Month: July 2015

Terrific Tetanurae #13: Mirischia asymmetrica

The forest seems to whisper as the dry season pours into the land, stripping trees of their leaves and animals of their color. We’re in Cretaceous Brazil, and the land is dominated by forest. In these woods, every animal must fight to survive, from the smallest of fishes to the largest of dinosaurs. One animal in particular is suffering from the dry climate. The animal in question is an old Irritator bull. The animal is already at a disadvantage, having lost part of his left arm in a battle with another spinosaur. The wound has become infected, and the old bull’s immune system is not presently strong enough to fight off the bug. For now, the bull must rest and hope for better weather. Unfortunately, another predator has set its sights on the spinosaur, and not as a rival, but as food.

A month passes, and the old bull’s health has improved. The infection, however, has taken its toll on the animal, and the Irritator has become weak. He must find food or die. In the corner of his eye he spots movement. He moves closer, and observes a small coelurosaur chasing a juvenile pterosaur. This is Mirischia asymmetrica, the most common predator in these woods. The small coelurosaur, noticing the gigantic spinosaur, hisses and spreads its frill of feathers, which are colored bright blue to daze predators. The little tetanuran darts into the bushes. The spinosaur, knowing not to expend lots of energy on such a small catch, lumbers away. He’ll have to wait another day to eat.

Mirischia asymmetrica is a tyrannoraptoran from the Cretaceous of Brazil. This coelurosaur was assigned to compsogathidae (Rauhut et. al., 2010), a group of small, gracile meat eating dinosaurs. In fact, Mirischia asymmetrica is the only known compsognathid from the Americas. That depends on whether Mirischia is actually a compsognathid. In his book Tetrapod Zoology, Darren Naish suggested that M. asymmetrica might be a tyrannosauroid. Of course, this idea has been explored by the wonderful community of paleoartists.

Mirischia most likely hails from the Santana Formation of Brazil (Martill et. al., 2000), and, if so, would have shared its environment with many other archosaurs, including the spinosaurid Irritator (Weishampel et. al., 2004). This spinosaur may have been the apex predator of the Santana ecosystem, while smaller predators like Mirischia foraged for prey on the forest floor. Another small theropod, Santanaraptor, also called the Santana Formation home (Weishampel et. al., 2004). In time, the ancient forests of South America would loose the bloodline of Mirischia as other predators colonized the landscape.

During the Cenomanian, new groups of theropods started to take the throne of top predator. During the Jurassic and Early Cretaceous, the megalosaurs and allosauroids reigned as the top predators of ecosystems across the globe. During the Late Cretaceous, however, new groups of killer dinosaurs rose up the ranks. To the north, the members tyrannosauroid group, of which Mirischia might belong to (and, if not, was closely related to) developed larger sizes to go after larger prey.

The skull of T. rex, a tyrannosaurid tyrannosauroid dinosaur. Photo by the author, 2015.

The skull of T. rex, a tyrannosaurid tyrannosauroid dinosaur. Photo by the author, 2015.

In the south, another group of carnivorous dinosaurs rose to the top. These were the abelisaurids, relatives of the Jurassic Ceratosaurus. In the Late Cretaceous, these blunt-faced, stubby-armed marauders would conquer the ecosystems of the southern hemisphere, leaving other large carnivores of other predatory groups few and far between.

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

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

In this way, the tyrannosauroids might have been prevented from conquering the south, and the domain of Mirischia fell to a rival group of killer dinosaurs.

Mirischia   by the author. Pencils on paper, 2015.

Mirischia by the author. Pencils on paper, 2015.

References 

1. Rauhut, O. W. M.; Milner, A. C.; Moore-Fay, S. 2010. “Cranial osteology and phylogenetic position of the theropod dinosaur Proceratosaurus bradleyi (Woodward, 1910) from the Middle Jurassic of England.” Zoological Journal of the Linnean Society 158(1):155-195. 

