Description of a new fossil diatom genus, Cribrionella gen. nov. (Bacillariophyta) from Quaternary sediments of Lake Ohrid

Phytotaxa ◽  
2016 ◽  
Vol 252 (1) ◽  
pp. 31
Author(s):  
ELENA JOVANOVSKA ◽  
ALEKSANDRA CVETKOSKA ◽  
SLAVICA TOFILOVSKA ◽  
NADJA OGNJANOVA-RUMENOVA ◽  
ZLATKO LEVKOV
Keyword(s):  
Evolutionary History ◽  
New Genus ◽  
Sensu Stricto ◽  
Lake Ohrid ◽  
Quaternary Sediments ◽  
Lake Prespa ◽  
The Family ◽  
Diatom Genus ◽  
History Of ◽  
Silicate Layers

A new diatom genus, Cribrionella gen. nov., is described from Quaternary sediments of Lake Ohrid. Cribrionella comprises distinct morphological features, such as: i) presence of submarginal alveoli followed by regularly or irregularly arranged areolae, ii) cribra on external areolar openings, iii) absence of silicate layers on internal areolar openings, but presence of thick and inwardly raised circumferential silica trabeculae, iv) rimoportulae positioned on costae, and v) absence of central fultoportulae. Detailed light and scanning electron microscope analyses were undertaken and used for comparison to morphologically related genera. The typus generis Cribrionella ohridana is compared to species from its morphologically closest genus Cyclotella sensu stricto (e.g., C. atomus, C. delicatula, C. bifacialis). Cribrionella ohridana has not been reported from the extant diatom flora of Lake Ohrid, nor in the nearby Lake Prespa. The discovery of a new genus in Lake Ohrid confirms again the importance of the lake, not only in light of species richness and endemicity, but also in evolutionary history of the family Stephanodiscaceae.

New cyriacotheriid pantodonts (Mammalia, Pantodonta) from the Paleocene of Alberta, Canada, and the relationships of Cyriacotheriidae

2010 ◽  
Vol 84 (2) ◽  
pp. 197-215 ◽  
Author(s):  
Craig S. Scott
Keyword(s):  
Phylogenetic Analysis ◽  
New Species ◽  
Fossil Record ◽  
Evolutionary History ◽  
New Genus ◽  
The Family ◽  
Two New Species ◽  
Unusual Combination ◽  
Early Paleocene ◽  
History Of

Cyriacotheriidae are a family of unusual small-bodied pantodonts known from the Paleocene of the Western Interior of North America. Cyriacotheriids possess a suite of dental characters similar to that of pantodonts (e.g., molar dilambdodonty, lingual molar hypoconulids), as well as several divergent features (e.g., molarized premolars, strong molar conules) that have been interpreted as “dermopteran-like.” the unusual combination of pantodont and dermopteran-like characters, combined with a limited fossil record, has made attempts at understanding the broader relationships of Cyriacotheriidae difficult. This paper reports on a new genus and two new species of cyriacotheriids from the Paleocene of Alberta, Canada, with both species significantly older than those of the only previously described cyriacotheriid, Cyriacotherium. Collectively, the dentitions of these new taxa exhibit derived characters seen in Cyriacotherium (e.g., robust molar conules, strong molar dilambdodonty) in addition to a number of plesiomorphies seen in more basal pantodonts (e.g., conspicuous molar entoconids, deep premolar ectoflexus) and, importantly, posterior premolars that are weakly molariform and non-dilambdodont. A phylogenetic analysis of the new cyriacotheriid, basal pantodonts, dermopterans, and dermopteran-like eutherians resulted in Cyriacotheriidae nesting within a monophyletic Pantodonta. the results strengthen previous hypotheses regarding the pantodont affinities of the family, and suggest that the dermopteran-like features seen in the more derived Cyriacotherium were acquired convergently. Although the discovery of new cyriacotheriids sheds light on the evolutionary history of the family, it cannot resolve the ongoing questions of pantodont origins; nonetheless, their discovery in strata of early Paleocene age indicates that significant parts of the evolutionary history of Cyriacotheriidae, and North American pantodonts more generally, have yet to be discovered.

