I Like Big Plants and I Cannot Lie – Fruit Size Increases in Absence of MegaHerbivores

The megaherbivore gap after the non-avian dinosaur extinctions modified trait evolution and diversification of tropical palms

Renske E. Onstein, W. Daniel Kissling, and H. Peter Linder

Summarized by Makayla Palm

What data were used? Qualitative data from modern palm tree fruit, phylogenetic data, and palm tree fossils are used in order to observe changes over time in the taxon Arecaceae, or the palm tree, from the Paleogene Period. After the end-Cretaceous extinction that wiped out the non-avian dinosaurs, mega-herbivores, or any herbivore larger than 1,000 kg ( ~2200 lbs), were nowhere to be found. For the most part, small mammals were left foraging for food, and angiosperms (flower-bearing plants) were able to catch a break. The combination of mammalian seed-spreaders and lack of large herbivores preying on angiosperms (palms in this case) meant that the plants were able to increase in numbers without worrying about defenses. These furry seed-spreaders (small animals that pooped out their seeds) were still spreading, allowing plants to grow and didn’t evolve many defense mechanisms like rough leaves or spines. The researchers hypothesized that they would observe three things about palm diversity in the fossil material from this time: the origin of plant armature (or defense structures like spikes) in the Cretaceous Period because of many large herbivores, the decrease in armature during the Post-Cretaceous Paleogene Megaherbivore Gap (PMHG), and the change in fruit size over time as the plants were able to diversify. 

Methods: Measurements of the palm tree fruit fossil material were taken in order to compare how fruit size changed over time within the megaherbivore gap and observations were made on when these changes in size happened, which supplemented the phylogenetic analysis. Living palms were observed in modern habitats, as were  their interactions with larger herbivores of modern times to better understand how the fossil palms may have interacted with herbivores from the Paleogene.

Results: The hypothesis that the first armature appeared in the Cretaceous was confirmed by fossil material, which indicates an increase in defense likely due to megaherbivores. The armature of plants with larger fruit decreased over time, which also supports the hypothesis of losing these defense structures over time with less predation. Despite the disappearance of megaherbivores in the end-Cretaceous, fruit size stayed relatively large (above 4cm). Plants with larger fruit diversified on a constant scale over time, whereas plants with smaller fruit decreased in diversity, counter to the second hypothesis. Overall, some hypotheses were supported, and some were not. 

 The six graphs each have three columns representing before, during and after the Paleocene MegaHerbivore Gap. Graph (a) represents a consistent speciation rate among large fruit (defined to be >4cm in length). Graph (b) represents a speciation of armature in leaves and stems, showing a negative dip during the PMHG with an increase before and after. Graph (c ) represents speciation of stem armature, with a similar pattern to Graph (b), showing a dip during the PMHG. Graph (d) represents the rate of fruit size evolution (from small to large) increasing during the PMHG, and a constant state before and after the gap. Graph (e) represents a transition of evolving armature in leaf and stem, decreasing during the gap and increasing again afterward. Graph (F) represents the evolution of just stem armature, which stays constant before and after the PMHG, but dips significantly during the event itself.
This box and whisker plot tracks the changes of palm trees from before, during, and after the Paleocene MegaHerbivore Gap (PMHG) following the Cretaceous extinction. The median value (middle value of data)is represented by the bar across the yellow box. The graphs show that armature decreases immediately following the extinction ~66mya and the speciation of fruit staying constant. These also show the increased fruit size during the PMGH.

 Why is this study important? A lot of end-Cretaceous Period studies focus on the end of the dinosaurs, what caused the mass extinction, and how the age of mammals began. This study shows a different perspective on a well-studied time period by using a combination of paleobotany and vertebrate paleontology, and observing how the absence of large herbivores affected how ancient palm trees changed ecologically. This documented diversity opened new doors for angiosperm evolution and led to an increase in forests, setting the stage for the next era of geologic time in North America, the Cenozoic. 

The big picture: The Paleogene megaherbivore gap is a time in geologic history where the absence of large herbivores after the non-avian dinosaur extinction greatly affected ecosystems and the change in the landscape to more dense forests. The lack of large herbivores to eat plants allowed plants to evolve fewer defensive structures and larger fruit, which allowed them to spread farther distances and in greater numbers, because of the increase in seeds. 

Article Citation: Onstein, R. E., Kissling, W. D., & Linder, H. P. (2022). The megaherbivore gap after the non-avian dinosaur extinctions modified trait evolution and diversification of tropical palms. Proceedings of the Royal Society B, 289(1972), 20212633.

