Sexual diploid and apomictic tetraploid races in Thrasya petrosa (Gramineae)

2005 ◽  
Vol 53 (5) ◽  
pp. 479 ◽  
Author(s):  
Carlos A. Acuña ◽  
Eric J. Martínez ◽  
Camilo L. Quarin
Keyword(s):  
New World ◽  
Phylogenetic Analyses ◽  
Embryo Sac ◽  
Reproductive Mode ◽  
Genetic System ◽  
Self Incompatibility ◽  
Genetic Origin ◽  
Widespread Species ◽  
Reproductive Structures ◽  
Close Relationship

Thrasya petrosa (Trin.) Chase is the most widespread species of a grass genus indigenous to the New World. Genetic systems in diploid (2n=2x=20) and tetraploid (2n=4x=40) races of T. petrosa were investigated. The diploid race exhibited embryological development typical of sexual reproduction, but failed to produce seed because of self-incompatibility, whereas the tetraploid showed embryological pathways characteristic of facultative apomixis. Consequently, some ovules showed a normal meiotic embryo sac, others had one to several aposporous sacs, and, finally, some ovules had one or more aposporous sacs beside the meiotic one. A uniform progeny test assisted by molecular markers confirmed that the main reproductive mode for the tetraploid race was apomixis, despite some sexual reproductive structures observed by cytoembryological analyses. The chromosome pairing patterns at meiosis suggested that autoploidy was the genetic origin of the tetraploid races of T. petrosa. In addition, the close relationship between Thrasya Kunth and Paspalum L. previously supported by phylogenetic analyses is further sustained by the particular genetic system shared by the two genera. The system involves co-specific sexual self-incompatible diploids and apomictic, pseudogamous and self-compatible polyploids.

The Pleurobemini (Bivalvia : Unionida) revisited: molecular species delineation using a mitochondrial DNA gene reveals multiple conspecifics and undescribed species

2018 ◽  
Vol 32 (3) ◽  
pp. 689 ◽  
Author(s):  
Kentaro Inoue ◽  
David M. Hayes ◽  
John L. Harris ◽  
Nathan A. Johnson ◽  
Cheryl L. Morrison ◽  
...  
Keyword(s):  
Species Identification ◽  
Phylogenetic Analyses ◽  
Freshwater Mussel ◽  
Conservation Strategies ◽  
Species Boundaries ◽  
Widespread Species ◽  
Geographic Structure ◽  
Close Relationship ◽  
Taxonomic Changes ◽  
Effective Conservation

The Pleurobemini (Bivalvia: Unionida) represent approximately one-third of freshwater mussel diversity in North America. Species identification within this group is challenging due to morphological convergence and phenotypic plasticity. Accurate species identification, including characterisation of currently unrecognised taxa, is required to develop effective conservation strategies because many species in the group are imperiled. We examined 575 cox1 sequences from 110 currently recognised species (including 13 Fusconaia and 21 Pleurobema species) to understand phylogenetic relationships among pleurobemine species (mainly Fusconaia and Pleurobema) and to delineate species boundaries. The results of phylogenetic analyses showed no geographic structure within widespread species and illustrated a close relationship between Elliptio lanceolata and Parvaspina collina. Constraint tests supported monophyly of the genera Fusconaia and Pleurobema, including the subgenus P. (Sintoxia). Furthermore, results revealed multiple conspecifics, including P. hanleyianum and P. troschelianum, P. chattanoogaense and P. decisum, P. clava and P. oviforme, P. rubrum and P. sintoxia, F. askewi and F. lananensis, and F. cerina and F. flava. Species delimitation analyses identified three currently unrecognised taxa (two in Fusconaia and one in Pleurobema). Further investigation using additional genetic markers and other lines of evidence (e.g. morphology, life history, ecology) are necessary before any taxonomic changes are formalised.

scholarly journals Linking morphological and molecular sources to disentangle the case of Xylodon australis

