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National Online Learning Day

September 15 is National Online Learning Day. Now that everyone should be well and truly back to school, I thought it would be a good time for a few miscellaneous notes on various resources.

Online Courses

Evolution: A Course for Educators. American Museum of Natural History via Coursera. Learn about evolution from an expert at one of the best places in the world to study it. Taught by Dr. Joel Cracraft, the course will cover everything you need to teach evolution well. The course is free and offers a paid certificate for teacher professional development hours. It is four weeks long and requires 5-8 a week. It begins October 1st, so you will be done by Halloween.

Introduction to Human Evolution. Wellesley College via edX. A subject that is endlessly fascinating, but seldom taught in schools. Learn about the origins of us from an expert. Taught by Dr. Adam Van Arsdale, the course is self paced, meaning you can start when you want. It takes 4-6 hours for four weeks and is free.

Paleontology: Theropod Dinosaurs and the Origin of Birds. University of Alberta via Coursera. A five week course headed by the esteemed dinosaur expert Dr. Phillip Currie on the anatomy, diversity, and evolution of theropods leading to birds. They offer a paid certificate for those needing the credit. Expect to spend 4-7 hours a week on the course. The course is free, but it started September 12, so join up now before you get too far behind.

Paleontology: Early Vertebrate Evolution. University of Alberta via Coursera. This course covers the evolution of vertebrates through the Paleozoic Era and is taught by Dr. Alison Murray. This is a four week course with an expected 3-5 hours per week. This course is free, but offers a paid certificate for those who need the credit. This course also started September 12th, so sign up now.

Dinosaur Ecosystems. University of Hong Kong via edX. A six week course on dinosaurs in their habitats. The course is taught by a collaboration of Dr. Michael Pittman and Dr. Xu Xing, along with other guests, all with an abundance of expertise on the topic. As a bonus, the course includes the work of one of my favorite paleoartists, Julius Csotonyi. The course requires 1-2 hours a week, so not a big time commitment. It is free, although it does offer a paid certificate for those who need the credit, and starts October 4th.

Dino 101: Dinosaur Paleobiology. University of Alberta via Coursera. Another course by Phil Currie, along with Dr. Betsy Kruk. This is a great introduction to dinosaurs. It is 12 weeks long and requires an estimated 3-10 hours per week, so expect more out of this course. The course is free and starts September 29th, so get signed up now.

Origins – Formation of the Universe, Solar System, Earth and Life. University of Copenhagen via Coursera. Learn how it all began by Dr. Henning Haack. This course is 12 weeks long and expects 5-7 hours a week. The course is free and starts September 17th, so don’t waste time signing up.

There are several more available. If you go to any of the course links shown here, they will guide you to other related courses that are available.

Websites

Tetrapod Zoology. Darren Naish has kept his blog, often abbreviated to TetZoo, for over a decade. Through all the years, he has provided multitudinous essays on a variety of animal groups, both extant and extinct. Sprinkled in are also essays on the truth of cryptids (Bigfoot, Nessie, and the like), paleoart, and other topics. Sadly, the blog at Scientific American has closed up shop. But don’t panic, because it has moved to another location. He has set up shop under his own banner at Tetzoo.com. Time to change your bookmarks.

Beautiful Minds. Scott Barry Kaufman has been writing a Scientific American blog about psychology off and on. He recently announced an upgrade to the blog allowing him to have a weekly online column, so expect more articles about human nature from him.

Science Sushi by Christie Wilcox has always been one of my favorite blogs. While I am not a marine biologist by any stretch, she has always been interesting to read. So it is sad to report her Discover blog is closing up shop. She is moving to ScienceSushi.com, but will not be adding regularly to it. She will continuing to write, so keep an eye out for her on the sites she lists in the post linked to here.

Dataset Search. You’ve heard of Google Search, Google Scholar, Google Maps, and a plethora of other ways Google lets people search the web. Now meet Dataset Search, for when you are trying to find data that has been published or stored online. This searches for data files or databases according to how they are identified, not by what is in the file.

Science without publication paywalls: cOAlition S for the realization of full and immediate Open Access, by Marc Shiltz. PLoS Biology. 2018. This article discusses Plan S, a proposal by a coalition of European leaders to make science articles free for everyone. In their words,  “no science should be locked behind paywalls!” (emphasis theirs).

Seriously, Science? A great blog on Discovermagazine.com that covered weird and humorous published research has been canceled. No word on why, the authors just said they were informed they would no longer have a slot on the blog roll. So long, Seriously Science, it was good to have known you.

Books

Return to Reason: The Science of Thought, by Scientific American. 2018. This ebook is a collection of essays discussing why facts don’t seem to matter to people or help persuade them and what we can do about it. Well worth a read.

Timefulness: How Thinking Like a Geologist Can Help Save the World, by Marcia Bjornerud. Princeton University Press. 2018. Most people can barely remember what they had for breakfast yesterday. We really aren’t well equipped to think about time on the scale of millions and billions of years. Dr. Bjornerud has written a great book to help people come to grips with the immensity of time. I highly recommend it.

Underbug: An Obsessive Tale of Termites and Technology, by Lisa Margonelli, Scientific American/Farrar, Straus and Giroux, 2018. This book is not really about termites. The study of termites is used as an illustration of scientific inquiry and the questions that researchers come across during their studies. There are questions about the termites, but also about how science is done and about humans viewed through a different lens.