2. Naish, Darren. 2010. Tetrapod Zoology Book One. Bideford: CFZ Press. p. 235. 

3. Weishampel, D. B; Dodson, P.; Osmólska, H. 2004. “Dinosaur distribution (Early Cretaceous, South America).” In: Weishampel, David B.; Dodson, Peter; and Osmólska, Halszka (eds.): The Dinosauria, 2nd Edition, Berkeley: University of California Press. Pp. 563-570.

A response to The Tetrapod Zoology Podcast #45: Why Lambeosaurines did, in fact, persist into the Maastrichtian

Recently episode #45 of the acclaimed Tetrapod Zoology Podcast was released, and, as usual, I found time to listen to it while illustrating for the Appalachia book. One point made by Darren Naish, however, caught my ear. While illustrating a point on the decline of the decadently frilled ceratopsians and crested lambeosaurines, he suggested that none of them persisted to the Late Maastrichtian. That might be true for the former of the two dinosaur groups, but the latter still hung to life in the-you-know-what continent. That’s right, Maastrichtian lambeosaurine bones have been found in deposits from Appalachia. Let me elaborate…

While in the west crestless forms like Edmontosaurus were almost the only surviving genera of the hadrosaurid lineage, the eastern shores of the newly-formed North American continent seem to still have supported the crested magnificence of the lambeosaurine hadrosaurs.

Edmontosaurus, everyone's  (except for me!) favorite Maastrichtian hadrosaur in all its glory. Photo by the author, 2014.

Edmontosaurus, everyone’s (except for me!) favorite Maastrichtian hadrosaur in all its glory. Photo by the author, 2014.

Indeterminate remains of a lambeosaurine have been reported from the Navesink Formation of New Jersey not only from one, but two localities. The Navesink Formation itself is a Maastrichtian deposit dating from around 70-66 million years ago. Gallagher (1993) reported indeterminate lambeosaurine remains from the West Jersey Marl Company’s Pit, Barnsboro, New Jersey, and Gallagher (2002) reported of indeterminate lambeosaurine remains from the Inversand Company marl pit locality in Gloucester County, New Jersey. It certainly seems a lambeosaurine was present in the Navesink ecosystem.

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

This is the partial leg of a juvenile Corythosaurus casuarius, a lambeosaurine dinosaur. This specimen was collected in South Dakota. Photo by the author, 2015.

Lambeosaurine remains have also been reported from elsewhere on Appalachia. Rich et. al. (1997) reported Lambeosaurine remains from the Maastrichtian of the Kanguk Formation. The occurrence of lambeosaurine remains in the Kanguk Formation not only has implications for the survival of lambeosaurines into the Maastrichtian, but also for the presence of possible “polar dinosaurs” in eastern North America.

It seems as though as they declined in the west, lambeosaurines still thrived in the east up until the very end of the Mesozoic.

Although I am being nitpicky with this short write-up, my goal is to emphasize the importance of research before stating scientific claims. I don’t mean to offend either Darren or John, but I wanted to catch this little sliver of misinformation.

References 

1. Gallagher, W. B. 1993. “The Cretaceous/Tertiary mass extinction event in the North Atlantic coastal plain.” The Mosasaur 5:75-154.

2. Gallagher, W. B. 2002. “Faunal changes across the Cretaceous-Tertiary (K-T) boundary in the Atlantic coastal plain of New Jersey: restructuring the marine community after the K-T mass-extinction event.” Catastrophic Events and Mass Extinctions: Impacts and beyond. GSA Special Paper 356:291-301.

3. Rich, T. H.; Gangloff, R. A.: Hammer. W. R. 1997. “Polar dinosaurs.” In P. J. Currie & K. Padian (eds.) Encyclopedia of Dinosaurs. San Diego: Academic Press. pp. 562-573.

Time for some Geology!

