Month: February 2016

Terrific Tetanurae 16: Betasuchus bredai

The wind dries the water spat onto the cold, grey trees by the waves to a salty brine as the sun heats the island already choked by heat. There are few trees here, as the island has been burnt through by fire and buried by floodwaters many times before. Fortunately for the animals which still cling to the isle, the ground shines green with flowers, moss, and ferns. Herds of dwarfed lambeosaurs traverse the land, scraping off the greenery from the pale earth. At their feet, coelurosaurs dash to and fro, eating insects which have been disturbed by the grazing hadrosaurs. Little dromaeosaurs, bearing distinct sickle claws, prowl the wilderness alone. The small size of the island prevents them from forming packs, in which competition would kill the feathered dinosaurs. Alone, they must be cautious, as larger predators stalk this island of dwarfs. 

Abelisaurs, short armed and blunt-headed carnivores, lie in wait next to water holes. These ten foot long killers are among the largest animals of the island, and are most easily able to bully dromaeosaurs away from kills. 

As a herd of hadrosaurs stops to drink, an unfortunate male is spotted by an abelisaur, which, like a bull, charges and rams into the hadrosaur. Dazed and bruised, the hadrosaur bellows for its herd, but all other dinosaurs have fled the scene in panic. The abelisaur continues to attack, finally forcing the hadrosaur down to the rugged ground, where it dies. 

The abelisaur barely gets a nibble of the hadrosaur carcass when a loud trumpeting sound is heard from the tree. Out of the blue bursts a theropod, though it is unlike the dromaeosaurs and abelisaurs of the island. It is a Betasuchus, a relative of tyrannosaurids. The theropod lunges at the abelisaur with its claws, its dark feathers trembling in the wind. The abelisaur, gored by the feathered theropod, trots away. If the wound becomes infected, the abelisaur may die. 

During the Cretaceous, Europe was reduced to scattered islands surrounded by tempestuous seas filled with whale-sized predators. Where France and Germany now are, ocean allowed but of few nesting grounds for terrestrial organisms. Limited ground meant that animals dependent on dry land could only get so large, dramatically changing the evolution of European Cretaceous dinosaurs. To the east, fossil remains from dinosaurs of Hateg Island provide remarkable glimpses into a world of miniature sauropods, tiny ornithopods, and gigantic pterosaurs. To the west, the remains of abelisaurs, such as Tarascosaurus, as well as those of dromaeosaurs, such as Pyroraptor, have been discovered. Looming in the ocean depths surrounding these islands were mosasaurs, giant marine squamates which hunted the abundant fish, invertebrate, and marine reptiles of the Cretaceous. These giants are well known from the Netherlands, where the type specimen of Mosasaurus hoffmannii was unearthed from a quarry in Maastricht.

Nearby, a more obscure predator left but one reminder of its existence. A partial femur, named Megalosaurus bredai, was described in 1883, and would be the first terrestrial Maastrichtian vertebrate known to science (Seeley, 1883). The name of the animal would later be changed to Betasuchus bredai  (Von Huene, 1932). 

There has been confusion over what type of theropod dinosaur the femur belongs to. It has been found to be from an ornithomimosaur, or “ostrich dinosaur” in a few studies (Von Huene, 1926)(Russell, 1972). However, the femur has also been considered to have come from an abelisaur (Loeuff  & Buffetaut, 1991)(Tykoski & Rowe, 2004). Abelisaurs were large predators of Europe during this time, with forms like Arcovenator appearing in France (Tortosa et. al., 2013).

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The skull of Majungasaurus, an abelisaurid dinosaur. Photo by the author, 2015.

Perhaps the most interesting classification of this animal has been as a relative of the Appalachian tyrannosauroid Dryptosaurus  (Carpenter et. al., 1997). This classification, if true, could have implications for the origin of Dryptosaurus aquilunguis  and other Appalachian tyrannosaurs like it. It would also paint a different picture of Betasuchus as a dwarf version of the 8 meter Appalachian predator, using large claws on its forearms as well as slicing teeth for handling prey.

The ecology of Betasuchus is just as obscure as the animal itself. However, a possibly diverse fauna of hadrosaurs from the Cretaceous of the Netherlands and northern Belgium. Two possible distinct lambeosaurine taxa, as well as a possible euhadrosaurian, may have lived alongside Betasuchus (Jagt et. al., 2003). An abelisaurian or dryptosaurian Betasuchus would likely have preyed on these hadrosaurs. Dromaeosaurs may have also existed alongside Betasuchus, as the group was present in Europe during the Late Cretaceous (e. g. Allain & Taquet, 2000).