Surprise Spinosaurid in Southern England…the Biggest in All of Europe??

A European Giant: a large spinosaurid (Dinosauria, Theropoda) from the Vectis Formation, (Wealden Group, Early Cretaceous) UK. 

Chris T. Barker​,  Jeremy A.F. Lockwood, Darren Naish, Sophie Brown, Amy Hart, Ethan Tulloch, and Neil J. Gostling

Summarized by Makayla Palm

What data were used? Fossil remains of a new theropod dinosaur from Southern England were discovered and excavated over several months’ time. These bones consisted of post-cranial fragments, or the parts of the skeleton below the skull. Most of the vertebrae, parts of the pelvis, and some ribs were identified from this specimen, also known as the White Rock spinosaurid. Measurements were taken of the fragments, and an evolutionary (phylogenetic) analysis was inferred to see where this theropod may fit on an evolutionary tree. 

Methods: Scientists measured these new bone fragments, and over 1,000 characteristics of the fragments were cataloged in a computer and compared to other theropods in a character database. This database categorizes dinosaurs by the features found within their bones, and accounts for the smallest of variations to be as specific as possible. These features also help place the theropod on a family tree by using computer programs that arrange all of the characters to identify which dinosaurs are closely related to one another.  

Results: This theropod’s size and other morphological features indicate that it is likely closely related to Spinosaurus, but may or may not be in the genus Spinosaurus. There is a lot of weathering of the fossil remains, which makes more specific categorization not possible at this time. The presence of canals within the bones suggests that post-death, something began to eat away at the theropod’s bones. Scientists have seen very similar features before in other Cretaceous theropods, and the canals are likely due to beetle pupae that dug their way through these bones after the dinosaur had died. The phylogenetic tree did not provide enough resolution to confirm a more specific group that this specimen belongs to, but the likelihood that it represents a new type of spinosaurid is high. This specimen is not only the first of its kind found in this geological location, but its size rivals all of the known specimens in Europe. 

A black and gray map indicates the size of the Island of Wight, where the spinosaurid in this paper was found and excavated. The Island is just south of England, and is ~50 km in length. The Spinosaurid was found on the northeastern side of the Island near Compton Bay. The closeness of the spinosaurid to the bay could indicate it was a coastal predator.
A geographical map of the Island Of Wight, just off the coast of Southern England. The spinosaurid indicated on the map is where the fossils were found. They are not far from Compton Bay,where the fossil was excavated.

Why is this study important? This study provides insight into the geologic history of Southern England with the presence of the first known large theropod. First, the Lower Cretaceous geological formations of western Europe have been defined as the origin of the spinosaurids. Secondly, the White Rock spinosaurid appears in the fossil record later than any known spinosaurid on the Island, indicating the presence of spinosaurids to last longer than before. The size of this spinosaurid may have warded off other predators, which might explain why fossils of other theropods have been found this late in other known Spinosaurus– bearing locations. This specimen is classified as a spinosaurid and not a Spinosaurus, because its bones were not preserved well enough to confirm a new taxon of Spinosaurus. More phylogenetic analysis, and the discovery of new material, will provide future insight into its taxonomic placement. 

The big picture: A new theropod has been discovered in Southern England, and its large size and location implies it is not only a new spinosaurid, but also one of the largest theropod dinosaurs in Europe to date. Its presence improves the known range of spinosaurids and may provide new insight into taxonomic variation within the spinosaurids. 

Citation: Barker, Chris T.,  Lockwood, Jeremy A.F., Naish, Darren, Brown, Sophie, Hart, Amy, Tulloch, Ethan, Gostling, Neil J.   “A European Giant: A Large Spinosaurid (Dinosauria: Theropoda) from the Vectis Formation (Wealden Group, Early Cretaceous), UK.” PeerJ, vol. 10, 2022, https://doi.org/10.7717/peerj.13543.

The Eastern Kunlun Tectonic Event and How It Intruded in the First Place

Silurian-Devonian Granites and Associated Intermediate-Mafic Rocks along the Eastern Kunlun Orogen, Western China: Evidence for a Prolonged Post-Collisional Lithospheric Extension

Jinyang Zhang Huanling Lei Changqian Ma Jianwei Li Yuanming Pan 

Summarized by Makayla Palm 

What data were used? The goal of this study was to gain insight into how the Kunlun mountain formation and surrounding area were initially formed. The Kunlun Mountain range primarily has an intermediate and mafic composition, with felsic granite intrusions, or dikes. Dikes are intrusions of magma that cut across previously formed layers and are an indicator of a secondary formation process. Depending on the mineral composition, or silica content, of these dikes (or intrusions) they will be either felsic, intermediate, or mafic, with felsic rocks containing the most silica. There are several kinds of secondary igneous rock formations found in the Kunlun called dikes. If the composition of the dike is different from the surrounding rock, this will provide insight into how the dikes formed in the Kunlun and how it can be explained using plate tectonic theory. 