Apart from the collecting I’ve done so far in Colorado (which, by the way, has turned up really nothing good), I have also gotten to witness some really interesting Rock Mountain geology. Here are a few highlights:

1. Beaver Lake

This lake, formed by glaciers and fed by snowfields, is situated above the resort town of Beaver Creek, and is home to trout and, of course, beavers, among other things. So far, my ventures have taken me to the lake twice, the first ascent more pleasant then the second, in which I was subject to two thunderstorms. Here are a couple pictures: IMG_4988

IMG_5023IMG_4997

I’ve also managed to witness some pretty beautiful sunsets and their affect on the color of the Gore range. Some peaks in the range rise to more then 13,000 feet above sea level, but all are under 14,000 feet. I managed to snap the pictures below during what became a very, very pretty evening.

IMG_5089

IMG_5082Finally, check out Cross Creek, a small waterway which, this year, rose to a point where I was scared to cross the bridge above it, lest I be washed away in the white water rapids!

IMG_4828That’s all for now, but stay tuned for more updates on the book and on the collecting trips. Thanks for reading!

Book Update 1: Salamanders are weird, guys!

What does almost two days of continuous writing due to someone? It makes them salamander-crazy. I’ve been working on the chapter discussing lissamphibians and I think I might go nuts! I must have read the description paper for Parrisia neocesariensis 16 times, if not more! Lissamphibians are a lot cooler then many give them credit for. At the Ellisdale site, a Marshalltown Formation storm deposit in New Jersey, so many incomplete fossil specimens of salamanders and frogs have been collected that it’s hard to keep track of them. We’re talking weird-looking salamanders extremely adapted for an aquatic lifestyle (these guys have serpentine bodies!!) that could grow up to a foot long and probably had an extremely wide gape. Then there are the frogs, and the indeterminate stuff, and so on, and so on. If you haven’t researched Mesozoic lissamphibians (which, I should mention, are rare in the fossil record), you should do so sometime as some of them are really interesting animals.

I am going to highlight Parrisia neocesariensis, which I believe to be one of the most fascinating animals known from the Cretaceous of New Jersey. The animal is classified as a batrachosauroidid salamander known from partial remains collected at Ellisdale (Denton Jr. & O’Neill, 1998). Batrachosauroidid salamanders are thought to be large, streamlined marine amphibians (the Florida Museum of Natural History’s website suggest a length of three feet or more for Batrachosauroides dissimulans, a species of batrachosauroidid). Long stalks on the occipital condyles indicate these salamanders had wide gapes. So we have a long, marine salamander that could open its mouth real wide present in the Late Cretaceous of New Jersey. Wow!

I’m Writing a Book

I was going going to make myself write one sometime, so why not now?

A few months ago, I got the idea to write a book about the prehistoric landmass called Appalachia. This is actually what inspired me to do Antediluvian Beasts of the East. You might be asking why I haven’t shared this earlier. Well, I just didn’t know if I would write a book until around 3 months ago. Dave Hone’s post also gave me confidence to announce this.

So far, the working title is Appalachia Prehistorica, although I doubt that will stay. If you have any suggestions on a title, feel free to comment below. I’ll be giving updates on this blog periodically. Let’s hope it goes well.

Terrific Tetanurae #12 : Mahakala omnogovae

In light of a recently discovered short-armed dromaeosaur, this friday we will check out another short-armed member of the family. Enter Mahakala omnogovae. 

75 million years ago, and Mongolia is covered by dry, somewhat barren plains intermingled with small forests, oases, and lakes. As a group of Pinacosaurus wander by a small forest, a male Velociraptor tries to attract mates using his colorful plumage. Suddenly, something catches the Velociraptor’s eye, and curiosity gets the better of him. He starts to jog toward the small theropod, which, in response, dashes away faster then the male Velociraptor can run. The male Velociraptor, somewhat depressed on not catching the theropod, a Mahakala, trots back to his post to continue his courtship display.

Meanwhile, the Mahakala dashes along the dry forest floor, searching for a meal. Suddenly, the Mahakala spots a small lizard, and slowly creeps toward the reptile. The Mahakala strikes and catches the lizard. It will be enough to sustain the dinosaur for the day, but soon hunger will require the animal to hunt again.

