Tag Archives: Dinosaurs

New Romanian Cretaceous vertebrate site

An article about Romanian locations and Hateg Island

Mátyás Vremir, Ramona Balc, Zoltán Csiki-Sava, Stephen L. Brusatte, Gareth
Dyke, Darren Naish & Mark A. Norell (2014) Petresti-Arini
Cretaceous Research 49: 13-38

http://www.sciencedirect.com/science/article/pii/S0195667114000093

Highlights

•Romania boasts some of the most unusual, insular dinosaurs in the fossil record.
•A new site preserves a unique late Campanian–earliest Maastrichtian fossil record.
•Dinosaurs and pterosaurs from this site are the oldest from the Haţeg Island.
•The Haţeg Island fauna was becoming established by the late Campanian.
•The site may suggest the earliest Haţeg faunas were somewhat distinct from later ones.

Aerodynamic performance of the feathered dinosaur Microraptor and the evolution of feathered flight

Aerodynamic performance of the feathered dinosaur Microraptor and the evolution of feathered flight

Gareth Dyke, Roeland de Kat, Colin Palmer, Jacques van der Kindere, Darren Naish & Bharathram Ganapathisubramani

Nature Communications 4, Article number: 2489 doi:10.1038/ncomms3489

Understanding the aerodynamic performance of feathered, non-avialan dinosaurs is critical to reconstructing the evolution of bird flight. Here we show that the Early Cretaceous five-winged paravian Microraptor is most stable when gliding at high-lift coefficients (low lift/drag ratios). Wind tunnel experiments and flight simulations show that sustaining a high-lift coefficient at the expense of high drag would have been the most efficient strategy for Microraptor when gliding from, and between, low elevations. Analyses also demonstrate that anatomically plausible changes in wing configuration and leg position would have made little difference to aerodynamic performance. Significant to the evolution of flight, we show that Microraptor did not require a sophisticated, ‘modern’ wing morphology to undertake effective glides. This is congruent with the fossil record and also with the hypothesis that symmetric ‘flight’ feathers first evolved in dinosaurs for non-aerodynamic functions, later being adapted to form lifting surfaces.

http://www.nature.com/ncomms/2013/130918/ncomms3489/full/ncomms3489.html

http://www.telegraph.co.uk/science/science-news/10317155/Dinosaur-theory-provides-insight-into-evolution-of-bird-flight.html
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Laura

Neonates and Embryos of Lufengosaurus

Are making waves in newsmedia… ☺

Reisz, R. R., Huang, T. D., Roberts, E. M., Peng, S., Sullivan, C., Stein, K., LeBlanc, A. R. H., Shieh, D., Chang, R., Chiang, C., Yang, C. & Zhong, S., 2013: Embryology of Early Jurassic dinosaur from China with evidence of preserved organic remains.
–Nature: Vol. 496, #7444, pp. 210-214 [doi: 10.1038/nature11978]

Abstract:

Fossil dinosaur embryos are surprisingly rare, being almost entirely restricted to Upper Cretaceous strata that record the late stages of non-avian dinosaur evolution. Notable exceptions are the oldest known embryos from the Early Jurassic South African sauropodomorph Massospondylus and Late Jurassic embryos of a theropod from Portugal. The fact that dinosaur embryos are rare and typically enclosed in eggshells limits their availability for tissue and cellular level investigations of development. Consequently, little is known about growth patterns in dinosaur embryos, even though post-hatching ontogeny has been studied in several taxa. Here we report the discovery of an embryonic dinosaur bone bed from the Lower Jurassic of China, the oldest such occurrence in the fossil record. The embryos are similar in geological age to those of Massospondylus and are also assignable to a sauropodomorph dinosaur, probably Lufengosaurus. The preservation of numerous disarticulated skeletal elements and eggshells in this monotaxic bone bed, representing different stages of incubation and therefore derived from different nests, provides opportunities for new investigations of dinosaur embryology in a clade noted for gigantism. For example, comparisons among embryonic femora of different sizes and developmental stages reveal a consistently rapid rate of growth throughout development, possibly indicating that short incubation times were characteristic of sauropodomorphs. In addition, asymmetric radial growth of the femoral shaft and rapid expansion of the fourth trochanter suggest that embryonic muscle activation played an important role in the pre-hatching ontogeny of these dinosaurs. This discovery also provides the oldest evidence of in situ preservation of complex organic remains in a terrestrial vertebrate.

Feathered ornithomimosaur and T. rex dining habits

These are way cooler than Pleistocene waterpigs. ;P :]

Collected from Ben Creisler’s message to Dinosaur Maling List (dinosaur (at) usc.edu)

New in Science:

Darla K. Zelenitsky, François Therrien, Gregory M. Erickson, Christopher L. DeBuhr, Yoshitsugu Kobayashi, David A. Eberth, and Frank Hadfield (2012):
Feathered Non-Avian Dinosaurs from North America Provide Insight into Wing Origins.
Science 338(6106): 510-514
DOI: 10.1126/science.1225376
http://www.sciencemag.org/content/338/6106/510.abstract

Previously described feathered dinosaurs reveal a fascinating record of feather evolution, although substantial phylogenetic gaps remain.
Here we report the occurrence of feathers in ornithomimosaurs, a clade of non-maniraptoran theropods for which fossilized feathers were previously unknown. The Ornithomimus specimens, recovered from Upper Cretaceous deposits of Alberta, Canada, provide new insights into dinosaur plumage and the origin of the avian wing. Individuals from different growth stages reveal the presence of a filamentous feather covering throughout life and winglike structures on the forelimbs of adults. The appearance of winglike structures in older animals indicates that they may have evolved in association with reproductive behaviors. These specimens show that primordial wings originated earlier than previously thought, among non-maniraptoran theropods.

