Ben Creisler
Some recent non-dino stuff:
Martin G. Lockley, Jong Deock Lim, Hong Deock Park, Anthony Romilio, Jae Sang Yoo, Ji Won Choi, Kyung Soo Kim, Yeongi Choi, Seung-Hyeop Kang, Dong Hee Kim & Tae Hyeong Kim (2020)
First reports of Crocodylopodus from Asia: implications for the paleoecology of the Lower Cretaceous.
Cretaceous Research Article 104441 (advance online publication)
doi:
https://doi.org/10.1016/j.cretres.2020.104441https://www.sciencedirect.com/science/article/pii/S0195667119303477
The distinctive crocodylian ichnogenus Crocodylopodus, previously reported only from a few Jurassic and lowermost Cretaceous sites in Europe and North Africa, occurs abundantly at several sites in the Cretaceous (?Aptian) Jinju Formation of Korea. It is therefore the first report of the ichnogenus from Asia. Comparison between known crocodylian ichnogenera show that Crocodylopodus and Batrachopus, the latter predominantly known from the Lower Jurassic, represent small trackmakers that left narrow walking trackways with no tail traces, mostly in fine-grained emergent, lacustrine shoreline facies. In contrast the large crocodylian ichnogenus Hatcherichnus represents swimming behavior of large animals in siliciclastic fluvial, coastal plain settings, particularly in North America, where they represent a swim track ichnofacies. Such contrast between large aquatic crocodylian tracks, which remain very rare in the Cretaceous of Asia, and small Crocodylopodus spoor, show that the Korean occurrences represent a different paleoecology characterized by diverse, mostly small lake basin tetrapods.
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Frank Seebacher (2020)
Is Endothermy an Evolutionary By-Product?
Trends in Ecology & Evolution (advance online publication)
doi:
https://doi.org/10.1016/j.tree.2020.02.006https://www.sciencedirect.com/science/article/abs/pii/S0169534720300525Highlights
Endothermy is rare among extant organisms, but it occurs across a broad range of distantly related taxa, which indicates that it appeared independently several times but has not radiated in many cases.
The teleology of evolutionary arguments is problematic in the light of evolutionary processes.
Regulators of energy balance have diversified over evolutionary time, but independently from any selective advantages of endothermy.
It is most parsimonious to interpret endothermy as an evolutionary by-product and one of many possible physiological states that emerge from energy balance regulation.
Endothermy alters the energetic relationships between organisms and their environment and thereby influences fundamental niches. Endothermy is closely tied to energy metabolism. Regulation of energy balance is indispensable for all life and regulatory pathways increase in complexity from bacteria to vertebrates. Increasing complexity of metabolic networks also increase the probability for endothermic phenotypes to appear. Adaptive arguments are problematic epistemologically because the regulatory mechanisms enabling endothermy have not evolved for the âpurposeâ of endothermy and the utility of current traits is likely to have changed over evolutionary time. It is most parsimonious to view endothermy as the evolutionary by-product of energy balance regulation rather than as an adaptation and interpret its evolution in the context of metabolic networks.
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Andrew N. Iwaniuk & ÂDouglas R. Wylie (2020)
Sensory Systems in Birds: What We Have Learned from Studying Sensory Specialists.
Journal of Comparative Neurology (advance online publication)
doi:
https://doi.org/10.1002/cne.24896https://onlinelibrary.wiley.com/doi/10.1002/cne.24896"Diversity" is an apt descriptor of the research career of Jack Pettigrew as it ranged from the study of trees, to clinical conditions, to sensory neuroscience. Within sensory neuroscience, he was fascinated by the evolution of sensory systems across species. Here, we review some of his work on avian sensory specialists and research that he inspired in others. We begin with an overview of the importance of the Wulst in stereopsis and the need for further study of the Wulst in relation to binocularity across avian species. Next, we summarize recent anatomical, behavioural and physiological studies on optic flow specializations in hummingbirds. Beyond vision, we discuss the first evidence of a tactile "fovea" in birds and how this led to detailed studies of tactile specializations in waterfowl and sensorimotor systems in parrots. We then describe preliminary studies by Pettigrew of two endemic Australian species, the plainsâwanderer (Pedionomus torquatus) and letterâwinged kite (Elanus scriptus), that suggest the evolution of some unique auditory and visual specializations in relation to their unique behaviour and ecology. Finally, we conclude by emphasizing the importance of a comparative and integrative approach to understanding avian sensory systems and provide an example of one system that has yet to be properly examined: tactile facial bristles in birds. Through reviewing this research and offering future avenues for discovery, we hope that others also embrace the comparative approach to understanding sensory system evolution in birds and other vertebrates.
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The Australian Mesozoic fish fauna is considered to be depauperate in comparison with fish faunas in the Northern Hemisphere. However, due to its geographical location as a potential radiation center in the Southern Hemisphere, Australiaâs Mesozoic fish fauna is important for understanding fish radiations. Most of the modern fish groups originated during the Mesozoic, but the first records of a modern fish fauna (freshwater and marine) in Australia does not occur until the lower Paleogene. Here, we review all known fossil fish-bearing localities from the Mesozoic of Australia, to improve the understanding of the record. The apparent low Australian Mesozoic fish diversity is likely due to its understudied status of the constituent fossils rather than to a depauperate record. In addition, we review recent work with the aim of placing the Australian Mesozoic fish fauna in a global context. We review the taxonomy of Australian fossil fishes and conclude that the assignments of many actinopterygians need major revision within a modern phylogenetic context. The vast majority of chondrichthyans are yet to be formally described; to the contrary all of the known lungfish specimens have been described. This study considers the microscopic and fragmented remains of Mesozoic fish already found in Australia, allowing a more complete view of the diversity of the fishes that once inhabited this continent.
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Free pdf:
Cynelos stenos n. sp.
The Neogene sediments of the North American midcontinent, undisturbed by tectonism, have long been the source of abundant well-preserved mammalian faunas critical to the definition of the North American Land Mammal ages (NALMA). In western Nebraska the early Miocene interval (c. 23 to 16 Ma) is exceptional for its succession of Arikareean and Hemingfordian mammals that establish a biostratigraphic standard for the region. Fluvial sands, silts, and gravels of the paleovalleys and floodplains of the Runningwater Formation (c. 18 Ma) have yielded a rich carnivore assemblage of more than 24 species, many of these representing Old World lineages that migrated into North America via the Bering corridor. Amphicyonid carnivores, among the largest of the Runningwater predators, often surpass their Old World equivalents in completeness and condition, and include species of the immigrant genus Cynelos Jourdan, 1862. Here is described the only intact skull and jaws of Cynelos known from the New World. It is assigned to a new species, Cynelos stenos n. sp., that in its size, the association of a cranium with articulated mandibles, and in its dentition (occlusal detail of P4-M3, m1-3) differs from all others of this genus previously reported from both North America and Europe.
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