We began the week with our first Mystery Monday for paleoaerie.org with the picture of an interesting Arkansas fossil. Today, Forum Friday will become Fossil Friday as well as we identify the fossil. Did you guess what it was? See if you were right below the picture.
Congratulations go to Allie Valtakis, who correctly identified it as a nautiloid cephalopod. This particular one is Rayonnoceras solidiforme. It has traditionally been placed within the Order Actinocerida, although some workers have placed them into the Order Pseudorthocerida, which is known for their resemblance to the more commonly recognized orthocerid cephalopods.
What are cephalopods, much less nautiloid cephalopods, you ask? Cephalopods are the group of molluscs that include squids, octopuses, and cuttlefish. There are three major groups: Coleoidia, which includes almost all the modern cephalopods; Ammonoidea, which includes almost all the extinct ones and are known for their complexly sutured shells; and the Nautiloidea, which are mostly extinct, the only living form is the Nautilus. The ammonoids and the nautiloids both formed shells. What differs between them is how they made them. Some of those in Coleoidia also form shells, but they have been greatly reduced and internalized, such as in squids, or lost altogether, such as octopuses. For those with external shells, they have the problem that shells don’t get bigger once the mineral is laid down, so they quickly grow out of their shells. They solve this by adding mineral to the front of the opening in an ever-increasing funnel, periodically walling off the back of the living chamber (leaving a small opening for the siphuncle that goes all the way through the shell, creating a series of gradually increasing sections.
The ammonoids are well known in the fossil record, particularly the subgroup called ammonites, having a diverse array of straight, curved, and coiled shells. What makes them unique from the nautiloids is the sutures between sections are wavy, sometimes showing astoundingly complicated patterns. The nautiloids, on the other hand, sport very simple, smooth curves. It is this group in which Rayonnoceras belongs.
Rayonnoceras lived about 325 million years ago in the Mississipian Period, although nautiloids as a group have been around since the Cambrian Period over 500 million years ago. What makes this particular species so interesting to Arkansans is that the largest nautiloid cephalopod ever found was discovered near Fayetteville, AR. It was 2.4 m (8 feet) and found in a rock unit named, appropriately enough, the Fayetteville Shale, a unit of dark gray to black shale and limestone, indicative of a warm, shallow marine environment without a lot of sediment input, much like many areas within the Bahamas today.
To recap what we’ve covered over on the Facebook page, we recommended a book discussing misunderstandings in human evolution and another in how evolution affects our health. We saw a hominid fossil hand bone that helped to show how we differed from australopithecines and genetics work that showed us how we didn’t differ from Neanderthals.
We read about genetics work that informed us how flowering plants evolved by doubling their own genes and stealing genomes from other plants. We learned about a “second code” within DNA and why the hype was bigger than the story, but may help us rethink our DNA analogies.
We saw how birds defend themselves against cheaters and learned the first lizards and snakes may have given live birth. We also got some information on how teaching and testing will need to change under the Next Generation Science Standards.
On a final note, this will be the last post this year on paleoaerie.org. Enjoy the holidays and join us in January, when we will be embarking on discussion of the Ordovician rocks and fossils in Arkansas. Over the spring, we plan on discussing several vertebrate fossils found in the state. There are several books and online resource reviews coming up as well. We will be adding to our Scientists in the Classroom and adding several new resources to the links pages. As always, we will be posting a plethora of current news items on Facebook, so stay tuned! In the meantime, tell us what you liked, didn’t like, want to see more of, and any questions you may have.
Likely thanks to upgrading computer systems and the joys of trying to figure out new setups and operating systems, there seems to have been a small glitch deleting the post that was supposed to go up Friday, so it is getting posted today. So let’s see if we can make lemonade from the lemon.
On Facebook, I started a new set of posts, in which I post a picture of a fossil found in or could be found in Arkansas and see if anyone can identify it. The first one I put up was of a mosasaur, a huge aquatic reptile that swam around Arkansas seas during the Cretaceous Period. People seemed to enjoy it, so I will be doing this on a regular basis. However, it has come to my attention that many places block Facebook, including a lot of schools. So I will be posting them on the blog. I will try to post a new picture every Monday and will then provide the answer on Friday, giving people the week to see if they can come up with the answer. Don’t worry about being wrong, we learn more from our failures than our successes anyway. You can’t win if you don’t play. So with that, let’s play! here is today’s pic. Can you tell me what it is?
In the meantime, if you missed out on all the stuff we covered on Facebook, here is a brief summary of most of hte stories.
