Climate & Paleo News

Here we will dissect recent publications in the fields of climate and evolution. Our goal is to provide a logical narrative while also picking out the data and importance of each study.

Newly discovered fossil frogs shed light on the Amazonian environment 10 million years ago

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Fossil Frogs from The Upper Miocene of Southwestern Brazilian Amazonia (Solimões Formation, Acre Basin)

Fellipe P. Muniz, Marcos César Bissaro-Júnior, Edson Guilherme, Jonas P. De Souza-Filho, Francisco R. Negri, and Annie S. Hsiou

Summarized by Ryan Taylor. Ryan lives in Clearwater, Florida, and is a student at the University of South Florida (USF) who is currently seeking a B.Sc. in geology. He also works as an assistant engineer for a civil engineering company in Tampa, Florida. One of Ryan’s favorite activities is going garage sale hunting every Saturday morning.

What was the goal of the paper? This study used newly discovered frog fossils, from the genus Pipa and Rhinella, from the southern Amazon to gain a greater understanding of what the biodiversity and the environment of the southern Amazon was like in the Late Miocene (6 to 11 million years ago). Scientists accomplished this by comparing the differences in the structure of the newly discovered Pipa and Rhinella to modern-day frogs of the same genus (a taxonomic rank above species).

What data were used?  Scientists used the bones of the frogs that were found at the Talismã site in the southern Amazonas of Brazil. These bones included the frogs’ ilium and ischium (hip bones), humeri (front legs), and other parts of the frogs’ skeletal structure. This fossil data was compared with data collected from previous studies for small, fossilized animals found in the same region. The researchers also collected samples of the bones of frogs that live in that area today to compare the differences in the structure against the fossil frogs that were found.

Methods:  The researchers recovered multiple samples of frog bones that were in the southern Amazonas region of Brazil by examining an exposed section of sediment layers (Fig. 1). Next, they identified differences in the bone structures of the fossil frogs as compared with the same species of living frogs that are found in the same area today. Using this data of the differences in bone structures, researchers performed an evolutionary tree analysis of the frogs they found to how they were related to other frogs alive today. This tree allows the researchers to see how the frog diversity changed over time to what we have today. They compared the bone structures of the newly found fossils to frogs known to be living there in the late Miocene supporting that the new frog fossils used to live there at that time too.

This figure shows a map of Brazil and focuses on a part of Brazil in the southwestern Amazon with the location of the fossil excavation and some of the rivers that are in the area. There is also a representation of a 5.3-meter-tall cross-section that was in the ground. This cross-section showed the clay/mud layers and the different types of fossils found in them. Reptiles were found between 1.12 and 0.68 meters deep. Fish, anurans (frogs), mammals, reptiles, and crustaceans (crabs) were found between 2.15 and 2.34 meters deep. More crustaceans were found between 2.34 and 4.89 meters deep.
Figure 1 shows the area where the samples of the new frog species were found. The layer in which the bones were found is helpful in finding the approximate age of the frog bones because each layer down from the top represents an older time in geologic history. The anurans (frogs) were found between 2.15 and 2.34 meters deep. Other animals that were found include: crustaceans, fish, mammals, and reptiles which all lived in the same time period the frogs lived.

Results: The researchers found two frog taxa here belonging to the genera Pipa and Rhinella. The results of this study showed that a diversity of frogs in genus Pipa lived in the southern Amazonas region. The Pipa fossils that were found are some of the oldest for the genus which supports a previous study that was done in Venezuela, showing Pipa also lived there in the late Miocene. The discovery of Pipa in the southern Amazonas gives an idea as to what type of environment this region had. Pipa is only known to live in aquatic environments near stagnate waters like lakes and swamps, showing that this is likely the type of environment that existed here in the late Miocene. Frogs in the genus Rhinella are not very dependent on aquatic environments and can live in a broader variety of habitats, but their tadpoles are dependent on a nearby water body. This study also found a possible new species of frog belonging to the genus Rhinella that also lived in the area. There are differences in the pelvis of the fossil Rhinella compared to today’s frogs, indicating that they are different species.

Why is this study important? This study is important because it showed what type of environment the southern Amazonas had in the late Miocene. They were able to see that the Amazonia used to have more lakes and was possibly less tropical, as compared to its modern-day rainforest environment. This study also added clarity to the evolutionary history of when these types of frogs may have evolved.

Broader Implications beyond this study: Any land species, like frogs, are not commonly preserved in the fossil record.  When these rarer fossils are found, they offer massive contributions to the scientific community.  

Citation: Muniz, F. P., Bissaro-Júnior, M. C., Guilherme, E., Souza-Filho, J. P., Negri, F. R., & Hsiou, A. S. (2022). Fossil Frogs from the Upper Miocene of southwestern Brazilian Amazonia (Solimões Formation, acre basin). Journal of Vertebrate Paleontology, 41(6). https://doi.org/10.1080/02724634.2021.2089853

Finding traces of food and guts in 588 million years old Ediacaran-type critters

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Guts, gut contents, and feeding strategies of Ediacaran animals.

Summarized by Nilmani Perera, a graduate student in the PhD program at the Geological Sciences program at the University of South Florida. She’s studying evolutionary patterns of Paleozoic (542–251 million years ago) echinoderms with Dr. Sarah Sheffield. She’s also interested in looking into their paleoecology and how it could have played a role in their diversification during this time. 

What was the hypothesis being tested (if no hypothesis, what was the question or point of the paper)?  This study focuses on understanding how Ediacaran animals fed, using three 558-million-year-old fossils from the White Sea area in Russia.

What data were used? Three different fossilized animals were used in this study; Kimberella, Calyptrina and Dickinsonia; Figure1). Rocks containing fossils and surrounding sediment from White Sea area in Russia were analyzed for the presence of fat molecules (lipid biomarkers) that came from their diet.