At approximately seventy centimeters long (Turner et. al., 2007), Mahakala was no giant predator. Mahakala was also found by Turner et. al. (2007) to be the most basal known dromaeosaurid. This animal is known from a partial skeleton, including portions of the skull (Turner et. al., 2007). As it turns out, the holotype represents what was either a young adult or a near-adult Mahakala. This was a mini-dromaeosaurid, indeed!

It is certainly possible this animal went after small prey such as insects, arthropods, and small lizards. I imagine the small dromaeosaurid darting across the ancient Mongolian landscape, snatching early wasps and the like from the ground, like a sort of ancient land-bound American kestrel. Mahakala might have also fallen prey to the larger dromaeosaurids and troodontids it co-existed with, including the famous Velociraptor and Saurornithoides. 

The iconic skull of Velociraptor mongoliensis at the American Museum of Natural History.

The iconic skull of Velociraptor mongoliensis at the American Museum of Natural History. Photo by the author, 2015.

Holotype skull of Saurornithoides at the American Museum of Natural History. Photo by the author, 2015.

Holotype skull of Saurornithoides at the American Museum of Natural History. Photo by the author, 2015.

Yet, as with almost every animal to have existed on Earth, Mahakala succumbed to extinction. The dromaeosaurids themselves would survive for around another 10 million years, when, during one of the largest extinction events in Earth’s history, an asteroid hit the planet we call home, causing drastic global environmental changes and damage. Mahakala itself would be remembered by the specimen of a young adult, locked away in a tomb of sandstone.

Mahakala omnogovae by the author. Pencils on paper, 2015.

Mahakala omnogovae by the author. Pencils on paper, 2015.

References

1. Turner, A. H.; Pol, D.; Clarke, J. A.; Erickson, G. M.; Norell, M. .2007. “A basal dromaeosaurid and size evolution preceding avian flight.” Science 317(5843): 1378–1381.

A Few Words on David Raup

As I’m sure some of you know, the first president of the Paleontological Society, passed away today at the age of 82. In remembrance, I’d like to share how his work helped me to become interested in the isolation and extinction of the paleofauna of Appalachia.

Some time ago, I read a little of his work on extinction patterns. Although I didn’t (and still don’t) agree with some of his theorems, his work got me interested in the gradual decline of species. His work opened me up to papers on extinction. Eventually, I stumbled upon one or two papers documenting the K-T extinction event on Appalachia, and I was hooked. Thank you, David Raup, for helping to position me down the road I have taken to this day. You will be missed.

My condolences go out to his family and friends during this sad time. If you have a story about Mr. Raup, please feel free to comment below.

PaleoNews #16

This is truly the week of the worms… 

NEW FINDINGS 

A couple of new discoveries have been published in these past two weeks, including the description of two new dinosaurs. One of the most significant finds, however, relates to a small animal known for many years: Hallucigenia. This small, spiky invertebrate existed during the Cambrian, and is famous for being part of the fauna found in the Burgess Shale. This animal had posed quite a mystery for some type regarding where its head was. A new study (Smith and Caron, 2015) solved the mystery. It turns out Hallucigenia sported an elongated head with simple eyes and a mouth which housed a ring of teeth. Tentacle-like appendages sprung from the front of the animal as well.

In other wormy news, a close relative of Hallucigenia has also been described.         Collinsium ciliosum, the new species in question, took spiky to a whole new level. The different sized spikes found on Collinsium ciliosum were such robust structures that they partially retained their 3D-shape even when the rest of the animal had been crushed during fossilization. Both Collinsium ciliosum and Hallucigenia are lobopodians, an extinct group of superficially worm-like invertebrates which lived from the Cambrian to the Carboniferous. Yang et. al. (2015) highlighted the diversity of this new species’ appendages. Collinsium was equipped with 6 pairs of fringed limbs likely used for filter-feeding, followed by 9 pairs of legs which sported claws. Collinsium was one of the first in a long line of extreme armor-bearers, and joins Hallucigenia as one of the weirdest organisms that time forgot.