Of the many new fossils and work on fossils that were reported on this month, we saw a new fossil primate that may have been ancestral to lemurs and lorises and giant, terrestrial pterosaurs of doom. We learned about the earliest flowering plant in north America, new crests for old dinosaurs and the promise and perils of resurrecting dinosaurs and other extinct animals..We learned about some amazing animals, from snakes that shrink their own heart and intestines between meals (and the genetic switches that allow them to do it), to animals with no stomachs. We learned about tool-using crocodiles and flower-mimicking insect predators. We learned that unidirectional breathing occurs in lizards as well as crocodiles and birds and why dinosaurs developed beaks.
We learned about evolutionary ghosts, how animals colonize new territory, and how unmasking latent variation within a population can lead to rapid evolution.We learned about the end-Cretaceous extinction and how the Siberian Traps caused the largest extinction event of all time.
We learned how evolution made it easier for people to believe in God than accept evolution and why fanaticism of any stripe can lead one astray. We read a discussion about the importance of scientists in science communication, and why we shouldn’t ignore Youtube. We found help in teaching controversial subjects in hostile environments and apps to help teach hard-to-grasp subjects like astronomical distance.
We learned about how bacteria avoid the immune system to cause disease, how they form an important part of breast milk, and the four billion year history of vitamins. We learned even bacteria have a hard time living deep inside the earth and how viruses can kill even antibiotic-resistant bacteria. We also read a review of a book on evolutionary medicine.Genetics work played a big role in the above stories, but it also gave us the discovery of a second code within DNA and more support for comb jellies being the first animals. We learned why protein incompatibilities make hybrids sterile and how early hominids interbred to form modern humans.
So, what were the stories you liked? Did it spark any thoughts, either good or bad? Was there anything that you saw that we didn’t mention? Share your thoughts and don’t forget to try your luck with identifying today’s Arkansas fossil!
It’s the beginning of December and more than a month since we’ve had a Forum Friday, but since most people were either still enjoying their Thanksgiving dinners or fighting through crowds of shoppers, I opted for a Monday meeting. October was a busy month and November followed suit. Most of what we posted on Paleoaerie since the last Forum was a rundown of the Society of Vertebrate Paleontology annual meeting in Los Angeles. A huge amount of material was presented at the meeting, of which we barely scratched the surface. We also reviewed The Big Golden Book of Dinosaurs, a great book for elementary kids.
We covered a lot on the Facebook page. Evolution in medicine got a lot of attention, including a whole online, open-access journal about it. We learned about evolutionary theory being used in the fight against the flu, malaria, HIV, and cancer, twice, no three times! We even learned why we have allergies, and if that isn’t enough for you, we found a whole series of papers on evolutionary theory in medicine for you.
Studies of human evolution had a good showing this month, starting with a new skull of Homo erectus changing our views of our ancestors and a book called “Shaping Humanity: how science, art, and imagination help us understand our origins.” We learned how women compete with other women and how natural selection can be tracked through human populations.
Modern experimentation has demonstrated how life may have gotten started chemically and how clay hydrogels may have helped. We watched the evolution of bacteria in a lab over 25 years. We also learned how evolution can evolve evolvability.
Evolution outdid itself with deep sea animals eating land plants and an amazing mimicry display. We learned why bigger isn’t necessarily better, why monkeys have colorful faces, and that large canines can be sexy.
In addition to all the news from SVP, we learned about two new giant theropods, the tyrannosaur Lythronax and the allosauroid Siats. We also learned about the toothed bird, Pelagornis and pachycephalosaurs. We also learned about research on what modern animals tell us about dinosaur brains. We also saw evidence that the Mesozoic may not have had as much oxygen as we thought.
Dinosaurs weren’t the only fossils of interest to be announced. A new unicellular organism is providing insights into the evolution of multicellularity. The oldest fossil of a big cat and a suction-feeding turtle were found, as well as the oldest known fossil ever, providing evidence of life almost 3.5 billion years ago. We read the beginning of a series on the evolution of whales and how the first tetrapods crawled onto the land. We learned about fossil giant mushrooms and watched the Red Queen drive mammals to extinction.
Putting 3D images of fossils on paleoaerie has always been one of the goals of the site and the potential for this to revolutionize geology has not gone unnoticed. The Smithsonian has taken up the challenge. If you want to learn how to do it, here is the paper for you.
We celebrated Alfred Russell Wallace and American Education Week. Along the way, we listened to the great David Attenborough describe the history of life and Zach Kopplin tell us about his efforts to keep creationism out of public schools in Louisiana.
For educational techniques and resources, we looked at BrainU and a website by the ADE and AETN. We examined the usefulness and pitfalls of gamification. We saw how to build your own sensors and use them in class. We discussed how to change people’s idea of change through business concepts the truth about climate change. We even saw doctoral dissertations via interpretive dance.
Do you have any gift ideas to share? Any of the stories particularly pique your interest? Let us know. Don’t just talk amongst yourselves, talk to us.