Ben Creisler
Some recent non-Mesozoic papers that may be of interest:
Caeruleodentatus lovei gen. et sp. nov.
Simon G. Scarpetta (2021)
Iguanian lizards from the Split Rock Formation, Wyoming: exploring the modernization of the North American lizard fauna.
Journal of Systematic Palaeontology (advance online publication)
DOI: 10.1080/14772019.2021.1894612
https://www.tandfonline.com/doi/full/10.1080/14772019.2021.1894612
Terrestrial ecosystems in North America changed substantially during the Neogene. Previous authors have documented changes in plants and mammals but squamates have received comparatively little attention. Several Miocene lizard fossils were described previously from the Split Rock Formation (Wyoming), which was deposited just before or during the mid-Miocene Climatic Optimum (c. 18â14âMa). I re-evaluate the identifications of some of the previously published fossil lizards from the Split Rock Formation and describe several new fossil lizards. I focus on the iguanians and revise the biogeographical and temporal context for the evolution of several clades. I establish a minimum age for crown Phrynosomatidae and describe the oldest known occurrence of Crotaphytidae. The fossils provide evidence of a relatively modern lizard fauna in central North America by ~17.5âMa and support a substantial turnover from the Eocene to the middle Miocene. I also describe a new taxon, Caeruleodentatus lovei, with a distinctive dentary morphology. The revised iguanian lizard fauna is more diverse than previously described. I discuss difficulties and considerations with using apomorphies to identify fossils, biogeographical biases that affect fossil identifications, and the previous and future use of fossils from the Split Rock Formation in divergence time analyses. I recommend that comparative samples used for identifying fossils should not be intentionally limited by biogeography or stratigraphy, and underscore the importance of topology selection when constructing an apomorphy-based diagnosis. While apomorphy-based diagnoses may decrease taxonomic resolution of fossil identifications, they do not necessarily decrease our capacity to interpret the phylogenetic, biogeographical or ecological significance of fossils.
http://zoobank.org/urn:lsid:zoobank.org:pub:F15984C6-144C-4110-A317-6714C6EEE295
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Free pdf:
Georgios L. GEORGALIS, Andrej ÄERÅANSKÃ & Serdar MAYDA (2021)
Late Paleogene herpetofaunas from the crossroads between two continents â new amphibian and reptile remains from the Oligocene of southern Balkans and Anatolia.
in FOLIE A., BUFFETAUT E., BARDET N., HOUSSAYE A., GHEERBRANT E. & LAURIN M. (eds), Palaeobiology and palaeobiogeography of amphibians and reptiles: An homage to Jean-Claude Rage.
Comptes Rendus Palevol 20(15): 253-275
doi:. https://doi.org/10.5852/cr-palevol2021v20a15
https://sciencepress.mnhn.fr/en/periodiques/comptes-rendus-palevol/20/15
Late Paleogene herpetofaunas from the crossroads between two continents â new amphibian and reptile remains from the Oligocene of southern Balkans and Anatolia.
in FOLIE A., BUFFETAUT E., BARDET N., HOUSSAYE A., GHEERBRANT E. & LAURIN M. (eds), Palaeobiology and palaeobiogeography of amphibians and reptiles: An homage to Jean-Claude Rage.
Comptes Rendus Palevol 20(15): 253-275
doi:. https://doi.org/10.5852/cr-palevol2021v20a15
https://sciencepress.mnhn.fr/en/periodiques/comptes-rendus-palevol/20/15
We describe here new amphibian and reptile remains from three Oligocene localities of Turkey. Two of the localities (Kavakdere and Kocayarma) are situated in southeastern Europe and the other one (Kargi 2) in Anatolia, both areas where Oligocene herpetofauna is practically almost unknown. The material consists of albanerpetontids, pelobatid anurans, turtles, crocodylians, lacertids, scinciformatans, anguines, and "tropidophiids". Albanerpetontids are for the first time identified in southeastern Europe, with the material being reminiscent of the younger species Albanerpeton inexpectatum Estes & Hoffstetter, 1976; the material potentially represents the oldest record of that species. Pelobatids, scinciformatans, and "tropidophiids" represent the oldest occurrences of these clades in the northeastern Mediterranean. The anguine genus Ophisaurus Daudin, 1803 is identified for the first time in the Paleogene of Eastern Europe. The "tropidophiids" are referred to two genera, Falseryx zyndlar & Rage, 2003 and tentatively also to Platyspondylia Rage, 1974, with the latter having been so far exclusively known from western and central Europe. The role of a potential southern dispersal route of taxa among Asia and Europe, involving the area of southern Balkans and Anatolia, similarly to what has been recently demonstrated for mammals, is highlighted also for amphibians and reptiles.
