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

New Species of Bryozoa discovered in Lake Valley Formation

Bryozoan Fauna of the Lake Valley Formation (Mississippian), New Mexico

By: Andrej Ernst, Karl Krainer, Spencer G. Lucas

Summarized by: Johnathan Cook. Johnathan Cook is a fourth-year undergraduate at the University of South Florida. He spent most of his life involved in missionary work overseas in Argentina. After graduating from an Argentine high school, he returned to the United States to receive his Associates Degree from Hillsborough Community College before transferring the University of South Florida. He is set to graduate in December of 2019 and plans to pursue a career in hydrogeology and water management.

What data were used? Bryozoans (aquatic colonial organisms that survived by filtering nutrients from the water they live in) that had been overlooked in previous studies of the Mississippian-age Lake Valley Formation were re-examined by researchers. They also took a fresh look at the environment they were found in to help gain a better understanding of past climate and how the environment has changed through time. Researchers also looked at the type of sediment and the size of the grains to determine the prevalent geologic processes at the time of its deposition.

Methods: The researchers examined the layers (also called members) of the Lake Valley Formation, noting sedimentary structures and characteristics. Bryozoans specimens were made into thin sections and studied through binocular microscopes to determine the genus and species of each specimen found (which is the only accurate way to determine bryozoan taxonomy).

Results: The study of this area found there to be ten species of Bryozoa in the rock record, one of which had been previously overlooked. The studied samples were taken from two members of the formation and indicate changes in the environment. The older layer, named the Andrecito Member, showed deep marine conditions which were quiet and calm, while the younger layer, named the Tierra Blanca Member, showed shallower conditions with higher energy. The characteristics of these two members are good indicators of environmental conditions present during their creation. The deep conditions of the Andrecito member suggest transgression (meaning sea level was high or rising) and the shallow conditions of the Tierra Blanca suggest regression or sea level falling. The species found in these environments demonstrated physical characteristics in support of this hypothesis. Bryozoans in the calmer environment had thinner branches, whereas those in higher energy were thicker.

A main tool used to help determine the genus and species was
measuring the spacing between structures-the zoaria (individual animals in a single colony) in the bryozoan fossil specimens. This was done under the microscope, as these measurements are quite small.

Why is this study important? This study shows further diversification of a fossil type thought to be well understood, as well as the importance of understanding the stratigraphy in combination with fossils to construct a picture of the processes that formed our continent. These specific species are endemic to North America and can give us an idea of the evolution of climate and its effect on North American rocks.

The Big Picture: The discovery of the diverse fossils along with the sedimentary layers provides a reminder that science is not infallible but often misses details that can alter our understanding or hypotheses of past life. How creatures adapt says a lot about the environment they inhabited and with every new data, we can create a clear and more accurate picture of the past. It is important to remember that a hypothesis is not set in stone but can be edited or even disproved as more data are collected.

Citation: Andrej Ernst, Karl Krainer, Spencer G Lucas. Bryozoan Fauna of the Lake Valley Formation (Mississippian), New Mexico. Journal of Paleontology, 92(4), 2018, p. 577–595.

Understanding and Dating Primate Fossils

100 years of primate paleontology 

By: Richard F. Kay 

Summarized by Ethan Schimpf. Ethan Schimpf is a geology major at USF. He graduates in December of 2019. Upon graduation, he plans to move to Idaho and get a job in the mining field. During his free time he like hunting, fishing, and working on cars.

What data were used? 336 different primate species have been identified through the discovery of fossils as of 2017. Most of these fossils are found in North America and consists of jaws and teeth. 

Methods: This study used amino acid traces left in the fossils to date major changes in primate evolution, like when the split between New World Monkeys and Old World Monkeys occurred and when the split between humans and chimpanzees likely happened. 

Results: Some major traits used to differentiate the two major types (New and Old World) were the shape of the skull and the ability to walk on two legs. This major split occurred around 30 million years ago. With the advancement of technology over the past 100 years, humans are able to study fossils on the molecular and genetic level. The fossils are analyzed for changes in amino acid chains. This allows them to see the evolution of the DNA itself over time. Being able to witness this enables a more accurate timing to be assigned to major changes in primate evolution. In using this process, it was discovered that chimpanzees and humans shared a common ancestor about 5 million years ago. It was also discovered that the genetic molecular evolution rate would slow down as the species grew to a larger body mass as well as a larger brain size.

