My Students Need Your Help

I'm going to cut right to the point here (in case the title didn't give it away). My students need your help. I know I am the goofy tooth blogger who writes about "Indominus rex" and little tiny teeth from the Triassic but the plain fact is that those little tiny teeth don't find themselves. In fact they like to stay hidden, the sneaky little fellows. My high school students in my paleontology program find the majority of them.

In case you didn't read my introduction post, I teach at Mission Heights Preparatory High School and run the nation's only paleontology program at a public high school. I am pretty dang proud of it and my students. We have been doing this since March of 2014 and we already have one publication with one of my students, another pre-print ready to go to review with student lead authors, and a student-led abstract accepted for presentation at the 75th Annual Society of Vertebrate Paleontology Annual Meeting in Dallas this year. All very exciting stuff and it has all been predicated on the field work we have been doing in the Late Triassic Chinle Formation at Comb Ridge, Utah.

In order to do this fieldwork, we have been relying on two things: rented vehicles, paid for by student fees and my personal truck. These two elements have allowed us to access field sites and bring back fossils to MHP but they have their drawbacks. Student fees create a burden on our students, especially in our low-income, rural community that we serve. Some of these students are classified as homeless. Most of our students are on free-and-reduced lunch, meaning that their annual family income qualifies them for government-provided school lunches. These are generally not kids who can afford a $75 fee to rent vehicles, get gas, and buy food. Several promising young scientists had to miss out on trips (and have since moved on from science all together) because their family lacked the means to support them in pursuing our fieldwork. This is a huge concern for me! I have trimmed by budget as much as possible but with the huge cost of renting vehicles for multiple days I cannot get my per-person cost down any lower for our regular spring fieldwork trips. If we care about having scientists accurately represent our society we should be concerned that low income students are dropping out of science because they feel they cannot participate.

The second drawback is in relation to my personal vehicle. It is a 2004 Ford Explorer Sport Trac. It is a great vehicle and has served me well but it has 186,000 miles on it. I was working at a quarry in Utah with the Natural History Museum of Los Angeles County last week and my truck malfunctioned. Now the fix was easy and relatively inexpensive, and since the crew had multiple vehicles they were not out of work while my truck was in the shop. My truck, however, was out of commission for a day and a half. On a multi-week trip this is not a huge deal but when we are working at Comb Ridge we are typically out for only two days. That is a huge blow! I was lucky enough to have my truck break down in Moab - that would certainly not happen with our Comb Ridge work since we rarely go into town. The nearest town, Bluff, also does not have a full-service auto repair facility and parts stores. In addition the NHMLA had multiple field vehicles available to get in and out of locations and haul gear. For our program we use my truck to haul all the gear and rented vehicles to haul all the students. If we had a breakdown with my truck in the field with students it could be a real disaster with no easy fix.

That is why I am asking for help. I am trying to raise $8,000 for a field vehicle for MHP. We have raised a bit over 1/8th of the total goal but we have a long way to go. I am hoping that if you care about students, paleontology, getting students involved in paleontology, or just creating a more science-literate society you will consider donating to our fundraiser. All money raised will go directly to the cost of a field vehicle or, if we are unable to purchase one, into renting field vehicles until the funds are depleted.

If you like learning about teeth, that is where the teeth come from. And I have more tooth posts coming up soon!

Bigger. Badder. More teeth?

Okay, show of hands: who has seen Jurassic World? If you haven't seen it I promise this article won't be spoiler-filled. I promise I won't discuss plot points. In fact, I won't discuss anything that you can't see in the trailers. What I will discuss, though, is teeth!

So if you have seen any of the promotional material for Jurassic World you know that the scientists have created a "genetically modified hybrid" named "Indominus rex." Leaving aside issues about genetic modification and dinosaurs in the Jurassic Park universe, one of the tag lines for this new animal was "Bigger. Louder. More teeth."

Jurassic World promotional image. Image (C) Universal Studios.

