Paleobiological analysis of the first record of redfieldiiform fish found in Korea from the Late Triassic

The first record of redfieldiiform fish (Actinopterygii) from the Upper Triassic of Korea: Implications for paleobiology and paleobiogeography of Redfieldiiformes

By: Su-Hwan Kim, Yuong-Nam Lee, Jin-Young Park, Sungjin Lee, Hang-Jae Lee

Summarized by: Jonathan Weimar

Jonathan Weimar is a geology major at the University of South Florida. Currently he is a senior and is very interested in space and natural hazards. After he obtains his degree, he plans to research the possible careers that coexist with his interests. Aside from geology, he loves making music and has a dream of becoming a professional music artist. 

What data were used? A new well-preserved fossil of redfieldiiform , a type of ray-finned fish, has been discovered from the Triassic Amisan Formation in South Korea. The fossil slightly differs from the regular morphology of redfieldiiform taxa and therefore, represent a new taxon called Hiascoactinus boryeongensis. 

Methods: The Amisan Formation reaches depths of up to 1000m thick and is broken up into three different sections: the lower member, the middle member, and the upper member. By looking at the floral assemblage of the Amisan Formation, scientists were able to date the depositional age of these fossils to be of the Late Triassic (about 237 million years ago). 

Results: The redfieldiiform fish belongs to the larger group called the ray-finned fishes, which make up the majority of fish in today’s oceans. While there have been many discoveries of the redfieldiiform fish in various continents such as North America and Australia, this is the first valid record of the ray-finned fish in Asia. Even though there have been previous records of the redfieldiiform fish in China, Siberia, and Russia, they have been inaccurate, and therefore the specimen in this article found in Korea is notably the first valid record of redfieldiiform fish in Asia. The redfieldiiform fish has many distinguishable characteristics that include: anal and dorsal fins with membranes between the rays,positioning of the anal and dorsal fins, a single-plated ray, and a spindle shaped body covered with scales. The official name given to the discovered fossil is Hiascoactinus boryeongensis. The genus name“Hiascoactinus” is Greek and Latin- based and refers to the unique dorsal and anal fins, while the species name “boryeongensis” refers to the city of Korea, Boryeong. The fossil has a length of 138mm and a width of 38mm. Almost all of the fossil is intact, except some parts of the caudal fin, furthest from the head, as well as parts of the skull and stomach region. Morphologically, there are differences between the new taxon Hiascoactinus boryeongensis and the redfieldiiform fish that have been scientifically researched. For example, there is a difference that focuses on the dorsal and anal fins of the fish. These fins are what help the fish directionally and are very important. A lot of ray-finned fish erect their fins to quickly get away from predators and go after prey as it helps with turning maneuvers. The dorsal and anal fins of the Hiascoactinus boryeongensis, however, are not fully connected between rays, unlike other closely related fish. This would have made it harder for them to complete turning maneuvers. Because of this, it is suggested that the species was slow swimming predators and went after prey that was inactive.

This figure shows us the specimen of the Hiascoactinus boryeongensis and a recreation of the fossil providing more detail of the structures. Parts of the caudal fin furthest from the head, parts of the skull, and parts of the abdomen are missing. That is an artistic representation of what the specimen could of looked like.

Why is this study important? This study is important for many reasons. Firstly, this fossil is well-preserved, which means that it has the greatest potential of revealing information about its physiology, morphology, and taxonomy. It allows for the study of the redfieldiiform group and provides information about how this species may have lived million years ago (e.g., the structures of the fins could indicate its swimming capabilities). Lastly, it shows that global sampling of fossils can reveal new evolutionary adaptations and biogeographic patterns of different species.   

The big picture: This study provides insight on the redfieldiiform fish and shows us how we can use morphological differences to define a new species. This article also shows us the importance of reevaluation of scientific evidence. The previous records of the ray-finned fish found in Russia and China were inaccurate and provided inaccurate biogeographic information on the redfieldiiform fish record. It was with this study and the well-preserved fossil founded in Korea that shows us the first true record of one of these fish in Asia.  

Citation: Kim, S., Park, J., Lee, S., & Lee, H. (2019). The first record of redfieldiiform fish (Actinopterygii) from the Upper Triassic of Korea: Implications for paleobiology and paleobiogeography of Redfieldiiformes. In 1011400475 778507242 Y. Lee (Ed.), Gondwana Research (Vol. 80, pp. 275-284). Amsterdam, Netherlands: Elsevier. doi:https://www.sciencedirect.com/science/article/pii/S1342937X19303211

Spinosaurus Teeth Open A New Window into the Lifestyle of This Unique Creature

Taphonomic evidence supports an aquatic lifestyle for Spinosaurus

By: Thomas Beevora, Aaron Quigleya, Roy E. Smith, Robert S.H. Smyth, Nizar Ibrahim, Samir Zouhric, and David M. Martill

Summarized by Jerold Ramos  

Jerold Ramos is a senior at The University of South Florida studying geology. Once he graduates, he hopes to develop experience working in a museum environment to one day become a museum educator. Captivated by the beauty and mystery of dinosaurs from a young age, he hopes that as a museum educator he can share the excitement and wonder that Earth’s history has to offer with people from around the world. In his free time, he enjoys hosting game nights with his friends and creating poorly photoshopped projects.