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Javier Fernández-López ◽  
M. Teresa Telleria ◽  
Margarita Dueñas ◽  
Mara Laguna-Castro ◽  
Klaus Schliep ◽  
...  
Keyword(s):  
New Zealand ◽  
Phylogenetic Analyses ◽  
Single Species ◽  
R Package ◽  
Molecular Data ◽  
Historical Collections ◽  
Close Relationship ◽  
Kinship Relations ◽  
History Of ◽  
Different Sources

AbstractThe use of different sources of evidence has been recommended in order to conduct species delimitation analyses to solve taxonomic issues. In this study, we use a maximum likelihood framework to combine morphological and molecular traits to study the case of Xylodon australis (Hymenochaetales, Basidiomycota) using the locate.yeti function from the phytools R package. Xylodon australis has been considered a single species distributed across Australia, New Zealand and Patagonia. Multi-locus phylogenetic analyses were conducted to unmask the actual diversity under X. australis as well as the kinship relations respect their relatives. To assess the taxonomic position of each clade, locate.yeti function was used to locate in a molecular phylogeny the X. australis type material for which no molecular data was available using morphological continuous traits. Two different species were distinguished under the X. australis name, one from Australia–New Zealand and other from Patagonia. In addition, a close relationship with Xylodon lenis, a species from the South East of Asia, was confirmed for the Patagonian clade. We discuss the implications of our results for the biogeographical history of this genus and we evaluate the potential of this method to be used with historical collections for which molecular data is not available.

A new species of Cleistocybe (Agaricales, Basidiomycota) from the Tibetan Plateau, China

Phytotaxa ◽  
2018 ◽  
Vol 336 (3) ◽  
pp. 286 ◽  
Author(s):  
HONG-MEI WU ◽  
JIA-QI LUO ◽  
KE WANG ◽  
RUN-CHAO ZHANG ◽  
YI LI ◽  
...  
Keyword(s):  
New Species ◽  
Tibetan Plateau ◽  
Phylogenetic Analyses ◽  
Morphological Observation ◽  
Morphological Description ◽  
The Tibetan Plateau ◽  
Sequence Analyses ◽  
The North ◽  
Close Relationship ◽  
A New Species

During field expeditions to the Tibetan Plateau, a collection of an undescribed species with several basidiomes was found. Morphological observation and DNA sequence analyses of the collection revealed a close relationship with Cleistocybe vernalis, the type species of the genus Cleistocybe. Therefore, a new species is proposed for the fungus with full morphological description accompanied by phylogenetic analyses. The discovery of the species extends the reported distribution of the genus from the north of America and Europe to Asia.

An expanded concept of Madisonia including miscellaneous species of Pleurothallidinae (Orchidaceae): evidence from molecular analysis

Phytotaxa ◽  
2021 ◽  
Vol 505 (1) ◽  
pp. 71-84
Author(s):  
ERIC DE CAMARGO SMIDT ◽  
A. L. V. TOSCANO DE BRITO ◽  
ANNA VICTORIA SILVÉRIO R. MAUAD ◽  
NICOLÁS GUTIÉRREZ MORALES
Keyword(s):  
Molecular Analysis ◽  
Amazon Basin ◽  
Phylogenetic Analyses ◽  
Monotypic Genus ◽  
Phylogenetic Information ◽  
Close Relationship ◽  
The Caribbean ◽  
Taxonomic Studies ◽  
Expanded Concept ◽  
New Nomenclatural Combinations

Prior taxonomic studies in subtribe Pleurothallidinae have suggested a close relationship between miscellaneous species featuring long-repent, segmented rhizomes, abbreviated ramicauls, few-flowered inflorescences, and flowers with partially connate sepals and trilobed lip. The lack of phylogenetic information for most species has prevented further conclusions or changes in their taxonomy; and as a result, they are currently assigned to several unrelated genera: Anathallis, Madisonia, Pabstiella, Pleurothallis, Sansonia and Specklinia. We performed phylogenetic analyses using nuclear (nrITS) and five plastid (matK, psbD-trnT, rps16-trnQ, trnH-psbA and trnS-trnG) markers and demonstrated that these species form an isolated clade which requires generic recognition. The name Madisonia, previously a monotypic genus endemic of the Amazon basin, is re-circumscribed and expanded to include nine species distributed in the Atlantic Rainforest and the Caribbean. Eight new nomenclatural combinations are proposed.