Fair enough. From the trailers you know that Dr. Wu says, "She was designed to be...bigger than the T. rex." This also makes sense -Tyrannosaurus is obviously a super-cool animal and would be a big draw at an amusement park like Jurassic World. If you were setting out to make a world-beating attraction then you could do worse than to choose T. rex. While other theropods may have been larger, it is certainly the most charismatic and probably the most well known. So when they are saying that "Indominus" is bigger, louder, and has more teeth they are probably comparing her to Tyrannosaurus.

There's just one problem with that. "Indominus" doesn't have more teeth that T. rex.

Skulls of Tarbosaurus (A) and Tyrannosaurus (B) by Jørn H. Hurum and Karol Sabath [CC BY 2.0], via Wikimedia Commons

As you can see, Tyrannosaurus has a combined total of 15 premaxillary and maxillary teeth. Now let's take a look at some of the promotional images and trailer stills from Jurassic World.

All images (C) Universal Studios.

How many teeth do you see? I count between nine to 11, depending on which motion-blurred image I'm using as reference. This is a situation different from, say David Peters, because in the case of "Indominus" there is no actual skull to do tooth counts with. Unfortunately I have to make do with images.

Here is Chris Pratt under a vehicle in a still taken from a Jurassic World trailer. I have numbered the teeth in the upper jaw (that I can make out), though the depth of field and motion blur make it difficult to be certain on their ID.

So last time I checked 9 < 15. Even 11 < 15. The big, scary "Indominus" has fewer teeth than a Tyrannosaurus. Maybe they were referring to ornithomimosaurs when they were making their comparison? Who can say.

Does this really matter? No, not really. Me nit-picking the strange, croc-toothed creation from Jurassic World doesn't change anything in the grand scheme of things. I just found it amusing that one of their promo points is in fact wrong. It doesn't impact how I feel about the movie, which I enjoyed. It shouldn't change how you feel about the movie.

Want more Jurassic World teeth analysis? Join me next time here at the Prehistoric Pub when I try to figure out what the heck is going on with the "Indominus" dentition!

A Toothy Issue

I am going to talk about teeth today. When I first knew I was going to get into paleontology I didn't think I would every really study teeth. I mean, teeth are neat and everything but I wanted to study dinosaurs! Dinosaurs, especially when I was younger, were mainly known for having relatively simple and easily-identifiable teeth that didn't tell us much besides diet. The only people who studied teeth were mammal paleontologists (which I foolishly looked down upon in my middle and high school years).

Even as I progressed through college I didn't pay much attention to teeth. Sure there were some odd teeth known from the Triassic Period, like Revueltosaurus and Tecovasaurus, but they were rare and the exception to the rule. I figured that they provided only marginal information on the ecosystem and that the major components were well known and understood - things like phytosaurs, metoposaurs, aetosaurs, and rare dinosaurs like Coelophysis. Well it turns out, unsurprisingly, that this view is naive and wrong.

Some of this change has come about from the work of Andy Heckert in the early years of this century. Although his treatise on Chinle microvertebrates is somewhat out of date now (it was published by the New Mexico Museum of Natural History and Science in 2004) it helped establish that the diversity of animals living in western North America was much higher during the Triassic Period than people had previously suspected. In addition to naming new taxa like Krzyzanowskisaurus, Protecovasaurus, and Crosbysaurus, his PhD work showed many new tooth types from the Chinle Formation and Dockum Group that had never been reported in the scientific literature!

Our work at Comb Ridge has focused on teeth. This is not because we set out to find lots of teeth. As with most things in paleontology you focus on what you find. At Comb Ridge we haven't found phytosaur skulls and troves of fossil fish like we do further north. We haven't found aetosaurs like in Arizona or mass graves of dinosaurs like in New Mexico. Instead we are finding teeth. Lots and lots of teeth. So many teeth that one locality, The Hills Have Teeth, may be the most productive microfossil site in Utah - it is certainly the most productive microsite in the Chinle of Utah. We have a dozen species represented, possibly more, from this one hill and they are all known from their teeth. So let's have a brief overview of tooth anatomy and terms so that it doesn't seem like I'm speaking gibberish in future posts.