Darwin and the Making of Sexual Selection, by Evelleen Richards. University of Chicago Press. 2017. This book tells the story of how Darwin figured out problems with natural selection by coming up with sexual selection. To my mind, sexual selection is a subset of natural selection, but it is generally viewed as separate, with natural selection being success based on fecundity and survival of offspring, whereas sexual selection deals with the choices of mates. However you look at it, sexual selection is an important concept and this book explores the origin of that idea.

The Dinosaur Artist: Obsession, Betrayal, and the Quest for Earth’s Ultimate Trophy, by Paige Williams. Hachette, 2018. Williams tells the story about a skeleton of a Tarbosaurus bataar, what could be described as a Mongolian Tyrannosaurus rex, and the long and confusing battle of who owned it and where it would eventually reside. The worldwide fossil trade is a morass of differing opinions, laws, and money. This book attempts to tease apart the strands to answer the question of who owns fossils.

Through a Glass Brightly: Using Science to See Our Species as We Really Are, by David P. Barash. Oxford University Press, 2018. As the great physicist Richard Feynman said, “The first principle is that you must not fool yourself–and you are the easiest person to fool.” Humans are masters of deluding ourselves, but science helps us remove the wool we place over our eyes to see things, and ourselves, as we truly are. Only then can we become the people we see ourselves as. That is the goal of evolutionary biologist Dr. Barash in this book.

The Book of Why: The New Science of Cause and Effect, by Judea Pearl and Dana McKenzie. Basic Books, 2018. A big problem that any educator sees is the rather unbelievable lack of understanding many people have about cause and effect. Please get this book and teach people about how cause and effect works. Since this book relates the science of cause and effect to robots and artificial intelligence, it will be the perfect addition to tech classes.

I think that is enough for now. It is certainly enough to keep you busy if you try even a few of the many offerings available for furthering your education or just indulging your curiosity. Enjoy. If you try them, come back and let us know what you thought of them.

The Geological Society of America meeting in Little Rock and new Arkansas Dinosaurs

On March 12-13, the south-central section of the Geological Society of America held their annual meeting in Little Rock, Arkansas. During that meeting, a session was held on paleontology in honor of Arkansaurus fridayi being named our State Dinosaur, even though it has never been officially scientifically named and it being the only dinosaur that has ever been found in Arkansas other than tracks. That all changed during the meeting. This post will focus on the Arkansas dinosaurs (yes, plural, that was not a typo). A later post will cover more fossil announcements.

The first talk on Arkansas dinosaurs came from our very own Dr. Rebecca Hunt-Foster, who did the initial work on Arkansaurus. She has a new paper that came out right after the meeting. She announced that Arkansaurus fridayi is now the officially recognized scientific name for our dinosaur. She also discussed her findings confirming it as an ornithomimid, one of the bird-mimics, like the Gallimimus made famous in Jurassic Park. That had been the first tentative identification, but her work previously showed that it did not match with other known North American ornithomimids. However, that was from a total known collection of nine specimens. We now have almost two dozen ornithomimids known from North America. When she compared Arkansaurus with the new material, she was able to confirm that the initial identification was indeed correct. Moreover, it showed that ornithomimids had the ability to disperse across the continent at the time. The Late Cretaceous interior seaway that bisected the continent had not yet closed off access by then.

Arkansaurus

Dr. Celina Suarez from the University of Arkansas at Fayetteville provided the most astounding talk of the session (ed. this was a repeat of the talk she gave at the national GSA meeting in Seattle in 2017). We knew we had titanosaurs and acrocanthosaurs in Arkansas from their foot prints. Now we have their bones as well. She presented a description of the first known Mesozoic multi-faunal vertebrate assemblage in Arkansas. In other words, she reported a collection of fossils that contained several different species. The fossils were found in Howard County within the Holly Creek Formation, a part of the Trinity Group that underlies the DeQueen Limestone. This is the same site which became famous for its dinosaur tracks.

Among the fossils included pieces of a titanosaur that is probably Sauroposeidon, one of the largest dinosaurs ever known. They like to call it Paluxysaurus in Texas, but further work has indicated that Paluxysaurus is a junior synonym of Sauroposeidon found in Oklahoma and now Arkansas. She also found pieces of an Acrocanthosaurus. For those who are not familiar with this dinosaur, it is a carcharodontosaurid, the same family as Giganotosaurus. This family is within Allosauroidea, the group containing Allosaurus and all its kin. Acrocanthosaurus was almost the size of Tyrannosaurus rex and with a small sail or ridge along its back and was the dominant predator of its time.

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Drawing of a Sauroposeidon proteles and an Acrocanthosaurus by Mike O’Brien.

That isn’t all though. They also found scutes from an ankylosaur. While it isn’t a lot, Kristy Morgan, one of her students, was able to determine that they likely belonged to a nodosaurid ankylosaur either most closely related to or actually was Borealopelta, a dinosaur from Canada just named in 2017 from the best preserved dinosaur fossil ever found.

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   Borealopelta markmitchelli. Image credit: Royal Tyrrell Museum.

