Tetrapod Evolution

2014 ◽  
Author(s):  
Michel Laurin
Keyword(s):  
Fossil Record ◽  
Molecular Phylogenetics ◽  
Minor Component ◽  
Early Carboniferous ◽  
Early Devonian ◽  
Extant Species ◽  
Extinction Events ◽  
A Minor ◽  
Tetrapod Evolution ◽  
Mass Extinction Events

Tetrapods include all extant limbed vertebrates (and those that lost limbs, such as gymnophionans and snakes) and many or all extinct ones (depending on the adopted definition). This large clade is represented by over 21,000 extant species: more than 7,000 species of extant amphibians and more than 13,000 species of amniotes, which include mammals and reptiles, the latter also including birds in many recent taxonomies. The origin of tetrapods can be followed back into the Early Devonian (419–393 million years ago), shortly after tetrapodomorphs (as stem-tetrapods are called) diverged from dipnomorphs (the largest clade that includes lungfishes but not tetrapods). The first tetrapodomorphs retained paired fins, but by the Middle Devonian (393–383 million years ago), the first limbed vertebrates had appeared. The tetrapod crown (the smallest clade that includes lissamphibians and amniotes) first appears in the fossil record in the Early Carboniferous. The group subsequently diversified fairly quickly and occupied a diversity of habitats (saltwater, freshwater, and terrestrial) by the Early Carboniferous. Amniotes appeared no later than about 317 million years ago (Ma), although they remained a minor component of the terrestrial biota until the Early Permian. The origin of turtles remains contentious, but the first undisputed stem-turtle and lepidosauromorphs (squamates, Sphenodon, and extinct relatives) are known from the Triassic, whereas archosauromorphs (which include birds and crocodiles) can be traced back to the Late Permian. Much of what we know about early tetrapod evolution is based on the fossil record, but our understanding of the subsequent evolution of the group has progressed tremendously in recent years through molecular phylogenetics. This article is organized into thematic sections, such as tetrapod origins, biodiversity evolution, and mass extinction events, as well as systematic sections that deal with various clades, especially (but not only) extant ones. Throughout, the emphasis has been on recent papers because their bibliographies usually include references to older, influential publications, although some older, very important papers are covered too.

The Fossil Record of the Pancrustacea

2020 ◽  
pp. 21-52 ◽  
Author(s):  
Thomas A. Hegna ◽  
Javier Luque ◽  
Joanna M. Wolfe
Keyword(s):  
Fossil Record ◽  
Hydrothermal Vents ◽  
Molecular Phylogenetics ◽  
Imaging Techniques ◽  
Extant Species ◽  
Evolutionary Studies ◽  
Molecular Phylogenetic ◽  
Terrestrial Habitats ◽  
Molecular Phylogenetic Data

Fossils are critically important for evolutionary studies as they provide the link between geological ages and the phylogeny of life. The Pancrustacea are an incredibly diverse clade, representing over 800,000 described extant species, encompassing a variety of familiar and unfamiliar forms, such as ostracods, tongue worms, crabs, lobsters, shrimps, copepods, barnacles, branchiopods, remipedes, and insects. Having colonized nearly every environment on Earth, from hydrothermal vents to terrestrial habitats, they have a diverse fossil record dating back to the Cambrian (540–485 Ma). The quality of the fossil record of each clade is variable and related to their lifestyle (e.g., free-living versus parasitic, benthic versus pelagic) and the degree of mineralization of their cuticle. We review the systematics, morphology, preservation, and paleoecology of pancrustacean fossils; each major clade is discussed in turn, and, where possible, fossil systematics are compared with more recent data from molecular phylogenetics. We show that the three epic clades of the Pancrustacea—Allotriocarida, Multicrustacea, and Oligostraca—all have Cambrian roots, but the diversification of those clades did not take place until the Middle and Late Paleozoic. We also address the potential affinities of three “problematic” clades: euthycarcinoids, thylacocephalans, and cyclids. We conclude by assessing the future of pancrustacean paleobiology, discussing new morphological imaging techniques and further integration with growing molecular phylogenetic data.

