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Fossil Friday

On Monday I posted a picture of a tooth from an animal that is a famous California resident, although is not generally considered an Arkansan. Were you able to figure it out?

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bc-067t-lgThe tooth is a canine from a Smilodon, the saber-toothed tiger (although not actually related to tigers). Smilodon fossils have been found in a few caves in the Ozarks of northern Arkansas, most notably Hurricane River Cave and the Conard Fissure (the Conard Fissure was excavated by Barnum Brown for the American Museum of Natural History, who also did a lot of famous dinosaur digs for them in the Rockies) . Originally, they were described as having come from two different species of Smilodon: S. fatalis and S. floridensis. Smilodon fatalis, sometimes called S. californicus, is well-known from the La Brea Tar Pits in California, although has been found throughout much of North America and Pacific coastal areas of South America. Smilodon floridensis was known primarily from, unsurprisingly, Florida and neighboring states. However, these days most researchers view them all as the same species, so just Smilodon fatalis. There are two other recognized species. Smilodon populator lived in South America and was bigger, with a few hundred more pounds on S. fatalis. Smilodon gracilis was half the size of S. fatalis and lived earlier than either of the other species, and is considered by some to be ancestral to them.

prehistoricpark.wikia.com

prehistoricpark.wikia.com

Smilodon fatalis is the quintessential Ice Age predator. It appeared about 2.5 million years ago and only died out about 10-13,000 years ago, so it may have been possible that Smilodon preyed upon early humans, at least along the Pacific coastal areas. It was a big, burly cat weighing up to 600 lbs. with heavily muscled forelimbs. Of course, it is best-known for its 7” long, serrated canines, thus the name Smilodon, meaning “carving knife tooth”. Smilodons were part of a group known as Machairodontinae, a subfamily within Felidae known as the “dirk-toothed cats.” These long teeth necessitated a jaw that could swing extraordinarily wide. Smilodon was specialized for killing large prey, such as bison, horses, and young mammoths and mastodons. Much debate has centered on how it dispatched its prey, with depictions of a Smilodon burying its canines in the skull or eviscerating its prey. However, more recent studies have indicated the canines were too fragile to withstand such treatment or couldn’t get a sufficient bite to properly tear into the abdomen. It is thought instead that Smilodon used its powerful forelimbs to stun and restrain the prey until it could bring its canines into play with its powerful neck muscles to slash the throat and cut the major arteries, causing the animal to bleed out quickly. They were not fast runners, preferring to attack from ambush, staying hidden within the vegetation of the forests and bushlands it preferred to live in.

Youngsteadt J.O., 1980: A saber toothed cat smilodon floridanus from hurricane river cave northwest arkansas usa. Nss Bulletin: 8-14

B. Brown, The Conard Fissure, A Pleistocene Bone Deposit in Northern Arkansas…,Memoirs of the American Museum of Natural History, Vol IX, Part IV, February 1908.

Mystery Monday

Mystery Monday

Today we have a picture by Ronny Thomas of a very well-known animal, although it is quite rare in Arkansas. In fact, only one has ever been found in the state. So what do you think it is? Stay tuned for the answer on Friday.

Fossil, and Forum, Friday

I’m sorry, but I forgot to post the Mystery Monday fossil on the blog. I posted the fossil on the Facebook page, but somehow failed to get it posted here, for which I apologize. Here is the fossil I posted, including the identifying portion cropped from the original picture. This image was taken from trilobites.info, a great website for all things trilobite.

