Numerical classification of the Pacific forms of Chlorodesmis (Chlorophyta)

1965 ◽  
Vol 13 (3) ◽  
pp. 489 ◽  
Author(s):  
SC Ducker ◽  
WT Williams ◽  
GN Lance
Keyword(s):  
Mixed Data ◽  
Critical Examination ◽  
Numerical Classification ◽  
Control Data ◽  
Green Algal ◽  
The Pacific ◽  
Algal Genus ◽  
Single Genus

The boundaries of the green algal genus Chlorodesmis are ill defined, and the reported species appear to overlap widely. Fourreen specimens of the large-celled (Pacific) forms have been subjected to critical examination; the specimens had previously been ascribed to three genera and eight species. Six characters (one qualitative, three 3-state, and two numerical) have been used; the numerical characters, for which measures of variation are available, have been subjected to a conventional statistical examination, and all six characters have been used in an analysis of the data by means of the mixed-data classificatory programme MULTIST on the Control Data 3600 at Canberra. The results strongly suggest that the specimens are referable to a single genus with only four species: C. caespitosa J. Agardh, C. comosa Harvey & Bailey, C. major Zanardini, and C. bulbosa (Womersley) Ducker.

scholarly journals The Rubisco small subunits in the green algal genus Chloromonas provide insights into evolutionary loss of the eukaryotic carbon-concentrating organelle, the pyrenoid

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Ryo Matsuzaki ◽  
Shigekatsu Suzuki ◽  
Haruyo Yamaguchi ◽  
Masanobu Kawachi ◽  
Yu Kanesaki ◽  
...  
Keyword(s):  
Evolutionary Biology ◽  
De Novo ◽  
Small Subunit ◽  
Plant Evolution ◽  
Reaction Products ◽  
Photosynthetic Organisms ◽  
Green Algal ◽  
Interesting Study ◽  
Algal Genus ◽  
The Relationship

Abstract Background Pyrenoids are protein microcompartments composed mainly of Rubisco that are localized in the chloroplasts of many photosynthetic organisms. Pyrenoids contribute to the CO2-concentrating mechanism. This organelle has been lost many times during algal/plant evolution, including with the origin of land plants. The molecular basis of the evolutionary loss of pyrenoids is a major topic in evolutionary biology. Recently, it was hypothesized that pyrenoid formation is controlled by the hydrophobicity of the two helices on the surface of the Rubisco small subunit (RBCS), but the relationship between hydrophobicity and pyrenoid loss during the evolution of closely related algal/plant lineages has not been examined. Here, we focused on, the Reticulata group of the unicellular green algal genus Chloromonas, within which pyrenoids are present in some species, although they are absent in the closely related species. Results Based on de novo transcriptome analysis and Sanger sequencing of cloned reverse transcription-polymerase chain reaction products, rbcS sequences were determined from 11 strains of two pyrenoid-lacking and three pyrenoid-containing species of the Reticulata group. We found that the hydrophobicity of the RBCS helices was roughly correlated with the presence or absence of pyrenoids within the Reticulata group and that a decrease in the hydrophobicity of the RBCS helices may have primarily caused pyrenoid loss during the evolution of this group. Conclusions Although we suggest that the observed correlation may only exist for the Reticulata group, this is still an interesting study that provides novel insight into a potential mechanism determining initial evolutionary steps of gain and loss of the pyrenoid.

OnAcanthogyrusn.g. from the Intestine of the Indian FishLabeo rohita, with a Note on the Classification of the Acanthocephala

1927 ◽  
Vol 5 (2) ◽  
pp. 109-120 ◽  
Author(s):  
Gobind Singh Thapar
Keyword(s):  
External Morphology ◽  
General Belief ◽  
Number Of Species ◽  
Single Genus

Of the various groups of Helminths, Acanthocephala has received the least attention from Helminthologists; so much so that even its classification is based on very arbitrary characters. This may partly be due to the general belief that infestation with these worms is very rare. The earlier accounts, such as that of Diesing (1851), which deals with a number of species from fishes, giving brief descriptions of their external morphology and a few generalised drawings, describe the various species under a single genus,Echinorhynchus.