Methods: Fossils  and sediment collected in the field were prepared and then analyzed using Gas chromatography–mass spectrometry (GC-MS). This is a method used to separate components in a mixture at very fine level, basically at the molecular level. Fat particles in the samples were separated based on their differences in chemistry. Researchers looked for the presence of specific combination of lipid molecules in these samples, which can indicate the origin of the molecules. Comparing the ratios of the different types of molecules allowed them to figure out whether the signal came from the actual organisms or from the surrounding rock. This also allowed researchers to determine if the organism had a digestive tract (also referred to as gut) inside its body

Results: There were several significant findings that came out of this study. First, researchers discovered that the lipid breakdown process in Kimberella and Calyptrina is the same as in modern invertebrates, such as mollusks (like clams) and worms. Secondly, they were able to point out that Kimberella grazed on microbial mats and Calyptrina fed on particles in the sea water or in the marine sediment, like modern day tube worms would do. Thirdly, it was shown that both these organisms had a gut in which their food was digested. Interestingly, none of the specimens of Dickinsonia studied indicated that they possessed a gut, so they either took in food particles by osmosis (where particles move across a membrane) or could have possessed an external digestive system in which they secreted enzymes into the environment to breakdown food and then absorb it through their body. 

The figure contains three Ediacaran animals preserved in rock as fossilized impressions. A. The first figure is of Kimberella, preserved in a light gray color rock and is roughly half an inch long. It is pear-shaped, flat and has a couple of layers to it. B. The second figure is of Dickinsonia, preserved in a light brown color rock. It is leaf-like with ridges radiating from a central axis and about 3.5 inches along its length. C. The third figure is of Calyptrina, preserved on the surface of a beige color rock. It is flat, long, and worm-like with some dark color patches along its length.
Figure 1; Ediacaran fossils used in this study. A. Kimberella, B. Dickinsonia, C, Calyptrina (Scale bar used in Figures A, 5mm; B, 10mm and C, 5mm)

Why is this study important? The findings of this study are important because there’s a lot of research going on to understand how earliest animals evolved and how similar they were to animals we see today. Ediacaran- age animals represent an important turning point in the study of how animal bodies came about and how similar they are to major animal groups we see today. In this study, the lipid molecules preserved with the fossils  allowed researchers to compare them to modern animals with similar life modes. 

Broader Implications beyond this study: This method of biomarker identification can be applied to learn more about the trophic structure in ecosystems that are hundreds of millions of years old. The beauty of it is that this method can be used even when the gut is not preserved, because the method is only using the lipid molecules derived from the diet. 

Citation: Bobrovskiy, I., Nagovitsyn, A., Hope, J.M., Luzhnaya, E., & Brocks,J.J.,  (2022). Guts, gut contents, and feeding strategies of Ediacaran animals. Current Biology, 32, 5382–5389. https://doi.org/10.1016/j.cub.2022.10.051

Using Shark Teeth to Compare Past and Present Shark Populations Along the Southern Coast of Brazil

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Quaternary fossil shark (Neoselachii: Galeomorphii and Squalomorphii) diversity from southern Brazil

Sheron Medeiros, Maria Cristina Oddone, Heitor Francischini, Débora Diniz, Paula Dentzien-Dias

Summarized by Max Raynor, a 4th year undergraduate student pursuing a bachelor’s degree in geology from the University of South Florida. Max currently works for a surveying company in Tampa, where he focuses on making digital maps of the Earth’s surface and ocean floor.  When he isn’t studying geology or working, he enjoys fishing, collecting and curating vintage clothing, and playing tennis.

What was the hypothesis being tested? Scientists used fossil shark teeth to quantify differences between shark populations throughout the Quaternary Period (the past 2.58 million years of Earth’s history). The shark teeth used for this study were collected along the beaches of the Rio Grande do Sul Coastal Plain (RSCP), which extends along Brazil’s southernmost shorelines. Scientists compared and contrasted structural differences between shark teeth to test hypotheses on changing climate conditions throughout the Quaternary and how changes over time affected shark populations along the Rio Grande do Sul. 

What data were used? The data collected in this study included 3,611 shark teeth that had been found on the beaches of the RSCP since 1996. Using the simple technique of manually collecting shark teeth from the beach, researchers were able to find a variety of species to use for this study.

Methods: Participating in a well-documented data collection process known as “beachcombing”, researchers scanned the exposed beach area and picked out shark teeth by hand. The gravelly nature of beach grains, as well as the less-than-perfect condition of many of the teeth found, made it increasingly difficult to find desirable samples over time. The collected teeth were subsequently sent to a laboratory where they were sorted and classified by species. A classified tooth would be analyzed from two different views: where a tooth was adjacent to the tongue (lingual), and where a tooth was adjacent to the inside of the mouth (labial). The characteristics of a tooth from these angles provide the information necessary to correctly identify the corresponding shark species.

Results: By observing the characteristics of the teeth sampled, scientists identified 3,611 teeth belonging to13 different species of shark in the dataset (Fig. 1). While about ¾ of the data were able to be identified to the species, some were only able to be identified to the genus, and some teeth were rendered unidentifiable due to physical alterations and erosion over time. The order Lamniformes represented just 3 of the 13 taxa identified, but was responsible for 2,390 teeth sampled, or 66.18% of the dataset. Carcharius taurus, commonly known as the sand tiger shark and belonging to Lamniformes, was the most abundant species overall with 2,027 identified teeth. With respect to species diversity, the majority of the diversity belonged to the shark order Carcharhiniformes, which represented 8 of the 13 species identified. Carcharhinus leucas, also known as the bull shark, was the most abundant species of the Carcharhiniformes with 191 teeth sampled. 11of the 13 species identified are still found in the region, indicating that the shark community and climate conditions of the RSCP throughout the Quaternary have been fairly similar over the past 2.58 million years.

Figure A: Pie chart of shark orders sampled, from highest to lowest percentage of teeth found per order: Lamniformes (2,390 teeth), Carcharhiniformes (821 teeth), Hexanchiformes (10 teeth), Squatiniformes (2 teeth), and 388 teeth that were unable to be identified to the species.Figure B: Pie chart of the number of teeth sampled from each species, from most teeth found per species to least: Carcharius taurus (2,027 teeth), Carcharadon carcharias (283 teeth), Carcharhinus leucas (193 teeth), Carcharhinus brachyurus (90 teeth), Isurus oxyrinchus (80 teeth), Sphyma (51 teeth), Carcharhinus longimanus (21 teeth), Galeocerdo cuvier (18 teeth), Notorynchus cepedianus (10 teeth), Galeorhinus galeus (3 teeth), Squatina (2 teeth), and Rhizoprionodon (1 tooth). There were 444 Carcharhinus teeth that could not be identified to a species, as well as 388 unidentified teeth.
Pie charts depicting (A) The orders of shark represented by teeth collected in this study and the number of samples belonging to each (B) The species of shark represented by the amount of teeth identified per species in this study.