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Here is Bristolia for comparison. This image is also from trilobites.info

Here is Bristolia for comparison. This image is also from trilobites.info

It was correctly identified as a trilobite, although this one is the species Irvingella, not Bristolia as was guessed. Irvingella is very similar, but lacks the tail spine and the second set of spines is a little farther down the body. They are both listed as “fast-moving low-level epifaunal” feeders by the Paleobiology Database, which means they scurried quickly about over the ocean floor. But whereas Bristolia is thought to have been a deposit feeder, much like a crawfish, Irvingella was a carnivore, preying on worms, bugs, and such. They both lived in offshore marine environments, but whereas Bristolia has been found mostly in shallower waters, Irvingella has been found widespread from offshore throughout the continental shelf and even deeper water. This may have more to do with Bristolia having only been found in a few places in the southwestern United States while Irvingella has a much broader range throughout much of North America and Asia. They both lived in the Cambrian Period, although Bristolia seems to have lived a little earlier than Irvingella (there are some discrepancies in the published records making it difficult to compare exactly, this is partly due to revisions of the time scale and refinements in age estimates over the decades making detailed comparisons problematic).

Since our last Forum Friday recap, we have started a new year. We have reviewed the Walking with Dinosaurs movie. We identified an Exogyra ponderosa oyster,  Archimedes bryozoan, Aetobatus eagle ray, and this Irvingella trilobite.

Over on the Facebook page so far this year, we have seen some amazing animals, including sharks that glow in the dark, a fish that walks on land, and a caterpillar who’s tobacco breath repulses spiders. We even learned why sharks don’t make bone, but polygamous mice have big penis bones and an organism that changes its genetic structure seasonally.

A green biofluorescent chain catshark (Scyliorhinus retifer). Livescience.com. Credit: ©J. Sparks, D. Gruber, and V. Pieribone

A green biofluorescent chain catshark (Scyliorhinus retifer). Livescience.com. Credit: ©J. Sparks, D. Gruber, and V. Pieribone

We saw two articles on fighting dinosaurs. We learned how they took over the planet and discussed scaly dinosaurs for a change. We found out some ancient marine reptiles were black and Tiktaalik had legs.

A lot of articles hit the press on human evolution in 2013. We also found out (some) humans developed the ability to tolerate lactose to not starve and how we smell sickness in others. We also found a great book on Evolution & Medicine. We also saw evidence of how our actions affect the evolution of other animals and someone who thinks they can understand dog language.

We read that plants may have caused the Devonian extinction event, a genetic study saying placental mammals originated before the end-Cretaceous extinction event despite no fossils ever having been found, and that small mammals with flexible schedules handle climate change better than big mammals that keep a stricter schedule.

We found a great , concise explanation of evolution and three different short videos on the history of life on earth, two of them animated and set to music. We also heard Neal DeGrasse Tyson urge more scientists to do more science outreach (and how to cook a pizza in 3 seconds). Unfortunately, we also heard about the deplorable conditions during filming on Animal Planet and creationism in Texas public schools, as well as how the failure to take evolution into account can screw up conservation efforts.

So what did you like? Did you guess the fossil? Is there anything you want to see? Let us know.

Fossil Friday

Another week has gone by and so little done here. I started my Vertebrate paleontology class this week and if you think it takes a lot of work to take one, just imagine the amount of time it takes to design one.

So today, we announce the mystery fossil from Monday. Did you have any idea what it was? It stumped everyone on the Facebook page, so if you couldn’t figure it out, don’t feel bad. It was a hard one. These are not terribly uncommon fossils, but most people are completely unfamiliar with them, despite the fact that anyone who visits a public aquarium has seen its living relatives.

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This is part of a tooth plate from a ray, most likely Aetobatus, the eagle ray. They are filter feeders eating plankton and have been around since the Miocene 20 million years ago. While none have been found in Arkansas that I know of, they have been found in pretty much every state around us, so I expect so collector out there somewhere has probably found some here. Check us out Monday for a new fossil!

Spotted_Eagle_Ray_(Aetobatus_narinari). Wikipedia.

Spotted_Eagle_Ray_(Aetobatus_narinari). Wikipedia.

UPDATE: I need to correct a mistake I made in this post. Eagle rays, like Aetobatis here, were and are not filter feeders. The large rays, like the Manta ray in the same family, are indeed filter feeders, the smaller rays, like Aetobatus and its close relative Myliobatis, another ray that lived in the area at the same time (as well as earlier in the Eocene over 40 million years ago), were durophagous, meaning they used their teeth to crush shelled prey, such as clams, crabs, and shrimp. The main part of the tooth brought to bear on the prey item is the flat, plate-like part.

spottedeaglerayjawFor this picture and much more information on the current species of eagle rays, go to the Florida Museum of Natural History.