Granite is a commonly found felsic rock in the Kunlun and is formed intrusively (or underground). The mineral contents of the granite can tell the researchers how fast or slow the magma cooled, which will ultimately help answer the question of how the dikes formed. Within the granite, there were zircon crystals present with radioactive uranium decaying into lead. These ratios were recorded in order to estimate ages within the mountain range to determine when the different magma-cooling events took place. To summarize, this paper uses physical samples of the igneous rocks in the area to study mineral composition and isotope data from these rocks, too. 

Methods: The samples that were collected from different rock types in this area were studied under a microscope in order to observe the composition and individual mineral grains. In plate tectonics, there are two kinds of plates: continental plates and oceanic plates. Granite (felsic) comprises less dense continental plates, while basalt (mafic) comprises a denser oceanic plate. In the Kunlun, the researchers observed several granite inclusions surrounded by mafic rock. The isotope ratios of uranium to lead were recorded and radiometrically dated. These data determine if the different intrusions formed at the same time, or if they formed during several events. This would help support or reject the hypothesis they posed that when the continental and oceanic plates collided, creating the Kunlun Mountains, the edge of the oceanic plate broke while bending under the continental plate (the oceanic plate always goes underneath a continental plate, due to higher density).

Results: The radiometric dating of the granite inside the intrusions (the magma formations added after the formation of the surrounding rock) indicated four different formation events, with the earliest taking place 427-414 million years ago (mya) and the latest from 373-357mya. (For more about how radiometric dating works visit Geologic Time.) The variation in the composition of the rocks (felsic, mafic, etc) indicates a complicated tectonic history; along with the multiple events of granitic intrusions, scientists also found ophiolites (oceanic crust that was pushed onto land during an oceanic- continental plate collision), which indicates that a piece of the oceanic plate was pushed up and broken off during the collision. 

A volcano sits on top of igneous rock layers. The volcano is not erupting, but has a magma plume underneath it. There are also intrusive igneous rock formations in the figure. There is a pluton (depending on its size, it is either a stock or batholith) and there are dikes cutting through the rock layers. The rock layers are labeled on the left side, in order of fastest cooling, smaller crystals on the top, to slower cooling, larger crystal sizes on the bottom. The pluton lies at the very bottom of this image with yellow magma.
This figure demonstrates the relationship of cooling rates to crystal sizes. Since the granite of the Kunlun has large crystals, it would be represented by a dike that was set deeper into the rock layers because of longer cooling periods. The lower horizontal layers represent the mafic layers of the Kunlun, which also had large crystals. Figure Citation: Beckett, Megan. Flickr, Siyavula Education , 23 Apr. 2014, https://www.flickr.com/photos/121935927@N06/13598553484/. Accessed 30 June 2022.

Why is this study important? This study looked to test the hypothesis of a broken oceanic plate’s impact on the formation of the Kunlun mountain range and gain more specific knowledge of its origin. By taking inventory of its intrusive rock formations, getting radiometric dating for these intrusions, and noting the differences in mineral compositions, they were able to confirm their hypothesized four magma events. These events represent different periods of magma formation, which confirms the researcher’s hypothesis about oceanic plate breakage during a collision. 

The big picture: Clues from igneous geology, such as large crystal size, rock type, and mineral composition can give researchers details on how large formation events took place. Isotopes within radiometric dating were used to separate events from one another and place them in chronological order. This particular study answered questions about the origin of the Kunlun Orogen, or mountainous landscapes.

Citation: Zhang, Jinyang, Huanling Lei, Changqian Ma,  Jianwei Li,  Yuanming Pan. “Silurian-Devonian Granites and Associated Intermediate-Mafic Rocks along the Eastern Kunlun Orogen, Western China: Evidence for a Prolonged Post-Collisional Lithospheric Extension.” Gondwana Research, vol. 89, Oct. 2021, pp. 131–146., https://doi.org/10.1016/j.gr.2020.08.019.