Why is this study important: The diversity of shark species along the RSCP is important to note because it supports hypotheses posed in other studies that climate conditions have changed little throughout the Quaternary in this region. The two species found in the study that are not current residents of the RSCP, Carcharodon carcharias (Great White Shark) and Carcharhinus longimanus (Oceanic Whitetip Shark) are noteworthy, because they live in open oceanic environments today and are rarely found in the coastal RSCP, The presence of oceanic sharks such as these indicate higher sea levels along the RSCP at times throughout the Quaternary Period compared to present day. Periods of cooler and warmer weather were drivers of changes in sea level and climate changes throughout the Quaternary, resulting in periodic occurrences of shark species that migrated from both warmer and colder waters.

Broader Implications Findings from this study will allow paleontologists and biologists alike to assess how coastal and oceanic shark populations respond to a changing climate and marine ecosystem. Further research on this using different methods than beachcombing could potentially identify different results, as beachcombing can sometimes favor the collection of larger teeth, as it ismore obvious it is to the eye of the collector. Bulk collecting, collecting sediment and sorting it in the lab, may capture different results, but this will require future research. 

Citation: Medeiros, S., Oddone, M. C., Francischini, H., Diniz, D., & Dentzien-Dias, P. (2023). Quaternary fossil shark (Neoselachii: Galeomorphii and Squalomorphii) diversity from Southern Brazil. Journal of South American Earth Sciences, 122, 104176. https://doi.org/10.1016/j.jsames.2022.104176 

Cambrian and Ordovician Trilobite Injuries

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New records of injured Cambrian and Ordovician trilobites

Summarized by Matthew Gaborik, an undergraduate student studying geology at the University of South Florida. He will be graduating with the class of 2023. After his undergraduate program, he plans to gain some experience and return to school for a Master’s program. When he’s not studying geology, he likes to play mechanic, kayak, and hike.

What was the point of the paper? The point of the paper was to present new findings on select abnormal (injured or malformed) trilobite fossils in order to expand the record of abnormal trilobite fossils and obtain a clearer understanding of trilobite predation.

Data used: Seven abnormal trilobite fossils, originally housed in the Australian Museum, the Utah Field House of Natural History State Park Museum (U.S.), and the Museums of Western Colorado (U.S.), were gathered for this study because they portray damage to the exoskeleton. These abnormal trilobite fossils were: Lyriaspis sigillum, from the Beetle Creek Formation in Australia, Zacanthoides, from the Half Moon Mine, which is part of the Chisholm Formation in Nevada (U.S.), Asaphiscus wheeleri (two specimens) and Elrathia kingii (two specimens), both of which are from the Wheeler Formation in Utah (U.S.), and Ogyogiocarella debuchii from a quarry in Wales. All formations from which these fossils were sourced are aged to around the middle Cambrian (~510 million years ago), except for O. debuchii, which is from the Middle Ordovician (~450 million years ago). 

Method: Fossils were treated with magnesium oxide (which highlights details on the specimen for photography), photographed, and examined for abnormalities. Additionally, a computer program, ImageJ, was used to measure the dimensions of the specimens and their abnormalities.

Results: L. sigillum specimen was found to have a U-shaped ident on the upper left side of the body. The Zacanthoides specimen was found to have a U-shaped indent on the lower left side of the body. The first A. wheeleri specimen was found to have an L-shaped indent on the lower left side of the body, and a U-shaped indent on the upper left side of the body. The second A. wheeleri specimen was found to have a small injury in the middle of the right-side of the body. The first E. kingii specimen was found to have a W-shaped indent along most of the left-side of the body. The second E. kingii specimen was found to have a V-shaped indent in the middle of the right-side of the body. The O. debuchii specimen was found to have a W-shaped indent towards the very bottom of the body. None of the specimens possess abnormalities that indicate damage due to genetic malformations or sickness. Therefore, it is likely that the abnormalities on these fossils are from injuries. Previous studies have shown that these types of indentations are usually a result of failed predation. Therefore, these abnormalities in the specimens described above (i.e., the indentations; Fig. 1) are concluded to be evidence of failed predation.

Figure one shows photographs of two E. kingii fossils. The fossils are oval shaped with rounded heads and bottoms with defined ridges (spines) across the thorax. The fossils are about 30mm in width. One of the fossils has a W-shaped indent along most of the left-side of its body. The other fossil has a V-shaped indent in the middle of the right-side of its body.
Figure 1: Pictures 1 & 2 show an E. kingii fossil with a W-shaped indent on spines one through seven on the left-side of the thorax (middle section). Pictures 3 & 3 show an E. kingii fossil with a V-shaped indent on spines seven and eight on the right-side of the thorax.

Why is this study important? This study is important because it provides insight into the environment from which these trilobites come from and how the predators in this environment would have operated. For example, this specimen of L. sigillum is the first known case of an injured trilobite from the Beetle Creek Formation, and only the second case of predation from the Beetle Creek Formation (middle Cambrian). Additionally, the abnormalities (injuries) on the L. sigillum indicate that durophages, which are predatory animals that consume organisms with harder exteriors, like trilobite exoskeletons, were likely present in the environment. Furthermore, the A. wheeleri described in this study is the first documented injury on this genus and species of trilobite, which indicates that A. wheeleri may have experienced higher rates of predation than previously believed.

Broader implications beyond this paper: This study is a prime example of how past environments can become clearer with closer examination of fossils. Fossils are one of our best available methods of piecing together the puzzles of the past. As stated before, the injuries on the L. sigillum indicate that durophages might have been present in the environment, which tells us more about how trilobites functioned as prey in the middle Cambrian. Predation rates in the middle Cambrian are not currently well understood, so this evidence adds more information to what is currently known. 