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This is the partial leg of a juvenile Corythosaurus casuarius, a lambeosaurine dinosaur. Photo by the author, 2015.

Betasuchus bredai evinces the obscurity of some of the earliest known prehistoric vertebrates. The only known specimen, a partial femur, is a hint at an ancient island ecosystem where hadrosaurs roamed, pterosaurs stalked, and theropods hunted.

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Betasuchus bredai by the author. Colored pencils on paper, 2015.

References

  1. Seeley, H. 1883. “On the dinosaurs from the Maastricht beds.” Quarterly  Journal of the Geological Society of London 39: 246-253.
  2. Von Huene, F. 1932. “Die fossile Reptil-Ordnung Saurischia, ihre Entwicklung und Geschichte.”Monographien zur Geologie und Palaeontologie  4: 1-361.
  3. Von Huene, F. 1926. “The carnivorous Saurischia in the Jura and Cretaceous formations, principally in Europe.”Revista del Museo de La Plata 29:35-167.
  4. Russell, D.A. 1972. “Ostrich dinosaurs from the Late Cretaceous of western Canada.” Canadian Journal of Earth Sciences 9: 375–402.
  5. Loeuff, J. & Buffetaut, E. 1991. “Tarascosaurus salluvicus nov. gen., nov. sp.,dinosaure théropode du Crétacé supérieur du Sud de la France.” Geobios 24 (5): 585-594.
  6. Tykoski, R.S. & Rowe, T., 2004.”Ceratosauria.” In: Weishampel, D. B.; Dodson,P.; and Osmólska, H. (eds.): The Dinosauria (2nd Edition) Berkeley: University of California Press. pp. 47-70.
  7. Tortosa, T.; Buffetaut, E.; Vialle, N.; Dutour, Y.; Turini, E.; Cheylan, G. 2013. “A new abelisaurid dinosaur from the Late Cretaceous of southern France: Palaeobiogeographical implications.” Annales de Paléontologie (advance online publication). doi: http://dx.doi.org/10.1016/j.annpal.2013.10.003
  8. Carpenter, K.; Russell, D.; Baird, D.; Denton, R. 1997. “Redescription of the holotype of Dryptosaurus aquilungis (Dinosauria: Theropoda) from the Upper Cretaceous of New Jersey.” Journal of Vertebrate Paleontology  17: 561–573.
  9. Jagt, J. W. M.; Mulder, E. W. A.; Schulp, A. S.; Dortangs, R. W.; Fraaije, R. H. B. 2003. “Dinosaurs from the Maastrichtian-type area (southeastern Netherlands, northeastern Belgium).” Palevol 2: 67–76.
  10.  Allain, R. & Taquet, P. 2000. “A new genus of Dromaeosauridae (Dinosauria, Theropoda) from the Upper Cretaceous of France.” Journal of Vertebrate Paleontology 20: 404-407.

Darwin Day 2016: The State of Evolutionary Theory in Modern Times

Today marks the 207th anniversary of the birth of one of the key minds in shaping the theory of evolution-Charles Darwin. Born in England, the man who would one day get international fame took a liking to natural history as a young boy. Along with his brother Erasmus, he would attend Shrewsbury School. Darwin later apprenticed as a doctor before going to the University of Edinburgh, where he studied medicine. Around the same time, he learned taxidermy.

Eventually, he would embark on the famous Voyage of the Beagle, studying the ecosystems of such places as Patagonia. He would later write on Geology and Botany, as well as conducting research on and postulating the theory of natural selection. Perhaps his best known works are the famous volumes The Origin of Species and The Descent of Man. Unfortunately, he received much negative attention for his work during his lifetime.

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A specimen of Archaeopteryx at the American Museum of Natural History. Fossils of this dinosaur provided Darwin and his colleagues, such as Thomas Huxley, with evidence of evolution.

Today, instead of delving into the details of the life of Charles Darwin, I’d like to talk about evolution, the concept he helped to postulate, in modern times. As many readers may know, many still dispute the concept of evolution. Furthermore, a warped understanding of modern evolutionary theory is certainly present in the general populous.

But who could blame them? From book cover to TV screen to movie, we are exposed to an incomplete or sometimes even false view of the concept. The idea of an unbroken lineage from microbe to fish to reptile to monkey to man is so commonly exemplified it is almost impossible to not hear, read, or see it when one is interested in evolution.

One of the most common ways to convey the idea of the theory is by showing a picture of a hunched-over chimp transitioning to an upright man. We continue working with the media and educators to make sure everyone interested understands that we are learning about and changing our understanding of evolutionary theory every day.