Systematic evidence from gene duplication and regulation

1990 ◽  
Vol 3 (1) ◽  
pp. 145
Author(s):  
DJ Colgan
Keyword(s):  
Gene Duplication ◽  
Evolutionary History ◽  
Tandem Duplication ◽  
Fragment Length Polymorphism ◽  
Duplicate Genes ◽  
Polymorphism Analysis ◽  
Multiple Origins ◽  
The Family ◽  
History Of ◽  
Phylogenetic Hypotheses

This paper is a review of the use of information regarding the presence of duplicate genes and their regulation in systematics. The review concentrates on data derived from protein electrophoresis and restriction fragment length polymorphism analysis. The appearance of a duplication in a subset of a group of species implies that the members of the subset belong to the same clade. Suppression of the duplication may render this clade apparently paraphyletic, but may itself be informative of relations within the lineage through patterns of loss of expression in all, or some tissues, or through restrictions of the formation of functional heteropolymers in polymeric enzymes. Examples are given of studies which have used such information to establish phylogenetic hypotheses at the family level, to identify an auto- or allo-polyploid origin of polyploid species and to determine whether there have been single or multiple origins of such species. The likelihood of homoplasy in the patterns of appearance and regulation of duplicates depends on the molecular basis of the duplication. In particular, the contrast between the expected consequences of tandem duplication and the expression of pseudogenes emphasises the value of determining the mechanism of the original duplication. Many instances of sporadic gene duplication are now known, and polyploidisation is a common event in the evolutionary history of both plants and animals. So the opportunities to discover duplicationrelated characters will arise in many systematic studies. A program is presented to increase the chances that such useful information will be recognisable during the studies.

Cymatosirella Dąbek, Witkowski & Sabbe gen. nov., a new marine benthic diatom genus (Bacillariophyta) belonging to the family Cymatosiraceae

Phytotaxa ◽  
2014 ◽  
Vol 183 (2) ◽  
pp. 120
Author(s):  
PRZEMYSŁAW DĄBEK ◽  
KOEN SABBE ◽  
ANDRZEJ WITKOWSKI ◽  
COLIN ARCHIBALD ◽  
KRZYSZOF J. KURZYDŁOWSKI ◽  
...  
Keyword(s):  
New Genus ◽  
Light And Electron Microscopy ◽  
Benthic Diatom ◽  
Western Cape ◽  
Western Cape Province ◽  
Line Drawings ◽  
The Family ◽  
Diatom Genus ◽  
Electron Microscopical ◽  
First Time

We present a new marine benthic diatom genus Cymatosirella gen. nov. The genus belongs to the family Cymatosiraceae and has been assigned to the subfamily Extubocelluloideae on the basis of ultrastructural cell wall features. It has isovalvate cells with undulate valves and is characterized by the absence of tubular processes and the occurrence of hollow spines which are observed for the first time in the Cymatosiraceae. The new genus contains four species, two of which are transferred from the genus Cymatosira, viz. Cymatosirella capensis comb. nov. and Cymatosirella minutissima comb. nov., and two which are new to science, viz. Cymatosirella benguelensis sp. nov. and Cymatosirella taylorii sp. nov. Cymatosirella capensis is chosen as the generitype. The new genus includes a group of very small taxa inhabiting the intertidal zone of the Atlantic Ocean with three species in South Africa and one in Europe. C. capensis was originally described by Giffen from Langebaan Lagoon (a shallow marine inlet in the southern part of Saldanha Bay, Western Cape Province), on the basis of light microscopy only, and has to date only been illustrated by line drawings. C. minutissima, so far only known from the Westerschelde estuary (The Netherlands), has previously been documented in more detail using both light and electron microscopy. Here, we present the results of detailed light and electron microscopical investigations of C. capensis, both from its original type material and from recently collected samples from the type locality and neighboring littoral areas in the Western Cape Province, and of the new species C. benguelensis and C. taylorii, also from Western Cape localities. All species are compared with similar small taxa belonging to the Cymatosiraceae, subfamily Extubocelluloideae.

