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Yearly Archives: 2017
2017 is at an end. While the year has had a lot of things that will make us say good riddance, the year in paleontology was extraordinary. To give you an idea of just how extraordinary, let’s look at what has been discovered. Far too much has gone on, so we can’t look at everything, but if we just look at the new species that have been published, it will give us a decent proxy. Using that as a measure, what a year it has been.
111 angiosperms (flowering plants). One new species is Foveomonocolpites ravni, fossil pollen from the early Cretaceous of Isreal.
7 Gingoales, 20 conifers, 27 other seed plants. and 55 other plant fossils, and this doesn’t even include 4 new red algae, one of which is Rafatazmia chitrakootensis from India, the oldest known plant fossil at 1.6 billion years old.
23 cnidarians. including this jellyfish from the Cambrian.
68 bryozoans and 56 brachiopods,
82 malacostracans (crabs), 87 ostracods, and 9 other crustaceans
112 coleopterans, 2 dermapterans, 1 dictyopterans, 50 dipterans, 20 hemipterans, 47 hymenopterans, 5 mecopterans, 22 neuropterans, 25 odonates, 10 trichopterans, and 44 other insects
72 arachnids, 32 trilobites and 33 other arthropods
79 ammonoids and 31 other cephalopods, 140 gastropods, 71 bivalves, and 11 other molluscs
42 conodonts, 1 early jawless vertebrate, 5 placoderms, 22 sharks and their relatives, and 102 bony fish
3 temnospondyls, 3 lissamphibians, and 2 other amphibians
12 turtles, 9 crocodilians,
42 nonavian dinosaurs, including 9 ornithischians (including Zuul, the destroyer of shins and the most complete ankylosaur), 21 theropods, and 12 sauropods.
20 birds, 6 pterosaurs, 1 basal archosauriform named Teleocrater, and 3 other reptiles.
11 non-mammalian synapsids, 5 metatherians, 10 xenarthrans, 1 elephant, 4 sirens (dugongs and manatees), 5 bats, 25 ungulates, 14 cetaceans, 11 carnivorans, 6 lagomorphs (rabbits and hares), 66 rodents, 6 primates, 20 other eutherians, and 6 other mammals.
55 other animals, as well as 54 various other organisms, including foraminfera and others of uncertain affinities.
All told, 2003 new species. So whatever else happened this year, it was a good year for paleontology. Here’s hoping that 2018 is good all the way around.
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.
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).
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.
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.
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.
Today 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.
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.
We 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.
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!
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.
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.
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.
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.
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.
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.
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!
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.
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.
Unfortunately, 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.
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.