What data were used? Two collections of fossilized teeth found in separate riverbed deposits within South Eastern Morocco were used for this study. In total, 1,245 teeth were collected and sorted into appropriate groups based on their taxonomic order or genus.

Methods: Fossils were collected at two different sites in Morocco. Site One excavated fossils from an exposed bed, while the fossils from Site Two were bought from a mining group that had discovered them previously. Beevora and their team chose to focus on teeth, as they could assign these teeth to a taxonomic order (e.g., Carnivora [dogs and cats], Primates [including chimps and humans], and Saurischia [theropod and sauropod dinosaurs]) or even more specifically to a family or genus level. In this case, Beevora and their team were able to assign many of the teeth to the genus Spinosaurus.

Figure 1. Left: Pie chart displaying the distribution of fossils within Sites One and Two. Charts A and C represent all fossils at Sites One and Two respectively, while charts B and D represent the collection of fossilized teeth. The images to the right represent teeth from Site Two belonging to Spinosaurus (Scale bar- 10mm).

Results: After analyzing the fossils collected from both sites, this study found that the amount of Spinosaurus teeth at each site was abnormally high when compared to the teeth of other creatures found in the area. At Site One, 921 fossils were uncovered and of these 921, a total of 317 of these were teeth. From these teeth, about 47.9% (152) of these teeth were Spinosaurus teeth. The only creature to have a similar count in teeth was Onchopristis, an ancient sawfish from the Cretaceous Period, with 50.2% (159) of the teeth belonging to this fish. At Site Two, 1261 fossils were purchased from a miner and of these 1261 fossils, a total of 928 of these fossils were teeth.  At this location, a greater assemblage of Spinosaurus teeth were identified. Here Spinosaurus teeth made up about 43.9% (407) of the teeth found, making it the most abundant species represented at this site. Once again, the only other creature to have a similar representation at the site is Onchopristis, with 40.4% (375) of its teeth making up the collection found at Site Two. The rich supply of Spinosaurus teeth found at both sites suggest a more aquatic lifestyle for Spinosaurus. From the data collected in both sites, these sites likely represented aquatic environments due to the high presence of teeth from Onchopristis, an entirely aquatic animal, making up about half of the teeth found at each site. A creature that does not live an aquatic lifestyle, or spend a significant time in the water, would not leave as many remains in the environment. As an example, Site One discovered a single tooth from Carcharodontosaurus, another large therapod dinosaur that is thought to be strictly land-dwelling. This single tooth is more in line with what would be expected from a creature with a terrestrial lifestyle as it would only approach the water to drink or feed on a creature nearby. If Spinosaurus was terrestrial like Carcharodontosaurus, then it would not have such a prominent representation at these sites. Rather than wading by the water’s edge like a heron or flamingo, Spinosaurus may have spent much of its time in the water actively swimming to catch prey. This collection of teeth in aquatic deposits and Spinosaurus’ established morphology, including reduced hind legs, elongated skull, and paddle-like tail structure, further support the hypothesis that Spinosaurus lived an aquatic lifestyle.

Why is this study important? The findings from this study change what we know about both Spinosaurus and how we define dinosaurs today. Like other non-avian (i.e., non-bird) dinosaurs, Spinosaurus was often pictured to be a terrestrial creature, only visiting aquatic areas when it needed water. However, thanks to recent discoveries in the last five years, we now know that it likely lived a more aquatic lifestyle. This lifestyle is something that is not seen with any other known non-avian dinosaur so far. Dinosaurs are often defined as exclusively terrestrial creatures, a definition that no longer applies to the Spinosaurus. With the recent discoveries involving Spinosaurus, it may be worth reevaluating the lifestyles of other members of the family Spinosauridae, as it is possible that other Spinosauridae adopted an aquatic lifestyle long before Spinosaurus.   

The big picture: Spinosaurus has been an enigmatic fossil ever since it was discovered in 1915. After its remains were destroyed during World War II, the image and lifestyle of Spinosaurus remained a mystery to paleontologists for several years. Now that more of its fossils are being unearthed, paleontologists can reconstruct this unique creature and illustrate the environment it inhabited. From these recent discoveries, we now know that Spinosaurus lived a life unlike any other dinosaur recorded in the fossil record. As there are numerous dinosaurs missing from the fossil record, whether it be through failed preservation or destruction by plate tectonics, it is possible that there are others that share this aquatic lifestyle.

