Museum of Nature and Science

Dallas, TX, United States

Museum of Nature and Science

Dallas, TX, United States
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Gangloff R.A.,University of California at Berkeley | Fiorillo A.R.,Museum of Nature and Science
Palaios | Year: 2010

The late CampanianMaastrichtian Liscomb Bonebed is the richest source of dinosaur remains thus far documented in the polar regions. This bed is formally defined herein and assigned to the upper part of the Prince Creek Formation; the bonebed and several other organic-rich beds are part of a 178 m sequence of fluvial and volcaniclastic deposits. The Liscomb Bonebed is a mudstone rich in clay, comminuted plant remains, and palynomorphs with a total organic carbon (TOC) of 6.8010.55. It contains a multitaxic, low-diversity, dinosaur assemblage, dominated by Edmontosaurus sp., which is primarily represented by late juveniles. Four theropod taxa are almost exclusively represented by isolated teeth. With >6000 specimens collected, the assemblage is characterized by a Minimum Number of Individuals (MNI) of 36, dominance of Voorhies Groups I and II, and an underrepresentation of teeth, skulls, and girdles. Bones are highly fragmented and exhibit low weathering and abrasion indices. Bite marks occur on slightly more than 1 of elements. The densest accumulations of bone are typically found in the middle third of the bed with the largest bones at the bottom. The Liscomb Bonebed assemblage resulted from mass mortality associated with overbank floods that formed floodplain mires and ponds. Data from the current study clearly establish the Alaskan Arctic as the year-round residence of a rich dinosaur fauna and add further support to the hypotheses that even high-latitude hadrosaurids were gregarious and formed social groups. © 2010 SEPM (Society for Sedimentary Geology).

Fiorillo A.R.,Museum of Nature and Science | Mccarthy P.J.,University of Alaska Fairbanks
Journal of Iberian Geology | Year: 2010

We report a likely neoceratopsian manus track from an exposure of the Nanushuk Formation along the Colville River in northern Alaska. The track described here contains the impressions of five digits, arranged as an arc, which identify this specimen as a manus. Details of the impression suggest that it is neoceratopsian rather than ankylosaurian. The length of the chord of the arc of the track is approximately 25 cm, which is half the size of manus tracks found west of Denver, Colorado, USA attributed to the 10 m long Maastrichtian Triceratops. The Nanushuk Formation is a succession of complexly intertonguing marine and nonmarine strata interpreted as shelf, deltaic, strandplain, fluvial, and alluvial overbank deposits. Deposited in the foreland basin north of the Brooks Range, the rock unit is present throughout most of the northern foothills belt and subsurface of the central and western North Slope coastal plain. Fossil and radiometric data place this outcrop within the Albian. If the identification of this track is correct, this is one of the earliest occurrences of neoceratopsians from North America. The occurrence of this track in Alaska substantiates the biogeographic model of faunal exchange between Asia and North America through a Cretaceous land bridge known as Beringia.

Fiorillo A.R.,Museum of Nature and Science | McCarthy P.J.,University of Alaska Fairbanks | Flaig P.P.,University of Alaska Fairbanks
Palaeogeography, Palaeoclimatology, Palaeoecology | Year: 2010

Several dinosaurian bonebeds occur within the Campanian-Maastrichtian portion of the Prince Creek Formation of northern Alaska along a 45. km stretch of the Colville River. These beds are characterized by the occurrence of bones from large numbers of juvenile to sub-adult dinosaurs entombed in a hydraulically incompatible fine-grained matrix. The skeletal elements show little evidence for articulation, though there is evidence for association. Further, the bones show little evidence of post-mortem alteration such as prolonged exposure to weathering, predation, or trampling. The sediments of the Late Cretaceous to Paleocene Prince Creek Formation represent a continental succession deposited on a high-latitude, low-gradient alluvial/coastal plain. Deposition occurred in trunk channels, on distributary-channel splay complexes, in interdistributary bays, and on floodplains. These bonebeds formed under unique paleoclimatic and paleogeographic conditions. Although mean annual temperatures on the coastal plain were higher during the deposition of the Prince Creek Formation than modern temperatures, the evolving Brooks Range orogenic belt formed the southern edge of the Colville basin, providing a high-latitude, cooler alpine environment in close proximity to these warmer lowland environments. Seasonal flow due to the combination of snow melt and alpine permafrost in the ancestral Brooks Range likely produced regularly occurring seasonal floods, which are the likely killing mechanism that resulted in the formation of these bonebeds. © 2010 Elsevier B.V.

Parrish J.T.,University of Idaho | Fiorillo A.R.,Museum of Nature and Science | Jacobs B.F.,Southern Methodist University | Currano E.D.,Miami University Ohio | Wheeler E.A.,North Carolina Museum of Natural science
Palaeogeography, Palaeoclimatology, Palaeoecology | Year: 2010

A new formation, the Ketavik Formation, is proposed for Paleogene rocks of Katmai National Park near Brooks Camp. The type section is in an area previously mapped as the Jurassic Talkeetna Formation. The proposed formation was deposited in a fluvial environment. It is distinct from the coeval Copper Lake Formation on the southeast side of the Alaska Peninsula volcanic arc and was deposited in a different river system. The Ketavik Formation may include previously mapped, undifferentiated Tertiary rocks, at least some of which are similar in age, that are scattered along a belt parallel to and northwest of the present magmatic arc. The Ketavik Formation contains dicot and coniferous leaf and wood fossils that indicate a warm temperate climate. © 2009 Elsevier B.V.