Mystery Monday

Mystery Monday

It’s been a very busy weekend, so this will be a very short post. today I simply want to introduce the latest mystery fossil. This is a bizarre little fossil, measuring less than 2 cm across. It’s not the best picture, I admit, but there is enough resolution to identify it to at least the Order. I will post a clue a day until Friday, when I will reveal its identity. Good luck, take a guess, and have fun.

Tuesday’s clue: These teeth are used to eat animals much, much smaller than the animal it came from.

Wednesday’s clue: We are very popular at many aquariums.

Thursday’s clue: Some people say i have wings, but I do not fly. I may have a cold heart, but I don’t bite.

Fossil Friday

It has been a strange week, what with trying to catch up from the holidays and all. So this post will be brief. On Monday, I posted this picture of a commonly found fossil in Arkansas, provided you look in the right places. Here were the clues.exogyra

Clue 1: It’s from the Cretaceous.

Clue 2: It’s modern day relatives are widely considered a delicacy.

Clue 3: This is no wilting lily. This creature is big and bold. It shows how twisted it is on the outside for all the world to see. Dude, that’s heavy.

Were you able to figure it out?

So for the final reveal:  Exogyra ponderosa. Allie Valtakis was able to figure out it was a mollusc, specifically a bivalve (clam), in the Order Ostreoida, Family Gryphaeidae. While mosasaurs swam the oceans and dinosaurs walked the shores, these Late Cretaceous oysters made huge oyster beds throughout the coastal waters. Like all oysters, they were filter-feeders, collecting microscopic particles of food from the water. You can find them in south-central Arkansas within several rock units, but most particularly in the Marlbrook Marl, a limy mudstone. They are known for their large, heavy, rough bottom shell with a curled, hornlike part near the hinge. The top shell is much smaller and flatter, but still a good size, something like a cap on a coffee cup, if your coffee cup was kind of bowl-shaped. They are sometimes called Devil’s toenails, but that name usually refers to a different clam called Gryphaea, an oyster that is also in the Family Gryphaeidae, but a different subfamily. If you look under a microscope at the shell, you may notice that it is very porous, giving the Family the nickname of foam or honeycomb oysters.  Some are still alive today, such as Hyotissa hyotis, the giant honeycomb oyster

E. ponderosa was one of the earliest clams of this genus that was named, by Ferdinand Roemer in 1852, a German lawyer who gave up law to study geology in Texas, thus his title as the Father of the Geology of Texas.  You can fossils of them from Texas to New Jersey and Delaware, south through Mexico and Peru.

Until next time, as Dr. Scott The Paleontologist would say, ‘Get out there, get into nature, and make your own discoveries.”

Mystery Monday and Walking With Dinosaurs Movie Review

Mystery Monday

Last Friday I posted clues to a mystery fossil. The clues were 1) I lived in AR during the Mississippian Period roughly 330 million years ago and am a very common fossil to find here. 2) Many people think I’m a coral, but I’m not. 3) I am named after a famous Greek mathematician and inventor. Who, or more precisely, what am I? Allie Valtakis got the right answer as the bryozoan, Archimedes.  Here is what the Arkansas Geological Survey says about it.

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The Bryozoa grow attached to the sea-floor as do corals, but they differ significantly from corals in terms of soft-part anatomy.  The bryozoans are exclusively colonial and fall into two broad groups, the lacy colonies and the twig-shaped colonies.  Individual “houses” (zooeciums) lack the radial partitions found in corals, but they are divided transversely by partitions called diaphragms (Fossils of Arkansas).  Bryozoans can also grow as incrustations on the shells of other organisms and are commonly associated with reef structures.