Citation: Bicknell, R., Smith, P., Howells, T., & Foster, J. (2022). New records of injured Cambrian and Ordovician trilobites. Journal of Paleontology, 96(4), 921–929. doi:10.1017/jpa.2022.14

A Study on the Effect of Barnacle Attachment to Loggerhead Turtle Fossils

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Bone Modification Features Resulting from Barnacles Attachment on the Bones of Loggerhead Sea Turtles (Caratta caretta), Cumberland Island, Georgia, USA: Implications for the Paleoecological, and Taphonomic Analyses of Fossil Sea Turtles

J-P Zonneveld, Z.E.E. Zonneveld, W.S. Bartels, M.K. Gingras, and J.J. Head 

Summarized by Jackson Asbrand, a current undergraduate at the University of South Florida’s School of Geosciences.

Data being used: Recent Loggerhead sea turtle skeletal material washed up off the Atlantic coast from Virginia to Florida, USA were the subjects of this study, along with any barnacles that were attached to the turtle skeletons.

The point of this paper: The purpose of the paper is to investigate the relationship between bone modification on sea turtles, such as pits (circular holes) and divots, and barnacles that attached to the bones before the turtle died (Figure 1).

Methods: Scientists gathered the skeletal material at various beaches along the east coast.  The skeletons were measured, described, and photographed, with osteological (bone) elements such as depressions or pits being noted. Some of the barnacle pits were recreated in clay to better study the specific shape of the trace left behind. Finally, all of the osteological features were plotted on a digital master sketch of the entire turtle skeleton in order to compare common types of pits on different bones and across skeletons. Each barnacle was identified on the master sketch using a gray circle. The circle would become darker depending on how many barnacles were found in that specific spot.  

Results: The barnacles leave pits on turtles by using either mechanical abrasion (physically wearing the shell down) or excreting a substance that allowed the animal to permanently attach itself to an object. After attaching to the shell, the barnacle causes bioclaustration, or a biological reaction by the host organism in response to an injury or infection by a parasitic organism (in this case, the barnacle). This leads to the bone holes and pits being created, contributed both by the secretion and the bioclaustration. However, this secretion must be renewed to continue being attached to the turtle, so most of the barnacles fall off after death, leaving only the bone pits remaining. There were six types of bone pits that scientists identified. Type 1 is a shallow, but smooth hole. Type 2 is deeper than type 1 and have a smooth, but still angled bottom, Type 3 is similar to 2, but with a flat bottom. Type 4 is a deep pit with many smaller pits on the bottom. Type 5 is a tube-shaped hole that runs even deeper into the bone. The last type, 6, is a ring-shaped indent on the surface of the bone. Broad bone pits were common on most of the skeletons, some digging deeper into the bone than others; in head bones, these pits were generally shallower. There is also a large range of how many barnacles were actually on the head, ranging from zero to even 70 individual bone pits on one unfortunate turtle. The results are similar for the top part of the turtles’ shells, which had a variety in both the depth and the number of bone pits, although they were slightly more common on the front half of the shell than the back half. On the bottom part of the shell, there is little to no relationship between the modification of the skeletons and the barnacles, as they leave no evidence of it occurring. Type 1 pits were seen on the head bones and both sides of the shell. Type 3, 4, and 5 were only seen on the shell. Type 6 was far less common than the rest of the types and were also only seen on the shell. Types 1-4 were all preserved between the barnacle and the bone, meaning that the barnacles did not use physical force to cause the bone pits, but rather dissolve them using secretions Type 5s used both physical and chemical force, as they penetrated through the skin straight to the bone. Type 6 rings were also caused solely by chemical reactions.

Six pictures of turtles are shown in the figure. One returning to the ocean from the beach, one in the ocean with dozens of barnacles on the back of its shell, a third with smaller barnacles on the side of the shell, a fourth with fewer ones atop the edge of its shell, and a fifth and sixth image are zoomed in to highlight the third and fourth turtles’ barnacles’ locations.
Several loggerhead turtles with barnacles in various spots on their shells, in which some will remain on the bone after the turtle dies. A particularly dense cluster of barnacles can be seen in image C, which all are permanently attached via secretion. The types of pits, like those identified in this study, aren’t specified here, since the pits are classified after the death of the organisms.

Why is this study important?: We can use this data to identify patterns in how barnacles not only attach to Loggerhead turtles and dig deeper into how their relationship works, but also other species of turtles, or even other marine animals with which barnacles could also share a similar parasitic relationship. 

Broader Implications beyond this study: This study creates a template to look further at bone modification on sea turtles other than loggerheads from the Cenozoic and Mesozoic Eras, or in other words, up to 252 million years ago. This study also provides insight into how a symbiotic relationship between two species could be permanently preserved in the fossil record, as interactions such as these are not as often preserved.  

Citation: Zonneveld, J.-P., Zonneveld, Z. E. E., Bartels, W. S., Gingras, M. K., and Head, J. J. (2022). Bone modification features resulting from barnacle attachment on the bones of loggerhead sea turtles (caretta caretta), Cumberland Island, Georgia, USA: Implications for the paleoecological, and taphonomic analyses of Fossil Sea Turtles. PALAIOS, 37(11), 650–670. https://doi.org/10.2110/palo.2022.021 

The Early Evolution of Penguin Body Size and Flipper Anatomy: Insights from the Discovery of the Largest-known Fossil Penguin

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Largest-known fossil penguin provides insight into the early evolution of sphenisciform body size and flipper anatomy

Daniel T. Ksepka, Daniel J. Field, Tracy A. Heath, Walker Pett, Daniel B. Thomas, Simone Giovanardi, and Alan J.D. Tennyson

Summarized by Faris Al-Shamsi, a geology student at the University of South Florida, currently in his senior year of undergraduate studies. His passion for geology fuels his commitment to sharing scientific knowledge with others. Faris is currently working on a project to simplify a challenging scientific article for general audiences, reflecting his dedication to communicating complex ideas to diverse readerships. After graduation, he plans to pursue a career in geology and continue to promote scientific literacy among the public.

