Monday, August 1, 2016

Digging up our Triceratops: Count Trikeula!


This rather small rainstorm blew north of us
Photo: J. WIlson


Why not begin with a bit of rain?

Our first week in the field started with quite a lot of rain. This can be a real problem for fieldwork out on the prairie as the dirt roads quickly absorb the rain and become an impassable mire. Even if you are able to drive through the mud, you can leave huge ruts that can damage the roads in the long term. In these situations it's smarter to sit tight and wait out the weather: you can't dig bones in the rain anyway.

I had wanted to start our season at "Count Trikeula": a decent-looking Triceratops skull site discovered by crew member Danny Anduza last year. However, Count Trikeula is not immediately accessible in bad weather. As such, we've been jumping about among 3 main sites, hitting Count Trikeula when we can, and heading to some more accessible sites when that wasn't possible. On the blog, I'm going to talk about the sites individually so we're going to start with Count Trikeula.

 
Triceratops sp.. Drawing: D. Anduza.


'Count Trikeula' 

This is a site that we had exposed a little bit last year. Count Trikeula is a 3/4 grown Triceratops, which is fairly average size for a Triceratops, but still a very big animal! 

In 2015 we could see that Count Trikeula  had a good-looking frill at the back of the skull, but we couldn't tell how much of the skull and skeleton might be there as our permit only allowed us to dig a fairly small hole.


In 2015 we could see the rear edge of the frill, and the cheek spike
Art: D. Anduza


Cue 2016 and our excavation permit! We spent a half day clearing overburden, then dug in around the skull.

2016: Hell Creek rocks are not particularly hard so you usually only need hand tools to remove overburden.
Photo: Kit Robison
After the overburden was done, we peeled away the protective tarp and cover we had placed over the site in 2015.
Photo: Kit Robison

Once the overburden was completed, we set up a shade tarp and started digging!
Photo: D. Fowler

It became apparent rather quickly that the front of the face had been damaged before the skull had been buried, 67 million years ago. This was a shame as I was hoping that this site might give us a new datapoint for ongoing research on how Triceratops evolves through the Hell Creek Formation. 

In 2014, I coauthored a research paper which described how Triceratops skulls collected from low in the Hell Creek Formation have a small nose horn and belong to the species Triceratops horridus; whereas skulls found in the upper part of the formation have large nose horns and belong to Triceratops prorsus. The skull of Count Trikeula is low in the Hell Creek, so it should have a small nose horn, but sadly it doesn't seem to be preserved.


Our digging revealed the back of the skull is quite complete, but the face is mostly broken away.
Photo: H. Flora



Schematic showing which parts of the skull were well preserved.

The frill of Count Trikeula is much more wide than we typically see in Triceratops prorsus, suggesting that it does not belong to that species. Also, the bases of the brow horns are wide and robust. This is supportive of Count Trikeula belonging to Triceratops horridus, but we will need to clean all the bones back in the lab to test this hypothesis properly.

Count Trikeula has a 70% complete parietal bone (middle of the frill) which is actually quite rarely preserved in Triceratops. It also has a injured squamosal (corner of the frill). These features make Count Trikeula a good specimen to help in our research on Triceratops evolution and behavior.

The right squamosal of Count Trikeula has rough bony growths on the surface, indicating an injury that occurred during life
Photo: D. Fowler
Okay, that's it for this blog post. We're continuing to work at Count Trikeula when weather permits, but the next blog post will be about one of out other sites!

Cheers,

Denver.

PS. If you're in Malta, MT, stop by the Great Plains Dinosaur Museum to see some of our latest finds temporarily on display until we head back to Dickinson ND.


Tuesday, July 19, 2016

July 2016: Back in the Hell Creek Formation!


Outcrop of the Hell Creek Formation near our camp. Photo: Kit Robison.


My field crew and I are back looking for dinosaurs on the American Prairie Reserve (APR) in northern Montana!

If you've followed the blog before, you'll know that in 2015 the APR kindly provided us funding to survey the reserve for fossils. We focused our prospecting in outcrops of the dinosaur-rich Hell Creek Formation, which records the final years the Cretaceous Period, ~ 67 Million years ago. Exposures of the Hell Creek Formation on APR land are mostly the lower part of the Formation. This is very interesting for our ongoing Hell Creek research as the species found in the lower part fo the formation differ from those of the upper, and it is much less well sampled. We need more dinosaurs from the lower!

In 2015 we found 60 new sites, including 30 microsites, a juvenile Triceratops frill, and a very interesting site with the skulls of three different dinosaurs weathering out, one of which might be a medium-sized Tyrannosaurus rex

We have returned in 2016 armed with a fistful of BLM excavation permits so that we can properly dig at some of the more promising sites. I will be posting updates and photos through the season. Hopefully we will have some cool specimens to report on!