“Bryozoans are tiny colonial marine animals that are present in marine and fresh water today.  They are sessile benthonic animals (fixed to seabed) that are filter feeders and prefer shallow seas, living fairly close to shore (neritic).  One bryozoan called Archimedes (see picture below) is abundant in Mississippian age rocks in Arkansas and is so plentiful that one of the rock formations called the Pitkin Limestone was once referred to as the “Archimedes Limestone”.  Generally, only small pieces of bryozoans that resemble “fronds” are preserved in Mississippian and Pennsylvanian age rocks in the Ozark Plateaus Region.

References:

Freeman, Tom, 1966, Fossils of Arkansas:  Arkansas Geological Commission

Bulletin 22, 53 p., 12 pls., 15 figs., 1 map.

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Archimedes “fronds”

Way to go, Allie!

Can you guess this week’s fossil? I will do things a bit differently this time. Unlike previous fossils, in which I told people on the Facebook page as soon as someone provided the correct answer, I will not reveal the answer until Friday, so you have plenty of time to give it a try. In addition to the picture (note the scale) below, I will provide one clue every day until Friday. Good luck!

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Clue 1: It’s from the Cretaceous.

Clue 2: It’s modern day relatives are widely considered a delicacy.

Clue 3:  This is no wilting lily. This creature is big and bold. It shows how twisted it is on the outside for all the world to see. Dude, that’s heavy.

Come back tomorrow for the answer! You can also find it on the Facebook page.

 

Walking with Dinosaurs 3D movie review

I went to see Walking With Dinosaurs 3D this weekend. My kids were interested in seeing the movie and I liked the BBC “Walking with Dinosaurs” TV mini-series, so we were all eagerly anticipating the movie. I had read a few reviews of the movie, some by paleo people, who said the dinosaurs were great, but the voices were terrible, which gave me pause, but it’s a BBC movie on dinosaurs, how bad could it be, right?

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Sadly, not like this.

Sad to say, I have to agree with most of the reviewers. This movie may be much more enjoyable if you can’t hear it. To begin with, whatever expectations you may have, forget them. If you are going in expecting to see a big screen version of the BBC “Walking with Dinosaurs,” you will be disappointed by the cartoon voices and plot. If you are looking for light entertainment for little kids, you might be a bit surprised by the rather jarring breaks providing a subpar, documentary-style educational interlude which will kick everyone out of the story.

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More like this, but with better graphics.

The film reminded me nothing so much as a cross between the BBC documentary-style series and The Land Before Time movie series, failing at both. I think the reason for this is because it seemed to clearly start off with the idea of it being a kid-friendly movie along the lines of the TV series, but some executive decided after it was made that it was not going to draw enough kids. So the movie was recut and really bad dialogue added to it instead of the normal narration one would expect in a nature documentary, along with completely superfluous modern scenes bookending the film, wasting the talents of otherwise fine actors. The voices were obviously added as an afterthought because the dinosaurs do not act like they are speaking. I could even occasionally hear the original dinosaurian bleating and honking in the background even as they are supposedly talking. The dialogue, as Brian Switek noted in his review, destroyed any emotion that may have been evoked by the scenes that were supposed to be emotionally powerful. What should have been poignant, heart-tugging scenes were drained of any impact by juvenile pratterings that never ceased. I found myself wishing for the dinosaurs to just shut up once in a while. As a result, it is a movie that may be enjoyable for a little kid, but eminently forgettable. Bambi was a much more riveting emotional experience, not to mention more educational about the lives of deer.

