Ben Creisler
Some recent non-dino papers:
Early Plotopteridae Specimens (Aves) from the Itanoura and Kakinoura Formations (Latest Eocene to Early Oligocene), Saikai, Nagasaki Prefecture, Western Japan.
Paleontological Research 25(2):145-159
doi: https://doi.org/10.2517/2020PR018
https://bioone.org/journals/paleontological-research/volume-25/issue-2/2020PR018/Early-Plotopteridae-Specimens-Aves-from-the-Itanoura-and-Kakinoura-Formations/10.2517/2020PR018.short
Preprint free pdf version:
http://www.palaeo-soc-japan.jp/publications/pr/earlyview/2020PR018_Mori_Miyata%20revised2.pdf
Plotopterids, commonly known as "penguin-like birds", are wing-propelled diving birds known from the latest Eocene to middle Miocene in the eastern and western Pacific Rim. Here, we describe two new specimens of the family Plotopteridae, a right femur from the Itanoura Formation (latest Eocene to earliest Oligocene), and a distal half of a right tibiotarsus from the Kakinoura Formation (early Oligocene), both at the lower part of the Nishisonogi Group, Saikai City, Nagasaki Prefecture, Kyushu, southwestern Japan. The femur is slightly younger than or potentially as old as the earliest plotopterid known from Japan and the U.S.A. CT scanning revealed that it has a dense cortical bone, justifying its taxonomic assignment to the family Plotopteridae. It resembles the femur of Olympidytes, which was previously considered endemic to North America, in its femoral neck, well developed trochanter femoris, and straight facies articularis antitrochanterica, but is not assignable to any known genus. The tibiotarsus resembles that of Olympidytes in the presence of a well-developed trochlea catilaginis tibialis, a large embossment lateral to the pons supratendineus, and a deep incisura intercondylaris, and therefore referable to Olympidytes. The possibility of hindlimb-propelled diving in the family Plotopteidae was also discussed. These new specimens suggest the early diversity of the family in Japan was higher than previously thought.
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Free pdf:
MÃrton VENCZEL, ZoltÃn SZENTESI & James D. GARDNER (2021)
New material of the frog Hungarobatrachus szukacsi Szentesi & Venczel, 2010, from the Santonian of Hungary, supports its neobatrachian affinities and reveals a Gondwanan influence on the European Late Cretaceous anuran fauna.
GEODIVERSITAS 43(7): 187-207
DOI: https://doi.org/10.5252/geodiversitas2021v43a7
https://sciencepress.mnhn.fr/en/periodiques/geodiversitas/43/7
MÃrton VENCZEL, ZoltÃn SZENTESI & James D. GARDNER (2021)
New material of the frog Hungarobatrachus szukacsi Szentesi & Venczel, 2010, from the Santonian of Hungary, supports its neobatrachian affinities and reveals a Gondwanan influence on the European Late Cretaceous anuran fauna.
GEODIVERSITAS 43(7): 187-207
DOI: https://doi.org/10.5252/geodiversitas2021v43a7
https://sciencepress.mnhn.fr/en/periodiques/geodiversitas/43/7
The Late Cretaceous anuran Hungarobatrachus szukacsi Szentesi & Venczel, 2010 was erected for isolated ilia and tibio-fibulae from the Santonian-age IharkÃt locality, in northwestern Hungary. On the strength of ilial features, H. szukacsi was interpreted as a neobatrachian and possible ranoid, making it the only pre-Cenozoic occurrence for both clades in Laurasia. New ilia and the first examples of skull bones (incomplete frontoparietals, squamosals, maxillae, and angulosplenials) from the type locality provide new insights into the taxonomic distinctiveness, osteology, and evolutionary history of H. szukacsi. In addition to its diagnostic ilia (e.g., dorsal crest tall and ornamented laterally with prominent ridges; extensive interiliac tubercle developed across entire medial surface of acetabular region), H. szukacsi is characterized further by having a moderately hyperossified skull exhibiting such traits as frontoparietals, squamosals, and maxillae externally covered with prominent pit-and-ridge and weakly developed tuberculate ornament (i.e., exostosis), frontoparietals solidly fused along midline, frontoparietals expanded posterolaterally to form a broad squamosal process, squamosals expanded anteroposteriorly to form a plate-like lamella alaris, and maxilla articulating posteriorly with the quadratojugal to form a solid bony âcheekâ. The first cladistic analysis to include H. szukacsi corroborates its neobatrachian status, but consistently places it among hyloids, rather than ranoids as originally proposed. Indications of hyloids on the African continent and in Madagascar during the Late Cretaceous, suggest that the ancestor of H. szukacsi may have dispersed from Africa, across the proto-Mediterranean and into Europe, prior to the Santonian.
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RaÃl Orencio GÃmez & Guillermo Fidel Turazzini (2021)
The fossil record and phylogeny of South American horned frogs (Anura, Ceratophryidae).