Finally, pieces of two other theropods were found. They found pieces identified as Deinonychus antirropus, Velociraptor’s big cousin, as well as Richardoestia. Deinonychus is well known as the archetypal dromeosaur, the dinosaurs with the famed sickle-clawed toe. Richardoestia is much less well known, making this identification curious. All that is really known of this dinosaur is a set of jaws and some isolated teeth. Three species have been named, but at least one has been suggested to be a sebecid crocodylomorph. It is likely that once more of this genus is discovered, some or all of the species will not survive, at least as they are now. But for now, we will count it as an Arkansas dinosaur until shown otherwise.

Richardoestesia

Richardoestia. CURRIE, RIGBY & SLOAN, 1990

This just touches on the fossils found in this assemblage. We now have a much bigger glimpse into Cretaceous Arkansas. Stay tuned for more. For now, we can say that southwest Arkansas 120 million years ago looked something like this.

https://www.youtube.com/watch?v=ueBM9QxebNsyoutube

 

What the Colombian fossil lizard fish has in common with the Arkansas saber-toothed herring

Three years ago, a ten year old boy was visiting a monastery in Colombia. Being a curious boy, he looked around at his surroundings. He could have done like others have done for centuries and not paid that much attention to the stones upon which he walked, but he didn’t. He noticed a curious fossil fish in one of the flagstones. Most people, if they noticed it at all, would have simply given it a passing nod of interest. He, on the other hand, took a picture of it and sent it to the local Paleontology Research Center to see if they knew what it was.

Firstly, I amazed they even had a local paleontology research center, most places don’t. Secondly, it is amazing that the boy took the time to bring it to their attention. Thirdly, it is amazing that someone there noticed what they had and brought it to the attention of the needed experts. All these amazing, unusual occurrences have resulted in an article in the January 31 edition of the Journal of Systematic Paleontology detailing the new fossil species discovered by that boy. Sadly, no one knows how to contact him to let him know about the publication. The researchers have his name and email, but have apparently been unable to contact him to give him his copy of the paper about his fish.

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The fish he discovered was named Candelarhynchus padillai, after the Monastery of LaCandelaria near Ráquira, Colombia, where it was found. The stone for the flagstone came from a nearby quarry.  According to the authors of the paper, the rocks in the quarry corresponding to the flagstones were “fossiliferous, finely laminated, light to dark grey, indurated mudstones ofthe lower-middle Tuonian San Rafael Formation…” The rock strata also contained numerous plankton, ammonites, clams, and crabs; so quite a rich fauna. The Turonian is 89.8-93.9 Mya, according to the latest GSA time scale, so we are talking roughly 92 Mya. 

The fossil is excellently preserved, with slabs containing both part and counterpart, meaning that when they split the slab, pieces and impressions were left on both sides. The whole body can be seen, with nice detail around the head, as well as impressions of the soft tissue portions of the fins. At 27 cm (just over one foot), it is a decent-sized fish. It’s a thin fish, with a long skull full of tiny, conical teeth. It was clearly a fast-swimming predator, and likely prey for a lot of larger species.

Credit to Oksana Vernygora 2

The reports on the fish said that it does not have any living relatives. That is true, in a way, but also not. The specific family the phylogenetic analysis placed it in is Dercetidae, an extinct family that all died out in the Cretaceous. However, if we look a bit broader, it is in the Order Aulopiformes. This order is mostly known for a variety of mostly deep water fish known as lizard fishes, which is why all the news reports of this find have said Candelarynchus was a “lizard fish.” Even though it is in the same Order, it is not in the same family as any of the modern lizard fish.

But the title of this post mentioned Arkansas and I have thus far not done so. Vernygora reports that current analyses of fossil aulopiforms include three main families: the Dercetidae, Halecidae, and the Enchodontidae. One of the most prominent Cretaceous fish from Arkansas is Enchodus, commonly called the “saber-toothed herring.”

This is a terrible name because Enchodus has nothing to do with herrings. It was at one time considered part of Salmoniformes, making it closer to salmon. However, more recent analyses have consistently placed it in Aulopiformes, specifically within the Enchodontidae, making it closer to lizard fish. This makes a good deal of sense to me because, if you add the fangs from a payara, commonly known as the vampire fish, onto a lizard fish, you have  pretty good idea of what Enchodus was like.

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Payara. Image credit Exotic Fish Wiki

Fossil lizard fish then were quite abundant in the Late Cretaceous in both worldwide range and diversity. They may not be the most recognized fish today, but they have a long history and make for great fossils that can be found in a lot of places, including southwestern Arkansas.

 

The giant Arkansas fossil catfish

Did you know that Arkansas once had catfish more than three meters long and weighing, depending on who you believe, as much as 450 kg? That makes the world record catfish of today look positively puny.

The proof can be found at the Arkansas Geological Survey. The skull of one such monster is on display in the second floor display case. It was found in 1983 off Highway 79 near Camden. The bones were pulled from the Claiborne Formation, or more specifically, the Sparta Sand.

ClaibornegeomapAGS

The Claiborne Group can be found in much of the South-Central part of the state, as well as on Crowley’s Ridge. It is Eocene in age (34-56 Mya). According to the Arkansas Geological Survey, the Claiborne is primarily non-marine and is comprised of mostly fine-grained rocks ranging from silty clays to medium-grained sandstones, with the occasional lignitic coal bed. The shales usually have the variegated tans and grays often seen in terrestrial  sediments, with brown and black organic-enriched layers intermixed. Fossils are common from the units, with plant fossils common, as well as trace fossils. Of particular interest here are the reptile and fish bones that have been found here.