Citation: Beevor, T., Quigley, A., Smith, R. E., Smyth, R. S. H., Ibrahim, N., Zouhri, S., & Martill, D. M. (2021). Taphonomic evidence supports an aquatic lifestyle for Spinosaurus. Cretaceous Research, 117. https://doi-org.ezproxy.lib.usf.edu/10.1016/j.cretres.2020.104627  

Imaging Technology and its Effect on Interpersonal Relationships in the Paleontology Lab

Trust in Technicians in Paleontology Laboratories. A look into the growing use of computed tomography (CT) imaging and its legitimacy among professional researchers in the lab.

by Caitlin Donahue Wylie

Summarized by Cresencia del Pino 

Cresencia del Pino is an undergraduate geology student at the University of South Florida. After receiving her degree, she intends to join the professional workforce and attain her Professional Geologist title. When she is not studying geology, she enjoys mountain biking, camping and hiking with her pup, Zion. 

What data was used? The author used data from semi-structured qualitative interviews (a set list of questions, but researchers can deviate from them) conducted by researchers, lab technicians, and others in several universities across the United States, Germany, and The United Kingdom from 2009 to 2013. 

Methods: The author created a semi-structured interview to understand professional opinions on CT imaging, fossil preparators, and their role in maintaining a social hierarchy within a scientific research community. 

Results: This study gathered qualitative data on how the emergence of digital imaging techniques has affected the social structures within the lab. The author states a resounding skepticism towards the use of CT scans and images as a proxy for physical fossil specimens. Researchers rely on the trust forged between fossil preparators [people who clean and prepare fossil specimens by chipping away at surrounding rock], over the imaging captured by CT technology. They [professionals in the field] claim that CT imaging is not detailed enough, and subject to too much human error when calibrating the bounds that are used to capture fossil within rock. Therefore, CT imaging should be used as a tool to support fossil discovery along-side true hand samples in a “mixed-method” approach. However, the author notes that this skepticism may stem from innate bias to hold the social structure of the lab constant, where researchers are explicitly or implicitly ranked above lab technicians. 

Synchrotron [a type of digital imaging like CT, where X-rays are used to measure density] image of a burrow that contains two fossils. This image introduces an advantage of digital imaging, where scientists can see inside a rock. This is a faster method than traditional fossil preparation which also preserves the trace fossil of the burrow, as well as the skeletons inside. Source: Fernandez et al. (2013).
Why is this study important? This study elucidates, through interviews, the motives of research professionals being skeptical of digital imaging technology. Although critiques of the technique are valid, it omits otherwise greater advantages, such as being able to see fossil in rock, without the need for skilled, time-consuming preparation. These advantages are overlooked, because the growing acceptance of CT imaging would mean more specialized technicians would be required to combine and create images, leading to a decline in skilled fossil preparators, ultimately upsetting the social structure of the lab. From the interviews, the author notes that there is also an included scapegoat when using digital imaging, that allows disagreements between colleagues to “blame the technology”, instead of the interpretation of their cohort, which ultimately can affect trust between members of the lab. 

The big picture: Technology is advancing at a rapid pace in today’s modern scientific society. In a world where pandemics are a reality, and the need for social distancing and remote learning is a necessity, the demand for digital formats has increased exponentially. Digitized fossil scans can ultimately increase the accessibility of fossils, therefore allowing specimens to be studied remotely from researchers who may not have the privilege, or ability, to travel. There may no longer be room for the stigmatization of digital fossils against traditional hand samples. While technology is still advancing, there needs to be an acceptance for change within the community, and flexibility when it comes to the shifting positions and ranks within the lab. 

Citation: Wylie, Caitlin Donahue. “Trust in technicians in paleontology laboratories.” Science, Technology, & Human Values 43.2 (2018): 324-348.

Discovery of new Cretaceous Beetles could uncover new paleoecological interactions in Cretaceous forests

Coleoptera in amber from Cretaceous resiniferous forests

By: David Peris

Summarized by: Austin Spencer

Bio:  Austin Spencer is a geology major at the University of South Florida and is currently a senior. Once he earns his degree, he plans to work for the Florida Department of Environmental Protection with the Florida Geological Survey and eventually would like to work at a community college teaching an introductory geology class to help teach a new generation of potential geologists. When he is not studying geology, he enjoys reading, hiking, and cycling in his free time.