Systematics and biogeography of the “Metacryphaeus group” Calmoniidae (Trilobita, Devonian), with comments on adaptive radiations and the geological history of the Malvinokaffric Realm

1993 ◽  
Vol 67 (4) ◽  
pp. 549-570 ◽  
Author(s):  
Bruce S. Lieberman
Keyword(s):  
New Species ◽  
South African ◽  
Evolutionary History ◽  
Geological History ◽  
Parsimony Analysis ◽  
Evolutionary Patterns ◽  
The Family ◽  
History Of ◽  
Adaptive Radiations ◽  
Rapid Diversification

Phylogenetic parsimony analysis was used to classify the Siegenian–Eifelian “Metacryphaeus group” of the family Calmoniidae. Thirty-eight exoskeletal characters for 16 taxa produced a shortest-length cladogram with a consistency index of 0.49. A classification based on retrieving the structure of this cladogram recognizes nine genera: Typhloniscus Salter, Plesioconvexa n. gen., Punillaspis Baldis and Longobucco, Eldredgeia n. gen., Clarkeaspis n. gen., Malvinocooperella n. gen., Wolfartaspis Cooper, Plesiomalvinella Lieberman, Edgecombe, and Eldredge (used to represent the malvinellid clade), and Metacryphaeus Reed. The malvinellid clade is most closely related to a revised monophyletic Metacryphaeus. Typhloniscus is the basal member of the “Metacryphaeus group,” and the monotypic Wolfartaspis is sister to the clade containing the malvinellids and Metacryphaeus. Six new species are diagnosed: Punillaspis n. sp. A, “Clarkeaspis” gouldi, Clarkeaspis padillaensis, Malvinocooperella pregiganteus, Metacryphaeus curvigena, and Metacryphaeus branisai. Primitively, this group has South African and Andean affinities, and its evolutionary history suggests rapid diversification. In addition, evolutionary patterns in this group, and the distribution of character reversals, call into question certain notions about the nature of adaptive radiations. The distributions of taxa may answer questions about the number of marine transgressive/regressive cycles in the Emsian–Eifelian of the Malvinokaffric Realm.

Adaptive convergent evolution of genome proofreading in SARS-CoV2: insights into the Eigen’s paradox

2021 ◽  
Author(s):  
Keerthic Aswin ◽  
Srinivasan Ramachandran ◽  
Vivek T Natarajan
Keyword(s):  
Convergent Evolution ◽  
Genome Stability ◽  
Evolutionary History ◽  
Rna Binding ◽  
Phylogenetic Analyses ◽  
Comparative Genome Analysis ◽  
The Family ◽  
History Of ◽  
Key Residues

AbstractEvolutionary history of coronaviruses holds the key to understand mutational behavior and prepare for possible future outbreaks. By performing comparative genome analysis of nidovirales that contain the family of coronaviruses, we traced the origin of proofreading, surprisingly to the eukaryotic antiviral component ZNFX1. This common recent ancestor contributes two zinc finger (ZnF) motifs that are unique to viral exonuclease, segregating them from DNA proof-readers. Phylogenetic analyses indicate that following acquisition, genomes of coronaviruses retained and further fine-tuned proofreading exonuclease, whereas related families harbor substitution of key residues in ZnF1 motif concomitant to a reduction in their genome sizes. Structural modelling followed by simulation suggests the role of ZnF in RNA binding. Key ZnF residues strongly coevolve with replicase, and the helicase involved in duplex RNA unwinding. Hence, fidelity of replication in coronaviruses is a result of convergent evolution, that enables maintenance of genome stability akin to cellular proofreading systems.