Numerical classification of French vegetation of Carici caryophylleae – Genistetea lobelii J.-C. Klein 1972

2021 ◽  
Vol 42 ◽  
pp. e68062
Author(s):  
Pauline Delbosc ◽  
Mathieu Le Dez ◽  
Jean-Bernard Bouzillé ◽  
Kevin Cianfaglione ◽  
Frédéric Bioret
Keyword(s):  
Expert System ◽  
Dominant Species ◽  
Numerical Classification ◽  
Distribution Map ◽  
Diagnostic Species ◽  
Plant Associations ◽  
Formal Definitions ◽  
Twinspan Classification ◽  
New Association

Carici-Genistetea lobelii Klein 1972 corresponds to cyrno-sardinian oromediterranean cushion scrub and related grasslands. In France, this class is only present in Corsica and the syntaxonomic scheme is debated among phytosociologists. The aim of this paper is to highlight the main plant associations of Carici-Genistetea lobelii Klein 1972 and to define the diagnostic species for each phytosociological unit. We compiled 519 vegetation plots and we applied EuropeanVegetationChecklist expert system for the classes of European vegetation to retain only vegetation plots belonging to Carici-Genistetea lobelii. We obtained a dataset with 189 vegetation plots and we classified them with Modified TWINSPAN classification. Our analyses recognized 6 plant associations and 3 sub-associations already described in the literature; and to describe a new alliance corresponding to the supra-mediterranean vegetations (Genistion salzmannii), a new association (Brimeuro fastigiatae-Juniperetum nanae) and its sub-association (alnetosum suaveolentis). For each of them, we identified diagnostic, constant and dominant species and produced their distribution map. Formal definitions were then written for each phytosociological unit (from subassociation to class) and grouped in an expert system to automatically classify the vegetations of Carici-Genistetea lobelii.

Numerical Classification of Thermus Isolates from Globally Distributed Hot Springs

1989 ◽  
Vol 11 (3) ◽  
pp. 250-256 ◽  
Author(s):  
J. Andrew Hudson ◽  
Hugh W. Morgan ◽  
Roy M. Daniel
Keyword(s):  
Hot Springs ◽  
Numerical Classification ◽  
Globally Distributed

scholarly journals X.—The Aborigines of Tasmania. Part III. The Hair of the Head compared with that of other Ulotrichi and with Australians and Polynesians

1915 ◽  
Vol 50 (2) ◽  
pp. 309-347 ◽  
Author(s):  
William Turner
Keyword(s):  
New Guinea ◽  
The Other ◽  
Malay Peninsula ◽  
The Pacific ◽  
University Of Edinburgh ◽  
The Individual ◽  
The University

A number of years ago I began to form and arrange in the Anatomical Museum of the University of Edinburgh a collection of the hair of the head to illustrate the varieties in colour and character which exist in the Races of Men. In a classification of the races based on the colour and characters of the hair, anthropologists have usually adopted the suggestion made by Bory de St Vincent, and have divided them into two groups: Leiotrichi, with straight, smooth hair; and Ulotrichi, with woolly or frizzly hair. Each of these again is capable of subdivision.In this memoir I intend especially to examine the Ulotrichi, which comprise two well-marked subdivisions. In one the hair is very short, and is arranged in small spiral tufts, the individual hairs in which are twisted on each other, a mat-like arrangement of compact spiral locks closely set together being the result. In the other the hair is moderately long, the locks are slender, curled or spirally twisted in a part of their length and terminate at the free end in a frizzly bush-like arrangement. Ulotrichous hair is found in various African races, in the aborigines of Tasmania, New Guinea, the Melanesian Islands in the Pacific, in the Negritos of the Malay Peninsula and of some of the islands of the Asiatic Archipelago. The Leiotrichi are Australians, Polynesians, Mongols, Malays, Indians, Arabs, Esquimaux and Europeans.

A Global Phylogenomic Study of the Thelypteridaceae

2021 ◽  
Vol 46 (4) ◽  
pp. 891-915
Author(s):  
Susan Fawcett ◽  
Alan R. Smith ◽  
Michael Sundue ◽  
J. Gordon Burleigh ◽  
Emily B. Sessa ◽  
...  
Keyword(s):  
Morphological Characters ◽  
Morphological Evidence ◽  
Phylogenetic Studies ◽  
The Family ◽  
Likelihood Analysis ◽  
Single Genus ◽  
The Subject ◽  
Recent Classification ◽  
Phylogenomic Study

Abstract— The generic classification of the Thelypteridaceae has been the subject of much controversy. Proposed taxonomic systems have varied from recognizing the approximately 1200 species in the family within the single genus Thelypteris, to systems favoring upwards of 30 genera. Insights on intrafamilial relationships, especially for neotropical taxa, have been gained from recent phylogenetic studies; however, in the most recent classification, 10 of 30 recognized genera are either non-monophyletic or untested. We sequenced 407 nuclear loci for 621 samples, representing all recognized genera and approximately half the known species diversity. These were analyzed using both maximum likelihood analysis of a concatenated matrix and multi-species coalescent methods. Our phylogenomic results, informed by recently published morphological evidence, provide the foundation for a generic classification which recircumscribed 14 genera and recognized seven new genera. The 37 monophyletic genera sampled demonstrate greater geographic coherence than previous taxonomic concepts suggested. Additionally, our results demonstrate that certain morphological characters, such as frond division, are evolutionarily labile and are thus inadequate for defining genera.

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