Hypothesis: The study investigates new fossils, including the recently discovered largest-ever penguin, named Kumimanu fordycei, found in New Zealand. Scientists used these fossils to clarify the evolutionary relationships between this new species and other know penguin species in the evolutionary history record in order to gain a better understanding of their evolutionary development. 

Data used: Researchers discovered penguin fossils in rocks from the late Paleocene Epoch (55.5-59.5 million years ago). They found various bones, including the humerus (upper arm bone) and wing bones. Researchers also used data sets of previously described fossil penguin species, created by scientists Bertelli and Giannini, which included 279 morphological characteristics to compare different species of penguins.

Methods: First, they created 3D digital replicas of the recently discovered bones using a handheld laser scanner and processing software, then finalized the 3D replicas using a software called Blender. Second, they conducted phylogenetic analyses by analyzing morphological characters between different samples of penguin bone to understand different species of penguins’ relationships and evolution over time. Two types of analysis were used: parsimony analysis, which seeks to find the simplest explanation of an evolutionary tree with the fewest evolutionary changes, and Bayesian analysis, which uses statistical methods to estimate an evolutionary tree. They used a large set of data created by scientists called Bertelli and Giannini with 279 characteristics to compare different types of penguins, and the scientists added data from the new fossils they discovered. The scientists modified existing characteristics which means they compared the physical traits of the new species with old species to determine how similar or different they are. Researchers used the length and proximal width (closest to the shoulder) of the humerus to estimate body mass of different penguin species using mathematical equations. 

Results: The study looked at the wing bones of ancient penguins and compared them to those of modern underwater diving birds like diving petrels and alcids (like puffins) through evolutionary tree analyses. Using the mathematical equations for determining size, researchers determined the new penguin fossils likely belonged to a giant, extinct penguin. The researchers estimated the body mass of the new species, Kumimanu fordycei, to be 148.0 kg (326 lbs) based on the length of its humerus, which measured 236 mm. Researchers found that some features of the wing bones in the ancient penguins are similar to those in fossil flying birds, which suggests that these early giant penguins may have kept some features that were once necessary for flying but would have been less efficient for swimming. Because modern day penguins are far smaller than these fossils, it indicates that smaller body sizes were likely selected for along the evolutionary pathway of these birds. 

Chart with the geologic timeline at the bottom ranging from Cretaceous (73 million years ago) to Pleistocene Epoch (nearly recent) and two penguin family trees on the left side: one on the top constructed using parsimonious comparison of physical traits representing the penguin Kumimanu fordycei as closely related to many other species, while the tree on the bottom constructed using complex statistical analysis and it represents the penguin Kumimanu fordycei sharing the same node (branch) with Kumimanu biceae species. The chart represents a drawing of three penguins on the right, starting from the left, penguin 3, which represent penguin Kumimanu fordycei is the largest one, second we have Petradyptes stonehousei, which is the second largest, and last the extant penguin Aptenodytes forsteri which is the smallest. They have the actual bones inside them that were found in fossils colored in white, while non-preserved bones are colored in gray. Crownward (advanced and closer to the tips of the evolutionary tree) penguins exist more than other species with a lifetime ranging from Paleocene Epoch (65 million years ago) to recent while other species lifetime range from Paleocene Epoch to Eocene Epoch (65 million years ago – 50 million years ago)
Figure 1 This figure shows the family tree of penguins with x-axis representing time in million years and the epochs. Family trees started from the Paleocene Epoch, which was about 60 million years ago. The figure is made up of two different kinds of trees. The first one is based on parsimony analysis which is the simplest explanation of a tree taking the fewest changes of the evolutionary changes, and the second one is based on Bayesian analysis which uses statistical methods. The figure also includes pictures of three different penguin species: 3. The largest known penguin Kumimanu fordycei 4. The second new species and genus Petradyptes stonehousei 5.the living penguin Aptenodytes forsteri. The white bones shown on the pictures of the ancient penguins are the actual bones that were preserved, while the gray bones used to complete the skeleton of the penguin even though they are not preserved just in order to show the difference in size between penguins 3,4, and 5 in physical traits.

Why is this study important? The discovery of the largest penguin humerus ever found, and the estimation of body mass based on this bone provides valuable insights into the evolution and growth patterns of penguins. Additionally, the study provides evidence that penguins reached their upper limit of body size early in their evolutionary history and experienced a decrease in size over time, which can provide insights into the impact of environmental factors such as climate change and competition for food resources on the evolution of organisms.

Broader Implications beyond this study: Body size in the fossil record can open a number of questions about how an animal lived. Researchers think penguins lost their flying capabilities before these larger penguins described here  evolved. This might provide a potential reason for the increase on body size: without the ability to fly, penguins faced fewer selection pressures to keep a smaller body size. Researchers also think penguins evolved in Zealandia, where the fossils from this study were located. The large body size of these particular penguins may have given them better control over their body temperatures (called thermoregulation) and allowed for them to disperse to other areas of the world by being able to swim greater distances. This gives researchers new hypotheses to test about how penguins reached and established populations in other continents. 

Citation: Ksepka, D., Field, D., Heath, T., Pett, W., Thomas, D., Giovanardi, S., & Tennyson,(2023). Largest-known fossil penguin provides insight into the early evolution of sphenisciform body size and flipper anatomy. Journal of Paleontology, 1–20. doi:10.1017/jpa.2022.88

How ocean acidification and ocean warming modify the physiology of coral reef fishes and the migrating temperate fishes

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Future shock: Ocean acidification and seasonal water temperatures alter the physiology of competing temperate and coral reef fishes

Angus Mitchell, Chloe Hayes, David J. Booth, Ivan Nagelkerken

Summarized by Shruti Verma, an incoming undergrad student, interested in environmental science, biochemistry and computer programming. She wishes to become a researcher. 

Hypothesis: The purpose of this paper was to assess the relationship between changing marine environment and the physiology of coral reef fish and competing temperate fish, which are migrating into coral reef fish habitats.

