Tag Archives: paleobiology

Feet On The Ground: The Menefee

After a trying time in the Crevasse Canyon Formation, we had high hopes for more abundant fossils in the Menefee.  This was our first time prospecting this strata but we had teamed up with Andy Heckert and his summer students from Appalachian State University to check out some sites that Andy had found several years ago.  As usual our first day was inspiring but also a bit overwhelming.  Looking out over the expanse of Menefee exposure, it felt like one could spend a lifetime out here prospecting…

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Menefee exposures go on and on…

Unlike the Crevasse Canyon, we found bone all over the place on day one out here, but much of it was encased in nodules. In most cases, mineral growth had invaded the bone, changing it’s structure.  We pulled a partial leg in decent condition before heading up section to find better preserved materials.

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exposed digits from a dinosaur limb

Turned out looking in the younger part of the formation was a good idea.  The next day we found a fruitful basin with a lot of exposed bone, a decent turtle preserved in a sandstone cliff face, and not too far from there, a couple of good sites with multiple dinosaur bones.

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This is what it looks like to find a turtle in a cliff. The shell in cross-section is sticking out just above Lisa’s right arm
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Although a portion of the shell was lost due to erosion of the cliff face, as we chiseled the sandstone from around it, a pretty good carapace began to emerge.
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why, I ask, does our most promising dinosaur site have to be found under 15 feet of this….?

We spent about 10 days in the Menefee prospecting and surface collecting from various sites.  Again the abundance of tracks, both dinosaur, croc, and turtle kept us fairly busy. We were fortunate to find a natural cast of an enormous croc track on the under surface of a sandstone lens bearing pad and scale impressions. It turned out to be a tricky but quick collect as we undercut the block, capped it with plaster, and let it drop to the ground (thankfully, not on any members of the team…) into a rimmed depression we devised.

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stabilizing the croc track before work begins

We had our fair share of injuries and illnesses this trip with altitude sickness, falls, and even kidney stones and a lot of long, back-to-back days of wandering around solo prospecting, which leads to some interesting bouts of creativity.

While Lisa was inventing camp mascots, I tried my hand at a desert snowman…

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Hi Hank
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not bad!

Although our fossil finds were few and far between, there was an abundance of wildlife discoveries including several close encounters with rattlesnakes!

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Rattlers didn’t seem bothered much by our traipsing around

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At the end of our season in the Menefee, we headed further south to explore the northernmost exposures of the Moreno Hill.  Here we found nearly nothing for days aside from some microsites and a single iguanodontipodid track.  Still, we had found enough promising localities this year and last to return in 2018 for a fruitful season. Even if it does involve a week of jackhammering through a sandstone cliff to get at the bones.

Next up….  Montana!

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Kicking off in New Mexico

Long days and poor cellular service prevented us from blogging in real time during our first expedition of 2017 to Upper Cretaceous formations in northwest New Mexico.  We were able to keep up on Twitter though, so for the expedition play-by-play, check out #NMdinodig17 @expeditionlive.

Still… in the few days after Montana and before heading out to Utah this summer, I thought it’d be a good time to catch you up on how things went.

Last year we kicked off our pilot expedition to the Moreno Hill and Crevasse Canyon formations, strata that span a key, underrepresented interval in the fossil record of dinosaur evolution on the North American continent.  Finding fossils in the Moreno Hill Formation isn’t easy and we spent two weeks, prospecting 8-10 miles a day, with little to show for it last season.  We did find a productive basin near the end of our trip with fossilized turtles, a large croc osteoderm, a lot of random dinosaur bone, and one intriguing locality with over 40 ornithischian vertebrae exposed on the surface (Elk Run).

This year we hoped to open excavations at Elk Run, but our permits were not approved in time so… instead of excavating there, we continued to prospect for productive new areas in northwest New Mexico.  We were particularly interested in the Coniacian-Santonian aged Crevasse Canyon Formation and spent about four days hunting around in fairly good exposures.  The first two nights we woke up to snow (some of us with our tents collapsed onto our faces…), but soon enough things began to warm up.

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there’s nothing like waking up to snow in the desert

We could find only a single published record of dinosaur bone recovered from the Crevasse Canyon–a partial duckbill dinosaur jaw bone. Thus we knew there was potential, but also, that the Crevasse Canyon would make us work for it.  We didn’t have a great deal of luck this year but we begin finding some dinosaur bone on the last couple of days, and ultimately one nice limb bone that continued into the hill.

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A bit of limb bone on the surface

We also found a great leaf locality, and a ton of dinosaur tracks, which are all over the Crevasse Canyon.  I literally pitched my tent on a track horizon in camp and tracks could be found just about everywhere we wandered.

