Ben Creisler
Some recent non-dino papers that may be of interest:
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Emily J. Lessner (2020)
Quantifying neurovascular canal branching patterns reveals a shared crocodylian arrangement.
Journal of Morphology (advance online publication)
doi: https://doi.org/10.1002/jmor.21295
https://onlinelibrary.wiley.com/doi/10.1002/jmor.21295
Quantifying neurovascular canal branching patterns reveals a shared crocodylian arrangement.
Journal of Morphology (advance online publication)
doi: https://doi.org/10.1002/jmor.21295
https://onlinelibrary.wiley.com/doi/10.1002/jmor.21295
Highly branched dendritic structures are common in nature and often difficult to quantify and therefore compare. Cranial neurovascular canals, examples of such structures, are osteological correlates for somatosensory systems and have been explored only qualitatively. Adaptations of traditional streamâordering methods are applied to representative structures derived from computed tomographyâscan data. Applying these methods to crocodylian taxa, this clade demonstrates a shared branching pattern and exemplifies the comparative utility of these methods. Additionally, this pattern corresponds with current understanding of crocodylian sensory abilities and behaviors. The method is applicable to many taxa and anatomical structures and provides evidence for morphologyâbased hypotheses of sensory and physiological evolution.
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New and updated articles in eLS (electronic Life Sciences) online book
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Pedro L. Godoy & Alan H. Turner (2020)
Body Size Evolution in Crocodylians and Their Extinct Relatives.
eLS
doi: https://doi.org/10.1002/9780470015902.a0029089
Body Size Evolution in Crocodylians and Their Extinct Relatives.
eLS
doi: https://doi.org/10.1002/9780470015902.a0029089
Crocodylians are currently facing evolutionary decline. This is evinced by the rich fossil record of their extinct relatives, crocodylomorphs, which show not only significantly higher levels of biodiversity in the past but also remarkable morphological disparity and higher ecological diversity. In terms of body size, crocodylians are mostly large animals (>2âm), especially when compared to other extant reptiles. In contrast, extinct crocodylomorphs exhibited a 10âfold range in body sizes, with early terrestrial forms often quite small. Recent research has shed new light on the tempo and mode of crocodylomorph body size evolution, demonstrating a close relationship with ecology, in which physiological constraints contribute to the larger sizes of marine species. Abiotic environmental factors can also play an important role within individual subgroups. Crocodylians, for instance, have been experiencing an average size increase during Cenozoic, which seems to be related to a longâterm process of global cooling.
Key Concepts
Although Crocodylia is currently a depauperate group, the fossil record of its closest extinct relatives, crocodylomorphs, can provide important evidence to answer major evolutionary questions, such as on extinction and diversity loss.
Crocodylomorph body size has varied significantly over time, as well as between subgroups, ranging from relatively small (<1âm) to gigantic (>10âm) species.
Crocodylomorph body size evolution is not consistent with an overall trend towards large or smaller sizes through time; instead, multiple shifts to different evolutionary regimes can explain the observed body size values.
Climate alone cannot explain the evolution of body size in all crocodylomorphs, but some environmental factors had stronger influence on individual subgroups.
The usually larger sizes of aquatic and marine crocodylomorphs can be explained by physiological constraints associated with thermoregulation and lung capacity when under the water.
A strong correlation between temperature and body size found for members of the crownâgroup (Crocodylia) indicates that species became larger on average as the world became cooler during the Cenozoic.
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Luis M. Chiappe & Alyssa Bell (2020)
Mesozoic Birds
doi: https://doi.org/10.1002/9780470015902.a0029218
https://onlinelibrary.wiley.com/doi/10.1002/9780470015902.a0029218
Based in part on the previous version of this eLS article "Mesozoic Birds" (2001) by Luis M Chiappe.
Birds are living dinosaurs, an evolutionary transition increasingly well documented in the abundant fossil record of Mesozoic birds. The avian fossil record begins 150 Ma (million years ago) in the late Jurassic, and for the next 85 million years, birds experienced an evolutionary radiation resulting in a wide range of body forms and lifestyles, occupying all continents and many different environments. This Mesozoic radiation culminated in the appearance of modern birds, Neornithes, in the late Cretaceous, and the loss of several archaic groups during the mass extinction event at the end of this period.
Key Concepts
Mesozoic Birds
doi: https://doi.org/10.1002/9780470015902.a0029218
https://onlinelibrary.wiley.com/doi/10.1002/9780470015902.a0029218
Based in part on the previous version of this eLS article "Mesozoic Birds" (2001) by Luis M Chiappe.