What data were used? 60 coral reef fishes (A. vaigiensis)  and 180 temperate fishes (A. strigatus) were collected from a coast in Australia

Scientists measured:

  • Fish’s energy (total lipid content)
  • Fish’s feeding (stomach fullness)
  • Fish’s ability to deal with stress (Malondialdehyde concentration (MDA) and total antioxidant capacity(TAC))
  • Overall health (Fulton’s condition index)

Temperature and pH levels were monitored regularly inside tanks where fish were kept.

Methods: 

  1. Setting up the tanks: Scientists used transparent water tanks with small holes and bubbled pure carbon dioxide (CO2) to increase acidity. Water temperature was altered to mimic future summer and winter conditions. The temperature of  23°C, and pH 8.1 were selected as control conditions to reflect the current winter temperatures in the natural breeding range of coral reef fish populations.
  2. Initializing shoaling: Two groups were created – coral reef fish mixed (N= 60) with temperate fish (N= 60) of varying body sizes (mimicking actual reef conditions), temperate-only mixed with temperate fishes of similar body sizes (to decrease competitive advantage) (N= 120) After 40 days of treatment, fishes were euthanized, after being fed completely, to analyze stomach fullness. 
  3. Assessing water chemistry: Water’s total alkalinity was measured using Gran titration on the 24-25th day of the experiment.
  4. Measuring protein content, MDA and TAC: The TAC kits measured the total concentration of antioxidant macromolecules, antioxidant molecules, and enzymes in the fish’s white muscle tissue. TAC and MDA were then calculated using specific formulas.
  5. Fulton’s condition index: Individual fish were weighed and measured for length before and after the experiment, and their body condition was assessed using Fulton’s condition index, which was calculated from weight and length. Treatment effects on body condition were determined by subtracting the final Fulton’s condition index from the initial index.

Results: 

Two horizontal panels. The top is 'Coral Reef Fish' and the bottom is 'Competing Temperate Fish'. There are three circles, the middle (yellow) is the current summer temperatures. To the right, there is a red circle indicating future summer conditions with a box to the lower left with the predicted shifting conditions. To the left, there is a blue circle indicating future winter conditions with a box in the lower right with the predicted shifting conditions.
This diagram shows how future water temperatures and ocean acidification could affect coral reef and temperate fish physiology. Arrows indicate significant changes in measured functions, with comparisons made between future winter/summer and current summer conditions. ‘*’ indicates higher response in mixed-species paired temperate fish, while ‘#’ denotes a significant increase in a given function under projected future conditions.

Key takeaways:

  • Lipid content in coral reef fish increased in colder winters (below 20°C) and exhibited decreased physiological performance, suggesting that they struggled to survive in future winter conditions.
  • In hotter summers (above 26°C), temperate fish experience more oxidative damage.

Coral reef fishes will benefit from ocean warming as their habitat range will increase, but they may struggle to survive during future winters. Simultaneously, competing temperate fishes will benefit from the presence of smaller coral reef fishes as temperate fishes will have a competitive advantage due to their greater body size. But this might not be the case when coral reef fish size increases in future summer. In future summer, temperate fishes will experience higher cell damage, and coral reef fishes will have the competitive advantage. Therefore the combined effect of decreased winter and increased summer temperatures on the competition between temperate and coral reef fish is not entirely clear yet. 

Why is this study important? Understanding the future consequences of migration altered physiology and altered shoaling interaction are crucial to determining the likelihood of survival of a fish species in the face of global warming.

Broader Implications beyond this study: It has been well documented that ocean acidification and ocean warming result in migration of fishes between different zones. However, more research needs to be conducted on the effects this behavior has on the shoaling interactions and the physiology of the migrating fish species. Even the smallest changes in environmental conditions can have great physiological impacts on certain fish species as outlined in this study.   

Citation: A. Mitchell, C. Hayes, D.J. Booth, et al., 2023. Future shock: Ocean acidification and seasonal water temperatures alter the physiology of competing temperate and coral reef fishes, Science of the Total Environment. https://doi.org/10.1016/j.scitotenv.2023.163684

New Species of Chalk Forming Organisms and Further Accumulations Found within the Faafu Atoll, Maldives

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New Species of Chalk Forming Organisms and Further Accumulations Found within the Faafu Atoll, Maldives 

Summarized by Nathan Baker, who is a senior and future geologist at the University of South Florida. His interest in the geosciences lie within geophysics and tectonics. He hopes to attend graduate school in structure and plate tectonic studies. Outside the classroom, Nathan enjoys going to the gym, hanging out with friends, and being active outdoors. 

Hypothesis: This research aims to pinpoint the distribution of coccolithophores, a type of algae and microorganism too small to be seen by the naked human eye (and the organism that chalk is composed of), in the Faafu Atoll of the Indian Ocean’s Maldives while introducing a new species, Alisphaera bidentata. The study delves into the variety of coccolithophore species in the ocean, examining the correlation between the number of species and water temperature through measuring a number of different variables, explained below. Moreover, this paper provides insight into the ecological and environmental impacts that these microorganisms have on the climate.

Data Used: The study analyzes the area surrounding the island using various data points, such as location, depth, time, weather, temperature, conductivity, pH, O2 levels, O2 saturation percentage, and the amount of chlorophyll in the water. Scientists also collected and identified samples of coccolithophores to determine species diversity. 

Methods: As part of this study, three water samples were collected from Faafu between November 2nd and November 6th, 2018. The samples were taken from both deep reefs (between 45 m and 3050 m deep) and flat reefs (which separate lagoons and the deep ocean). Each sample was recorded with a GPS device. Water temperature and oxygen concentrations were measured at each location. Surface samples of water containing coccolithophores were collected from a boat using a bucket off the coast of the islands. Along with this, vertical water samples at 0 m, 10 m, 25 m, and 40 m deep were collected using devices that can withstand high-pressure environments in the deeper ocean. Once the samples were collected, water analysis began. The first step in analyzing the samples was filtration. Samples containing two liters of water were sent through filters that separated the organisms from the saltwater. These organisms were then dried and viewed under a microscope to record the number, concentration, and types of coccolithophores.

