Ben Creisler
Some recent (mainly) non-dino papers:
L. J. Krumenacker (2019)
Paleontological and chronostratigraphic correlations of the mid-Cretaceous Wayan-Vaughn depositional system of southwestern Montana and southeastern Idaho.
Historical Biology (advance online publication)
DOI: 10.1080/08912963.2019.1582035
The Mussentuchit Member of the Cedar Mountain Formation of eastern Utah represents the best source of data on Cenomanian vertebrate assemblages from North America. However, increasing data has recently been forthcoming from the late Albian to Cenomanian Wayan Formation of Idaho and Vaughn Member of the Blackleaf Formation of Montana, which are both at least partially coeval with the Mussentuchit Member. While the paleontological assemblages of the Wayan Formation and Vaughn Member are fragmentary, numerous vertebrate forms are represented, with the small burrowing neornithischian Oryctodromeus cubicularis dominating these assemblages. The differences between the Wayan Formation and Vaughn Member assemblages, the Mussentuchit and few other mid-Cretaceous assemblages are likely a result of some combination of preservational biases, paleogeography, and paleoenvironmental differences. The chronostratigraphy, fossil content, bracketing facies, and ages of the Wayan Formation and Vaughn Member suggest these sediments represent the same depositional system prior to disruption by subsequent tectonic and volcanic events. This assemblage from the Wayan Formation and Vaughn Member is here termed the Wayan-Vaughn Assemblage (WVA). Continued work in the WVA, particularly with microvertebrate materials, may reveal additional shared taxa between the WVA and other coeval units.
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NOTE: This paper names new taxa but I don't have access to provide the names for now. Also, the English translation is not yet posted
V. R. Alifanov (2019)Â
Lizards of the Families Eoxantidae, Ardeosauridae, Globauridae and Paramacellodidae (Scincomorpha) from the Aptian-Albian of Mongolia.
Paleontological Journal 53(1): 73-86 (Russian edition)
DOI: 10.1134/S0031031X19010033
The paper discusses the classification of the lizard infraorder Scincomorpha. In more detail it covers the history and problems of studying such fossil families as Eoxantidae, Ardeosauridae, Globauridae and Paramacellodidae. The listed lizard families are replenished with new species from the AptianâAlbian deposits of Mongolia.
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Jaimi A. Gray, Mark N. Hutchinson & Marc E. H. Jones (2019)
Exceptional disparity in Australian agamid lizards is a possible result of arrival into vacant niche.
The Anatomical Record (advance online publication)
Australia provides abundant examples of continentalâscale evolutionary radiations. The collision of two continental shelves around 30 Ma facilitated an influx of squamates and the subsequent squamate radiations resulted in high taxonomic diversity. The morphological disparity seen in these major squamate groups, however, remains underexplored. Here, we examine the major cranial proportions of over 1000 specimens using 2D linear measurements to explicitly quantify the morphological disparity of Australian agamid lizards (Amphibolurinae) and compare it to that of agamid, acrodont, and iguanian clades from other parts of the world. Our results indicate the Australian Amphibolurinae have exceptionally high cranial disparity, and we suggest that this is linked to the relaxed selective environment that greeted the founders of Amphibolurinae when they first arrived in Australia.
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E.A Zvonok & I.G. Danilov (2019)
Paleogene Turtles of the Crimea.
Paleontological Journal 53(1): 61-72 (Russian edition)
DOI: 10.1134/S0031031X19010148
This paper describes remains of fossil turtles from five Paleogene localities of the Crimea, two of which are of the Danian age (Ak-Kaya 2 and Saharnaya Golovka) and three ones are of the Bartonian age (Ak-Kaya 1, Bakhchisaray and Prolom). The most studied is the turtle fauna of Ak-Kaya 1 locality which includes three taxa: sea turtles Argillochelys sp. (Cheloniidae) and Cosmochelys sp. (Dermochelyidae) and indeterminate soft-shelled turtle (Trionychidae indet.). Argillochelys sp. shows similarities with Argillochelys antiqua (KÃnig, 1825) from the Eocene of Europe. New data expands knowledge on the intraspecies variability and distribution of turtles of the genera Argillochelys and Cosmochelys. Indeterminate cheloniids (Bakhchisaray, Prolom and Saharnaya Golovka), dermochelyids (Bakhchisaray and Prolom) and trionychids (Ak-Kaya 2 and Prolom) are described from other Paleogene localities of the Crimea.
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Free pdf:
Ingmar Werneburg & Wolfgang Maier (2019)Â
Diverging development of akinetic skulls in cryptodire and pleurodire turtles: an ontogenetic and phylogenetic study.Â
Vertebrate Zoology, 69(2): 113-143.