This graph shows the increase of fossils found within the last 100 years, starting with the first to be described, Adapsis, in 1821. With the abundance of fossils that have been found, scientists have been able to learn a lot more about the evolutionary history of the group that includes humans.

Why is this study important? Over the last 100 years the number of primate fossils being discovered has increased dramatically. The amount of primate fossils is still very low compared to other organisms and the quality of fossils is low. When putting together the evolution of primates through the fossil record, a major distinction was made between Old World Monkeys and New World Monkeys. The New World monkeys consist of shrew and lemur type primates, while the Old world Monkeys included groups like gorillas and chimpanzees. A later a common ancestor was found between humans and chimpanzees. This study allows us to date when major splits occurred during primate evolution. Through the examination of primate fossils major distinctions between common ancestor could be discovered and dated.

The big picture: The geographical distribution of different primates is thought to be due to the changes in sea level over time. At times of low sea level, land bridges formed and allowed primates to travel to different land masses. Then, when the sea levels rose,  primates became stuck in certain areas or separated from other populations of species. The timing of major primate evolution can be dated to similar times of higher seas when species were forced to remain in a particular area. This forced isolation resulted in the gain and loss of traits and, ultimately, new species forming. When dating the different primate fossils, changes in the DNA can be linked to major environment changes due to Earth’s changing climate.

Citation: Kay, Richard F. 100 years of primate paleontology. American journal of physical anthropology 165.4 (2018): 652-676.

Complex Relationships of Pararotadiscus guishouensis in Life and Death

Paleoecological Significance of Complex Fossil Associations of the Eldonioid Pararotadiscus guishouensis with other Faunal Members of the Kaili Biota (Stage 5, Cambrian, South China)

by: Yuanlong Zhao, Mingkun Wang, Steven T. LoDuca, Xinglian Yang, Yuning Yang, Yujuan Liu, and Xin Cheng

Summarized by: Dinah Hunsicker. Dinah Hunsicker is currently an undergraduate senior studying Geology at the University of South Florida.  She will earn her Bachelor’s degree at the end of 2019. She has a passion for science, music, mathematics, and spends much of her time outdoors. She loves to garden and paint, and absolutely loves collecting cool rocks and minerals! (Favorite mineral: azurite).

What data were used? 628 collected fossil specimens from the Kaili Formation, Guizhou Province, South China preserved in association with the Pararotadiscus guishouensis, an organism that has a high likelihood to have shared symbiotic relationships with other groups. P. guishouensis is an eldonid, a medusoid (e.g., like jellyfish) -shaped organism that scientists aren’t entirely sure what groups it belongs to. 

Methods: Associated fossils were classified into 4 types of relationships with P. guishouensis  (symbiosis (interacting with one another), co-burial, attachment of benthic taxa on P. guishouensis carcasses, and scavenging of carcasses after death.

The figure above shows a variety of organisms preserved in the fossil record showing different types of symbiotic relationships with Pararotadiscus guizhouensis. Parts 5 and 6 show the symbiotic relationships between this fossil and brachiopods and how many brachiopods could be found in association on one organism.

Results: I have broken this into the 4 sections defined above. Symbiotic Relationship: brachiopods, trilobites, and juvenile echinoderms in this area were found to have symbiotic relationships with Pararotadiscus guishouensis (P. g.). Benthic (lived on the seafloor): organisms latched onto P. guishouensis, taking advantage of the calmer water current, giving them an opportunity to expand their ecological niche. Co-burial: it makes sense that since many of the previously mentioned critters latch on to P. g, they’ve committed to life and death with their host. Additionally, a variety of fragmented and partial fossils (bits and pieces of trilobites, brachiopods, echinoderms and algae) buried around the same time are also associated with P. guishouensis. Post-Mortem Attachment: the carcass of P. guishouensis was an oasis of solid mass on the soft-sediment seafloor, leading to a multitude of species taking up life habits on the carcasses of P. guishouensis, including colonization by echinoderms. Post-Mortem Scavenging: Among the 628 specimens, 24% are preserved with squiggling traces of surface scavenging, associated with worm-like creatures called Gordia marina. No evidence of any other type of scavenging relationship has been detected.

Why is this study important? This study contributes to the growing body of evidence that the ecology of the Cambrian biosphere was more intricate and complex than previously suspected; originally, scientists assumed the Cambrian had a general lack of ecological diversity. Insights relating to organismal interactions during the Cambrian can help us further our understanding about the inter-complexities of life on this planet through a broad lens of time.