What data were used? Beetle fossils discovered in Cretaceous-age amber from around the world. The age and location of these Cretaceous amber deposits are shown in Figure 1 on the stratigraphic chart of the Cretaceous. It is important to point out that no new materials from Myanmar were collected for this study. Paleontological associations have come together against buying and collecting fossils from Myanmar due to the human rights violations that are occurring in the country. You can read more here: Statement from the Society of Vertebrate Paleontology

Figure 1: Stratigraphic Chart of the Cretaceous period and the ages and locations of Cretaceous amber deposits containing beetle fossils.

Methods: This study used a digital microscope to create up close images of fossil beetles in amber, as well as information from other scientific papers to create a taxonomic list of new beetle species found in various deposits of Cretaceous amber up to 2019. The taxonomic list can be found in the papers Appendix A.

Results: Coleoptera is an order that contains all species of beetles. This study highlights newly discovered species of coleoptera that are preserved in amber, which is fossilized tree sap, from the Cretaceous Period (~129-66 Ma). This study has revealed that there have been 364 new species discovered from Cretaceous-age amber. When an insect is preserved in amber, it is often preserved in great detail. This allows researchers to study the beetles as they were millions of years ago. This has led to ecological discoveries found from these new fossils. Some of the fossils discovered have shown a feeding structure called a spore brush, which is used to eat spores from fungi. These spore brushes have been observed in some modern mycophagous beetles, which are fungal feeding beetles. This discovery shows that fungal feeding beetles have been around since the Cretaceous. Another discovery from the study of Cretaceous fossil beetles is their role as pollinators. Today, bees and butterflies are known as the main pollinators; however, before bees and butterflies evolved to be pollinators, beetles were important insect pollinators. Researchers have found in the fossil record from these Cretaceous beetles that there are patterns of adaptations shown from the Early Cretaceous to modern pollinating beetles. Ancient beetles have also been thought as one of the causes of large-scale resin production from trees that go on the form the Cretaceous amber deposits, however, this has never been proven. The study uses an example from a beetle known as an ambrosia beetle, from Miocene Epoch (~23-5 Ma). These beetles are known to bore into wood and deposit ambrosia fungus into the wood, which they use as a food source. These beetles are known to be abundant in Miocene-age amber, which leads researchers to believe that beetles could be the cause of damage to resin-producing trees in other time periods as well. 

Figure 2: A collection of beetles in Cretaceous-age amber. A represents an adult male of Cretaretes minimus . B represents an adult Lymexyildae specimen and C represents an adult Elateroidea specimen.

Why is the study important? Coleoptera includes more than 400,000 species of beetles, which makes up about 25% of all living organisms. Beetles are important organisms for many different ecological interactions around the world. Beetles are pollinators, decomposers, and primary consumers. Since beetles are such an important part of ecosystems it is important that we understand the evolution of these organisms throughout history and how they interacted with past ecosystems to get a better understanding of modern beetles and their importance.

The big picture: This study highlights the abundance of beetles found recently in Cretaceous amber. With the discovery of these new species more research can be done to better understand how these organisms interacted with Cretaceous ecosystems as well as the evolution of beetles to modern day, though it is important to ensure ethical collection of amber fossils. This study will hopefully lead to new discoveries of Coleoptera and their supposed involvement in resin production in Cretaceous forests as well. 

Citation: Peris, D., Coleoptera in amber from Cretaceous resiniferous forests, Cretaceous Research Vol. 113 (2020), https://doi.org/10.1016/j.cretres.2020.104484 

Ordovician paleontology in Australia and its global significance

Ordovician strata in the Cliefden Caves area, New South Wales: a case study in the preservation of a globally significant paleontological site

By I. G. Percival, B. D. Webby, and H. D. T. Burkitt

Summarized by Joseph Stump. Joseph Stump is an undergraduate geology major at the University of South Florida. After graduating high school in Sebring, Florida in 2004, Joseph was unsure about which career he wanted to pursue, making college difficult without an end goal to strive towards. In 2006 he enlisted in the United States Army as an airborne Satellite Communications Operator and Maintainer. Staff Sergeant Stump received an honorable discharge from the Army in 2016 and has been using the Post 9/11 GI Bill to earn his degree since then. Thus far, he has completed an Associates in Arts in Engineering from Hillsborough Community College and is currently in his final year of obtaining his B.S. in Geology, with a minor in Geographical Information System Technology. Joseph is set to graduate in Summer 2020. Upon graduation, he would like to pursue a career studying/monitoring/managing Florida’s water resources and coastal habitats.