Results: Scientists found that the density of coccoliths in surface waters was lower than that in waters with depths of 1-2 m, and the density continued to increase towards the bottom depths in both the lagoon and deep ocean environments. When investigating the vertical samples, scientists noted that there was a 1℃ decrease in temperature, observed from the surface to depths of 40m, along with a decrease in oxygen concentration within the lagoon environment. Within the open ocean environment, there was a 0.5℃ decrease in temperature, along with a decrease in oxygen concentration. Chlorophyll readings demonstrated overall low concentrations at all stations but showed a slight increase at larger depths.

Out of the multiple coccoliths species identified (16), only two were abundantly common within both open water and lagoon areas. The most abundant species were Gephyrocapsa oceanica and Oolithotus antillarum (as shown in figure 1). The concentrations of G. oceanica and O. antillarum increased with depths in both the lagoon and deeper ocean. Within these increasing depths, minor species also became more prevalent. An interesting find was that all 16 species of coccoliths existed in all of the sampled environments. Researchers also discovered a new species of coccolith (Alisphaera bidentata), which among the lesser commonly occurring species in these samples; further testing will be needed to understand the organism’s lifestyle.

Left: circular coccolithophore comprised of thin ridged plates with a bridge in the middle of each plate. The plates are layered on each other in a stacked orientation building on top of each other.Right: circular coccolithophore comprised of thin smooth plates with a small pit in the center of each plate. These plates are layered on each other with each plate’s connection oriented in the southern direction. Each organism is approximately 5–10 micrometers in diameter.
Figure 1: Gephyrocapsa oceanica (left) and Oolithotus. Antillarum (right); modified from microtax.org).

Study Importance: This study mapped the overall abundance of coccolithophores of the island of Faafu Atoll in the Maldives. The data showed that, of the 16 species found, the most abundant were Gephyrocapsa oceanica and Oolithotus antillarum. Along with these major species, numerous minor species were also detected within the waters around Faafu. Scientists, through this study, were better able to quantify how coccolith diversity is related to water conditions. 

Broader Implications. This study is important due to the effects coccoliths can have on the environment. Coccolithophores can affect the environment through the use of photosynthesis. By removing CO2 within the oceans and atmosphere, coccolithophores play a role in stabilizing ocean acidity and atmospheric conditions, and broadly  play a role in stabilizing climate and ocean health. Additionally, the pH in the ocean can be influenced by the amount of CO2 removed from the water, which, in turn, can prevent marine disasters such as coral bleaching and red tides. Furthermore, comparing the data of these coccoliths to other regions of the world can help identify the rate of CO2 absorption and possibly identify reasons why certain regions are affected by global warming more than others.

Full citation: Malinverno, E., Leoni, B., & Galli, P. (2022). Coccolithophore assemblages and a new species of Alisphaera from the Faafu Atoll, Maldives, Indian Ocean. Marine Micropaleontology, 172, 102110. https://doi.org/10.1016/j.marmicro.2022.102110

Discovery of new fossil net-wing insect species in the Democratic People’s Republic of Korea

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A new fossil lacewing (Ithonidae) from the Lower Cretaceous (Barremian-Aptian) Sinuiju Formation, Democratic People’s Republic of Korea

By: Kwang Sik So and Chol Guk Won 

Summarized by Karla Rodriguez, a senior geology undergraduate major at the University of South Florida. She has always had an interest in hydrology and geophysics. She is currently a water quality scientific technician at the Southwest Florida Water Management District. Once she graduates, she is planning to continue work in the private sector of hydrogeology. Outside of work, she loves playing competitive video games, hoping to join tournaments in the future.

Hypothesis: The purpose of this research was to describe the first fossils of a net-wing insect, belonging to the lacewings group, found in the Democratic People’s Republic of Korea (DPRK) and establish these finds as an entirely new genus and species. This paper describes the morphology of Sinuijuala paekthoensis gen. et sp. nov. (gen. et. sp. nov. means new genus and species), and compares it to known, related lacewings.

Data used: Recovered Sinuijuala paekthoensis specimens were encapsulated in a portion of shale (fine-grained sedimentary rock deposited in aquatic environments) within the Lower Cretaceous Sinuiju Formation, located in Sinuiju City, North P’yŏngan province of DPRK.  The lacewings were continuously buried by sediment, flattening the organisms. However, the burial allowed for unique preservation of wing features, head, and thorax (the middle part of the body). Wing venation provides one-of-a-kind patterns that can distinguish net-winged individuals, like lacewings, from other types of winged insects.

Methods: All recovered specimens were kept in the Paleontology laboratory at Kim II Sung University, which is in Pyongyang, DPRK. Microscope photographs of recovered Sinuijuala paekthoensis were taken with a Zeiss Discovery V20 microscope. Drawings of the images were created using Adobe Photoshop software. The number and positions of veins in the wing of the samples were measured using a microscope.

Results: This study provides the first documentation of lacewing fossils in DPRK. Researchers determined that Sinuijuala paekthoensis shares similarities with Ithonidae, a taxonomic family grouping of lacewings. Features like the lack of regular wing veining in part of the wing, and the branching of cross veins further in the middle anterior of the wing, as seen in Figure 1, are shared with the insect family, Ithonidae. Other fossils that have been found in the Sinuiju Formation are fossils of woody plants, indicating Sinuijuala was likely a woodland insect, similar to modern lacewings. 

The top two photographs are both sides of a recovered Sinuijuala paekthoensis gen. et sp. nov. sample, shown side by side. Black and white wing venation drawings are underneath their respective reference photographs. Vein abbreviations which specify parts of the wing are next to the drawings: R, radius; Rs, radial sector; MA, media anterior; MP, media posterior; CuA, cubitus anterior; R1, first branch of R; C, costa; Sc, subcostal. The photographs and drawings are shown with 2.0 mm scale bars. A US nickel is around 2.0 mm thick. The specimens are cemented in yellowish shale; wing, the thorax, and the head is clearly seen on the surface. The wings have Sc veins that start closest to the body, and branch out into Rs, MA, MP, and CuA veins away from the body.
Figure 1. Two photographs of a specimen of Sinuijuala paekthoensis gen. et sp. nov. (A, B) and corresponding line drawings (C, D) which illustrate observed wing venation in the sample image. Vein abbreviations are used to distinguish parts of the wing: R, radius; Rs, radial sector; MA, media anterior; MP, media posterior; CuA, cubitus anterior; R1, first branch of R; C, costa; Sc, subcostal. The wings have subcostal veins that start closest to the body as singular veins, and branch out into multiple veins veins away from the body. There were many subcostal veins observed, but fewer costal cross veins were present, which the authors noted as important in describing this particular fossil.