The Scars of a Mastodon’s Tusk and the Story it Reveals About the Mastodon’s Bachelor Experience

Male Mastodon Landscape Use Changed with Maturation (late Pleistocene, North America)

Joshua H. Miller, Daniel C. Fisher, Brooke E. Crowley, Ross Secord, and Bledar A. Konomi

Summarized by Makayla Palm 

What data were used? The tusks from a single male mastodon specimen (the “Buesching” mastodon, housed in the Indiana State Museum) that died in its early thirties were analyzed in two stages of its life (teenage and adult) in order to understand how, as a bachelor, it moved away from its herd and interacted with other adult mastodons in what was likely a breeding ground. The skull and tusks of this particular specimen have scratches, dents and markings likely caused from fighting with other males over potential female mates. These marks inspired researchers to focus on mating behavior; they hypothesized that the place where the mastodon fossils were found was the same location as its summer breeding ground. Scientists also examined modern-day relatives like elephants, which added insight into the following data: isotope changes in both oxygen and strontium and the growth “rings” of the tusks during teenage and adult years, which shed light on how the mastodon might have moved seasonally. 

Methods: In order to test the hypothesis of the mastodon’s seasonal moving in his later years, scientists examined and compared changes in tusk growth throughout its life. The exterior damage on the tusks was observed and recorded to factor into results. The mastodon tusks grew each year by depositing a ring of dentin, which is dense tissue that is bony, similar to what makes up teeth. By looking at the differences in the rings, scientists can determine changes in lifestyle. In particular, to learn about where the mastodon traveled, two different isotopes were measured: one to determine seasonal temperature changes (an oxygen isotope) and the other for change in environment and age (a strontium isotope).

Results: The visible damage observed on the mastodon’s skull is consistent with a hypothesis scientists proposed of males fighting for territory and mates. This happened in seasonal periods of musth, an annual event where male mastodons experienced extra fighting based on increased aggression while on the search for a mate, leading to increased clashing tusks in the height of mating season. The dentin growth deposits show evidence of low nutrition value in the same growth years the male would be expected to separate from the herd. There was also a noticed abundance of nutrients a couple of years later, inferring it had become successful on its own as an adult. Oxygen and strontium isotopic changes in the tusk show that the mastodon traveled to a warmer location around the same time each year; the two isotope ratios indicate a pattern of more frequent visits to its summer ‘bachelor pad’ (or breeding ground) and as the mastodon got older, it was able to travel further from its typical location. 

Two graphs represent the frequency in which the mastodon visited his breeding grounds. The first graph (on the left) represents his teenage years, and the second graph (on the right) represents his adult years. The adolescent years show no interaction at the fossil location site (where the mastodon bred and was later excavated), but consistent travel far away from the breeding ground. The adult graph shows consistent interaction at the breeding site, indicated with a red horizontal bar above the “near fossil location” label. The adult graph indicates the same consistent travel away from the breeding grounds as the adolescent graph, implying the addition of the breeding ground travel was an addition he found as he sexually matured.
The figure represents the changes in the oxygen isotope that indicate warmer temperatures. The warmer temperatures are inferred to be the mating grounds for this particular mastodon. This figure shows no interaction at this site in its adolescent years, but consistent interaction there as an adult. There is a consistent pattern where it left the breeding grounds in both teenage and adult years. The fossil location is where the mastodon was excavated.

Why is this study important? A male mastodon perished after fighting to the death for a mate. Its tusks were analyzed for growth patterns and changes in trace isotopes to better understand where the mastodon went, its pattern of seasonal travel, and its behavior throughout its lifetime.

The big picture: This story sheds light on the behavior of mastodons as they matured over time, as well as male behavior displayed during mating season. The quality of the preserved tusks allowed researchers to learn about this mastodon’s teenage and adult life and compare the differences over time. 

Citation: Miller, Joshua H.,  Fisher, Daniel C., Crowley, Brooke E., Secord, Ross and Konomi, Bledar A.  “Male Mastodon Landscape Use Changed with Maturation (Late Pleistocene, North America).” Proceedings of the National Academy of Sciences, vol. 119, no. 25, 2022, https://doi.org/10.1073/pnas.2118329119.

Learning About the Leopards in the Cederburg Mountains

Population size, density, and ranging behaviour in a key leopard population in the Western Cape, South Africa

Lana Müller, Willem Daniel Briers-Louw, Barbara Catharine Seele, Christiaan Stefanus Lochner, Rajan Amin

Summarized by Habiba Rabiu, a student of environmental geosciences at Fort Hays State University. Habiba is interested in all aspects of environmental science and conservation & sustainability. She would like to work in educating others about those topics. In her free time, she likes to read, write, and bake.