The Sparta Sand in particular is a thick bed that can be several hundred feet think. It is a fine to medium-grained sandstone that is typically light-colored, either a whitish or light gray, with thin beds or brown or grayish sandy clay and lignite. It has been considered an important aquifer for the region. The sediment is thought to have been laid down by rivers during a regression of the marine shoreline farther south. In other words, we are looking at the flood plain of a river meandering its way to the ocean, much like southern Arkansas and Louisiana is today. Only back then, the catfish grew much bigger than they do now.

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So what do we know of this fish? We know it was a siluriform catfish, most likely in the Ictaluridae family, along with all the other North American catfish. It was probably something like the giant Mekong river catfish and lived in similar environments. The Eocene was warmer than it is now, so it was likely even more tropical than it is today. Beyond that, we don’t know a lot. The fossil has never been fully studied and described as far as I am aware. In 1983, Dr. John Lundberg, a noted expert in fossil catfish and currently chief curator at the Academy of Natural Sciences of Drexel University, corresponded with the AGS about studying it, but thus far, I don’t know what, if anything, came of it.

Buffalo National River: Boone Formation

If you are looking for a great place to begin your canoeing experience, or just a quiet river to float down with great views, you can’t go wrong with the Buffalo National River in Arkansas as it flows through the Ozark and Boston Mountains. In 1972, Congress declared the Buffalo to be a National River, the first river to be so designated in the Unites States, which protects it from industrial use and any construction that might change the natural character of the river. It is renowned for its clean water and spectacular bluffs. People come from all over to camp in the park, hike its trails, and float the river. Much of the river is easy to float, so a welcome adventure for novices, although the upper reaches can be challenging.

buffalo-river-map

This is the first of many posts about the geology of the river and the fossils that can be found in the park. Please note that this is a national park, so collecting fossils within the park boundaries is strictly prohibited. However, many of the formations discussed herein can be found throughout large portions of the Ozarks, so if you want to collect fossils, consult a geologic map and find a road that runs through the formation outside the park to find suitable roadcuts. Fossil collecting is allowed on state land, so just make sure you are not in a national park, national forest, or on someone’s private land (unless you have their permission).

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AGS EWS-7. Stratigraphic column for upper Buffalo River

 

The Buffalo river cuts through several formations which are mostly Ordovician or Mississippian in age (~470 to 320 Mya). You can find geologic maps in pdf format of the Buffalo National River here and here.In the western reaches, the primary formation is the Everton Formation, but in the central and eastern portions of the river, the Boone Formation dominates. There are numerous bluffs displaying thick sections of the Boone.

The United States Geological Survey describes the Boone Formation as “mainly finely crystalline limestone with some cherty limestone and interbedded chert and minor shale. Approximately 400 ft. maximum thickness.” There is a lot of limestone in the Ozarks, but the nodules and thin beds of chert make the Boone stand out from the others.

Copy of boonecave

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It is early Mississippian in age, although exactly how old is a bit debateable. The USGS lists it as being in the Meramecian/Osagean stages, which places it mostly in the Middle Missippian. However, the Arkansas Geological Survey says it is in the Kinderhookian/Osagean stages, which are mostly early Mississippian. These stages are regional North American names, so you won’t find them on standard geological time scales meant to be used globally. At any rate, the Boone formed approximately 340-359 million years ago.

During the Paleozoic Era, the ocean had several cycles of raising and lowering sea levels. During the time the Boone Formation was forming, the region was a near shore marine environment, which explains the limestone and shale. The chert has typically been ascribed a biogenic origin, possibly the result of blooms of diatoms and radiolarians, both of which are single-celled organisms that make shells from silica, rather than the more common calcium carbonate which helped form the limestone. These organisms have also been presumed to form the Arkansas novaculite, a formation of metamorphosed microcrystalline quartz that reaches up to 900 feet in thickness. However, recent work indicates that both the Boone chert and the novaculite were formed from volcanic ash, created by an island-arc volcanic chain that existed about where the Ouachita Mountains are today.

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“Honeycombed” rocks seen along the Buffalo. NPS, Buffalo National River.

 

Northern Arkansas is known for its widespread karst topography, meaning it has a lot of sinkholes and caves, most of which are in the Boone Formation. The cave systems are so extensive that at periods of very low flow, the entire Buffalo River is swallowed up and becomes subterranean in a few areas. The Boone forms the ceiling of the most famous cave in Arkansas, Blanchard Springs Caverns, which are well worth visiting if you find yourself in northwest Arkansas. On a side note, you may find references to the Boone in Blanchard Springs being as young as 310 million years old, but with better refinement of dating techniques and better dating of the rocks, that date has been pushed back.

The next posts in this series will cover the fossils that have been found in the Boone Formation. Stay tuned.

 

 

 

 

National Fossil Day

NFD_-2017_Poster-96dpi-613pxtallToday is National Fossil Day™. The National Park Service holds this annual event on the second Wednesday every year to coincide with Earth Science Week sponsored by the American Geosciences Institute. Earth Science Week highlights the important role of earth sciences in our everyday lives and “to encourage stewardship of the Earth.” National Fossil Day is, as NPS says, “held to highlight the scientific and educational value of paleontology and the importance of preserving fossils for future generations.”