Also keep an eye on my Twitter feed (@df9465) for regular photos.

Gratuitous truck photo: My recently acquired field truck in its natural habitat, with paleo plates!
Crew members Holley Flora and Jack Wilson pose awkwardly next to our trusty trailer, complete with resident mouse.


Okay, that's the intro done. I will post something about actual fossils tomorrow!


Friday, March 18, 2016

A juvenile Tyrannosaurus braincase?

 

An exciting development (maybe) this week for #FossilFriday. On the left is a braincase fragment from one of our new 2015 sites. On the right is the braincase of Timurlengia, a small tyrannosaur from Uzbekistan described this week by Brusatte et al.. Now, this photo is of the inside of the braincase, and I was struck by the similarity to our specimen. Could we have a (juvenile) tyrannosaur skull coming out of our site? When we found it we realized it was a braincase of course, and it is a bit too gracile to be from an ornithischian (we think), but there are not too many specimens to compare it to.

It's only a fragment I know, but that's how you find these important sites: ID the frags and dig deeper! (besides, this site already has a juvie pachy and thescelosaur...)

Opinions welcomed!

Hell Creek Formation. American Prairie Reserve. Montana.

Friday, October 30, 2015

Iguanodon Footprints cast in red mudstone for Fossil Friday

It's been a while since I posted fossil photos for "Fossil Friday", so here are the missing photos that I posted to Facebook over the past few weeks.

Iguanodon Footprints

Although dinosaur footcasts preserved in Wessex Formation sandstones are perhaps more obvious, there are many preserved out in the vividly coloured mudstones too. Infilled footprints can often be found at the boundary (contact) between beds of different colours. This red-infilled footcast was probably made by an Iguanodon.

Wessex Formation, Barremian, Lower Cretaceous, ~130 Ma, Grange Chine, Brighstone foreshore, Isle of Wight, UK.


The three toes of the hindfoot are especially well defined in this footcast.
Here is another in the same horizon, a little more weathered.

This is the exposure itself at Grange Chine (Brighstone foreshore). You can see two red footprints in the foreground.

 

 

Ammonites in the lower chalk 

Collecting ammonites from the glauconitic marl with my dad and brother (pictured). Usually you find small Schloenbachia and Mantelliceras, but occasionally the big species turn up. Old Park Hotel, Isle of Wight, UK; Lower Chalk, Cenomanian, ~95 Ma, Upper Cretaceous.

How many ammonites can you see in this picture?


A mammoth day out

Back in the day, I used to run fossil-hunting field trips for armies of ten year olds. This is probably the best thing ever found on my trips: a mammoth tooth. We were actually looking for dinosaur bone in the Wealden, but Letitia brought this up to me and asked what it was, so I then had to explain about the Pleistocene gravels that form the upper 2m or so of the cliffs. This was shortly after we met a man on the beach who had found a lost baby stoat and had it crawling around all over his jacket. The kids were already pretty excited about that, so the mammoth tooth sent them wild!

 
This was quite a few years ago now. Still better than anything I have found from the Pleistocene.


Some associated pterosaur bones

Some pterosaur bones for #fossilfriday. My dad collected these a few years ago from the Vectis Formation, UK. Pterosaur material is supposedly rare, but turns up fairly regularly if you know what to look for. Collecting pterosaur bones in the UK helped me to identify a few pieces that I have found or helped describe from the Late Cretaceous of the USA. One day I will get round to describing the pterosaur bits we have found in the UK too.

Vectis Fm, lower Aptian, Lower Cretaceous, Isle of Wight, UK.

Pterosaur limb bones in coquina (storm bed) dominated by the bivalve Filosina.



Fossil lobster (okay, it's more shrimp-sized...)

A small Meyeria magna lobster, preserved in 3D. These are very attractive little fossils, and quite abundant if the right layer is exposed and you know what you are looking for.

Lower Lobster Bed, Lower Greensand (Aptian), Atherfield, Isle of Wight, UK.


Everyone likes to find fossil crustaceans, especialy when they have fine detail such as the tiny spines on this Meyeria.
 

Sunday, October 4, 2015

When stegosaurs had smarts

This week, I'm posting scans of a recently acquired postcard.

The postcard dates from around the 1960's, but it features an 1895 poem which regales the hypothesis that an enlarged space in the pelvises of many dinosaurs meant that they might have possessed a second brain. Paleontologists are still interested in the possible function of the swollen spinal canal, but it is no longer considered to have housed a hindbrain.