Free pdf:
Siegfried Schloissnig, Akane Kawaguchi, Sergej Nowoshilow, Francisco Falcon, Leo Otsuki, Pietro Tardivo, Nataliya Timoshevskaya, Melissa C. Keinath, Jeramiah James Smith, S. Randal Voss, and Elly M. Tanaka (2021)
The giant axolotl genome uncovers the evolution, scaling, and transcriptional control of complex gene loci.
Proceedings of the National Academy of Sciences 118 (15): e2017176118
doi: https://doi.org/10.1073/pnas.2017176118
https://www.pnas.org/content/118/15/e2017176118
Free pdf:
https://www.pnas.org/content/pnas/118/15/e2017176118.full.pdf
Significance
The axolotl is an important model organism because it is a tetrapod with a similar body plan to humans. Unlike humans, the axolotl regenerates limbs and other complex tissues. Therefore, the axolotl contributes to understanding evolution, development, and regeneration. With sophisticated tools for gene modification and tissue labeling, a fully assembled genome sequence was a sorely missing resource. Assembly was difficult because the genome size is 10Ã that of humans. Here, we use a cross-linking strategy called Hi-C to link together fragmented genome sequences to chromosome scale. We show that gene regulation occurs over very large genomic distances and that mitotic chromosomes are packaged efficiently.
Abstract
Vertebrates harbor recognizably orthologous gene complements but vary 100-fold in genome size. How chromosomal organization scales with genome expansion is unclear, and how acute changes in gene regulation, as during axolotl limb regeneration, occur in the context of a vast genome has remained a riddle. Here, we describe the chromosome-scale assembly of the giant, 32 Gb axolotl genome. Hi-C contact data revealed the scaling properties of interphase and mitotic chromosome organization. Analysis of the assembly yielded understanding of the evolution of large, syntenic multigene clusters, including the Major Histocompatibility Complex (MHC) and the functional regulatory landscape of the Fibroblast Growth Factor 8 (Axfgf8) region. The axolotl serves as a primary model for studying successful regeneration.
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Free pdf:
Virginia Abdala, Luciana Cristobal, MÃnica C. SolÃz and Daniel A. Dos Santos (2021)
Geographical Information System Applied to a Biological System: Pelvic Girdle Ontogeny as a Morphoscape.
Frontiers in Ecology and Evolution 9: 642255.
doi: https://doi.org/10.3389/fevo.2021.642255
https://www.frontiersin.org/articles/10.3389/fevo.2021.642255/full
Geographic Information System (GIS) is a system that captures, stores, manipulates, analyzes, manages, and presents spatial or geographical data. As this technological environment has been created to deal with space problems, it is perfectly adaptable to solve these type of issues in the context of vertebrate comparative morphology. The pectoral and pelvic girdles are key structures that relate the axial skeleton with the limbs in tetrapods. Owed to their importance in locomotion, the morphology, development, and morphogenesis of these structures have been widely studied. The complexity of the structures and tissues implied in the development of the girdles make quantitative approaches extremely difficult. The use of GIS technology provides a visual interpretation of the histological data, a general quantitative assessment of the processes taking place during the ontogeny of any structure, and would allow collecting information about the changes in the surface occupied by the different tissues across the ontogenetic processes of any vertebrate taxa. GIS technology applied to map morphological structures would be a main contribution to the construction of the vertebrate ontologies, as it would facilitate the identification and location of the structures. GIS technology would allow also us to construct a shared database of histological quantitative changes across the ontogeny in any vertebrate. The main objective of this study is to use GIS technology for spatial analysis of histological samples such as these of the pelvic girdle using histological cuts of anurans and chicken, allowing thus to construct a morphoscape, analogous to a landscape. This is the first attempt to apply GIS tools to ontogenetic series to infer biological properties of the spatial analysis in the context of comparative biology. More frequent use of this technology would contribute to obtaining more profitable and biologically informative results.
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Jeffrey H. Schwartz (2021)
Evolution, systematics, and the unnatural history of mitochondrial DNA.
Mitochondrial DNA Part A: DNA Mapping, Sequencing, and Analysis (advance online publication)
doi: https://doi.org/10.1080/24701394.2021.1899165
https://www.tandfonline.com/doi/full/10.1080/24701394.2021.1899165
The tenets underlying the use of mtDNA in phylogenetic and systematic analyses are strict maternal inheritance, clonality, homoplasmy, and difference due to mutation: that is, there are species-specific mtDNA sequences and phylogenetic reconstruction is a matter of comparing these sequences and inferring closeness of relatedness from the degree of sequence similarity. Yet, how mtDNA behavior became so defined is mysterious. Even though early studies of fertilization demonstrated for most animals that not only the head, but the spermâs tail and mitochondria-bearing midpiece penetrate the egg, the opposite â only the head enters the egg â became fact, and mtDNA conceived as maternally transmitted. When midpiece/tail penetration was realized as true, the conceptions 'strict maternal inheritance', etc., and their application to evolutionary endeavors, did not change. Yet there is mounting evidence of paternal mtDNA transmission, paternal and maternal combination, intracellular recombination, and intra- and intercellular heteroplasmy. Clearly, these phenomena impact the systematic and phylogenetic analysis of mtDNA sequences.
