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Current Biology : CB May 2023In the early 19th century, long before the discovery of the dinosaurs, scientists and the public alike were faced with the realization that strange beasts, wholly...
In the early 19th century, long before the discovery of the dinosaurs, scientists and the public alike were faced with the realization that strange beasts, wholly extinct, were once populating Earth's ancient oceans. In no small part, this realization was through the discovery of the first plesiosaurs (and ichthyosaurs) along the Dorset coast of England in the seaside town of Lyme Regis. There was this large marine reptile resembling a large sea turtle, but with four evenly shaped flippers and looking as though a large snake had been pulled through its carapace. It was soon to be named scientifically Plesiosaurus, in reference to its greater similarity to living reptiles than the Ichthyosaurus (Figure 1). While the Ichthyosaurus was relatively easily understood as a fish-shaped reptile descended from land-living ancestors, the Plesiosaurus was beyond comprehension, even though incomplete skeletons had been unearthed already in the early 18th century. Plesiosaurs seemed so alien that the first complete skeleton, discovered by the famed Mary Anning a little more than 200 years ago (Figure 1A), was considered a fake by the leading anatomist of the day, the Baron Georges Cuvier in Paris. Only study of the original specimen convinced him of the authenticity of this animal but reinforced his seminal insight that there is extinction.
Topics: Animals; Male; Animal Shells; Dinosaurs; England; Environment
PubMed: 37220726
DOI: 10.1016/j.cub.2023.04.018 -
Current Biology : CB Oct 2021Global trade of wildlife is a major driver of species decline. The trade in wildlife actually plays a much larger role in our daily lives than many people realize, and...
Global trade of wildlife is a major driver of species decline. The trade in wildlife actually plays a much larger role in our daily lives than many people realize, and its use and legality are surprisingly complex. Wildlife trade includes the trade of any organism, including fungi, plants and animals, sourced from the wild. This comprises thousands of wild species, including over 7600, or nearly one quarter, of terrestrial vertebrate species. Trade in wildlife is worth billions annually via commercial fishing at $180 billion, timber at $227 billion and fashion at $2.5 billion - in addition to largely unquantified trade for meat, medicine, ornamental use and pets. Wildlife trade, such as that of ivory, is the subject of intense public debate, international regulation and criminal prosecution, while trade of other species is more often overlooked. How wildlife trade is regulated and what is legal and illegal varies both between and within taxonomic groups and depends on where and how trade occurs. Wildlife trade across most sectors has increased since monitoring began, for example, between 1996 and 2018 the global fish market rose from $40 billion to $180 billion, wood from $65 billion to $137 billion and reptile leather for fashion trade from $140 million to $600 million. In concert, the annual number of trades legally traded through CITES has also grown, from under 5000 transactions in 1977 to peaking at over 1.3 million in 2015, with shipment size increasing in parallel and seizures of illegally traded species showing similar trends. Balancing the needs of people for livelihood generation, especially with access and benefit-sharing rights, with the impact on species survival remains difficult. Issues like the role of trophy and sports hunting within conservation remain a topic of debate in the conservation community. Finding approaches that enable long-term species survival, are equitable and do not undermine livelihoods is a constant challenge.
Topics: Animals; Animals, Wild; Commerce; Conservation of Natural Resources; Humans; Meat; Reptiles
PubMed: 34637735
DOI: 10.1016/j.cub.2021.08.056 -
Current Biology : CB Sep 2022Catania provides an introduction to tentacled snakes and their ingenious ability to capture fish.
Catania provides an introduction to tentacled snakes and their ingenious ability to capture fish.
Topics: Animals; Colubridae; Fishes; Snakes
PubMed: 36167038
DOI: 10.1016/j.cub.2022.08.003 -
Philosophical Transactions of the Royal... Mar 2020The Archosauria are a highly successful group of vertebrates, and their evolution is marked by the appearance of diverse respiratory and metabolic strategies. This... (Review)
Review
The Archosauria are a highly successful group of vertebrates, and their evolution is marked by the appearance of diverse respiratory and metabolic strategies. This review examines respiratory function in living and fossil archosaurs, focusing on the anatomy and biomechanics of the respiratory system, and their physiological consequences. The first archosaurs shared a heterogeneously partitioned parabronchial lung with unidirectional air flow; from this common ancestral lung morphology, we trace the diverging respiratory designs of bird- and crocodilian-line archosaurs. We review the latest evidence of osteological correlates for lung structure and the presence and distribution of accessory air sacs, with a focus on the evolution of the avian lung-air sac system and the functional separation of gas exchange and ventilation. In addition, we discuss the evolution of ventilation mechanics across archosaurs, citing new biomechanical data from extant taxa and how this informs our reconstructions of fossils. This improved understanding of respiratory form and function should help to reconstruct key physiological parameters in fossil taxa. We highlight key events in archosaur evolution where respiratory physiology likely played a major role, such as their radiation at a time of relative hypoxia following the Permo-Triassic mass extinction, and their evolution of elevated metabolic rates. This article is part of the theme issue 'Vertebrate palaeophysiology'.