In honor of the day, I am going to give you a whirlwind tour of some of our most outstanding fossils from all over the state. People may not think of Arkansas as being rich in fossils, but we have a rich natural history spanning 500 million years. To give you a quick summary of the wide array of fossils, just check out the map on the fossil page, reproduced below.

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Arkansas Geological Survey regional map, annotated with reported fossils.

The most fossiliferous region in the state is the Ozarks, without a doubt. It is a favorite fossil collecting spot for many people, even though much of the area is national forest or national park owned, which prohibits fossil collecting. Nevertheless, fossils may be collected on any roadcut. I-65 near Leslie has several fossiliferous roadcuts. You are most likely to find abundant examples of crinoids, bryozoans like the screw-shaped Archimedes, clams and brachiopods, ammonoids (mostly goniatites), corals such as horn corals and tabulate corals, as well as the occasional echinoid and trilobite, along with many other types of fossils. This list of fossils makes it plain that the Ozarks are dominated by marine deposits, but you can find the occasional semi-terrestrial deposit loaded with plants like Calamites and Lepidodendron.

Top, left to right: Calamites, spiriferid brachiopod, blastoid echinoderm, goniatite ammonoid. Bottom left to right: Archimedes bryozoan, crinoid with calyx and fronds (very rare, mostly you just find pieces of the stalk).

There are a few fossils that particularly stand out. One is Rayonnoceras, a nautiloid ammonoid, which reached lengths of over two meters, making it one of the longest straight-shelled ammonoids ever found. The other is a shark named Ozarcus. While shark teeth are common, it is rare to find one that preserves parts of the skull and gill supports. At 325 million years, Ozarcus is the oldest one like this ever found and it changed the way we viewed shark evolution, indicating that modern sharks may be an offshoot of bony fish, not the other way around.

bc-067t-lgWe can’t leave the Ozarks without talking about Conard Fissure, a spectacular collection of Pleistocene fossils. Barnum Brown excavated the first chamber of the cave in 1906, pulling out thousands of fossils or all kinds, many of which were new to science. Of course, of all of them, the ones that most people remember were 15 skeletons of Smilodon, the largest of the saber-toothed cats. The one pictured to the right is a cast of one from La Brea, California. All of ours are held at the American Museum of Natural History.

The Ouachita Mountains are not nearly as fossiliferous, but they have two important types of fossils that are commonly found: graptolites (below left) and conodonts (below right, not from AR, Scripto Geologica). Graptolites are thought to be closely related to pterobranchs, which are still living today, even though the graptolites themselves are all from the Paleozoic Era. Most of the time, Graptolites look like pencil marks on slate, but if you find a good one, you can see they are often like serrated files that may come branched or coiled. The reason these are important is because they are hemichordates, the closest group to the chordates, all animals with a spine (either a stiff rod or actual bone). Conodonts, on the other hand, are the closest we have to the earliest vertebrates, looking like nothing so much as a degenerate hagfish.

graptolitesconodontsscriptageologica.jpg

The coastal plain is quite fossiliferous and has attracted the majority of press because it is here where you will find Cretaceous aged rocks and that means dinosaurs and their compatriots. Here you will find thousands of Exogyra oysters. Scattered among them, you can find numerous shark teeth, along with teeth from Enchodus, the saber-toothed herring (although not really a herring), especially if you look in the chalk beds. You can also find the rare example of hesperornithids, extinct diving birds, as well as fossil crocodilians.

But of course, the main draws here are the marine reptiles and the dinosaurs. Mosasaur vertebrae are not uncommon, although the skulls are. More rarely, one can find plesiosaur (the article only mentions elasmosaurs, which are a type of plesiosaur, but most plesiosaur fossils in Arkansas cannot be identified that closely) vertebrae as well.And then of course are the dinosaurs. We only have a few bones of one, named Arkansaurus, but we have found thousands of footprints of sauropods, the giant long-necked dinosaurs. Since the sauropods that have been found in Texas and Oklahoma are titanosaurs, such as Sauroposeidon, it is a good bet the footprints were made by titanosaurs. A few tracks have also been found of Acrocanthosaurus, a carnivorous dinosaur like looked something like a ridge-backed T. rex. Acrocanthosaurus reached almost 12 meters, so while T. rex was bigger, it wasn’t bigger by much.

Top left: Mosasaur in UT Austin museum. Top right: Plesiosaur vertebra from southern AR. Middle left: reconstruction of Arkansaurus foot. Middle right: statue of Arkansaurus (out of date). Bottom left: Sauropod footprints. Bottom right: Acrocanthosaurus footprint, Earth Times.

The eastern half of the state is dominated by river deposits from the Mississippi River, so the fossils found there are mainly Pleistocene aged, with the exception of a few earlier Paleogene fossils near Crowley’s Ridge. Pleistocene deposits can be found all over the state, as they are the youngest, but are most common in the east. In these deposits, a number of large fossils have been found. A mammoth was found near  Hazen, but we have almost two dozen mastodons scattered over the state. I already mentioned Smilodon, but we also have  , the giant short-faced bear, dire wolves, giant ground sloths, and even a giant sea snake named Pterosphenus. Most unusual of all is a specimen of Basilosaurus, which despite its name meaning king lizard, was actually one of the first whales. Considering the month, I would be remiss not to include Bootherium, also known as Harlan,s musk ox, or the helmeted musk ox.

Top left: Mastodon on display at Mid-America Museum. Top right: Basilosaurus by Karen Carr. Bottom left: Arctodus simus, Labrea tar pits. Wikipedia. Bottom right: Bootherium, Ohio Historical Society.