Handy guide for some of the most common tooth terms I made based on an image from Lopez et al. (2015). Scale bar = 1 mm. CC-BY 4.0

List of Dental Anatomical Terms and Definitions

• Apex - the "top" or tip of a tooth; the portion furthest away from the gumline.
• Apical - a directional term, referring to things towards the apex.
• Asymmetrical - a tooth, viewed from the apex, that does not have the same profile on the lip-side as it does on the tongue-side.
• Base - the "bottom" of the tooth; the portion of the tooth at the gumline.
• Basal - a directional term, referring to things towards the gumline.
• Carina - a distinct ridge or edge, usually found along the leading or trailing edge of the tooth.
• Cingulum - a ridge, "waist", or "belt" of thickened enamel running around the tooth near the gumline.
• Circular - refers to a tooth that is circular in outline when viewed from the apex.
• Conical - a tooth that when viewed from the side has a roughly cone-shaped or pyramidal outline.
• Crown - the portion of the tooth from the gumline to the tip. What most people think of when they use the word "tooth."
• Denticles - triangular or angled protrusions along an edge used for cutting food. Can be angled towards the apex or facing perpendicular to the crown height. In some species these can be subdivided into smaller denticles.
• Dentine - the tough inner material that makes up most of a tooth. Very hard but not shiny.
• Distal - the part of the tooth facing the back of the mouth. In older literature this is sometimes referred to as "posterior."
• Enamel - the tough, shiny, outer surface of a tooth. A very hard material!
• Infolding - used to be commonly referred to as "labyrinthodont", which means "maze tooth." These are places on the tooth where the enamel is folded in towards the center of the tooth. It appears wrinkled.
• Labial - the side or portion of the tooth that faces the outside of the mouth. Labial literally means "lips."
• Laterally compressed - refers to a tooth that is much thinner "side to side" than it is "front to back" when viewed from the apex.
• Lingual - the side or portion of the tooth that faces the inside of the mouth. Lingual literally means "tongue."
• Mesial -  - the part of the tooth facing the front of the mouth. In older literature this is sometimes referred to as "anterior."
• Occlusal - the surface, face, or point of the tooth that would rub against ("occlude") the opposite tooth from the opposite jaw. Sometimes used in place of apical when referring to a viewing angle.
• Recurved - a tooth that, when viewed from the side, has the back (distal) side curved inward, so that the edge looks like a half-moon.
• Resorption pit - a pit on the base of a tooth, showing where bone and dentine were reabsorbed by the animal to allow the tooth to be shed.
• Root - in animals with teeth set into sockets, the root is the dentine that extends below the gumline into the jaw to anchor the tooth.
• Serrations - like on a steak knife, these are small notches on the edge of a tooth for cutting or slicing food.

Okay, so there are a number of terms there but I think I've given the definitions in terms that aren't too hard to follow for the average person. Let me show a few examples of teeth so I can sort of show how these terms are used "in the real world."

Crosbysaurus tooth. Scale distance = 1 mm.

The above picture is of part of a Crosbysaurus tooth from one of our sites at Comb Ridge. It shows denticles, the pointed cutting parts on the distal edge (or carina) of the tooth. Each of the pyramid-shaped structures has smaller bumps on them - these are the accessory denticles. This picture is in labial view.

Crosbysaurus tooth. Scale distance = 1 mm.

Here is another view of the same tooth. Here we are looking at the tooth in mesial view with the apex on the right and the base on the left. You can see a resorption pit at the base - it looks like the tooth is hollow. You can notice that this tooth is laterally compressed - it is much narrower than it is tall.

Archosauriform tooth. Scale distance = 1 mm.

Last example. Here is an archosauriform tooth in basal view. The front of the mouth, or mesial side, would be towards the right while the back of the mouth, or distal side, is to the left. You can see in this view that the tooth is asymmetrical - the labial and lingual sides are not equal. This picture also gives a decent view of the resorption pit located in the middle of the base here. That tells us that this is a shed tooth crown.

Thanks for making it through this! I know there were a lot of terms but I promise they will come in handy for many of my future posts. And now you can impress your dentist with your knowledge of dental terminology! The paleontology of teeth (Odontology) is not just for mammal paleontologists. All of this work with microfossils and Triassic teeth has certainly given me a new appreciation of how important these little things can be and what they can tell us about an ecosystem. Just what specifically can they tell us? That sounds like another blog post in its own right.