Ultrastructural Aspects of the Self-Incompatibility Mechanism in Lycopersicum Peruvianum Mill

1973 ◽  
Vol 12 (2) ◽  
pp. 403-419 ◽  
Author(s):  
D. DE NETTANCOURT ◽  
M. DEVREUX ◽  
A. BOZZINI ◽  
M. CRESTI ◽  
E. PACINI ◽  
...  
Keyword(s):  
Pollen Tube ◽  
Tube Wall ◽  
Degradation Mechanism ◽  
Embryo Sac ◽  
Pollen Tubes ◽  
Self Incompatibility ◽  
Weak Reaction ◽  
General Hypothesis ◽  
Incompatible Pollen ◽  
Compatible Pollen

The experimental results obtained show that the tip of the incompatible pollen tube bursts open after the outer-wall has considerably expanded in the intercellular spaces of the conducting tissue and the inner-wall has disappeared and numerous particles have accumulated in the tube cytoplasm. These particles, which measure approximately 0.2 µm in diameter and give a weak reaction to the test of Thiéry, differ in many respects from the vesicles normally present in compatible pollen tubes growing through the style; they appear to resemble, in some cases, the spheres which are discharged by the compatible pollen tubes after they have reached the embryo-sac. It is considered that these observations support the current belief that the tube wall is the site of action for the incompatibility proteins and suggest that self-incompatibility is not a passive process resulting from lack of growth stimulation but an active event which leads to the destruction of the incompatible pollen tubes. The degradation mechanism involved appears similar to the one which enables the compatible pollen tube to release its contents in the degenerated synergid and presents some analogies with the lytic process taking place in virus-infected cells. The general hypothesis is presented that the particles observed in the cytoplasm of self-incompatible pollen tubes consist of a mixture of incompatibility proteins and of basic constituents of the tube wall.

Review of the New World species of Microplitis Foerster (Hymenoptera, Braconidae, Microgastrinae) attacking Sphingidae (Lepidoptera, Bombycoidea)

2021 ◽  
pp. 1-21
Author(s):  
Mostafa Ghafouri Moghaddam ◽  
Sloan Tomlinson ◽  
Samuel Jaffe ◽  
Diana Carolina Arias-Penna ◽  
James B. Whitfield ◽  
...  
Keyword(s):  
North America ◽  
New Hampshire ◽  
New World ◽  
Phylogenetic Analyses ◽  
Eastern North America ◽  
Plant Association ◽  
Distribution Map ◽  
New Host ◽  
World Species ◽  
Allegheny Mountains

Abstract Microplitis Foerster is a highly diverse and cosmopolitan genus within Microgastrinae (Hymenoptera, Ichneumonoidea, Braconidae). Microplitis ceratomiae Riley, a widely distributed North American species, exclusively attacks sphingid caterpillars. In this paper, M. ceratomiae is reported parasitizing a caterpillar of Sphinx poecila Stephens (Sphingidae) which was collected feeding on Spiraea alba Du Roi (Rosaceae), a species of white meadowsweet native to the wet soils of the Allegheny Mountains and other portions of eastern North America. Here, we report and describe this new host-parasitoid-food plant association in southern New Hampshire, and include a distribution map for the species. Biological, ecological and phylogenetic analyses, and an identification key for the nine known species of Microplitis that attack sphingids in the New World are provided.

scholarly journals Phylogeny and morphology of genus Nephrocytium (Sphaeropleales, Chlorophyceae, Chlorophyta) from China

Phytotaxa ◽  
2017 ◽  
Vol 319 (1) ◽  
pp. 84 ◽  
Author(s):  
XUDONG LIU ◽  
HUAN ZHU ◽  
BENWEN LIU ◽  
GUOXIANG LIU ◽  
ZHENGYU HU
Keyword(s):  
Phylogenetic Analyses ◽  
Light And Electron Microscopy ◽  
Taxonomic Position ◽  
Phylogenetic Position ◽  
Phytoplankton Communities ◽  
Close Phylogenetic Relationship ◽  
The Family ◽  
Close Relationship ◽  
Molecular Phylogenetic