A mixed-feeding Equus species from the middle pleistocene of South Africa

2004 ◽  
Vol 62 (3) ◽  
pp. 316-323 ◽  
Author(s):  
Thomas M. Kaiser ◽  
Tamara A. Franz-Odendaal
Keyword(s):  
South Africa ◽  
Minor Component ◽  
Middle Pleistocene ◽  
Feeding Strategies ◽  
Mixed Feeding ◽  
Dietary Flexibility ◽  
Extant Species ◽  
Dietary Strategy ◽  
Mammalian Herbivore ◽  
A Minor

The dietary regime of Equus capensis from the Middle Pleistocene of South Africa is investigated by mesowear analysis. Results indicate that the mesowear signature of this species resembles that of two extant mixed feeders, the Grant's Gazelle (Gazella granti) and the Thomson's Gazelle (Gazella thomsoni), suggesting a mixed feeding dietary strategy for E. capensis. The mesowear signature of a contemporaneous population of Equus mosbachensis from Europe (Arago, France) is also determined for comparative purposes and has a typical grazing signature. In general, all extant species of Equus are believed to be almost exclusively grazers. However, a considerable degree of dietary flexibility is recently reported. The dietary signal of E. capensis is considered to be the result of feeding on the unique fynbos vegetation, which was beginning to establish itself at this time in southwestern South Africa. Grasses are a minor component of this floral kingdom. Our findings thus provide further evidence for the unexpected flexibility in feeding strategies of Equus, the most widely distributed equid taxon in the Quaternary. They highlight the potential use of the attrition"abrasion wear equilibrium as a habitat indicator, by mirroring the availability of food items in mammalian herbivore ecosystems.

Mass extinction events and the plant fossil record

2007 ◽  
Vol 22 (10) ◽  
pp. 548-557 ◽  
Author(s):  
Jennifer C. McElwain ◽  
Surangi W. Punyasena
Keyword(s):  
Mass Extinction ◽  
Fossil Record ◽  
Plant Fossil ◽  
Extinction Events ◽  
Mass Extinction Events

Evidence for extinction selectivity throughout the marine invertebrate fossil record

Paleobiology ◽  
2009 ◽  
Vol 35 (4) ◽  
pp. 553-564 ◽  
Author(s):  
G. Alex Janevski ◽  
Tomasz K. Baumiller
Keyword(s):  
Species Richness ◽  
Mass Extinction ◽  
Fossil Record ◽  
Marine Invertebrate ◽  
Species Level ◽  
Geologic History ◽  
Extinction Selectivity ◽  
Extinction Events ◽  
Open Question ◽  
Mass Extinction Events

The fossil record has been used to show that in some geologic intervals certain traits of taxa may increase their survivability, and therefore that the risk of extinction is not randomly distributed among taxa. It has also been suggested that traits that buffer against extinction in background times do not confer the same resistance during mass extinction events. An open question is whether at any time in geologic history extinction probabilities were randomly distributed among taxa. Here we use a method for detecting random extinction to demonstrate that during both background and mass extinction times, extinction of marine invertebrate genera has been nonrandom with respect to species richness categories of genera. A possible cause for this nonrandom extinction is selective clustering of extinctions in genera consisting of species which possess extinction-biasing traits. Other potential causes considered here include geographic selectivity, increased extinction susceptibility for species in species-rich genera, or biases related to taxonomic practice and/or sampling heterogeneity. An important theoretical result is that extinction selectivity at the species level cannot be smoothly extrapolated upward to genera; the appearance of random genus extinction with respect to species richness of genera results when extinction has been highly selective at the species level.

Molecules, Morphology, Fossils and the Origination and Extinction Dynamics of Scleractinian Corals

2011 ◽  
Vol 17 ◽  
pp. 61-77
Author(s):  
Marcos S. Barbeitos
Keyword(s):  
Coral Reefs ◽  
Fossil Record ◽  
Molecular Phylogenetics ◽  
Evolutionary Dynamics ◽  
Scleractinian Corals ◽  
Future Research ◽  
Marine Biodiversity ◽  
Mass Extinctions ◽  
Extant Species ◽  
The Impact

The history of Scleractinian corals, richly documented by the fossil record, is one of complex dynamics linked to the dynamics of coral reefs themselves. In spite of all the waxing and waning of marine biodiversity throughout the post-Paleozoic, scleractinians have remained remarkably resilient as a lineage and have traversed two mass extinctions and repeated episodes of global change before becoming the chief builders of modern coral reefs. Understanding this history becomes all the more relevant in face of the current human driven coral reef biodiversity crisis. The advent of molecular phylogenetics has changed our perspective of those dynamics because it has uncovered pervasive morphological convergence in traditionally used taxonomic characters, revealing that the current classification is highly artificial. Taxonomy not only obscures important patterns, but also introduces artifacts into estimates of origination and extinction obtained directly from the fossil record. I present a brief review of the impact of molecular phylogenetics on the current understanding of coral evolution, with emphasis on the recently uncovered phyletic link between photosymbiotic, reef dwelling and azooxanthellate, deepwater coral biota. Then, I discuss the role of molecular-based techniques in a future research agenda of the evolutionary dynamics of the order. The greatest challenge for the future is the re-assessment of morphological characters from a cladistic perspective so that extinct and extant species are integrated in a unified phylogenetic framework, allowing rigorous testing of hypotheses on the fascinating biodiversity dynamics of the order.