Methods: The article utilized data gathered from at least 60 published scientific papers and nearly 300 species of fossils (including calcisponge stromatoporoids, sponges, corals, trilobites, nautiloids, conodonts, brachiopods, radiolarians, and cyanobacteria (‘algae’)) within the Cliefden Caves area of New South Wales, Australia, with several of these being endemic (localized) to this area, to support its significance for preservation of global significance. The main threat to this area, and the need for the preservation, is the proposed construction of a dam, which would result in the flooding and destruction of valuable scientific lands and the fossils within it. 

Results: The fossils contained within the rocks of this area include the world’s oldest known brachiopod shell beds. Brachiopod shells are excellent zone fossils, meaning they can help reconstruct the environment by the shape of their shells. Brachiopods are generally zoned by sediment grain size relationships of their shell shapes; meaning, certain species of brachiopods seem to correlate with different sizes of grains (i.e., different environments). Also present are the earliest indisputable rugose corals found anywhere on Earth, an extinct type of coral. If the proposed dam construction is approved in this area, one of the most diverse deep-water sponge faunas ever recorded is in jeopardy of being destroyed and lost from the fossil record forever. The authors of this article all agree that, despite the significant research already done on the area by scientists, there is more to be discovered in the area that holds truths to the history of life on Earth.

A Belubula shell bed from Cliefden Caves; this specific type only occurs in this locality, so far as scientists know. These brachiopods are preserved mostly articulated (both shells together) and in situ (in place where they originally lived on the sediment). Scale bar is a Australian 50 cent coin (32mm diameter)

Why is this study important? This area is important to study due to its ability to better understand the Earth’s geologic and paleontological history. During the Ordovician, the oldest complete vertebrate fossils can be found, and this is where plant life began to migrate onto land, with animals soon to follow. It is also important to understand the climate of Earth during this time frame, as it exploded with diversity (i.e., the Ordovician Radiation), but it ended with what some consider the second largest extinction in Earth’s biological record. Some argue that this extinction was not ecologically major; however, the best way to understand these events and uncover the facts is to study the geologic and paleontological evidence left behind (where available). The issue with studying the geology/paleontology of the Ordovician is the lack of availability of fossil evidence relative to other periods. The end of the Ordovician is marked by glaciation. When a glaciation occurs, oceanic water regresses (moves away from land) and when the glaciers melt, the ocean transgresses (moves towards land). The problem is that these dynamic ocean conditions causes major erosion of any sediments/fossils deposited and often deletes them from the geologic record as an unconformity (“missing time” in a sample of sediments). The flooding that will result from constructing a dam in the region will have the same history erasing effects on the paleo environment as the ancient sea-level changes.

The Big Picture: Human population growth requires a higher demand on water and electricity; however, the current plans of placing a dam in the Cliefden Caves area of New South Wales will have significant negative impacts on the availability of current geologic and paleontological important rocks. A universal fact of life is that if history is not learned from, it is doomed to be repeated. Current global conditions are trending towards a climate that is uninhabitable by the human species. The significance of understanding these events is that measures could possibly be put into effect to mitigate or prevent global cataclysm of anthropogenic causation. Although geological and paleontological research does not often go synonymous with saving lives, the discoveries from their research can potentially impact the longevity of our species and others’.

Citation: Percival, I.G., Webby, B.D., and Burkitt, H. D. T. “Ordovician strata in the Cliefden Caves area, New South Wales: a case study in the preservation of a globally significant paleontological site.” Australian Journal of Earth Sciences, 2019. https://doi.org/10.1080/08120099.2019.1574271

 

Science Communication at The University of South Florida

Sarah here –

If you’ve been following Time Scavengers, you may have seen the paleo news posts that my students have written, which have been great! This post is a summary post about what I learned and what my students learned throughout the course of this project. I teach an upper- level class for geoscience majors at The University of South Florida called paleontology and stratigraphy. When I was designing what the course would look like, I tried to think about the skills I most wanted my students to have upon leaving. As most of my students in my classes won’t become paleontologists— they’ll go into a wide variety of science jobs— I wanted to find skills that will help them, no matter where they go. A lot of the things I want them to learn are already skills emphasized in a lot of college classes, including the ones I teach— critical thinking, evidence- based arguments, hypothesis testing, and other things. But one thing that I value a lot in science is the ability to communicate clearly with anyone, not just scientists. 

The talks, seminars, and papers that I see and read and resonate with most are those that are easily accessible. It’s hard to get engaged and get excited about a topic (even something in my field!) if I have to continuously stop and think about what the person might be trying to say— I think most people would probably feel the same. I wanted my students to practice explaining scientific concepts in a way that anyone who wanted to read it would understand, so that when they wrote papers, presented research talks, talked to future clients, or even chatted with people about their science in cabs or at family gatherings, they could remember how to break down complicated concepts in an effective way without removing the main points of the science. 

Example of the graphics made to showcase the USF Paleo/Strat student work. These were shared on the Time Scavengers social media channels.