This is nowhere near all the fossils that can be found in Arkansas, but it does give a taste of our extensive natural history covering half a billion years. After all, we wouldn’t be the Natural State without a robust natural history. Happy National Fossil Day!

Mystery Fossil Revealed

Monday I posted a set of pictures showing an Arkansas fossil. Were you able to figure it out. Check below for the answer.

This skull and mandible comes from the Madrean Archipelago Biodiversity Assessment (MABA) website. I couldn’t find a good picture of an actual fossil, so I used this modern example instead. Below is a living version.

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Myotis leibii, Eastern small-footed bat. Credit: Gary Peeples/USFWS

The skull is that of Myotis leibii, the eastern small-footed Myotis. Myotis bats are also called mouse-eared bats, the most famous of which is the little brown bat, Myotis lucifugus. The other fossil bat in Arkansas is the big brown bat, which is not in the genus Myotis at all. It is in the genus Eptesicus (E. fuscus specifically).

I have talked about E. fuscus before, where I talked a bit about bats in general. I didn’t go into their phylogeny at all, so I will talk about that here. Bats as a whole belong to the order Chiroptera, which is the sister group to a group called Fereuungulata. That group includes artiodactyls, cetaceans (whales and dolphins), carnivorans, and pangolins. Altogether, Chiroptera and Fereuungulata form the horribly named Scrotifera. Why do I say it is horribly named? Besides the fact that naming such a large group after scrotums is a bit odd, take a look at the simplified mammal phylogeny illustrated by Darren Naish.

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Notice what is NOT in Scrotifera. That’s right. Primates, such as us. Yes, we are more closely related to rats and squirrels than we are to bats, dolphins, or cats and dogs. We are also not included in the group named for a feature we possess.

Both Myotis and Eptesicus are Vesper bats, meaning they belong in the family Vespertilionidae, along with over 300 other bat species. When it comes to diversity, mammals could easily be described as rodents, bats and their less common relatives, seeing as how those two groups include 60% of all mammals. Vesper bats are in the suborder Microchiroptera, the micro bats. The other suborder, Megachiroptera, is composed of the fruit bats like the flying foxes. The two suborders are rather lopsided in numbers, with just under 200 species in Megachiroptera and over 1000 in the Microchiroptera. This is the traditional classification at any rate.

There is another phylogeny that splits it up slightly differently and gives them different names. Megachiroptera has become Yinpterochiroptera and includes the horseshoe bats in the group called Rhinolophoidea as well as the lesser and greater false vampire bats in the genus Megaderma. Everything else that was in Microchiroptera  is in Yangochiroptera.

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You can read more about it here, or in the original paper here.

So returning to the vesper bats, these include most of the bats people are likely to run into, which is why  the bats in this group are sometimes called common bats. Most of the bats in this group have rather plain faces and are insectivores. Myotis leibii itself belongs in the group Myotinae, marked in the red box in the phylogeny below, which was also put together by Darren Naish.

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The interesting thing about this is that Eptesicus, the big brown bat, is in the serotine clade, up near the top of the tree and quite a distance away from Myotis, the little brown bat. Eptesicus is also sometimes called a house bat, but the house bats are in the group Scotophini, which while still in Vespertilioninae, is not closely related within the group. This is part of the reason common names can get confusing. just because the common names are similar and overlap doesn’t necessarily mean they are at all closely related.

M. leibii itself lives in forests throughout eastern North America, in spotty patches from Canada to Arkansas and Georgia. It is a small bat, weighing only about 5 grams and with a wingspan of less than 10 cm. Unusually for its size, it is long lived, living as long as 12 years and tolerates the cold better than most other bats, so spends less time in hibernation than other bats.

The fossil record of M. leibii is sparse, although the fossil record for Myotis in general is fairly good for bats. According to molecular data, the genus Myotis first appeared roughly 16 Mya, with the North American clade splitting off no more than 9 Mya. However, the actual fossil data indicates Myotis is far older, with the earliest known Myotis fossil being 33 Mya to the earliest Oligocene, although in North America, the record only extends to the late Miocene no more than 23 Mya. Interestingly, the fossil record for M leibii demonstrates a range far greater than the current distribution, with fossils being found as far as Oregon. In Arkansas, fossils are limited to one spot, which happens to be the same spot Eptesicus has been found: pleistocene deposits within the Conard fissure. If one looks in the original publication of Conard Fissure by Barnum Brown, one will find Vespertilio fuscus and Myotis subulatus, but both of those names have been changed in the intervening 110 years, to Eptesicus fuscus and Myotis leibii.

Monday Mysteries

It is long past time I resurrected Monday Mystery fossils. So to celebrate the season, here is a little animal whose relatives, or at least representations thereof, shall be widely seen over the next month.

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If you think you know what this is, please leave your identification in the comments. I will let everyone know what it is and where fossils like this have been found in Arkansas on Friday. Have a great October!