scholarly journals Myotis Gerhardstorchi Sp. N. and Comments on the European Fossil Record of Myotis Frater Group (Mammalia, Chiroptera)

2019 ◽  
Vol 75 (3-4) ◽  
pp. 315-342
Author(s):  
Ivan Horáček ◽  
Eva Trávníčková
Keyword(s):  
Fossil Record ◽  
Molecular Phylogenetics ◽  
Early Pleistocene ◽  
Late Cenozoic ◽  
The Czech Republic ◽  
European Species ◽  
Fossil Material ◽  
Extant Species ◽  
History Of ◽  
A New Species

Abstract A new species, Myotis gerhardstorchi sp. n., supposedly close to M. sicarius and M. frater group, is described from MN 15 site Beremend 26 (Hungary). M. frater group, now restricted to vicariant ranges in E Asia, Siberia and Central Asia, is further reported from three Pliocene and two Early Pleistocene mass bat assemblages from the Czech Republic, Poland and Slovakia. The odontological diagnosis of the group is presented, together with comparisons of the fossil material with extant species of the group, and W Palearctic taxa of the genus, both fossil and Recent. Molecular phylogenetics reveals that the above-mentioned Asiatic taxa, together with the European species M. daubentonii and M. bechsteinii, the index fossil of the W Palearctic Late Cenozoic bat communities, compose a distinct phylogenetic entity called Myotis Clade III. Here we argue that the history of Clade III in the W Palearctics was contributed also by clades close to its stem line, and those related to the Asiatic forms that later disappeared from that region. Finally, a list of taxa, both fossil and Recent, composing the Myotis Clade III is provided.

Protonation effects on dynamic flux properties of aqueous metal complexes

2009 ◽  
Vol 74 (10) ◽  
pp. 1543-1557 ◽  
Author(s):  
Herman P. Van Leeuwen ◽  
Raewyn M. Town
Keyword(s):  
Complex Formation ◽  
Metal Ion ◽  
Good Description ◽  
Minor Component ◽  
Outer Sphere ◽  
Metal Species ◽  
Central Metal ◽  
Inner Sphere ◽  
A Minor ◽  
Protonated Ligand

The degree of (de)protonation of aqueous metal species has significant consequences for the kinetics of complex formation/dissociation. All protonated forms of both the ligand and the hydrated central metal ion contribute to the rate of complex formation to an extent weighted by the pertaining outer-sphere stabilities. Likewise, the lifetime of the uncomplexed metal is determined by all the various protonated ligand species. Therefore, the interfacial reaction layer thickness, μ, and the ensuing kinetic flux, Jkin, are more involved than in the conventional case. All inner-sphere complexes contribute to the overall rate of dissociation, as weighted by their respective rate constants for dissociation, kd. The presence of inner-sphere deprotonated H2O, or of outer-sphere protonated ligand, generally has a great impact on kd of the inner-sphere complex. Consequently, the overall flux can be dominated by a species that is a minor component of the bulk speciation. The concepts are shown to provide a good description of experimental stripping chronopotentiometric data for several protonated metal–ligand systems.

Modeling Extinction

2003 ◽  
Author(s):  
M. E. J. Newman ◽  
R. G. Palmer
Keyword(s):  
Evolutionary Biology ◽  
Large Scale ◽  
Competitive Exclusion ◽  
Applied Mathematics ◽  
Santa Fe ◽  
New Approach ◽  
Self Organized ◽  
Self Organized Criticality ◽  
Extinction Events ◽  
Mass Extinction Events

Developed after a meeting at the Santa Fe Institute on extinction modeling, this book comments critically on the various modeling approaches. In the last decade or so, scientists have started to examine a new approach to the patterns of evolution and extinction in the fossil record. This approach may be called "statistical paleontology," since it looks at large-scale patterns in the record and attempts to understand and model their average statistical features, rather than their detailed structure. Examples of the patterns these studies examine are the distribution of the sizes of mass extinction events over time, the distribution of species lifetimes, or the apparent increase in the number of species alive over the last half a billion years. In attempting to model these patterns, researchers have drawn on ideas not only from paleontology, but from evolutionary biology, ecology, physics, and applied mathematics, including fitness landscapes, competitive exclusion, interaction matrices, and self-organized criticality. A self-contained review of work in this field.

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