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a little poking around my tent and voila! track casts

We wrapped up this part of the trip by revisiting a cool ornithopod dinosaur track site I found last year.  This time we brought geology undergraduates from Wake Tech, as part of our National Science Foundation GEOPATH award.  Here we documented the site, took photographs to create a photogrammetric model, and evaluated the track morphology and number of trackways preserved.  We’ll be presenting this research at the Geological Society of America’s annual meeting in Seattle.

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Wake Tech student Katie Berry examines the track block

After wrapping up in the Crevasse Canyon we packed up camp and headed north to hunt around in the Menefee Formation.

 

Did Plants Make Feathered Dinosaurs Dumb?

Short answer, no.

Want to know more… by all means read on.

Today, colleagues from the University of Bristol, National University of Mongolia, Ohio University and I took aim at the doctor/patient confidentiality pact by publishing some very personal information on a research subject of ours.  Fortunately, I don’t think this particular patient is going to get their feathers ruffled about it.  Turns out, paleontologists are smarter than we often get credit for.  In fact, we’ve got this whole messy doctor/patient thing figured out… just work on patients that are already dead… in this case, for over 90 million years.

copyright Mark Anderson www.andertoons.com
copyright Mark Anderson http://www.andertoons.com

One fortuitous day, we got the chance to do just that.  The only good skull of a rare and whacky group of theropod dinosaurs known as Therizinosauria made the trek from Mongolia to the UK on holiday.  While there, UK paleontologists realized that the skull of the therizinosaur Erlikosaurus was REALLY, REALLY, REALLY, overdue for its check-up.  So they took Erlikosaurus’s head to a CT scanning facility for its 90 million year annual physical.

The fossilized skull of Erlikosaurus andrewsi from the Cretaceous of Mongolia
The fossilized skull of Erlikosaurus andrewsi from the Cretaceous of Mongolia

Why Erlikosaurus?  Well, for starters, therizinosaurs are downright weird animals, which makes them really interesting to weird people (erg.. uh.. cough.. I mean “scientists”). Although they are theropods and therefore cousins of bloodthirsty predators like Velociraptor, therizinosaurs were clearly not taking a bite out of anyone.  Sometimes it is hard to envision an advanced therizinosaur like Erlikosaurus as doing anything at all, other than finding a nice soft spot in the Cretaceous landscape to pop a squat and eat all day long.  A quick run down of the therizinosaur anatomy makes this blaringly evident.  These guys had tiny heads, tightly packed minuscule teeth, long necks, stocky legs with fat feet, hand claws up to four feet long, and giant bloated bellies. They also reached enormous body sizes up to 13,000 lbs. When I was in grad school I used to get this point across by comparing therizinosaurs to a cross between a gorilla, an ostrich, and Edward Scissorhands.  If you ask me, the analogy is still apropros.

Luis Rey's vision of what an advanced therizinosaur looked like in the flesh.
Luis Rey’s vision of what an advanced therizinosaur looked like in the flesh.
How to build a therizinosaur 101.
How to build a therizinosaur 101.


The question is… did the loss of predatory behavior coincide with a loss of smarts and a loss of sensory capabilities in therizinosaurs?  No one knew. By CT scanning the skull, we were able to reconstruct soft tissue of the brain and inner ear of Erlikosaurus and tackle this intriguing question.  The result?  Despite its rather slow appearance, Erlikosaurus was not a dumb as a box of rocks.  Although, these kind of estimates are admittedly crude, it seems as if Erlikosaurus was just a bit shy on the intelligence scale when compared to early birds, but likely a bit ahead of the great hunter T. rex.  Pair this with the fact that Erlikosaurus had above average hearing capabilities for an animal its size and a higher than predicted sense of smell, and suddenly therizinosaurs don’t seems as dimwitted as…. well, as they look.

Scans did reveal that one Erlikosaurus sense could’ve benefited from some improvement–its vision, which probably wasn’t the best.  Whatever these guys were eating, they were likely munching in the pure light of day.

Reconstructed soft tissues in the head of Erlikosaurus: brain (blue), cranial nerves (yellow), and inner ear (pink).
Reconstructed soft tissues in the head of Erlikosaurus: brain (blue), cranial nerves (yellow), and inner ear (pink).

The implications are interesting. Despite leaning toward vegetarianism, therizinosaurs seem to have kept the keen sensory toolkit they inherited from their predatory ancestors.  All of which means that the brainpower and good senses of therizinosaurs had more to do with their place on the family tree as close cousins to birds than their dietary preference.  Its also good to know that, should you ever encounter Erlikosaurus as a result of, say a time machine fluke, it could hear your terrified whimpers but would be kind enough not to eat you.  (Just don’t sneak up on it at night or you could lose an eye).

Couldn’t say the same about T. rex.

The paper “The Endocranial Anatomy of Therizinosauria and its Implications for Sensory and Cognitive Function” by S. Lautenschlager, E. Rayfield, P. Altangerel, L. Zanno, and L. Witmer, is freely available to the public via the journal PLoS ONEhttp://dx.plos.org/10.1371/journal.pone.0052289