What data were used? The researchers chose an area in the Cederburg Mountains in Western Cape, South Africa, about 200 km north of Cape Town. In the Western Cape Province, there is about 50,000 km² of potential leopard habitat, but only 30% of it is in conservation areas or mountain catchment zones. The density of the leopard population in the province is among the lowest in the country with only 0.25–2.3 individuals per 100 km2, however their home ranges are relatively large (35–910 km²). The aim was to determine the number of individual leopards in the region and the amount of land they occupy.

Methods: The area of study chosen was 2,823 km² in size and 73 camera traps were set up with a mean distance of 2.78 km between each trap. The cameras were placed along any trails or natural features that the leopards were likely to come across or had shown evidence of having already been there. The cameras operated 24 hours a day and took three images each time they were motion-triggered. From the pictures taken, the leopards were manually identified and digitally differentiated using a software that could distinguish each leopard’s unique spotted pattern. 

In addition to the pictures, the researchers also used various software and databases to track the population size and density, site use, and ranging habits of the leopard population, as well as any livestock depredation (or attacks) that occurred. This information contributed to creating a more complete picture of the leopards in the area and their movements. One topic that required special attention was the difference between the leopard movements in winter versus the summer, as the changing seasons had a significant effect on how far the leopards had to move for food and other resources.

Results: From the photographs taken, 63 adult leopards were identified (31 females, 26 males, and 6 of unknown sex.) In the summer, the leopard density was estimated to be 1.62 leopards per 100 km² and more concentrated towards the center of the study area, while in the winter the leopards were more spread out, causing the density to decrease to 1.53 leopards per 100 km². In both seasons, leopard density was higher in females with a female to male ratio of 2.42:1 in the summer and 2.45:1 in the winter.

The leopards were found to be present in nearly the entire area studied, with a total of 2,638 pictures being taken of them at 95% of the camera traps. The habitat type and altitude of the different parts of the study area did not seem to make a difference in the leopards’ movement. As could be inferred from the density measurements, the female leopards tended to keep their activity within a smaller radius around the center of the study area, occupying an average space of 117 km² in the summer and 182 km² in the winter, while the male leopards had an average range of 456 km² in the summer and 856 km² in the winter. The average number of instances of livestock attacks did not appear to differ in number from previous research. The mean number of livestock killed was 7.7 during the summer and 14.9 during the winter.

Images are the same size and shape depicting an oval-shaped region. In the left image, the black dots, yellow circles, and red crosses are all situated towards the center of the oval, with little to no activity shown in the outermost ⅓ part all around. Both the black dots and yellow circles appear mostly in clusters, with a few outliers. In the right image, the black dots are shown mostly on the periphery of the oval, with a few clusters in the center. The yellow dots are slightly more spread out but are all situated towards the center of the oval, as are the red crosses.
The image on the left depicts movement of the adult female leopards in the winter, and the image on the right shows movement of adult male leopards. Activity centers are shown as black dots, capture locations as yellow circles, and trap locations as red crosses.

Why is this study important? This research is a thorough study of the leopard population in the Cederburg Mountain region that employed several methodologies and programs. It supports previous research regarding the average low density (less than 2 leopards per 100 km2) of the leopard population in the Eastern and Western Cape Provinces of South Africa. 

The big picture: Since 2016, leopards have been listed as Vulnerable on the International Union for Conservation of Nature’s Red List. This status is due to a variety of factors, many of which are anthropogenic, or human caused, including habitat loss, loss of food sources, poaching for sale or body parts, and killing by farmers attempting to protect their livestock. Tackling issues of conserving threatened animals requires precise data about the animals’ population and activity.

Citation: Müller L, Briers-Louw WD, Seele BC, Stefanus Lochner C, Amin R (2022) Population size, density, and ranging behaviour in a key leopard population in the Western Cape, South Africa. PLOS ONE 17(5): e0254507. https://doi.org/10.1371/journal.pone.0254507

New Species of Sea Anemone Found with Symbiotic Relationship to a Hermit Crab

Carcinoecium-Forming Sea Anemone Stylobates calcifer sp. nov. (Cnidaria, Actiniaria, Actiniidae) from the Japanese Deep-Sea Floor: A Taxonomical Description with Its Ecological Observations

Akihiro Yoshikawa, Takato Izumi, Taekya Moritaki, Taeko Kimura, Kensuke Yanagi 

Summarized by Michael Hallinan 

What data were used? 16 specimens of a new species of sea anemone (Stylobatus calcifer) were collected by beam trawl from Japan’s Sea of Kumano. All specimens were collected at a depth of 100 to 400m, with 6 of them being treated with ethanol immediately for DNA extraction. Most of the others were anesthetized and treated with a variety of chemicals for structural analysis, only one was further studied through behavioral observation prior to being treated with ethanol. In addition to the sea anemones, the shells used by the sea anemones and the symbiotic host hermit crabs were identified. 