Students chose a recently published paper of their own interest and wrote a draft of their summary. Then, they had a chance to learn a bit more about the peer review process scientists go through (check out more on how peer review and publishing works here) by trading drafts with a partner and reviewing their work for clarity, accuracy, and grammar. I made final suggestions as the editor. Finally, the posts were published on this site! You can read all of my excellent students’ work here: USF Paleo/Strat

Students really seemed to enjoy this project, so much so that I had an idea for this spring and summer: to get students involved in a long term project to develop their scientific communication skills. Over the next few months, you’ll start seeing posts from my students who are writing a series of blogs and paper summaries as they work to develop their scientific communication skills. If you haven’t yet had a chance to meet Kailey, Lisette, Baron, or Mckenna, check out their bios now! 

Examining the Morphology of Brachiopods to determine how the Late Ordovician Mass Extinction and Silurian Recovery affected long-term evolutionary trends

Effects of mass extinction and recovery dynamics on long-term evolutionary trends: a morphological study of Strophomenida (Brachiopoda) across the Late Ordovician mass extinction

by Judith A. Sclafani, Curtis R. Congreve, Andrew Z. Krug, and Mark E. Patzkowsky

Summarized by Soraya Alfred. Soraya Alfred is currently pursuing an undergraduate degree in Geology with a minor in Geographic Information Systems. She is a senior and intends to further her education by attending graduate school and then working in a Geology-related field. In her free time, she enjoys hanging out with friends and doing yoga.

What data were used? The distinct morphology of the shells of 61 species of Strophomenida (a type of extinct brachiopods) and 45 ancestor nodes, obtained from an evolutionary (phylogenetic) analysis.

Methods: Morphometric (shape differences) analysis was done through the use of principal coordinate analysis (PCO), which was used to plot the character data from the time- scaled phylogeny in morphospace. Morphospace is a type of graph used to represent the different morphologies of organisms, with different axes representing variables that define the characteristics of an organism. Twenty morphospace plots were made for the twenty set time-intervals between the early Ordovician and Devonian.

Results: When the morphospace at the time of the Ordovician mass extinction was examined, the data showed that the geometric center of the taxa that survived the extinction is similar to that of the genera that went extinct during the mass extinction. This implied that there were no specific morphologic characteristics that were targeted during the extinction event and, hence, was random. On the other hand, examination of the morphospace of the survivors of the Ordovician extinction, compared to the morphospace of the new genera that appeared in the Silurian showed that the center of mass shifted. This meant that the new taxa that emerged after the extinction filled a different region in morphospace, suggesting that origination was selective towards certain features. 

Figure showing the 20 morphospace plots for different time intervals. Members of Strophomenida occupy little morphospace in the lower Ordovician, but increase their area in morphospace during the Great Ordovician Biodiversification Event in the Darriwilian. After the mass extinction, new taxa that emerge in the Sillurian occupy the upper left half of morphospace which was previously unoccupied. The taxa that originated in the Devonian slowly become extinct into the Devonian.

Why is this study important? The Strophomenida order of brachiopods had a large geographic range, as well as a long geologic existence, making it ideal to study the repercussions of a mass extinction. As such, the results of this study can be applied to different lineages that were affected during the extinction in order to see how such events affect evolutionary history.

The big picture: Due to the fact that extinction happened randomly to taxa, a large amount of phylogenetic diversity was maintained, which made it possible for a great amount of diversification during the Silurian recovery. This diversification, however, resulted in less variability of morphology, which caused a morphological bottleneck. It is not possible to tell whether these changes were advantageous in an evolutionary sense or not, and so more has to be done to examine the true ecological effect of the Ordovician mass extinction. It was only through the examination of the characteristics of both the extinction and recovery period that we can begin to fully understand the evolutionary history of Strophomenida and similar patterns in other invertebrate taxa point to understand if this pattern was isolated or happened across multiple groups.

Citation: Sclafani, J. A., Congreve, C. R., Krug, A. Z., & Patzkowsky, M. E. (2018). Effects of mass extinction and recovery dynamics on long-term evolutionary trends: A morphological study of strophomenida (brachiopoda) across the late ordovician mass extinction. Paleobiology, 44(4), 603. Retrieved from http://ezproxy.lib.usf.edu/login?url=http://search.ebscohost.com/login.aspx?direct=true&db=edo&AN=133394289&site=eds-live

Ecological impacts of mass extinctions with data from the fossil record

Quantifying ecological impacts of mass extinctions with network analysis of fossil communities

By A. D. Muscente, Anirudh Prabhu, Hao Zhong, Ahmed Eleish, Michael B. Meyer, Peter Fox, Robert M. Hazen, and Andrew H. Knoll

Summarized by: Paul Ward. Paul Ward is a geology major at the University of South Florida. Currently, he is a senior. Once he earns his degree, he plans on taking the GIT and plans to work in the hydrology field. When he is not working on geology, he likes to go fossil hunting and cook.