Why is this study important? The recovered specimens introduce a new genus and species of lacewings. This study was the first to find lacewings in DPRK, expanding the geographic range of these insects and increasing the total biodiversity of lacewings in the Early Cretaceous. The discovery of the net-winged insects here suggests the Sinuiju Formation may represent similar environments to other geological formations of the same age, such as the Yixian Formation in the People’s Republic of China, the Crato Formation in Northeast Brazil, and many others. 

Broader Implications beyond this study: Finding new species of lacewings in DPRK shows that new discoveries can expand the biodiversity and biogeographic range of fossil insects, which are not commonly preserved in the fossil record. The compaction of the shale allowed for rare preservation of their delicate wings and unique features. Knowing more about how they were preserved, too, may help us identify other places where delicate organisms may have been encapsulated in sediment and fossilized. There are many more insect species waiting to be discovered, including but not limited to, lacewings!

Citation: So, & Won, C. G. (2022). A new fossil lacewing (Ithonidae) from the Lower Cretaceous (Barremian-Aptian) Sinuiju Formation, Democratic People’s Republic of Korea. Cretaceous Research, 138, 105288. https://doi.org/10.1016/j.cretres.2022.105288

Newly discovered fossil evidence of a close relative to all animals (Animalia)

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First putative occurrence in the fossil record of choanoflagellates, the sister group of Metazoa

Carolina Fonseca, João Graciano Mendonça Filho, Matías Reolid, Luís V. Duarte, António Donizeti de Oliveira, Jaqueline Torres Souza & Carine Lézin 

Summarized by Jacob Fogg, who  is a student at the University of South Florida studying geology. All his life he has been interested in the natural world and how it works. He came into USF as an undeclared major and after taking an intro environmental science course, he was hooked. Jacob hopes to work in some capacity as a geologist when he graduates from USF in 2023. 

Purpose of Study: Choanoflagellates are single celled organisms that have been found to be the closest living relative to animals that we know of. We know this because sponges, which are a part of the animal kingdom, contain cells called choanocytes that behave in the same manner as choanoflagellates. Despite knowing a great deal about these organisms and their relationship with animals, scientists have never found evidence of them in the fossil record until now. With new fossil evidence of choanoflagellates, scientists can now study the structure and function of these organisms, in relation to how they work in animals, and the environment in which they lived many years ago.

Data Used: 22 rock samples were collected from the Betic Mountain System in southern Spain. These rocks are from the Cretaceous Period, approximately 100 million years ago, when this area was a shallow sea. The samples contained a material called kerogen, which is a form of organic matter that has undergone heat and pressure. If kerogen is continuously exposed to more heat and pressure, then it will eventually become the natural gas that we use in our everyday lives. It was in the kerogen that scientists were able to find the preserved choanoflagellate fossils.
Methods: Researchers crushed up the collected samples and treated it with an acid bath to remove the rock material. Then, they concentrated the kerogen using a heavy liquid and centrifuged the kerogen (meaning, the scientists placed the samples in a machine that spun the kerogen, causing it to separate from any excess water). The kerogen was then placed on slides and examined under a microscope and exposed to white and blue florescent lights to pick out organic particles. It was here where scientists were able to find choanoflagellate fossils. The fossils were then analyzed through the process of confocal laser scanning microscopy (CLSM). This process takes microscopic photos of the samples using high resolution imaging, which can be used to create a 3D model of what you are imaging. CLSM is a very sophisticated imaging process.

Results:  Using the 3D model from CLSM (Fig. 1), scientists were able to directly observe the structure of the choanoflagellates. In the model they created, scientists could see how the choanoflagellates form colonies. The choanoflagellates do this by constructing intercellular bridges and using their filopodia (similar to antennas) to connect their cell bodies together and create a large colony. Scientists were also able to make out the cell bodies of individual choanoflagellates and their flagella (similar to tails). When analyzing the organic material of the rocks, scientists were able to find other microorganisms, such as freshwater microplankton. This suggests that the choanoflagellates in the samples collected were in freshwater environment. Now, in the future, if we find choanoflagellate fossils somewhere in the world, we can infer what type of environment was likely present when the choanoflagellates were living.

Photos A-F look like a hairy ball. The ball is composed of the individual cell bodies of the choanoflagellates which looks like smaller round structures. The hair coming from the large ball is the flagellate of the individual cells. The hairy ball is approximately 60 micrometers in diameter. That’s 0.06 millimeters!
Figure shows the 3D model of choanoflagellates constructed from CLSM. Photo A shows a choanoflagellate colony. They bind together and use their tails (flagella (flagellum singular), the wavy lines that come off of the round structure) to grab food and bring it into the colony. Photos D and F show the cell body of an individual member of the colony.


Why is this study important?  This study is important because choanoflagellates are the link between bacterial organisms and sponges, which are likely among the earliest evolved animals. This means that choanoflagellates are one of the most closely related living things to animals, despite not being animals themselves. . Understanding how these organisms form colonies and sustain themselves can give us insight into how the compare to similar cells that are contained in animal bodies. We can then get a better understanding of how animal cells work.
Broader Implications beyond this study: Now that we have fossilized evidence of choanoflagellates, we have a link between animals and eukaryotic cells. With further research, we may be able to find transitional fossils that show how choanoflagellates became incorporated into animal cells, like in sponges. 

Citation: Fonseca, C., Mendonça Filho, J. G., Reolid, M., Duarte, L. V., de Oliveira, A. D., Souza, J. T., & Lézin, C. (2023). First putative occurrence in the fossil record of choanoflagellates, the sister group of Metazoa. Scientific Reports, 13, 1242.