In dinosaur news, a new oviraptorid has been described. The partial skeleton of Huanansaurus ganzhouensis includes a well preserved skull, which is nearly complete. This oviraptorid was closely related to the more well-known Citipati. The partial skeleton of this new dinosaur will help us further understand oviraptorid anatomy, as well as add to the known Chinese oviraptorid taxa.

The ceratopsian dinosaur recently put on display at the Royal Ontario Museum has been described. Wendiceratops pinhornensis is one of only 8 known ceratopsids from the time interval between the Turonian and late Campanian stages of the Cretaceous. As such, the nasal horncore of the early ceratopsid Wendiceratops suggests that prominent nasal horncores evolved multiple times among ceratopsids (Evans & Ryan, 2015). The presence of this new form as adds to our growing understanding of the early radiation of ceratopsid dinosaurs, which would evolved into a menagerie of forms during the very end of the Cretaceous.

Wendiceratops pinhornensis by the author. Pencils on paper, 2015.

Wendiceratops pinhornensis by the author. Pencils on paper, 2015.

THE INTERNET AND PALEONTOLOGY 

Sarah of the Geological Society of London discusses the invertebrate fauna of Ordovician Morocco. You can find that post here. If you enjoy learning about the beginnings of modern animals, this is the post for you.

At Extinct Monsters, Ben concludes his “Framing Fossil Exhibits” series. If you’re interested in the art of fossil mounting, you should go read the post here.

Mark Witton talks dromaeosaurids, specifically depicting them engaging in behavior not often illustrated. You can find the artwork-filled post here.

FEATURED FOSSIL (NEW SEGMENT) 

This week we highlight one of the Merycoidodon skulls in the Stamford Museum’s collections.

IMG_2896

That’s all for now! Thanks for reading!

Antediluvian Beasts of the East : Ornithotarsus immanis

It’s morning in the woodland, 79 million years ago, and the sounds of the forest greet the rising sun. Within a cluster of Gunnera plants, a male dromaeosaurid displays his plumage to a somewhat uninterested female, while a pair of mammals dash across the earth. A sudden, triumphant bellow sends the dromaeosaurids darting into the trees, leaving the mammals to forage in peace. The bellow came from a young male Hadrosaurus foulkii, the most common dinosaur of the woodland. Typically, Hadrosaurus foulkii travel in closely-knit herds, but males are often exiled, only to return to the herd during mating season. Being solitary means that this young male Hadrosaurus foulkii lacks the protection of the herd, and is an easy kill for the predators of the forest. Yet predators aren’t the only threats in these woods.

The young male hadrosaur stops to browse on some tall shrubs, without a whim in his mind, but suddenly, with the volume of a ship horn, an immense bellow from behind the shrubs makes the young hadrosaur jump. The emperor of these forests has arrived. Meet Ornithotarsus immanis. This 39 foot, 7 ton male is twice as long and three times as heavy as the 20 foot, 2 ton young male Hadrosaurus foulkii. A whole herd of the giant hadrosaurs emerge from the forest, prompting the young Hadrosaurus to flee. These gentle giants pose no threat to the smaller hadrosaur, but instead use their bulk to tip over trees and defend themselves.

The herd of Ornithotarsus is on their way to the highlands, where they will graze on the various plants which make up the highland’s plains. But there’s a catch. The wet season, while giving life to the plants the Ornithotarsus herd will feast on, leaves the highlands wet and cold, no place for an exposed hadrosaur. These hadrosaurs, however, have a remarkable adaptation. Unlike the hadrosaurs of the lowlands, who bear scutes over their body save for the occasional bristle-like proto-feather ancestral to the order ornithischia, a thick pelt of modified proto-feathers insulate the Ornithotarsus immanis while they occupy the highlands. They are, indeed, woolly hadrosaurs.