Journal of Systematic Palaeontology (advance online publication)
doi: https://doi.org/10.1080/14772019.2021.1892845
https://www.tandfonline.com/doi/full/10.1080/14772019.2021.1892845
The fossil record and phylogeny of South American horned frogs (Anura, Ceratophryidae).
Journal of Systematic Palaeontology (advance online publication)
doi: https://doi.org/10.1080/14772019.2021.1892845
https://www.tandfonline.com/doi/full/10.1080/14772019.2021.1892845
South American horned frogs (Ceratophryidae), with their large heads, wide gapes and fang-like teeth, are among the most charismatic, best-known and well-studied neobatrachian anurans. The family comprises 12 extant species with hyperossified skulls and has a relatively rich fossil record, particularly in the Pampas, which dates back to the late Miocene. However, several records have been overlooked in recent summaries, and many taxonomic assignments remain indeterminate or are questionable and have yet to be tested within a quantitative phylogenetic framework. Here we provide a complete up-to-date survey of the palaeontological record of Ceratophryidae, including some remarkable new records. We also tested their systematic position through comprehensive phylogenetic analyses based on osteological data, providing several synapomorphies for all relevant nodes. Finally, we discuss these integrated data in relation to divergence time estimates, and propose a set of fossil calibrations that provide hard minimum bounds for crown-group Ceratophryidae and the subclades within it, and illuminate the acquisition of polyploidy within the group.
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Lorenzo Alibardi (2021)
Regeneration in anamniotes was replaced by regengrow and scarring in amniotes after land colonization and the evolution of terrestrial biological cycles.
Developmental Dynamics (advance online publication)
doi: https://doi.org/10.1002/dvdy.341
https://anatomypubs.onlinelibrary.wiley.com/doi/10.1002/dvdy.341
Regeneration in anamniotes was replaced by regengrow and scarring in amniotes after land colonization and the evolution of terrestrial biological cycles.
Developmental Dynamics (advance online publication)
doi: https://doi.org/10.1002/dvdy.341
https://anatomypubs.onlinelibrary.wiley.com/doi/10.1002/dvdy.341
An evolutionary hypothesis explaining failure of regeneration among vertebrates is presented. Regeneration derives from postâembryonic processes present during the life cycles of fish and amphibians that include larval and metamorphic phases with broad organ reorganizations. Developmental programs imprinted in their genomes are reâutilized with variations also in adults for regeneration. When vertebrates colonized land adopting the amniotic egg, some genes driving larval changes and metamorphosis were lost and new genes evolved, further limiting regeneration. These included neural inhibitors for maintaining complex nervous systems, behavior and various levels of intelligence, and adaptive immune cells. The latter, that in anamniotes are executioners of metamorphic reorganization, became intolerant to embryonicâoncofetalâantigens impeding organ regeneration, a process that requires deâdifferentiation of adult cells and/or expansion of stem cells where these early antigens are formed. The evolution of terrestrial lifecycles produced vertebrates with complex bodies but no longer capable to regenerate their organs, mainly repaired by regengrow. Efforts of regenerative medicine to improve healing in humans should determine the diverse developmental pathways evolved between anamniotes and amniotes before attempting genetic manipulations such as the introduction of "anamniote regenerative genes" in amniotes. This operation may determine alteration in amniote developmental programs leading to teratomes, cancer or death.
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Free pdf:
Bernd Pelster (2021)
Using the swimbladder as a respiratory organ and/or a buoyancy structureâBenefits and consequences.
Journal of Experimental Zoology Part A: Ecological and Integrative Physiology (advance online publication)
doi: https://doi.org/10.1002/jez.2460
https://onlinelibrary.wiley.com/doi/10.1002/jez.2460
A swimbladder is a special organ present in several orders of Actinopterygians. As a gasâfilled cavity it contributes to a reduction in overall density, but on descend from the water surface its contribution as a buoyancy device is very limited because the swimbladder is compressed by increasing hydrostatic pressure. It serves, however, as a very efficient organ for aerial gas exchange. To avoid the loss of oxygen to hypoxic water at the gills many airâbreathing fish show a reduced gill surface area. This, in turn, also reduces surface area available for other functions, so that breathing air is connected to a number of physiological adjustments with respect to ion homeostasis, acidâbase regulation and nitrogen excretion. Using the swimbladder as a buoyancy structure resulted in the loss of its function as an airâbreathing organ and required the development of a gas secreting mechanism. This was achieved via the Root effect and a countercurrent arrangement of the blood supply to the swimbladder. In addition, a detachable air space with separated blood supply was necessary to allow the resorption of gas from the swimbladder. Gas secretion as well as gas resorption are slow phenomena, so that rapid changes in depth cannot instantaneously be compensated by appropriate volume changes. As gasâfilled cavities the respiratory swimbladder and the buoyancy device require surfactant. Due to high oxygen partial pressures inside the bladder airâexposed tissues need an effective reactive oxygen species defense system, which is particularly important for a swimbladder at depth.