The big picture: This well-preserved group of organisms, such such as brachiopods, trilobites, echinoderms, and a type of ancient sea worm co-habituated and had multi-layered, complex biotic relationships with Pararotadiscus guishouensis at the site of the Kaili Formation in China, giving us insight into the lives of these ancient sea critters, contributing to our conceptions and understandings about Cambrian life.

Citation: Zhao, Y., Wang, M., LoDuca, S., Yang, X., Yang, Y., Liu, Y., & Cheng, X. (2018). Paleoecological Significance of Complex Fossil Associations of the Eldonioid Pararotadiscus guizhouensis with other Faunal Members of the Kaili Biota (Stage 5, Cambrian, South China). Journal of Paleontology, 92(6), 972-981. https://doi.org/10.1017/jpa.2018.41

Understanding the Permian-Triassic transition with fossil data before and after the mass extinction event

Environmental instability prior to end-Permian mass extinction reflected in biotic and facies changes on shallow carbonate platforms of the Nanpanjiang Basin (South China) 

Li Tian, Jinnan Tong, Yifan Xiao, Michael J. Benton, Huyue Song, Haijun Song, Lei Liang, Kui Wu, Daoliang Chu, Thomas J. Algeo

Summarized by: Baron C. Hoffmeister. Baron Hoffmeister is currently an undergraduate senior at the University of South Florida pursuing a degree in Environmental Science and Policy with a minor in Geology. After graduation, he plans to attend a graduate program for environmental management. When graduate school is complete, he plans on working for the National Parks services. Baron is apart of the geology club as well as the fishing club and spends his free time hiking, fishing, and socializing with friends.

What data were used? Fossil taxa found in Southern China carbonate platforms that date back to the Permian-Triassic extinction event, ~251 million years ago. This data sheds light on the mass extinction event that spans the Paleozoic and Mesozoic Eras. 

Methods: Analytical evaluation of fossils present from three separate stratigraphic areas across South China, from before, during, and after the Permo-Triassic extinction event. 

Results: In this study, the fossil data evaluated at each site led to the discovery of common trends. Each formation had similar fossil accumulations, even though the formation would have been located a far distance apart. This means that each location was affected similarly  by the same event for the accumulation of similar fossils to appear in the corresponding strata. This is hypothesized to be the late Permian mass extinction. Another similarity between the three areas was that each section had a foraminifera gap between strata boundaries. At the same time, each boundary represented a different aspect of a shallow marine environment. For example, the Wennga Formation had strata before the extinction boundary that was littered with Permian fauna fossils that occurred in shallow marine environments. Post-extinction boundary strata didn’t possess these fossils. This is another indication of the severity of the mass extinction event. The Taiping section had different types of rock formations with different compositions; the transition of the rock from before the extinction to after showed a rapid die-off of organisms living in this area. Finally, in the Lung Cam section, there were fewer fossils than the other two (most likely due to poor fossil preservation conditions); however, the fossils that were found resembled those in the other sections studied. Further, the Lung Cam section had foram gaps consistent with the other sections.

Skeletal composition within strata at each study section. The three sections had similar organisms preserved in each and even showed similar gaps in fossil occurrences, indicating where the extinction event happened.

Why is this study important? This study strengthens what we know about the Permian-Triassic transition. These fossils, across multiple areas, were present in a shallow marine environment and were greatly affected by environmental instability during this time. The strata at each location, Wengna, Taiping, and Lung Cam, are remnants from the fatal conditions in the marine environment at this time. This can better help us understand and conceive how shallow marine organisms could be affected today during climate change. 

The big picture: This study shows the significant changes in fossils from  before and after the largest extinction event in Earth’s history. There is consistent evidence within and between each section studied, indicating a widespread event that negatively affected shallow marine life during this time.

Citation: Tian, Li, Jinnan Tong, Yifan Xiao, Michael J. Benton, Huyue Song, Haijun Song, Lei Liang, Kui Wu, Daoliang Chu, and Thomas J. Algeo. “Environmental instability prior to end-Permian mass extinction reflected in biotic and facies changes on shallow carbonate platforms of the Nanpanjiang Basin (South China).” Palaeogeography, Palaeoclimatology, Palaeoecology 519 (2019): 23-36. DOI: 10.1016/j.palaeo.2018.05.011