Arkansas law: The Good Dinosaur and the Ugly

There are a number of things going on in the Arkansas legislature right now that deserve attention here. The first thing I want to mention is that Arkansas now has its own official state dinosaur.

arkansaurus

On February 17, 2017, Governor Asa Hutchinson approved House Resolution 1003 to list Arkansaurus fridayi as the official state dinosaur. This bill was pushed by a high school kid named Cypress Oury and sponsored by Greg Leding, AR House representative for District 86. As those of you who have been here before may remember, Arkansaurus is the informal name of the only dinosaur ever found in Arkansas.

agsarkansaurusfootUnfortunately, we only have half of one foot, so identification has proved elusive. The best that can be said is that it is some kind of primitive coelurosaurian theropod. It is not as derived as tyrannosaurids and certainly not a maniraptoran theropod or any of the others near to the avian line. Thus, while the new drawing by Brian Engh above is better than previous versions, it is highly speculative. The arms are almost assuredly wrong and should be longer. We don’t know if it had feathers or not. It likely did, but those feathers would have been unlikely to be as long as those shown in the drawing. They would more likely have been shorter and fuzzier. This is not to say the feathers Brian Engh drew are wrong, they are certainly plausible, but a bit more advanced than is likely for a coelurosaurian that far down the family tree.

When picking a state dinosaur, Arkansaurus is certainly the most likely candidate, being the only one with an actual body fossil. But it was not the only candidate. Arkansas is known for having some spectacular dinosaur trackways. The tracks include two types. The very great majority are from a large sauropod, possibly Sauroposeidon (or depending on the taxonomy one follows, Pleurocoelus or Paluxysaurus, which may or may not be all the same or all different). Since Sauroposeidon is one of the largest known dinosaurs, this would have made a fine candidate, but the taxonomic uncertainties and the lack of actual body fossil material make it less viable. The other possibility if Acrocanthosaurus, an almost sail-backed theropod related to Allosaurus. Unfortunately, while we have footprints, we have no actual bones of this one either. We only presume it was the track maker because there have been fossils of it found in both Oklahoma and Texas and it is the only theropod of the right size known in the general area.

That is the good news. Sadly, there is also bad news. The Arkansas legislature is on a religious kick these days, proposing a number of unconstitutional bills. One such bill is HB 2050, “An act to amend the Arkansas code to allow public school teachers to teach creationism and intelligent design as theories alongside the teaching of the origins of the earth and the theory of evolution; and for other purposes.” They always add “and for other purposes,” no matter what the bill is, just to cover their butts. This bill is clearly unconstitutional, as already decided by McLean vs. Arkansas Board of Education in 1982 and Ktzmiller vs. Dover Area School District in 2005. As Judge Overton said in 1982, “No group, no matter how large or small, may use the organs of government, of which the public schools are the most conspicuous and influential, to foist its religious beliefs on others.” The theory of evolution is one of the best supported by mountains of evidence and exhaustive, thorough research of any scientific theory currently accepted by science, whereas creationism and intelligent design fail all efforts to make them remotely scientifically plausible. The idea they can stand side by side with the theory of evolution as valid scientific explanations in a science classroom is an insult to all thinking people.

Then there is SJR7, by Senator Jason Rapert (the same man who, among other things, was responsible for the Ten Commandments monument being built on the Capital grounds), calling for Congress to  propose an amendment to define marriage as between one man and one woman.  Because the Supreme Court of the United States has already made same-sex marriage legal throughout the country, the Arkansas legislature wants Congress to overturn their ruling. This is based on their religious beliefs and ignores a number of facts, such as it not actually being supported by the Bible, it violates the First Amendment by pushing a specific religious view onto everyone, and most importantly for our purposes here, ignores biological reality (and why I am talking about it here). Humans are not just male and female. There are several ways that genetics and development can intertwine that cause a mixture of male and female, making separation into a binary sex impossible. This bill would make it illegal for them to marry at all. Moreover, the bill does not define “man” or “woman,” making it ambiguous whether people who are biologically one sex, yet identify as the other, are banned from marriage. Considering that what gender one identifies with and is attracted to has a strong biological underpinning and is not a “lifestyle choice,” there is little to make this bill viable through any explanation other than prejudice.

In relation to that bill is SB346, by Senators Greg Standridge and Gary Stubblefield is a bill to require people in public schools to use the bathrooms that match their biological sex. To begin with, these two senators do not know the difference between gender (sociological) and sex (biological). Secondly, they have no answer for intersex individuals who cannot be easily classified as male or female other than they are not allowed to go to the bathroom at all, which has been the unfortunate situation at some schools for transgender children. This bill was pulled, but another was filed by Senator Linda Collins’ Smith targeting government buildings. Apparently, the backlash from the state LGBT supporters, business owners, and the governor were not sufficient to dissuade the legislature they needed to act against an imaginary scourge.

And of course, this list would not be complete without trying to make the Bible the official state book, as attempted by Rep. Tosh in HR 1047. He, of course, touts the myth that “the Bible form the basis upon which our modern civilization is structured,” pretending that he is simply supporting the Bible for purely historical reasons. He goes on to say that the Bible is “considered by many to be a book of truth,.. is widely read,” and why not throw in that we have a bunch of other state symbols, why not a religious book too?

All of these bills at the very least face constitutional challenges and have already been ruled as unconstitutional in other court battles. All this will do is cost the state a fortune in legal bills and drive away tax dollars as businesses leave the state and tourists opt to go elsewhere. Moreover, it seriously harms science education as we continuously have to battle this form of ignorance.

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UPDATE: Now that the legislature has finished this session, how much damage did they get done? In terms of what has been mentioned here, not a lot, thankfully.