But their are other dangers awaiting the O. immanis on their journey to the highlands. packs of dromaeosaurids occupy the highlands year-round, and harass the herd of hadrosaurs in an attempt to pick off the young. Harsh storms also pose a threat, and often young, old, and weak hadrosaurs are separated from the herd during these tempests, and are left to find their way through the woods back to the herd or die in the dark forests below the bald peaks of the mountains.

The herd advances on. So far, only two individuals have been separated from the herd, neither of which being juveniles. The herd is almost to the end of their 170 mile, 3 day long, 2500 foot verticle climb to reach the highlands. There is, however, one more challenge they must face. The rock fields of the outer highlands are a nesting site for large azhdarchid pterosaurs. With wingspans of up to 30 feet, and heads shaped like swords, these flying archosaurs can injure even adult Ornithotarsus. The hadrosaurs have also developed a trick for dealing with the pterosaurs. Ornithotarsus bellow as a means of communication, but they also use their calls as a means of intimidation. The azhdarchids, for one, are terrified of the hadrosaurs’ loud bellows, and take to the skies as soon as they hear the first call, leaving the herd to safely pass between the rock fields.

The herd finally arrives at the highlands. In front of them lie the highland plains, and they waste no time in indulging themselves, the wind howling across the expanses of plant littered earth.

What we have of Ornithotarsus consists of a partial tibia, fibula, astralagus, and calcaneum (Prieto-Marquez, Weishampel, & Horner, 2006). These remains possibly hail from the Woodbury Formation of New Jersey (Colbert, 1948). The animal itself was apparently enormous (Colbert, 1948), with an estimated length of 39 feet (Holtz, 2012). In his 1948 paper, Edwin Colbert described the animal as follows: “This seemingly represents a very large hadrosaurian, larger then any others known from the eastern Cretaceous, but until additional material is forthcoming nothing definite can be said concerning this supposed species.” Sentences like that get me excited. If Ornithotarsus was the large hadrosaur Colbert suspected it of being, it would be the largest known terrestrial-animal from the Woodbury Formation.

Ornithotarsus consists of one species, O. immanis. Like many other dinosaurs from the Eastern US, it has been considered a nomen dubium by some workers (Prieto-Marquez, Weishampel, & Horner, 2006), and a synonym of Hadrosaurus foulkii as well (Baird & Horner, 1977) (Weishampel & Horner, 1990) (Horner et. al., 2004) (Weishampel, 2006). Colbert (1948) makes a good point, noting that the fragmentary nature of the Ornithotarsus immanis material causes anything said about the animal to be tentative at best. So what exactly can we say about O. immanis, even if the statement is tentative?

If Ornithotarsus immanis does hail from the Woodbury Formation, it is likely this gargantuan hadrosaur co-existed with the smaller H. foulkii. These animals might have co-existed by exploiting different food sources in the same I have suggested before concerning other hadrosaur genera. So what of (tentative) classification? Prieto-Marquez, Weishampel, & Horner, (2006) classified Ornithotarsus immanis as an indeterminate hadrosaurid, and based on Colbert’s statement, this seems to be the best we can do in terms of the classification of Ornithotarsus immanis until more complete specimens are discovered.

Hadrosaurus foulkii fossils displayed at the Philadelphia Academy of Natural Sciences, Drexel University. Photo from Wikipedia.

Casts of Hadrosaurus foulkii fossils displayed at the Philadelphia Academy of Natural Sciences, Drexel University. Photo from Wikipedia.

Besides Hadrosaurus, a variety of other animals are known from the Woodbury Formation. Hence the fact that the Woodbury Formation is a marine deposit, specimens of the shark Scapanorhynchus texanus, the fish Enchodus, and the sea turtle Catapleura repanda have been collected from the formation (Gallagher, 1993).

Scapanorhynchus texanus teeth. Photo by the author, 2015.

Scapanorhynchus texanus teeth. Photo by the author, 2015.