Topics: Alligators and Crocodiles; Animals; Biological Evolution; Birds; Fossils; Reptiles; Respiration
PubMed: 31928195
DOI: 10.1098/rstb.2019.0140 -
Genes Aug 2019In this contribution, the aspects of reptile and amphibian speciation that emerged from research performed over the past decade are reviewed. First, this study assesses... (Review)
Review
In this contribution, the aspects of reptile and amphibian speciation that emerged from research performed over the past decade are reviewed. First, this study assesses how patterns and processes of speciation depend on knowing the taxonomy of the group in question, and discuss how integrative taxonomy has contributed to speciation research in these groups. This study then reviews the research on different aspects of speciation in reptiles and amphibians, including biogeography and climatic niches, ecological speciation, the relationship between speciation rates and phenotypic traits, and genetics and genomics. Further, several case studies of speciation in reptiles and amphibians that exemplify many of these themes are discussed. These include studies of integrative taxonomy and biogeography in South American lizards, ecological speciation in European salamanders, speciation and phenotypic evolution in frogs and lizards. The final case study combines genomics and biogeography in tortoises. The field of amphibian and reptile speciation research has steadily moved forward from the assessment of geographic and ecological aspects, to incorporating other dimensions of speciation, such as genetic mechanisms and evolutionary forces. A higher degree of integration among all these dimensions emerges as a goal for future research.
Topics: Amphibians; Animals; Ecosystem; Evolution, Molecular; Genetic Speciation; Reptiles; Selection, Genetic
PubMed: 31455040
DOI: 10.3390/genes10090646 -
Nature Mar 2023The germline mutation rate determines the pace of genome evolution and is an evolving parameter itself. However, little is known about what determines its evolution, as...
The germline mutation rate determines the pace of genome evolution and is an evolving parameter itself. However, little is known about what determines its evolution, as most studies of mutation rates have focused on single species with different methodologies. Here we quantify germline mutation rates across vertebrates by sequencing and comparing the high-coverage genomes of 151 parent-offspring trios from 68 species of mammals, fishes, birds and reptiles. We show that the per-generation mutation rate varies among species by a factor of 40, with mutation rates being higher for males than for females in mammals and birds, but not in reptiles and fishes. The generation time, age at maturity and species-level fecundity are the key life-history traits affecting this variation among species. Furthermore, species with higher long-term effective population sizes tend to have lower mutation rates per generation, providing support for the drift barrier hypothesis. The exceptionally high yearly mutation rates of domesticated animals, which have been continually selected on fecundity traits including shorter generation times, further support the importance of generation time in the evolution of mutation rates. Overall, our comparative analysis of pedigree-based mutation rates provides ecological insights on the mutation rate evolution in vertebrates.
Topics: Animals; Female; Male; Birds; Evolution, Molecular; Fishes; Germ-Line Mutation; Mammals; Mutation Rate; Reptiles; Vertebrates
PubMed: 36859541
DOI: 10.1038/s41586-023-05752-y -
Brain, Behavior and Evolution 2022The author previously worked extensively on the broad problem of the evolution of the vertebrate pallium. He proposed various Bauplan models covering at least...
The author previously worked extensively on the broad problem of the evolution of the vertebrate pallium. He proposed various Bauplan models covering at least gnathostomes, based in the definition of a set of pallial sectors with topologically invariant positional relationships and distinct molecular profiles. Out of one of these models, presented as the "updated tetrapartite pallium model," a modified definition of the earlier lateral pallium sector (LPall) concept emerged, characterizing it in mammals as an unitary claustro-insular transitional (mesocortical) complex intercalated between the neocortex or dorsal pallium (DPall) above and olfactory cortex or ventral pallium (VPall) underneath. A distinctive molecular marker of the early-born deep claustral component of the LPall was found to be the transcription factor Nr4a2, which is not expressed significantly in the overlying insular cortex or in adjoining cortical territories. Given that earlier comparative studies had identified molecularly and topologically comparable VPall, LPall, and DPall sectors in the avian pallium, an avian Nr4a2 probe was applied, aiming to identify the reportedly absent avian claustro-insular complex. An early-born superficial subpopulation of the avian LPall that expresses this marker selectively through development was indeed found. This was proposed to be a claustrum homolog, whereas the remaining Nr4a2-negative avian LPall cells were assumed to represent a possible insular homolog. This last notion was subsequently supported by comparable selective expression of the mouse insular marker Cyp26b, also found restricted to the avian LPall. Some published data suggested that similar molecular properties and structure apply at the reptilian LPall. This analysis was reviewed in Puelles et al. [The pallium in reptiles and birds in the light of the updated tetrapartite pallium model. 2017]. Four years on, the present commentary discusses some international publications accrued in the interval that touch on the claustro-insular homology hypothesis. Some of them are opposed to the hypothesis whereas others corroborate or support it. This raises a number of secondary issues of general interest.
Topics: Animals; Birds; Mammals; Mice; Reptiles; Transcription Factors
PubMed: 34753135
DOI: 10.1159/000520742 -
Biology Letters Apr 2022In amniotes, daily rates of dentine formation in non-ever-growing teeth range from less than 1 to over 25 μm per day. The latter value has been suggested to represent...