Anyway, I thought the poem was quite clever, so here it is:

Front of postcard

Reverse of postcard

Another poem, this time from 1885, similarly reflects the Victorian fascination with paleontology. I sometimes wonder what was different about this time in the recent past, when scientific discoveries were so ingrained in the public consciousness that leading newspapers and magazines treated them not only as interesting facts, but as cultural objects of inspiration and humour. The modern media seem concerned only with the frivolous lives of shrill celebrity dimwits, or the opinions of boorish career politicians.

Anyway, I digress. This second (somewhat overlong) poem concerns the enormous eyes of the extinct marine reptile, Ichthyosaurus. I liked it. You should too.

From Punch magazine (1885); http://catalog.hathitrust.org/Record/000682156

Inspired by these kinds of things, since about 2011 once per field season my paleontology field crew have held a poetry evening, where we attempt to recount our experiences in pithy prose. Maybe if I can find some of the poems I will repost them here... or at least some of those that are repeatable in polite society...

Okay, back to work...

--- edit 6th October ---
I just noticed the implicitly racist "Aryan brain" line in the Ichthyosaurus poem. Apologies if anyone was offended; obviously this is a representation of the kind of discriminatory language and attitudes that were widespread in Victorian society.

Friday, September 18, 2015

Fossil Hedgehogs


A slightly different #fossilfriday this week ( I missed last week as I was busy hiking and looking for fossils on the American Prairie Reserve). Back in 2000 I found a very productive seam of microvertebrates in the Oligocene Hamstead beds of Boldnor on the Isle of Wight. We retrieved something like 300 mammal teeth from only about 1-2 kilos of sediment. Jerry Hooker (Natural History Museum, London) came over to Bristol University to see the fossils and told me that among our cache were the best preserved oldest hedgehog teeth in the world. I gather that there are older hedgehog remains, but these teeth are the best preserved. Anyway, everyone likes hedgehogs, so I was very pleased.

Fossil Hedgehog teeth. Adapted from Hooker (2010).


The specimens were donated to the NHM to be studied by Jerry. The above image is a figure from his 2010 paper and shows Scanning Electron Microscope photos of hedgehog teeth from Hamstead. I do not know if the teeth shown here are the ones I found, but I suspect they are.

The hedgehog teeth are part of the fossil fauna from immediately after the Grande Coupure extinction event that occurred in the northern hemisphere in the earliest Oligocene, about 34 million years ago.

This image is a bit plain though, so here's a photo to remind you of how cute hedgehogs are:

(image from pinlovely.com)

Reference

Hooker, J. J. "The ‘Grande Coupure’ in the Hampshire Basin, UK: taxonomy and stratigraphy of the mammals on either side of this major Palaeogene faunal turnover." Micropalaeontology, Sedimentary Environments and Stratigraphy: A Tribute to Dennis Curry (1912–2001) (2010): 147-215.

Friday, September 4, 2015

Baby Iguanodons!

Here are a couple of pictures of baby Iguanodon fossils that I have posted to Facebook for #FossilFriday.

This week: baby aff. Iguanodon tooth 

 A very small (~9mm) crown of a juvenile aff. Iguanodon from Chilton Chine, Wessex Formation, (Barremian, Lower Cretaceous, ~130 Ma), Isle of Wight, UK.


Aff. Iguanodon juvenile dentary tooth.
Scalebar in mm. Photo: Steve Sweetman.

Iguanodontid material is common in the UK Wealden, but juvenile material is always nice to find. This looks to be a dentary tooth, based on the broad diamond shape. For comparison, here's a photo of a medium-sized adult dentary tooth from Iguanodon bernissartensis:
 
Iguanodon bernissartensis tooth.
Photo from dinowight.org.uk

A few weeks ago: The best Iguanodon fossil

A few weeks ago (on my Facebook page), I posted this photo of another juvenile Iguanodon bone. It's a tiny thumb spike! The spike is a little bit worn as it has been rolling around the beach for a while, but you can see the "nail groove" running down the side.

When I found this back in the 1990's, I was not particularly experienced in identifying bones, so for a while I thought it was a crocodile tooth, but it is clearly bone.

Juvenile aff. Iguanodon thumb spike.



Friday, August 28, 2015

A Baryonyx tooth for #FossilFriday, plus blog bonus!

The unique crocodile-like tooth of Baryonyx





Tooth of the english fish-eating spinosaur Baryonyx walkeri. Possibly my favourite of the ~20 or so Baryonyx teeth I have collected (mainly due to the rich red and yellow colours), this is also the stratigraphically lowest, being from half way through Sudmoor bay. Wessex Fm, Barremian, Early Cretaceous, Isle of Wight, UK.

If you like Baryonyx teeth you can find another 20+ illustrated on my SVP poster from 2007. 15mb PDF available here.



Blog bonus!