Adams T.L.,Southern Methodist University | Fiorillo A.R.,Museum of Nature and Science
Palaeontologia Electronica | Year: 2011

A partial ichthyosaur skeleton is described from the Grayson Marl (Late Cretaceous: Early Cenomanian, ~97 Ma) from Tarrant County, Texas. Prior to this discovery, the Cretaceous record of Texas ichthyosaurs consisted of isolated vertebrae. The new specimen consists of a partial disarticulated skull and postcranial elements including a postfrontal, parietal, quadrate, angular, surangular, several teeth, and several vertebrae including the atlas-axis complex, coracoid, and articulated partial forelimb. The forelimb is diagnostic in having a zeugopodial element anterior to the radius, rectangular phalanges, and an intermedium that does not make contact with the humerus allowing referral to Platypterygius von Huene 1922. This occurrence is the youngest of that taxon in Texas and is consistent with late European occurrences of the genus Platypterygius. © Society of Vertebrate Paleontology November 2011.

Chinsamy A.,University of Cape Town | Thomas D.B.,University of Cape Town | Tumarkin-Deratzian A.R.,Temple University | Fiorillo A.R.,Museum of Nature and Science
Anatomical Record | Year: 2012

Recent biomechanical evidence has fuelled debate surrounding the winter habits of the hadrosaurian dinosaur Edmontosaurus (ca. 70 Ma). Using histological characteristics recorded in bone, we show that polar Edmontosaurus endured the long winter night. In contrast, the bone microstructure of temperate Edmontosaurus is inconsistent with a perennially harsh environment. Differences in the bone microstructure of polar and temperate Edmontosaurus consequently dispute the hypothesis that polar populations were migratory. The overwintering signal preserved in the microstructure of polar Edmontosaurus bone offers significant insight into the life history of dinosaurs within the Late Cretaceous Arctic. © 2012 Wiley Periodicals, Inc.

Suarez C.A.,University of Arkansas | Ludvigson G.A.,Kansas Geological Survey | Gonzalez L.A.,University of Kansas | Fiorillo A.R.,Museum of Nature and Science | And 2 more authors.
Geological Society Special Publication | Year: 2013

Stable oxygen isotope analysis of siderite and dinosaur tooth enamel phosphate from the Campanian-Maastrichtian Prince Creek Formation, Alaska, USA, are analysed to determine the palaeohydrology of the ancient Colville Basin north of the Ancestral Brooks Range. δ18O of freshwater siderites relative to V-PDB ranges between -14.86 and -16.21%. Dinosaur tooth enamel δ18O from three different sites (Kikak-Tegoseak, Pediomys Point, Liscomb) range between +3.9% and +10.2.0%. δ18Ometeoric water are calculated from δ18Osiderite that formed at seasonal temperatures ranging from -2 to 14.5°C, with a mean annual temperature of 6.3°C. At 6.3°C, the δ18Ow calculated from siderite ranged between -22.23 and -20.89% V-SMOW. Ingested water compositions are estimated from dinosaur teeth assuming body temperatures of 37°C and local relative humidity of 77.5%, resulting in values ranging from -28.7 to -20.4% V-SMOW, suggesting consumption of meteoric water and orographically depleted runoff from the Brooks Range. The ranges in calculated δ18Ometeoric water are compatible between the two proxies, and are mutually corroborating evidence of extremely 18O-depleted precipitation at high latitudes during the Late Cretaceous relative to those generated using general circulation models. This depletion is proposed to result from increased rainout effects from an intensified hydrological cycle, which probably played a role in sustaining polar warmth. © The Geological Society of London 2013.

Langenfeld A.,CNRS Systematics, Biodiversity and Evolution Institute | Prado S.,CNRS Laboratory of Communication Molecules and Adaptation of Microorganisms | Nay B.,CNRS Laboratory of Communication Molecules and Adaptation of Microorganisms | Cruaud C.,CNRS Systematics, Biodiversity and Evolution Institute | And 6 more authors.
Fungal Biology | Year: 2013

Although endophytes of conifers have been extensively studied, few data are available on Cephalotaxaceae. We examined foliar and stem endophytes of Cephalotaxus harringtonia, within its natural range in Japan and outside its natural range in France to study the effect of geography on endophyte community composition. In Japan, rapidly growing endophytes were dominant and may have masked the real diversity, in comparison to France where most endophytes were growing slowly. Analyses of ITS rDNA revealed 104 different Blast Groups among 554 isolates. Almost no overlap between endophyte assemblages of C. harringtonia from the two countries was observed. It seems that Japanese C. harringtonia trees, which should be well adapted to their native site, would host a specific, endemic endophyte community, while trees that have been introduced recently to a foreign site, in France, should have captured existing cosmopolitan and more generalist taxa. In Japan the majority of xylariaceous taxa, which dominated the communities, were unknown and, although closely related to Asian taxa, may be new to science. Dothideomycetes were more prevalent in France. Locally, urban environment, particularly in Japan, may have introduced some perturbations in the native endophyte community of C. harringtonia, with an abundance of generalist fungi such as Nigrospora and Colletotrichum. © 2013 The British Mycological Society.

Fiorillo A.R.,Museum of Nature and Science | Adams T.L.,San Antonio College
Palaios | Year: 2012

We report on the first record of a therizinosaur from Alaska. This record consists of a single pes track from the lower part of the Upper Cretaceous Cantwell Formation in Denali National Park, Alaska, United States. This is the northernmost occurrence for this group of dinosaurs, and the presence of this animal in Alaska offers the first support of the proposed biogeographic model of faunal exchange during the Cretaceous for these unusual theropods. Copyright © 2012 SEPM (Society for Sedimentary Geology).

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