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Mary P. Winsor (2021)
"I would sooner die than give up": Huxley and Darwin's deep disagreement.
History and Philosophy of the Life Sciences 43(53)
DOI: https://doi.org/10.1007/s40656-021-00409-3
https://link.springer.com/article/10.1007/s40656-021-00409-3
Free pdf:
https://link.springer.com/content/pdf/10.1007/s40656-021-00409-3.pdf
"I would sooner die than give up": Huxley and Darwin's deep disagreement.
History and Philosophy of the Life Sciences 43(53)
DOI: https://doi.org/10.1007/s40656-021-00409-3
https://link.springer.com/article/10.1007/s40656-021-00409-3
Free pdf:
https://link.springer.com/content/pdf/10.1007/s40656-021-00409-3.pdf
Thomas Henry Huxley and Charles Darwin discovered in 1857 that they had a fundamental disagreement about biological classification. Darwin believed that the natural system should express genealogy while Huxley insisted that classification must stand on its own basis, independent of evolution. Darwin used human races as a model for his view. This private and long-forgotten dispute exposes important divisions within Victorian biology. Huxley, trained in physiology and anatomy, was a professional biologist while Darwin was a gentleman naturalist. Huxley agreed with John Stuart Mill's rejection of William Whewell's sympathy for Linnaeus. The naturalists William Sharp Macleay, Hugh Strickland, and George Waterhouse worked to distinguish two kinds of relationship, affinity and analogy. Darwin believed that his theory could explain the difference. Richard Owen introduced the distinction between homology and analogy to anatomists, but the word homology did not enter Darwin's vocabulary until 1848, when he used the morphological concept of archetype in his work on Cirripedia. Huxley dropped the word archetype when Richard Owen linked it to Plato's ideal forms, replacing it with common plan. When Darwin wrote in the Origin of Species that the word plan gives no explanation, he may have had Huxley in mind. Darwin's preposterous story in the Origin about a bear giving birth to a kangaroo, which he dropped in the second edition, was in fact aimed at Huxley.
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abstract only for now:
Michael Buchwitz, Maren Jansen, Johan Renaudie, Lorenzo Marchetti and Sebastian Voigt (2021)
Evolutionary change in locomotion close to the origin of amniotes inferred from trackway data in an ancestral state reconstruction approach.
Frontiers in Ecology and Evolution (abstract only)
doi: 10.3389/fevo.2021.674779
https://www.frontiersin.org/articles/10.3389/fevo.2021.674779/abstract
Among amniote and non-amniote tetrapod trackways from late Carboniferous to early Permian deposits, certain trackway measures vary notably. Some of this variability can be attributed to evolutionary changes in trackmaker anatomy and locomotion style close to the origin of amniotes. Here we demonstrate that steps in early amniote locomotion evolution can be addressed by applying methods of ancestral state reconstruction on trackway data â a novel approach in tetrapod ichnology. Based on (a) measurements of 186 trackways referred to the Carboniferous and early Permian ichnogenera Batrachichnus, Limnopus, Hylopus, Amphisauropus, Matthewichnus, Ichniotherium, Dimetropus, Tambachichnium, Erpetopus, Varanopus, Hyloidichnus, Notalacerta and Dromopus, (b) correlation of these ichnotaxa with specific groups of amphibian, reptiliomorph, synapsid and reptilian trackmakers based on imprint morphology and (c) known skeletal-morphology-based phylogenies of the supposed trackmakers, we infer ancestral states for functionally controlled trackway measures in a maximum likelihood approach. The most notable finding of our analysis is a concordant change in trackway parameters within a series of ancestral amniote trackmakers, which reflects an evolutionary change in locomotion: In the ancestors of amniotes and diadectomorphs, an increase in body size was accompanied by a decrease in (normalized) gauge width and glenoacetabular length and by a change in imprint orientation towards a more trackway-parallel and forward-pointing condition. In the subsequent evolution of diadectomorph, synapsid and reptilian trackmakers after the initial diversification of the clades Cotylosauria and Amniota, stride length increased whereas gauges decreased further or remained relatively narrow within most lineages. In accordance with this conspicuous pattern of evolutionary change in trackway measures, we interpret the body size increase as an underlying factor that triggered the reorganization of the locomotion apparatus. The secondary increase in stride length, which occurred convergently within distinct groups, is interpreted as an increase in locomotion capability when the benefits of reorganization came into effect. The track-trackmaker pair of Ichniotherium sphaerodactylum and Orobates pabsti from the early Permian Bromacker locality of the Thuringian Forest fits well with the modelled last common ancestor of amniotes â with the caveat that the Bromacker material is younger and some of the similarities appear to be due to convergence.
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