I recently came across this old press photo (1983) for sale on the internet. The photo shows the original discoverer of Baryonyx, Mr. William (Bill) Walker, along with Sandra Chapman at the Natural History Museum, London. If you're as big of a fan of Baryonyx as I am, then you are probably familiar with the iconic photo of Bill Walker holding up the claw of the dinosaur that bears his name, but I had not seen this photo before (presumably taken at the same sitting). Enjoy!

Sandra Chapman (left) and Bill Walker (right) hold the enlarged hand claw of Baryonyx walkeri.
John Sibbick illustration in the background.
Vintage press photograph for sale at internet shopping website.

Presumably the flip side of the photo.

Friday, August 21, 2015

Iguanodon for Fossil Friday

#Fossil Friday

Over the years I have collected lots of fossils from all over the globe. I have started posting photos of these to my facebook page for #FossilFriday. I'm going to post them here on the blog too.

So far I've been focusing on fossils I have found on the Isle of Wight, UK. This is the best place in Europe to find dinosaur fossils.

So here's this week's image:

Iguanodon. The best dinosaur, or your money back.
This is the nicest Iguanodon tooth that I have found, which is not saying much really. The tooth is from the maxilla (upper jaw) and is nicely preserved as it is unworn, i.e. it had not yet been used by the dinosaur to chew with.

I suppose technically I should say that this is <probably> from Mantellisaurus, which is the new name for Iguanodon atherfieldensis. I'm not a big fan of taxonomists constantly renaming taxa. Collected from the Wessex Fm (Barremian; Lower Cretaceous, ~130 Ma), Brighstone, Isle of Wight, UK.


If you would like to see previous #FossilFriday posts on my Facebook page, head to the album here.

Thursday, July 23, 2015

Screenwashing, for victory!

So if you followed the link from my previous post over to the Great Plains Dinosaur Museum Facebook page, you would have seen a photo of a cute little pachycephalosaur squamosal spike that we found in the first week. Pachycephalosaurs are the famous dome-headed dinosaurs that are often shown headbutting each other (although the evidence supporting this behavior is controversial).

This pachycephalosaur spike came from "trucker's macrosite" which preserves a jumble of bones from various different species. Most of the time, bones in macrosites are water worn, or broken, but a small percentage are better preserved, so macrosites can be good places to look for skull bones, and other diagnostic elements.

One of the other interesting pieces collected from "truckers macrosite" is this fragment:

A braincase fragment from a theropod?
The specimen is constructed from quite thin-walled bone, and has numerous holes ("foramina") passing through it. I was wondering if this might be part of the braincase of a theropod dinosaur. The foramina would therefore represent the holes though which the cranial nerves passed. If anyone has a better idea for the identification of this bone, then I would be very appreciative (I am hoping it is not just parts of a large theropod vertebra).

Trucker's macrosite yielded additional pieces of theropod skull, but each of the interesting specimens from this site is incomplete, with broken ends where (presumably) pieces had broken off during recent weathering. So, in an attempt to find the missing parts of these tantalizing fragments, we returned to the site yesterday to do some intense surface collecting and screenwashing.

Peter Thomas (foreground) and Danny Anduza (shirtless) search for more treasures. Photo by Holley Flora.

Peter, Danny and Holley spent all day collecting every piece of bone from the surface and dry / wet screenwashing shovels of mud to find pieces that had been buried. Today we were trapped in camp by rain, so I started going through the surface collected material to see if we had any of our missing pieces.

Success!

Inside the third bag I looked in (collected by Holley) I found this little gem:

Pachycephalosaur squamosal spike, number 2!
The spiked tip is missing, so we will be back screenwashing again to try and find it!
Crewmember Holley Flora (one of my seasoned field crew from 2013 & 2014) had picked up another squamosal spike from a pachycephalosaur! This is almost certainly from the same specimen as our previous spike, so it is possible that there might be more at the site.

Pachycephalosaurus wyomingensis by Dr. Jordan Mallon.
The spikes we have found are from the back corners of the skull (squamosals) .
(Image from wikipedia)

You might be familiar with the recent research by my supervisor Jack Horner and Mark Goodwin from UCMP Berkeley. In 2009 they hypothesized that the dome and squamosal spikes of Pachycephalosaurus changed through growth. Young animals had no dome, but exhibited long spikes on the squamosals. The characteristic dome-head of Pachycephalosaurus developed through ontogeny, and was only fully-sized in adults. Curiously, adult Pachycephalosaurus had short rounded knobs on the squamosal, instead of the long spikes of youth.

The spikes that we found are quite small and fairly pointed (based on the angle of the sides, as the tips are missing), so we would interpret them as coming from a young Pachycephalosaurus.

As a bonus, in the next few bags of bone fragments, I found quite a few new pieces to go with the possible braincase. Overall, not a bad return for a rain day!

Reference