Free pdf:
Description: Extant turtles (Testudines) are characterized among others by an akinetic skull, whereas early turtles (Testudinata) still had kinetic skulls. By considering both ontogenetic and evolutionary adaptations, we analyze four character complexes related to the akinetic skull of turtles: (1) snout stiffening, (2) reduction of the basipterygoid process, (3) formation of a secondary lateral braincase wall, and (4) the fusion of the palatoquadrate cartilage to the braincase. Through ontogeny, both major clades of modern turtles, Pleurodira and Cryptodira, show strikingly different modes how the akinetic constructions in the orbitotemporal and quadrate regions are developed. Whereas mainly the ascending process of the palatoquadrate (later ossified as epipterygoid) contributes to the formation of the secondary braincase wall in Cryptodira, only the descending process of the parietal forms that wall in Pleurodira. This is related to the fact that the latter taxon does not develop an extended ascending process that could ossify as the epipterygoid. Whereas the palatoquadrate directly fuses to the braincase in pleurodires by forming appositional bone of quadrate (called EÃwein-fixation herein), both structures are ventrally bridged by the pterygoid in cryptodires. Phylogenetic evidence, including fossil data, suggests that the cryptodiran type of skull fixation is plesiomorphic for crown turtles and that the pleurodire condition evolved secondarily within the crown. Embryonic neck muscle activity may be the cause of this shift of the palatoquadrate. Hidden-necked retraction in cryptodires pulls the palatoquadrate in a posterodorsal and -medial direction during ontogeny, whereas side-necked retraction in pleurodires redirects the palatoquadrate posterolaterally and -medially. These different muscle forces may result in differing positions of the palatoquadrate in relation to the braincase and eventually result in the two different attachment types. Moreover, the general construction of the jaw adductor chamber is affected by alternative fusion modes, which secondarily result in two different types of the trochlear system of the external jaw musculature. Related to that, changes in feeding habit through turtle evolution may have also triggered increasing stabilizattion of the skull. Palatoquadrate fixation, finally, was an important prerequisite for the reduction of the exocranial bones of the temporal skull region.
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Free pdf:
Jindrich Brejcha, Jose Vicente Bataller, Zuzana Bosakova, Jan Geryk, Martina Havlikova, Karel Kleisner, Petr Marsik & Enrique Font (2019)
Body coloration and mechanisms of colour production in Archelosauria: The case of deirocheline turtles
bioRxiv 556670
Animal body coloration is a complex trait resulting from the interplay of multiple colour-producing mechanisms. Increasing knowledge of the functional role of animal coloration stresses the need to study the proximate causes of colour production. Here we present a description of colour and colour producing mechanisms in two non-avian archelosaurs, the freshwater turtles Trachemys scripta and Pseudemys concinna. We compare reflectance spectra; cellular, ultra-, and nano- structure of colour-producing elements; and carotenoid/pteridine derivatives contents in the two species. In addition to xanthophores and melanocytes, we found abundant iridophores which may play a role in integumental colour production. We also found abundant dermal collagen fibres that may serve as thermoprotection but possibly also play role in colour production. The colour of yellow-red skin patches results from an interplay between carotenoids and pteridine derivatives. The two species differ in the distribution of pigment cell types along the dorsoventral head axis, as well as in the diversity of pigments involved in colour production, which may be related to visual signalling. Our results indicate that archelosaurs share some colour production mechanisms with amphibians and lepidosaurs, but also employ novel mechanisms based on the nano-organization of the extracellular protein matrix that they share with mammals.
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Qi Wang, Liyana Lekamalage Theshani Navoda Chandrasena & Yanhui Lei (2019)
A critical review of the application of paleo-art in paleontological exhibition â a case study of the Dinosaurs of China exhibition in Wollaton Hall and Lakeside Arts, Nottingham
Museum Management and Curatorship (advance online publication)
Paleo-art has become an important element in paleontological exhibitions after a long development. Since 1996, new discoveries of feathered dinosaurs offer paleo-art an unprecedented freedom of creation, which provide both opportunities and challenges for curators. The Dinosaurs of China exhibition hosted in Nottingham in 2017 was a platform to test the best ways of showing contemporary paleo-art along with fossils on display. The experience gained from this exhibition confirmed that paleo-art could not only help visitors understanding but could also be misleading. Additionally, the key concerns revealed by the exhibition can also be found in other areas of science. Therefore not only should the selection and application of paleo-art be carefully evaluated by curator, but also the experience of using paleo-art should be shared as widely as possible with colleagues in other scientific disciplines.
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