Birds are living dinosaurs, an evolutionary transition increasingly well documented in the abundant fossil record of Mesozoic birds. The avian fossil record begins 150 Ma (million years ago) in the late Jurassic, and for the next 85 million years, birds experienced an evolutionary radiation resulting in a wide range of body forms and lifestyles, occupying all continents and many different environments. This Mesozoic radiation culminated in the appearance of modern birds, Neornithes, in the late Cretaceous, and the loss of several archaic groups during the mass extinction event at the end of this period.
Key Concepts
Birds evolved from maniraptoran theropod dinosaurs during the middle of the Mesozoic Era, over 150 Ma (million years ago).
Many unique adaptations of modern birds, from flight feathers to coloured eggs, evolved amongst their dinosaurian predecessors.
A broad diversity of preâmodern birds lived during the Cretaceous Period, their fossil record is well known from about 131 to 66 Ma.
The Mesozoic radiation of preâmodern birds paralleled many aspects of the biology of their living counterparts.
Neornithes, or modern birds, originated in the late Cretaceous, were the only group of birds to survive the extinction event at the end of this period, and went on to diversify into the abundant forms seen today.
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Yonghua Wu (2020)
Evolutionary Origin of Nocturnality in Birds
eLS
doi: https://doi.org/10.1002/9780470015902.a0029073
https://onlinelibrary.wiley.com/doi/10.1002/9780470015902.a0029073
Evolutionary Origin of Nocturnality in Birds
eLS
doi: https://doi.org/10.1002/9780470015902.a0029073
https://onlinelibrary.wiley.com/doi/10.1002/9780470015902.a0029073
The diel activity patterns of living animals are observable, whereas knowing about those patterns in ancestral or extinct animals remains a challenge. Differences in the diel activity patterns of animals may have led to morphological and genetic differences in their visual systems. Recent developments in reconstructing the traits of ancestral animals offer the opportunity to improve our knowledge of the diel activity patterns of ancestral animals. One of the most important findings is the nocturnality of the common ancestors of living birds. Accumulating evidence based on morphological, behavioural and molecular data suggest the potential importance of nocturnality in their early evolution. The nocturnality of birds may be traced back to theropod dinosaurs and ancestral archosaurs. The possible longâterm history of nocturnality of these diapsid lineages, which parallels that of synapsid lineages (e.g. ancestral mammals), may have facilitated the evolution of mammalâlike characters (e.g. endothermy) in birds.
Key Concepts
Diel activity patterns are basic features of animal behaviour, and knowledge of the diel activity patterns of animals is important for understanding their evolutionary history.
Living birds widely show at least some form of partial nocturnal activities during their life cycles.
The common ancestor of living birds may have engaged in considerable nocturnal activities.
There may have been a long evolutionary history of nocturnality in diapsid lineages, paralleling that found in synapsid lineages (e.g. ancestral mammals).
Nocturnality may have shaped the evolution of diapsid lineages (e.g. birds).
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Free pdf:
Viktoriia Kamska, Monica A Daley & Alexander Badri-SprÃwitz (2020)
3D anatomy of the quail lumbosacral spinal canal--implications for putative mechanosensory function.
Integrative Organismal Biology, obaa037 (advance online publication)
doi: https://doi.org/10.1093/iob/obaa037
https://academic.oup.com/iob/advance-article/doi/10.1093/iob/obaa037/5943883?searchresult=1
Birds are diverse and agile vertebrates capable of aerial, terrestrial, aquatic, and arboreal locomotion. Evidence suggests that birds possess a novel balance sensing organ in the lumbosacral spinal canal, a structure referred to as the 'lumbosacral organ' (LSO), which may contribute to their locomotor agility and evolutionary success. The mechanosensing mechanism of this organ remains unclear. Here we quantify the 3D anatomy of the lumbosacral region of the common quail, with a focus on establishing the geometric and biomechanical properties relevant to potential mechanosensing functions. We combine digital and classic dissection to create a 3D anatomical model of the quail LSO and use this to estimate the capacity for displacement and deformation of the soft tissues. We observe a hammock-like network of denticulate ligaments supporting the lumbosacral spinal cord, with a close association between the accessory lobes and ligamentous intersections. The relatively dense glycogen body has potential to apply loads sufficient to pre-stress denticulate ligaments, enabling external accelerations to excite tuned oscillations in the LSO soft tissue, leading to strain based mechanosensing in the accessory lobe neurons. Considering these anatomical features together, the structure of the LSO is reminiscent of a mass-spring based accelerometer.