What data were used: Data were collected using the Paleobiology Database on fossil occurrences, taxonomy, and diversity across mass extinction events through geologic time 

Methods: Using network theory (essentially, it means we treat fossil occurrences as complex and interconnected-like how many fossils interacted together in paleoecosystems) and the Paleontological database of fossil occurrence, taxonomy, and diversity over time, they compiled all of this data to show co-occurrence of fossils with a custom application that was made in python, a coding language. The results were then analyzed in RStudio.

Results: The data that was acquired during the project was compiled to create a record of fossilized species from the paleontological database to determine how communities are affected by ecological change. Using this dataset, it was shown how communities rise and fall during a mass extinction event (figure 1). The data that was acquired also shows the different severities on ecology of each extinction: for example, the Permo-Triassic extinction had an extremely severe negative impact on ecology, whereas other extinctions were not nearly as severe. Through the data it was also observed that the Devonian extinction importance was underestimated in the severity of the event. The data showed that it is close in severity to the K-Pg extinction event where it was previously a whole rank lower than observed in this study.

This diagram depicts the amount of diversity through geologic time; note the five mass extinctions and how they affected diversity differently. This graph is showing the “total swing” in diversity- the larger the peak, the more effect that it had on biodiversity.

Why is this study important: The significance of the data that was compiled shows us how the different taxa react to the severity of the extinction event and the selectivity that an event may have affected different communities compared to others. The data can also show us how these different extinctions affect ecological variation when compared (e.g., the Permo-Triassic had a negative impact on reef-building organisms, which when they go extinct, causes a significant ecological collapse). 

The big picture: This data analysis is important for the larger paleobiology community, due to the ability to show trends that occurred in the different geologic ages. With this, what is known about the causes of previous extinction events can show how different species react to different adverse conditions. With the example of coral ecology, we can better estimate how Earth’s ecosystems will react to climate conditions today from anthropogenic influences. 

Citation: Muscente, A. D., Prabhu, A., Zhong, H., Eleish, A., Meyer, M. B., Fox, P., Hazen, R., Knoll, A. (2018). Quantifying ecological impacts of mass extinctions with network analysis of fossil communities. Proceedings of the National Academy of Sciences of the United States, (20), 5217. https://doi-org.ezproxy.lib.usf.edu/10.1073/pnas.1719976115

A Brief Overview of Findings in the Newly Exposed Day Nunatak Region of Antarctica

Stratigraphy, sedimentology and paleontology of Upper Cretaceous deposits of Day Nunatak, Snow Hill Island, Antarctica

By Thomas S. Tobin, David Flannery, and Francis J. Sousac

Summarized by Michael de Koter. 

What type of data were used? Newly exposed outcrop on Day Nunatak, a region of sedimentary rock in Snow Hill Island of Antarctica, which was previously inaccessible to the sediments and fossils in the area. Most of these fossils were collected from off the ground, but where possible, they were extracted from in situ (in place). Aerial photography allowed for three-dimensional reconstruction of the area to track glacial ice movement. Hand samples collected in the field underwent petrological and SEM (scanning electron microscope) analysis to determine composition and characteristics.

Methods: Helicopters were used to access the field site where samples were collected by hand from trenches and outcrops. Structure by motion models were also created using data gathered by helicopters equipped to carry out three dimensional analysis. XRD (X-ray diffraction) analysis, petrological analyses via light and electron microscopy, and stable isotope analyses were carried out to learn more about the samples collected from Day Nunatak. 

Results: Overall, the fossils and sediments found and tested in the newly exposed outcrops of Day Nunatak are very similar to samples found in previous studies done on nearby Seymour Island of Antarctica. However, the mode of fossil preservation is variable across these outcrops, with fossils being more prevalent and found in pale concretions in Day Nunatak. For the majority of Snow Hill Island, reddish concretions around fossils are more common, though they occur in a lower frequency. No new species were discovered amongst the fossils in the newly exposed area of Day Nunatak. There was an abundance of Gunnarites collected to represent ammonite fossils from the area. Furthermore, there were no new species of mollusks or other types of fossils identified in the samples collected. Most of the sediments of the Day Nunatak sight are composed of quartz-rich sandy-siltstone that play host to carbonate concretions and well-cemented sandstone.

Satellite imagery taken of the Day Nunatak sight in reference to the larger region of Snow Hill Island. From these pictures, it is clearly seen that the exposed section of rock at Day Nunatak has been steadily growing in area over the last fifty years, with the largest exposed area occurring at the date nearest to the present day.