I’m glad to say that there have been great strides made in this effort lately. The larger online presence of the scientific community has resulted in the creation of popular science blogs. After 200 years evolution keeps on spreading among the minds of the human race.

So on this Darwin Day, let’s make a toast to the progress made over the past years. Let’s honor the minds who first came up with the theory. Let’s toast to the fact that their work is still honored and remembered.

 

 

PaleoNews #21: Duck-Billed Dinosaurs & The Mammals Which Mimicked Them

Hi All! Welcome to this week’s PaleoNews. Over the past few days, a new hadrosaur from the continent of Appalachia has been discovered (Which I’m very excited about) as well as an antelope who’s nasal anatomy seems to mimic that of hadrosaurian dinosaurs.

NEW FINDINGS 

One of the most interesting findings in the past few days has come out of the examination of the skull of an extinct antelope taxon called Rusingoryx atopocranion. This large, herbivorous mammal hails from the Late Pleistocene of Kenya and bears a nasal dome which may have been able to produce sounds like a trumpet. Incredibly, the ontogeny of Rusingoryx atopocranion bears similarities with that of lambeosaurine dinosaurs. O’Brien et. al. (2016) conclude that because of the similarities between the extinct antelope and lambeosaurs, osseous nasal crests develop only within specific enivronmental, ontogenic, and evolutionary circumstances.

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Rusingoryx atopocranion by the author. Pencils on paper, 2016. 

The past couple of months have been extremely successful for Appalachian paleontology. In the fall of 2015, the presence of leptoceratopsids on Appalachia was announced. Now, a new species of hadrosaurid dinosaur named Eotrachodon sheds light on the probable Appalachian origins for hadrosaurids. Eotrachodon orientalis is known from a partially complete skeleton with an extremely well preserved skull from the Mooreville Chalk Formation of Alabama. During the Cretaceous, Eotrachodon would have roamed around the coast of southwestern Appalachia, likely drinking from the rivers and deltas which ran directly into the Western Interior Seaway. A phylogenetic analysis by Prieto-Marquez et. al. (2016) has found Eotrachodon to be a sister taxon to lambeosaurinae and saurolophinae. The non-saurolophine non-lambeosaurine Hadrosaurus as well as Lophorhothon, a hadrosauroid extremely closely related to the ancestor of hadrosaurids, have been found on Appalachia, it seems likely that the birthplace of hadrosauridae was on the aforementioned landmass.

 

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Appalachian hadrosaurids, like this Hadrosaurus,  suggest that that Appalachia was the birthplace of the hadrosauridae. Artwork by the author. Colored pencils on paper, 2015. 

THE INTERNET AND PALEONTOLOGY

Dodos were incredible animals, but often they are thought of as evolutionary failures or simply just dumb animals. Check out this post at Twilight Beasts detailing these wonderful birds.

At The Bite Stuff, 

At Mark Witton’s Blog, he discusses the giant Deinosuchus and showcases his fantastic  artwork of the giant marine predator. You can find the post here.

At Extinct Monsters, Ben has written two fantastic articles comparing and contrasting the fossil exhibitions of the Perot Museum and the Houston Museum of Natural Science. These post will be especially interesting to those interested in in the aesthetics and scientific impact of museums. You can find the post on the Perot Museum here and the one on the HMNS here.

At SVPOW, you’ll find a couple posts on the evaluation of researchers and the introduction of LWM (Less Wrong Metrics) by Mike Taylor. You can find the posts here, here, here, and here.

At the Royal Tyrell Museum’s blog, they spotlight the newest lecture of their speaker series. Within it, Don Henderson discusses pterosaurs. You can find the post here.

FEATURED FOSSIL 

This week we have a C. megalodon tooth housed within the Stamford Museum’s collections. C. megalodon were massive sharks which preyed on a variety of marine animals, including whales, from the Miocene to the Pliocene epochs of the Neogene period.

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References 

1. O’Brien H. D.; Faith, J. T.; Jenkins, K. E.; Peppe, D. J.; Plummer, T. W.; Jacobs, Z. L.; Li, B.; Joannes-Boyau, R.; Price, G.; Feng, Y.; Tryon, C. A. 2016.”Unexpected Convergent Evolution of Nasal Domes between Pleistocene Bovids and Cretaceous Hadrosaur Dinosaurs.” Current Biology. DOI:10.1016/j.cub.2015.12.050

2. Prieto-Marquez, A.; Erickson, G. M.; Ebersole, J. A. 2016. “A primitive hadrosaurid from southeastern North America and the origin and early evolution of ‘duck-billed’ dinosaurs. “Journal of Vertebrate Paleontology: e1054495. DOI:10.1080/02724634.2015.1054495.

 

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