Vol 58 (11) ◽  
pp. 2096-2101
Author(s):  
Edward Kott ◽  
Robert W. McCauley ◽  
Gregory Humphreys
Keyword(s):  
Taxonomic Status ◽  
River System ◽  
Morphological Characters ◽  
Separate Species ◽  
Pigmentation Pattern ◽  
First Report ◽  
Breeding Behaviour ◽  
Lethal Temperatures ◽  
Grand River

Two forms of the Notropis cornutus (Luxilus) complex occur syntopically in the Grand River system. These have been interpreted by some authors as separate species and by others as subspecies. The forms can be distinguished morphologically by the number of predorsal scales and by pigmentation pattern. It has also been suggested that the upper lethal temperatures of the two differ.This is the first report of a study of these features in syntopic populations. The results indicate that neither physiological nor morphological characters can establish the taxonomic status of these forms and that what is needed is a detailed study of the breeding behaviour of these forms in areas of syntopy.

Reinstatement of Centaurea cyanomorpha (Asteraceae), an endemic species from Southeastern Bulgaria

Phytotaxa ◽  
2016 ◽  
Vol 268 (1) ◽  
pp. 46 ◽  
Author(s):  
STOYAN S. STOYANOV
Keyword(s):  
Taxonomic Status ◽  
Type Specimen ◽  
Detailed Examination ◽  
Morphological Characters ◽  
New Combination ◽  
Separate Species ◽  
Close Relatives ◽  
The Town ◽  
Distinct Taxon ◽  
Locus Classicus

Centaurea cyanomorpha, so far known only from a single plant collected in May 1926, was rediscovered and studied at its locus classicus Kara Bair, near the town of Topolovgrad (SE Bulgaria). Its taxonomic status varied in times and remained hitherto uncertain. The species has been treated as a synonym of C. pseudaxillaris, C. napulifera and C. depressa. However, a detailed examination of the type specimen and plants from the type locality, as well as additional plants from different localities indicate that C. cyanomorpha is a clearly distinct taxon and should be maintained as a separate species. Cyanus diospolitanus (≡ Centaurea diospolitana), recently described from Derventski Hills, Yambol Province (SE Bulgaria), has turned out to be identical to C. cyanomorpha and should be treated as a later heterotypic synonym of the latter. Comparisons of the key morphological characters of the close relatives C. cyanomorpha and C. pseudaxillaris and maps of their distributions are given. A new combination, Cyanus cyanomorphus comb. nov., is provided.

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