The genus Nephrocytium Nägeli is a common member of phytoplankton communities that has a distinctive morphology. Its taxonomic position is traditionally considered to be within the family Oocystaceae (Trebouxiophyceae). However, research on its ultrastructure is rare, and the phylogenetic position has not yet been determined. In this study, two strains of Nephrocytium, N. agardhianum Nägeli and N. limneticum (G.M.Smith) G.M.Smith, were identified and successfully cultured in the laboratory. Morphological inspection by light and electron microscopy and molecular phylogenetic analyses were performed to explore the taxonomic position. Ultrastructure implied a likely irregular network of dense and fine ribs on the surface of the daughter cell wall that resembled that of the genus Chromochloris Kol & Chodat (Chromochloridaceae). Phylogenetic analyses revealed that Nephrocytium formed an independent lineage in the order Sphaeropleales (Chlorophyceae) with high support values and a close phylogenetic relationship with Chromochloris. Based on combined morphological, ultrastructural and phylogenetic data, we propose a re-classification of Nephrocytium into Sphaeropleales, sharing a close relationship with Chromochloris.

New aristonectine elasmosaurid plesiosaur specimens from the Early Maastrichtian of Angola and comments on paedomorphism in plesiosaurs

2015 ◽  
Vol 94 (1) ◽  
pp. 93-108 ◽  
Author(s):  
R. Araújo ◽  
M.J. Polcyn ◽  
J. Lindgren ◽  
L.L. Jacobs ◽  
A.S. Schulp ◽  
...  
Keyword(s):  
New Zealand ◽  
Histological Analysis ◽  
Phylogenetic Analyses ◽  
External Morphology ◽  
Sister Taxon ◽  
Close Relationship

AbstractNew elasmosaurid plesiosaur specimens are described from the Early Maastrichtian of Angola. Phylogenetic analyses reconstruct the Angolan taxon as an aristonectine elasmosaurid and the sister taxon of an unnamed form of similar age from New Zealand. Comparisons also indicate a close relationship with an unnamed form previously described from Patagonia. All of these specimens exhibit an ostensibly osteologically immature external morphology, but histological analysis of the Angolan material suggests an adult with paedomorphic traits. By extension, the similarity of the Angolan, New Zealand and Patagonian material indicates that these specimens represent a widespread paedomorphic yet unnamed taxon.

scholarly journals A new genus and species of natricine snake from northeast India

Zootaxa ◽  
2019 ◽  
Vol 4603 (2) ◽  
pp. 241 ◽  
Author(s):  
VARAD B. GIRI ◽  
DAVID J. GOWER ◽  
ABHIJIT DAS ◽  
H.T. LALREMSANGA ◽  
SAMUEL LALRONUNGA ◽  
...  
Keyword(s):  
New World ◽  
New Genus ◽  
Phylogenetic Analyses ◽  
East Asian ◽  
Northeast India ◽  
Molecular Variation ◽  
New Genus And Species ◽  
Indian Populations ◽  
Western Palearctic ◽  
Molecular Phylogenetic

Based on the first molecular phylogenetic analyses of samples from northeast India, specimens referred to Rhabdops from this region are more closely related to the southeast and east Asian natricine genera Opisthotropis Günther, 1872 and Sinonatrix Rossman & Eberle, 1977 (as well as to New World and western Palearctic natricines) than to peninsular Indian (true) Rhabdops. Morphologically, these northeast Indian populations differ from other natricines by having a single (‘fused’ or unpaired) internasal shield and a single prefrontal shield. Given the morphological and phylogenetic distinctiveness of these northeast Indian populations, we refer them to a new genus, Smithophis gen. nov., and transfer Rhabdops bicolor (Blyth, 1854) to Smithophis bicolor comb. nov. Based on morphological and molecular variation within our northeast Indian sample, we additionally describe Smithophis atemporalis sp. nov. from the state of Mizoram.

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