HB 2050: This bill to allow creationism in the schools died on the vine. It was referred to committee, but the author of the bill never provided a full bill for the committee to read, so the session ended without further progress, meaning that the process will need to be started from scratch next year. WIN

SJR7: This resolution to ask the US Congress to approve an amendment to the constitution making marriage as between one man and one woman failed to pass after three attempts. The truly scary thing is that it got 50 votes, only 1 short of passing. WIN

SB346: The notorious bathroom bill never made it out of committee. WIN

HR 1047: The House resolution to make the Bible the official state book passed the House with a unanimous vote. Yes, you read that right. Not a single representative voted against it. Thankfully, this was only a resolution with no legal authority and the Senate will not vote on it until the next session, but still. Of course, what can one expect in a state which still says in the state constitution that an atheist cannot hold public office nor be considered competent to testify in court? LOSE.

In other news, HB 1040 prohibiting Sharia law from being enforced passed both houses of the legislature and signed by the Governor. The irony of this is that it was never legal in the first place. Our legal system just doesn’t work that way. This was just another bill to demonize Muslims. LOSE.

If you are teaching in a college, pay close attention to your students and don’t rile them up. A new law passed by the legislature and signed into law allows students to carry guns on campus, but good news, they still are not allowed to bring them into football stadiums because allowing them to do so might jeopardize Arkansas’s standing in the Sun Belt conference. Seriously.

Prehistoric Shark Week, Day 3: Flat Fish

For Day 3 (a little late, yes) of Prehistoric Shark Week, I want to bring to your attention the diversity of chondrichthyans that have opted for a flatter bauplan.

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Ray tooth

Sharks are generally split into two groups, the galeomorphs, which are mostly the more typical torpedo-shaped sharks, including the sharks that most people think of when they envision a shark. The other group is the squalimorphs. These sharks lack an anal fin and many of them have developed a penchant for flatter bodies and broad pectoral fins, and in some cases pelvic fins as well (although not all, such as the dogfish and frilled sharks). Up until recently, the batoids, otherwise known as skates and rays, were considered part of this group, the consensus being that they were a more specialized type of squalimorph shark that had taken flat to an extreme. But the most recent molecular studies have indicated that they are a group unto themselves. The batoids have a long fossil history, with a number of ray teeth found in the Cretaceous deposits of Arkansas, particularly the eagle ray family Myliobatidae. Their teeth are typically flat rectangles on top with a comb-like surface below. Another type of ray that can be found are the guitarfish, or Rhinobatos casieri. These pectoral fins of these fish extend to their head, giving them a triangular shaped front end of a more traditional shark-like back end.

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Shark classification. 

http://www.mesa.edu.au/seaweek2005/pdf_senior/is02.pdf

 

Skates and rays are generally very docile and would not be very threatening, spending their time scrounging about on the sea floor for benthic (living in or on the sea floor) invertebrates and the occasional fish. The same can’t be said for the last member of this group, the sawfish. Armed with a rostrum (its elongated snout) with teeth out to the side, the fish looks like it has a chain saw for a nose. The sawfish will swim into a school of fish and thrash its rostrum rapidly back and forth, spearing and stunning several fish, which it can then gobble up. They can also use it to dig up clams and crabs from the sediment. While they won’t attack humans, any human who provoked one may easily wind up perforated by the rostrum, probably not deadly but certainly painful. Most modern sawfish reach a respectable two meters, but the largest species, the green sawfish (Pristis zijsron) can top seven meters (24 feet). This is as large as the Cretaceous versions. Modern sawfish are typically put into the family Pristiformes. The Cretaceous ones are in their own family, called Sclerorhynchiformes and are not directly related, in that the Cretaceous ones are not thought to be ancestral to the modern ones. They are both put into the group Pristirajea, so they are thought to at least be related. But with the uncertainties in the relationships of the modern fish, the relationships with fossil forms are necessarily less certain. In any case, Arkansas sports several different species from this group, including Schizorhiza stromeri, Sclerorhynchus sp., Ischyrhiza mira, Ischyrhiza avonicola, and Ptychotrygon vermiculata. We were postively awash in sawfish.

Onchopristis numidus black JCS

Onchopristis. Cretaceous. Sawfishconservationsocietyblogspot.com

The true squalimorph sharks that have shown up in the Arkansas Cretaceous rocks are best represented by the Angel shark (Squatina hassei), which looks like an early rendition of a skate, so it is little wonder that most researchers viewed skates and rays as simply more specialized versions of these sharks. Nevertheless, it appears this is case of convergence, not homology (similarity due to relationship). If it is homologous, it isn’t directly so. It is possible both groups had a common slightly flattened ancestor and each took their own route from there.

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Rhinobatos hakelensis. Cretaceous guitarfish. Fossilmuseum.net

All of these fish are pretty docile hunters, scrounging around the sea floor for benthic organisms, all those animals that make their home in or on the sea floor sediments. They spend their time digging around the sand for crabs, clams, and other invertebrates, the occasional fish. When threatened by the presence of a predator, they hide on the bottom, using their shape to help them blend in with the seafloor. Neither the ones today or the ones in the Cretaceous would have bothered a human swimming around them.

Becker, Martin A., Chamberlain, John A., Wolp, George E. 2006. Chondricthyans from the Arkadelphia Formation (Upper Cretaceous: Upper Maastrichtian) of Hot Spring County, Arkansas