The story line was inconsistent with the idea of a nature documentary and a poor choice for a dinosaur movie. Whether or not the worst aspects of it were in the original script, I don’t know, but the final plot, while suitable for a cartoon Land Before Time, was wholly inappropriate for a nature “fauxmentary.” For a film that was supposedly educational, it pushed moral viewpoints which are only valid in human cultural environments and completely invalid in the natural world. The idea that intelligence and courage will overcome the thoughtless, testosterone-fueled belligerence of the larger alpha males is a noble sentiment and may work in a human context, but not in the depicted dinosaur society. Control of a herd of large herbivores that have evolved extravagant displays will never pass to the runt of a litter because he saves the herd in a time crisis due to his quick thinking. The plot line for the movie is far more appropriate to an after-school special involving actual, human children, not dinosaurs. As such, it completely destroys any educational effectiveness of the movie. The only education that remains is that dinosaurs lived in a snowy Alaska and that some dinosaurs had feathers, particularly the smaller theropod carnivores. I really like this aspect of the movie, but its authenticity in these aspects was completely undermined by the silliness of the rest of the movie.

To make it even more confusing in terms of genre plotting, the movie shows that females in the herd are dominated by the alpha male, but glosses over what that means in terms of sexual dominance. In a kid-based movie, this understandably only goes as far as hanging out with each other. In the natural world (and post-adolescent human worlds), as every adult in the audience will understand, it means the female submits to the alpha male’s sexual advances. In terms of a human kid’s movie, it sends very poor messages about the role of females in society. In terms of an educational nature show, it is intentionally misleading to spare the typical parental sensibilities of what is appropriate for kids to see.

In short, if you go to see this movie (which I would really recommend waiting until a rental, as it is not worth spending the price for a 3D movie), go expecting to see a mindless 80 minutes of passable, but forgettable, entertainment for children with no real educational value other than to say look, aren’t dinosaurs neat? Enjoy the graphics, ignore the rest.

Happy New Year! Welcome to 2014

happynewyearWelcome back! I hope everyone had a great holiday to mark the end of a great year. 2013 marked the inaugural year for Paleoaerie. Version 1 of the website was set up, providing links to a wealth of online resources on fossils, evolution, the challenges of teaching evolution and the techniques to do it well. The blog had 26 posts, in which we reviewed several books and websites, discussed Cambrian rocks in Arkansas and the dinosaur Arkansaurus,” and went to the annual meeting of the Society of Vertebrate Paleontology. We looked at geologic time and started a series on dinosaur misconceptions. We also had several Forum Fridays, recapping the many news stories reported on the Facebook page. One of the recent things we’ve started is Mystery Monday, posting a fossil of the week for people to try to identify. Speaking of which, to start off the new year, the first mystery fossil will be posted early. look for it at the end of this post.

In the upcoming year, we hope to expand the site, providing many more resources, along with continuing posts on Arkansas geology and fossils, including many more mystery fossils. Stick with us and you will learn about the history of Arkansas in a way that few people know. The site will be revamped to be more user-friendly and enticing to visitors. If plans materialize, we will be adding interactive activities, animations, and videos, many of which will be created by users of the site. Materials from workshops and talks will be posted for people to view and use. More scientists will be posted that have offered their services to teachers and students. We encourage you to contact them. They are there as a resource.

Of course, all of this does not come free. it takes money to provide quality services. Thus, more avenues of funding will be pursued, including other grant opportunities and likely a Kickstarter proposal. You may soon see a small button on the side of the website for Paypal donations. Any money donated will go first towards site maintenance. Other funds will go towards a student award for website design, a 3D laser scanner to put fully interactive 3D fossil images on the site, and materials for review and teacher workshops. If grant funding becomes available, additional money will be spent on research into the effectiveness and reach of the project. But even if no more funding becomes available, you can still look forward to continuing essays on Arkansas fossils, reviews of good books and websites, and curation of online resources suitable for teachers, students, and anyone else interested in learning about the endlessly fascinating history of life on planet earth.

I mentioned at the beginning about the latest mystery fossil. Here’s the first hint: it is a very common fossil found in Arkansas and lived during the Mississippian period roughly 330 million years ago. More hints and photos to come. Leave your guesses in the comments section. Don’t worry about getting it wrong, every success has lots of failures behind it. Errors are only stepping stones to knowledge.

Clue number 2: Many people think I’m a coral, but I’m not.

Clue number 3: I am named after a famous Greek mathematician and inventor.

What am I?

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