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Giuseppe Leonardi & Ismar de Souza Carvalho (2020))
Vertebrate Trace Fossils: the Congo's Brasilichnium mammaloid fossil footprints
Italian Journal of Geosciences (advance online publication)
DOI: https://doi.org/10.3301/IJG.2020.24
https://www.italianjournalofgeosciences.it/297/article-1064/vertebrate-trace-fossils-the-congo-s-em-brasilichnium-em-mammaloid-fossil-footprints.html
Vertebrate Trace Fossils: the Congo's Brasilichnium mammaloid fossil footprints
Italian Journal of Geosciences (advance online publication)
DOI: https://doi.org/10.3301/IJG.2020.24
https://www.italianjournalofgeosciences.it/297/article-1064/vertebrate-trace-fossils-the-congo-s-em-brasilichnium-em-mammaloid-fossil-footprints.html
The ichnogenus Brasilichnium, with its ichnospecies type Brasilichnium elusivum, was established for a very common and abundant kind of tracks from the Brazilian aeolian Botucatu Formation in Paranà Basin. It is nowadays a recognized ichnogenus on several continents. On the South American continent, it was found in Brazil and Paraguay. On the North American continent, it was found in Mexico and in several localities of the United States. In Asia it was found in Korea and China; and in Africa it was found in Tunisia, Namibia and Lesotho; while in Europe it was found only in Italy. A new occurrence of this ichnogenus (and also of the ichnospecies Brasilichium elusivum) is herein announced from Cretaceous arkose sandstones, at Kinshasa, Democratic Republic of Congo. Three slabs with several mammaloid footprints attributable to this ichnogenus were found in Kinshasa, in red sandstone slabs cladding facades of pre-independence (1960) buildings. These slabs were and are quarried at the NW margins of Kinshasa along the left banks of the Congo River, in the districts of Kimbwala and Mbudi. This material can be attributed to the Loia Formation (Berriasian-Aptian). These are the first tetrapod tracks in the Democratic Republic of Congo, and possibly in all of Central Africa. It is important to keep on surveying for tracks in the quarries and on the facades of buildings in Kinshasa, in order to increase the potential use of ichnology to environmental and palaeogeographic reconstructions.
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Philip Hunter (2020)
The rise of the mammals: Fossil discoveries combined with dating advances give insight into the great mammal expansion.
EMBO Reports: e51617
doi: https://doi.org/10.15252/embr.202051617
https://www.embopress.org/doi/abs/10.15252/embr.202051617
The discovery of extensive plant and animal fossils allows to paint a more detailed picture of how mammals arose after the demise of the dinosaurs 66 million years ago.
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Free pdf:
Paula Spaeth Anich, Sharon Anthony, Michaela Carlson, Adam Gunnelson, Allison M. Kohler, Jonathan G. Martin and Erik R. Olson (2020)
Biofluorescence in the platypus (Ornithorhynchus anatinus).
Mammalia (advance online publication)
DOI: https://doi.org/10.1515/mammalia-2020-0027
https://www.degruyter.com/view/journals/mamm/ahead-of-print/article-10.1515-mammalia-2020-0027/article-10.1515-mammalia-2020-0027.xml
Paula Spaeth Anich, Sharon Anthony, Michaela Carlson, Adam Gunnelson, Allison M. Kohler, Jonathan G. Martin and Erik R. Olson (2020)
Biofluorescence in the platypus (Ornithorhynchus anatinus).
Mammalia (advance online publication)
DOI: https://doi.org/10.1515/mammalia-2020-0027
https://www.degruyter.com/view/journals/mamm/ahead-of-print/article-10.1515-mammalia-2020-0027/article-10.1515-mammalia-2020-0027.xml
Biofluorescence, in which short wavelengths of light are absorbed and longer wavelengths are re-emitted by living organisms, has been observed in a wide range of fishes (Sparks et al. 2014), reptiles and amphibians (Gruber and Sparks 2015; Lamb and Davis 2020) and birds (Pearn et al. 2001; Weidensaul et al. 2011). Within mammals, biofluorescence of the pelage under ultraviolet (UV) light has been previously documented in nocturnalâcrepuscular New World taxa including marsupial opossums (Meisner 1983; Pine et al. 1985) and placental flying squirrels (Kohler et al. 2019). Here we document the discovery of fluorescence of the pelage of the platypus (Ornithorhynchus anatinus)--to our knowledge, the first report of biofluorescence in a monotreme mammal under UV light.
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