On the Nature site:

“How to eat a Triceratops” (with illustrations)
http://www.nature.com/news/how-to-eat-a-triceratops-1.11650

Apparently some cool stuff was presented in the SVP meeting… :/

–Mikko

A pliosaur that could have made a T. rex whimper

It’s official: A giant marine reptile that roamed the seas roughly 150 million years ago is a new species, researchers say. The animal, now named Pliosaurus funkei, spanned about 40 feet and had a massive 6.5-foot-long skull with a bite four times as powerful as Tyrannosaurus rex.

“They were the top predators of the sea,” said study co-author Patrick Druckenmiller, a paleontologist at the University of Alaska Museum. “They had teeth that would have made a T. rex whimper.”

Combined with other fossil finds, the newly discovered behemoth skeletons of P. funkei paint a picture of an ancient Jurassic-era ocean filled with giant predators.

In 2006, scientists unearthed two massive pliosaur skeletons in Svalbard, Norway, a string of islands halfway between Europe and the North Pole. The giant creatures, one of which was dubbed Predator X at the time, looked slightly different from other pliosaurs discovered in England and France over the last century and a half.

Now, after years of painstaking analysis of the jaw, vertebrae and forelimbs, the researchers have determined that Predator X is in fact a new species, and they have officially named it for Bjorn and May-Liss Funke, volunteers who first discovered the fossils.

The pliosaurs, marine reptiles that prowled the seas 160 million to 145 million years ago during the Jurassic period, had short necks, tear-shaped bodies and four large, paddle-shaped limbs that let them “fly through the water,” Druckenmiller told LiveScience.

The new species likely lived closer to 145 million years ago and ate plesiosaurs, related long-necked, small-headed reptiles.

http://www.msnbc.msn.com/id/49448852/ns/technology_and_science-science/#.UH-sRWlra9U

Reference: E. M. Knutsen, P. S. Druckenmiller, and J. H. Hurum. 2012. A new species of Pliosaurus (Sauropterygia: Plesiosauria) from the Middle Volgian of central Spitsbergen, Norway. Norwegian Journal of Geology 92:235-258 (can be downloaded from http://www.geologi.no/njg/currentissue/)

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Laura K. Säilä

Dinosaurs grew to outpace their young

Following nicely this week’s Kurten club discussion about environmental impact vs. biotic interactions…

Dinosaurs grew to outpace their young

Matt Kaplan

Some dinosaurs grew to gigantic sizes to avoid competition from their own young, rather than to take advantage of abundant oxygen, high temperatures and large territorial ranges, say two studies. But their largeness may also have proved their undoing.

http://www.nature.com/news/dinosaurs-grew-to-outpace-their-young-1.10465

Biology, not environment, drives major patterns in maximum tetrapod body size through time

Roland B. Sookias, Roger B. J. Benson, Richard J. Butler

Abiotic and biological factors have been hypothesized as controlling maximum body size of tetrapods and other animals through geological time. We analyse the effects of three abiotic factors—oxygen, temperature and land area—on maximum size of Permian–Jurassic archosauromorphs and therapsids, and Cenozoic mammals, using time series generalized least-squares regression models. We also examine maximum size growth curves for the Permian–Jurassic data by comparing fits of Gompertz and logistic models. When serial correlation is removed, we find no robust correlations, indicating that these environmental factors did not consistently control tetrapod maximum size. Gompertz models—i.e. exponentially decreasing rate of size increase at larger sizes—fit maximum size curves far better than logistic models. This suggests that biological limits such as reduced fecundity and niche space availability become increasingly limiting as larger sizes are reached. Environmental factors analysed may still have imposed an upper limit on tetrapod body size, but any environmentally imposed limit did not vary substantially during the intervals examined despite variation in these environmental factors.

http://rsbl.royalsocietypublishing.org/content/early/2012/04/12/rsbl.2012.0060

Ontogenetic niche shifts in dinosaurs influenced size, diversity and extinction in terrestrial vertebrates

Daryl Codron, Chris Carbone, Dennis W. H. Müller, Marcus Clauss

Given the physiological limits to egg size, large-bodied non-avian dinosaurs experienced some of the most extreme shifts in size during postnatal ontogeny found in terrestrial vertebrate systems. In contrast, mammals—the other dominant vertebrate group since the Mesozoic—have less complex ontogenies. Here, we develop a model that quantifies the impact of size-specific interspecies competition on abundances of differently sized dinosaurs and mammals, taking into account the extended niche breadth realized during ontogeny among large oviparous species. Our model predicts low diversity at intermediate size classes (between approx. 1 and 1000 kg), consistent with observed diversity distributions of dinosaurs, and of Mesozoic land vertebrates in general. It also provides a mechanism—based on an understanding of different ecological and evolutionary constraints across vertebrate groups—that explains how mammals and birds, but not dinosaurs, were able to persist beyond the Cretaceous–Tertiary (K–T) boundary, and how post-K–T mammals were able to diversify into larger size categories.

http://rsbl.royalsocietypublishing.org/content/early/2012/04/12/rsbl.2012.0240

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Laura

What is big, fluffy, and could tear you to shreds? Yutyrannus, the 9 m long feathered tyrannosauroid from China

Shamelessly stealing Tom Holtz’ thunder… 🙂

http://www.nature.com/nature/journal/v484/n7392/full/nature10906.html

Xu, X., Wang, K., Zhang, K., Ma, Q., Xing, L., Sullivan, C., Hu, D., Cheng,
S. & Wang, S., 2012: A gigantic feathered dinosaur from the Lower Cretaceous
of China.
–Nature: Vol. 484, #7392, pp. 92-95 [doi: 10.1038/nature10906]

–Mikko