Ornithotarsus immanis (if the remains do persist to the Woodbury Formation) is also the temporally oldest hadrosaur I’ve discussed so far. The Woodbury Formation is estimated to have been deposited between 80.5 and 78.5 million years ago (Gallagher, 2005). That beats out Hypsibema crassicauda of the Ellisdale site (=Marshalltown Formation, ~72 million years ago). The Hypsibema of the James King Marl Pits (= Black Creek Formation, ~84.9-70.6 million years ago) may have existed at the same time as Ornithotarsus. 

O. immanis was but one of the first giant hadrosaurs of the continent Appalachia. Hadrosaurs would thrive until the end of the Cretaceous, diversifying into a menagerie of forms on multiple continents. The fate of Ornithotarsus would be burial at sea, its remains eroding away until nothing but fragments remained to be found.

Ornithotarsus immanis by the author. Pencils on paper, 2015.

Ornithotarsus immanis by the author. Pencils on paper, 2015.

For more on gigantic hadrosaurids, see these articles:

Antediluvian Beasts of the East : Hypsibema missouriensis 

Antediluvian Beasts of the East : Hypsibema crassicauda 

References 

1. Prieto−Márquez, A.; Weishampel, D. B.; Horner, J. R. .2006. “The dinosaur Hadrosaurus foulkii, from the Campanian of the East Coast of North America, with a reevaluation of the genus.” Acta Palaeontologica Polonica 51(1): 77–98. 

2.Colbert, E.H.  .1948. “A hadrosaurian dinosaur from New Jersey.” Proceedings of the Academy of Natural Sciences of Philadelphia 100: 23–27.

3.Holtz, T. R. Jr; Rey, L. V. .2007. Dinosaurs: the most complete, up-to-date encyclopedia for dinosaur lovers of all ages. New York: Random House. (Updated during 2012) link: PDF .

4. Baird, D.; Horner, J. R. .1977.” A fresh look at the dinosaurs of New Jersey and Delaware.” The Bulletin of the New Jersey Academy of Science 22(2):50. 

5. Weishampel, D. B. ; Horner, J. R. .1990. “Hadrosauridae.” In D. B. Weishampel, H. Osmolska, and P. Dodson (eds.), The Dinosauria. Berkeley: University of California Press. p. 534-561.

6. Weishampel, D. B. .2006. “Another look at the dinosaurs of the East Coast of North America.” III Jornadas Internacionales sobre Paleontología de Dinosaurios y su Entorno, Salas de los Infantes, Burgos, Spain. Colectivo Arqueológico-Paleontológico Salense Actas:129-168.

7.Gallagher, W. B. .1993. “The Cretaceous/Tertiary mass extinction event in the North Atlantic coastal plain.” The Mosasaur 5:75-154

8. Gallagher, W. B. .2005. “Recent mosasaur discoveries from New Jersey and Delaware, USA: stratigraphy, taphonomy and implications for mosasaur extinction.” Netherlands Journal of Geosciences 84(3): 241.

It’s That Time of Year Again…

For much of the world, the middle of summer is approaching. For me, that means the most stressful, restless time of year outside of publishing a paper. That’s right, it’s fossil huntin’ season!

Earlier today, I went scouting for invertebrate fossil fragments. The fossils I was looking for are from the Minturn Formation, a carboniferous layer of brown-to-tan colored rock. Outcrops appear all over Vail valley, and so its not hard to find where to start looking. Unfortunately for me, today was pretty unproductive. Right now it’s 11:40 AM and I’ve had to pull out of the collection zone, as thunderstorms have just blanketed the valley.  Vail pass is completely overcast from what I can see, with clouds rolling into the Gore range. Thunderstorms in the Rockies are annoying, but pretty. I also just had some bad luck today when it came to the fossils I’ve found. A piece of coral and a couple fragments of invertebrate carapace are all I can say I’ve collected.

Hopefully tomorrow’s weather will allow for collecting conditions, but if not, it’ll be another day of research. If the weather really stinks, I’ll probably head to town or something. Oh well!