In amniotes, daily rates of dentine formation in non-ever-growing teeth range from less than 1 to over 25 μm per day. The latter value has been suggested to represent the upper limit of odontoblast activity in non-ever-growing teeth, a hypothesis supported by the lack of scaling between dentine apposition rates and body mass in Dinosauria. To determine the correlates and potential controls of dentine apposition rate, we assembled a dataset of apposition rates, metabolic rates and body masses for 80 amniote taxa of diverse ecologies and diets. We used phylogenetic regression to test for scaling relationships and reconstruct ancestral states of daily dentine apposition across Amniota. We find no relationship between body mass and daily dentine apposition rate (DDAR) for non-ever-growing teeth in Amniota as a whole or within major clades. Metabolic rate, the number of tooth generations, diet and habitat also do not predict or correspond with DDARs. Similar DDARs are found in large terrestrial mammals, dinosaurs and marine reptiles, whereas primates, cetaceans and some smaller marine reptiles independently evolved exceptionally slow rates. Life-history factors may explain the evolution of dentine apposition rates, which evolved rapidly at the origin of major clades.
Topics: Animals; Dentin; Dinosaurs; Mammals; Phylogeny; Reptiles; Tooth
PubMed: 35472282
DOI: 10.1098/rsbl.2022.0092 -
Seminars in Nuclear Medicine Sep 2023The bulk of biomedical positron emission tomography (PET)-scanning experiments are performed on mammals (ie, rodents, pigs, and dogs), and the technique is only... (Review)
Review
The bulk of biomedical positron emission tomography (PET)-scanning experiments are performed on mammals (ie, rodents, pigs, and dogs), and the technique is only infrequently applied to answer research questions in ectothermic vertebrates such as fish, amphibians, and reptiles. Nevertheless, many unique and interesting physiological characteristics in these ectothermic vertebrates could be addressed in detail through PET. The low metabolic rate of ectothermic animals, however, may compromise the validity of physiological and biochemical parameters derived from the images created by PET and other scanning modalities. Here, we review some of the considerations that should be taken into account when PET scanning fish, amphibians, and reptiles. We present specific results from our own experiments, many of which remain previously unpublished, and we draw on examples from the literature. We conclude that knowledge on the natural history and physiology of the species studied and an understanding of the limitations of the PET scanning techniques are necessary to avoid the design of faulty experiments and erroneous conclusions.
Topics: Animals; Swine; Dogs; Vertebrates; Reptiles; Amphibians; Fishes; Positron-Emission Tomography; Mammals
PubMed: 37438172
DOI: 10.1053/j.semnuclmed.2023.06.006 -
Journal of Ethnobiology and... May 2021Mexico harbours one of the greatest biocultural diversities of the world, where multiple social and natural elements and systems form complex networks of interactions in...
BACKGROUND
Mexico harbours one of the greatest biocultural diversities of the world, where multiple social and natural elements and systems form complex networks of interactions in which both culture and nature are mutually influenced. Biocultural states and processes are studied by ethnosciences, among them ethnoherpetology, which seeks understanding material and non-material expressions of the interactions between humans, amphibians, and reptiles. Herpetofauna has been part of the magic-religious world and source of goods for Mesoamerican cultures. This study aims to document and analyse the complex body of knowledge, beliefs, and practices on these vertebrates in the Nahua culture, the factors that have influenced progressive risk and loss of culture, habitat, and species, and the potential contribution of contemporary Nahua knowledge to biocultural conservation.
METHODS
Through 15 workshops with children and young people, and 16 semi-structured interviews to people 27 to 74 years old, we documented the contemporary Nahua knowledge in the communities of Aticpac and Xaltepec in the Sierra Negra, Puebla, central Mexico. Biological and ecological knowledge, use, management practices, legends, and perceptions on herpetofauna were emphasised in the study.
RESULTS
We obtained an ethnoherpetological checklist, grouping species into four general classificatory categories: kohuatl (serpents), kalatl (frogs and toads), ayotsi (turtles), and ketzo (lizards and salamanders), which included 21, 10, 1, and 11 ethnocategories respectively, based on the local Nahua knowledge of herpetofauna. Serpents, used as medicine, are the most culturally relevant. Due to perceptions of danger, beliefs, and actual snake bites, the main interaction with serpents is their elimination; however, some snakes are tolerated and maintained in captivity. The remaining species of local herpetofauna recorded are tolerated. Cultural aspects of reptiles and amphibians in the Nahua worldview were documented to influence the regulation of interactions of people with these vertebrates, but for younger generations, such aspects are less frequent or absent.
CONCLUSIONS
Interactions and cultural relationships between the Nahua people, amphibians and reptiles are complex, maintaining some aspects of the local worldview but also influenced by external factors and being constantly recreated and re-signified. Documenting and understanding the contemporary relations is essential to generate strategies in biocultural conservation of herpetofauna.
Topics: Amphibians; Animals; Conservation of Natural Resources; Ecosystem; Ethnicity; Humans; Knowledge; Mexico; Reptiles; Snakes
PubMed: 33980252
DOI: 10.1186/s13002-021-00460-1