Rautangaroa, a new genus of feather star (Echinodermata, Crinoidea) from the Oligocene of New Zealand

2018 ◽  
Vol 92 (5) ◽  
pp. 872-882 ◽  
Author(s):  
Tomasz K. Baumiller ◽  
R. Ewan Fordyce
Keyword(s):  
New Zealand ◽  
Detailed Analysis ◽  
Evolutionary History ◽  
New Genus ◽  
Intact Specimen ◽  
History Of ◽  
Recovered Material ◽  
Feather Star ◽  
Established Genus

AbstractWe describe a nearly complete, and thus extremely rare, feather star (Crinoidea, Comatulida) from Oligocene strata of North Otago/South Canterbury, New Zealand. A detailed analysis of this specimen, as well as newly recovered material and previously described fragmentary remains from nearby contemporaneous sedimentary units, in addition to relevant historical specimens, lead us to conclude that it cannot be placed in any currently established genus. A new genus,Rautangaroa,is proposed to accommodate it.This intact specimen ofRautangaroa aotearoa(Eagle, 2007), provides rare data on the morphology of arms and cirri. It represents the first example of arm autotomy and regeneration in a fossil feather star and thus has bearing on the importance of predation to the evolutionary history of this group.UUID:http://zoobank.org/c050dafd-93ba-4334-b11b-59209aabb588

Human Evolution

1984 ◽  
Vol 8 ◽  
pp. 182-198
Author(s):  
Catherine Badgley
Keyword(s):  
Human Evolution ◽  
Evolutionary History ◽  
Pan Paniscus ◽  
Homo Sapiens ◽  
Great Apes ◽  
Sister Group ◽  
The Family ◽  
History Of ◽  
Living Species ◽  
Single Living

The evolutionary history of humans is well understood in outline, compared to that of many other groups of mammals. But human evolution remains enigmatic in its details, and these are compelling both scientifically and personally because they relate to the biological uniqueness of humans. Humans are placed in the primate family Hominidae, which, in traditional classifications, contains a single living species, Homo sapiens. The closest living relatives of humans are great apes: the chimpanzees Pan paniscus and Pan troglodytes, the gorilla Gorilla gorilla, and the orangutan Pongo pygmaeus. These apes have traditionally been placed in the family Pongidae as the sister group of Hominidae. Living Hominidae and Pongidae, together with Hylobatidae (gibbons) comprise the modern representatives of the primate suborder Hominoidea.

scholarly journals Evolution and taxonomy of nematode-associated entomopathogenic bacteria of the genera Xenorhabdus and Photorhabdus: an overview

Symbiosis ◽  
2020 ◽  
Vol 80 (1) ◽  
pp. 1-13 ◽  
Author(s):  
Ewa Sajnaga ◽  
Waldemar Kazimierczak
Keyword(s):  
Evolutionary History ◽  
Entomopathogenic Nematode ◽  
Bacterial Species ◽  
Entomopathogenic Bacteria ◽  
Insecticidal Toxins ◽  
The Family ◽  
The World ◽  
History Of ◽  
Phylogenetic Origin ◽  
Animal Hosts

AbstractEntomopathogenic bacteria from the genera Photorhabdus and Xenorhabdus are closely related Gram-negative bacilli from the family Enterobacteriaceae (γ-Proteobacteria). They establish obligate mutualistic associations with soil nematodes from the genera Steinernema and Heterorhabditis to facilitate insect pathogenesis. The research of these two bacterial genera is focused mainly on their unique interactions with two different animal hosts, i.e. nematodes and insects. So far, studies of the mutualistic bacteria of nematodes collected from around the world have contributed to an increase in the number of the described Xenorhabdus and Photorhabdus species. Recently, the classification system of entomopatogenic nematode microsymbionts has undergone profound revision and now 26 species of the genus Xenorhabdus and 19 species of the genus Photorhabdus have been identified. Despite their similar life style and close phylogenetic origin, Photorhabdus and Xenorhabdus bacterial species differ significantly in e.g. the nematode host range, symbiotic strategies for parasite success, and arrays of released antibiotics and insecticidal toxins. As the knowledge of the diversity of entomopathogenic nematode microsymbionts helps to enable the use thereof, assessment of the phylogenetic relationships of these astounding bacterial genera is now a major challenge for researchers. The present article summarizes the main information on the taxonomy and evolutionary history of Xenorhabdus and Photorhabdus, entomopathogenic nematode symbionts.

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