HIGHLIGHTS
HIGHLIGHTS
Using a swimbladder for aerial respiration severely affects homeostasis of various body functions
Surfactant and a reactive oxygen species defense system are essential
Rapid changes in hydrostatic pressure can hardly be compensated
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Robin J. Vigouroux, Karine Duroure, Juliette Vougny, Shahad Albadri, Peter Kozulin, Eloisa Herrera, Kim Nguyen-Ba-Charvet, Ingo Braasch, Rodrigo SuÃrez, Filippo Del Bene & Alain ChÃdotal (2021)
Bilateral visual projections exist in non-teleost bony fish and predate the emergence of tetrapods.
Science 372(6538): 150-156
DOI: 10.1126/science.abe7790
https://science.sciencemag.org/content/372/6538/150
Dating the ipsilateral visual pathway
Bilateral visual projections exist in non-teleost bony fish and predate the emergence of tetrapods.
Science 372(6538): 150-156
DOI: 10.1126/science.abe7790
https://science.sciencemag.org/content/372/6538/150
Dating the ipsilateral visual pathway
In primates, visual connections are bilateral: Each eye sends neural connections to both sides of the brain. Vigouroux et al. looked at the evolutionary underpinnings of the bilateral visual system. A close look at the connections between the retina and the brain in a variety of fish species representing a span of evolutionary divergence revealed that contralateral connections seem to be universal. The ipsilateral connections, which add to the contralateral connections to form a bilateral visual system, arrived later in evolution but before the transition to land-dwelling animals.
Structured Abstract
INTRODUCTION
Depth perception [stereoscopic or three-dimensional (3D) vision] exists in vertebrate and nonvertebrate species and has been linked to binocularity, the partial overlap of the visual fields, and to disparities of the images coming from both eyes. In mammals, the right and left sides of the brain receive visual inputs from both eyes and compute their differences to extract 3D visual information. Mammals with front-facing eyes, such as primates and carnivores, possess a high fraction of ipsilateral fibers and therefore a higher degree of binocular overlap, whereas lateral-eyed prey mammals have a small amount of ipsilateral retinal axons and a more limited binocular overlap. This prevalent model also assumes that ipsilateral projections evolved within amphibians first and were absent in fishes. However, isolated and often conflicting data reported the presence of ipsilateral retina connections in fishes, without any clear correlation with eye position or predatory behavior.
RATIONALE
We decided to systematically investigate the presence of ipsilateral and contralateral visual projections in a panel of teleost and non-teleost fishes by using advanced histological methods and whole-mount brain imaging. We sampled a large spectrum of fish species, varying for eye position, predatory behavior, and evolutionary history. We further evaluated in fishes the level of conservation of the genetic program that, in mammals, is thought to specify ipsilateral visual projections.
RESULTS
By injecting fluorescent axonal tracers in the eyes of 11 fish species and imaging their brains after optical clearing, we analyzed their patterns or retinal connectivities at high resolution. Only contralateral projections were found in most teleost fishes. However ipsilateral projections were present in the most basally branching teleost fish and in non-teleosts. In the non-teleost spotted gar, we detected a proportion of ipsilateral fibers comparable to what was previously reported in rodents. The presence of ipsilateral connections did not correlate with eye position or the life history of the individual species. Ipsilateral visual projections were also present in lungfish, the closest living fish relative of tetrapods, including mammals. In mammals, the genetic program driving ipsilateral retina connectivity is initiated by the transcription factor Zic2. We analyzed ZIC2 _expression_ in humans and showed that it is expressed in the temporal retina quadrant where ipsilateral projecting cells are located. By contrast, no Zic2 _expression_ was detected in the spotted gar retina, despite the substantial proportion of ipsilateral projection in this species. Zic2 is also absent in retinal neurons of zebrafish, a teleost with only contralateral visual projections. However, we showed that ectopically expressing Zic2 in the zebrafish retina could induce the formation of ipsilateral connections.
CONCLUSION
Our data reveal that ipsilateral retina projections are a widespread feature in the fish visual system, with many species having a proportion of ipsilateral projections comparable to those in several mammals. Unlike in mammals, the presence of ipsilateral projections in fish does not correlate with animal life history or eye position in the head, but rather with phylogenetic position in the piscine tree of life. Ipsilateral visual projections are present in all non-teleost fish branches and thus were likely ancestral and then lost in modern teleosts. Because we further detected ipsilateral projections in the lungfish, a close relative to tetrapods, we propose that ipsilateral projections were present already in the last common ancestor of bony vertebrates. Although Zic2 is dispensable for ipsilaterally projecting cell specification in the gar retina, it is able to reactivate a genetic program that specifies the formation of these cells in zebrafish, where they are normally not present, further supporting deep homology of this trait among both aquatic and terrestrial bony vertebrates.
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