Why is this study important? The study of newly exposed segments of Antarctician stratigraphy allows for a more comprehensive geological history of the region to be created. Fossils and sediments found in the area- especially those that match other nearby regions of Antarctica- provide a wider range of evidence to link identical beds in different geographical areas together more thoroughly and, in so doing, provide a more comprehensive understanding of the region and its history.

The Big Picture: As more of the glacial ice in Antarctica is melting away as a result of global temperature rise, areas previously inaccessible to geologists for study will become more and more available to study. These changes in the observable regions of the continent will allow for stratigraphically relationships to paint a larger picture of the geologic history of the area. This study is one of the first of such that will be possible as glacial ice continues to recede. Thus far, the data demonstrates regional trends in biostratigraphy that are traceable across much of the larger area surrounding Day Nunatak, which helps to paint a more accurate cross section than was available even ten years ago.

Citation: Tobin, T.S., Flannery, D. and Sousa, F.J., 2018. Stratigraphy, sedimentology and paleontology of Upper Cretaceous deposits of Day Nunatak, Snow Hill Island, Antarctica. Cretaceous Research84, pp.407-419.

Drastic variation of cetacean (whale) fossils during the Neogene and Early Quaternary Periods

Stratigraphic Paleobiology of an Evolutionary Radiation: Taphonomy and Facies Distribution of Cetaceans in the last 23 Million Years

Stefano Dominici, Simone Cau and Alessandro Freschi

Summarized by Laura Martins. Laura Martins is a senior geology student at The University of South Florida. She plans to attend a Master program in Geophysics in the spring semester of 2021 out west. She dreams to work in seismological networking. She mostly spends the free days with her son and husband in different adventures such as visiting national parks, springs, Disney, and road trips!

What data were used? The study surveyed over 255 published  papers associated with Neogene (~23-2 million years ago) cetacean (whales, dolphins, porpoises) fossils within a global context (excluding ones found in Southern America, due to a lack of fossil evidence)

Methods: All individual specimens found in the survey were sorted and classified by facies (rock type that represents certain environments) and time intervals (Miocene to Pleistocene Epochs) of deposition. The research also included the number and the preservation quality of bones per skeleton of each example. Even though South American fossils were predicted to have high quality preservation setting due to its hypoxic/anoxic depositional environments, it was set apart because of its lack of even distribution during the Neogene. The study collected a total of 255 specimens with absolute age data and 117 specimens with sedimentary facies data.

Results: The collected data was plotted in two graphs; the first represents the distribution of fossil over time intervals and the second shows the relation between facies (environments) vs time. These illustrations indicate a slight increase of cetacean fossils during the Miocene, followed by a vast increase during the Pliocene. However, by the early Pleistocene, the number of fossils dropped significantly. Consequently, the study conveyed that the highest abundance of cetacean fossils were collected in offshore marine mudstones and sandstones facies, whereas the lowest amount was related to shoreface sandstone facies. It implies that very shallow and very deep waters are not the greatest environments for preservation of these fossils. The study found that offshore mudstone and delta sandstone facies have the highest amount of bones per skeleton, suggesting that these facies are good preservation sites for cetaceans, due to high rates of sedimentation (deltas) and low-pressure settings (offshore) that would minimize decay and scavenging of the organisms. Finally, the research suggests that the remarkable drop off of cetacean fossils in the early Pleistocene might be affected by taphonomy factors (meaning, taphonomy might be making the drop in diversity more severe than it actually was). 

A, Distribution of amount of cetacean’s fossils (%) in a time interval. B, Distribution of amount of cetacean’s fossil (%) over different facies.

Why is this study important? Cetaceans are the largest living marine animals that have ever lived. Through their fossil record, we can understand how their modern and extinct diversity and be explained by variations in taphonomy, taxonomy, loss of habitat, environment, climate and even massive extinction events. The study of this variation on the fossil record allows for the analysis of decay, preservation and environment settings of these large mammals, as well as the relationship of cetaceans with ecosystem changes, enabling the construction of evolutionary pattern trends.

The big picture: The study suggests that the peaks with the highest amount of cetacean fossils during late Miocene and Pliocene are correlated with an optimum climate. The vast drop of fossil localities during the late Pliocene accords with an extinction age. However, it is necessary to highlight that all of the evidence might be affected by taphonomy factors, such as scavengers contributing to loss of tissue and disarticulation.

Citation: Dominici et al. (2018). Stratigraphic paleobiology of an evolutionary radiation: taphonomy and facies distribution of cetaceans in the last 23 million years. Fossilia, Volume 2018: 15-17. https://doi.org/10.32774/FosRep-Pal.20.1810.051517