Methods: S. calcifer is a symbiotic species, it lives on the mollusc shells used by hermit crabs of the species Pagurodofleinia doederleini. The collected specimens were removed from the shells they were sitting on and dissected allowing for further analysis using different mixes of chemicals to help preserve and support the dissected parts during this series of observations. Following the visual observation, DNA was extracted from four of the specimens and compared to other species, with further comparisons to the most closely related species to analyze if the specimens found can be attributed to a new species. In addition to this qualitative data, a series of observations between one of the specimens and hermit crab were made in a seawater aquarium. These observations focused on recording the anemone’s interactions with the hermit crab, centered around the hermit crab’s shell, as well as what happened when a new shell was introduced. These observations were recorded and provided as supplementary material.

Results: S. calcifer was identified to be unique in its DNA, the shape of one of the muscles that manages openings in the anemone, direction of its mouth system, as well as the size distribution of its prey-capturing parts. However what sets it apart from previously known species even more is its symbiotic relationship and interactions with the hermit crab P. doederlein. Once the hermit crab discovered and moved into a new shell, it began to detach the sea anemone and encourage the sea anemone to transfer to the new shell through a series of pinches. There was no initial reaction from the sea anemone, but after about 43 hours from the hermit crab getting its new shell, the sea anemone has completed the transfer with it, mounting and covering the new shell. This allows the anemone to move across the seafloor by their hermit crab and collect food, while avoiding injury by being mounted on top of the shell. While symbiotic relationships between hermit crabs and sea anemones are known for over 30 other species, a hermit crab induced transfer to a new mollusc shell has never been observed until now.

A series of graphics labeled A through F that depict the various stages of the transition for the old hermit crab shell to the new hermit crab shell. (A) The hermit crab which has left its old shell and already moved into the new one begins to tap the central body of the sea anemone. (B) It uses its front claws to pinch the top of the anemone and remove the sea anemone from the old shell. (C) There is a lack of shell-mounting action from the anemone after removal. (D) The sea anemone is then flipped upside down by the crab and its center is aligned with the shell. (E) Finally it settles in on the host hermit crab’s new shell.
Behavioral sequence of the hermit crab transferring the sea anemone from the original shell to the new one. (A) The hermit crab which has left its old shell and already moved into the new one begins to tap the sea anemone. (B) It uses its front claws to pinch and remove the sea anemone from the old shell. (C) There is a lack of shell-mounting action from the anemone after removal. (D) The sea anemone is then flipped upside down by the crab and aligned with the shell . (E) Finally it settles in on the host hermit crab’s new shell.

Why is this study important? This study has expanded our understanding of taxonomy regarding sea anemones, but also provided a great observation of symbiosis between the hermit crab and anemone which not only allows us to better understand how both function but also opens the door for future research about the association between the two. All of this knowledge can better improve our ability to conserve as well as better understand relative biodiversity.

The big picture: A new species of sea anemone was discovered to have unique structural properties regarding its mouth and prey-capturing parts as well as a very unique symbiotic relationship with a hermit crab. The anemone is encouraged to transfer from shell to shell by the hermit crab. It mounts the shell inhabited by the crab as a means of transportation so it can acquire food easier. This new discovery allows us to better understand both respective organisms and their patterns but also conservation regarding both.

Citation: Yanagi, Kensuke (2022/04/01). Carcinoecium-Forming Sea Anemone Stylobates calcifer sp. nov. (Cnidaria, Actiniaria, Actiniidae) from the Japanese Deep-Sea Floor: A Taxonomical Description with Its Ecological Observations. The Biological Bulletin, 242, 127-152. doi: 10.1086/719160

 

Michaela Falkenroth, Sedimentologist

The image is a selfie of a girl in a black jumper. She has a green toothbrush sticking out of her mouth and an amused look on her face. The background is a backbeach area with reddish sand and a couple of thorny shrubs. You can make out tire tracks and footsteps on the sand. The sky is whitish blue and the lighting shows that the sun is just rising.
When you are a field geologist that studies beaches, chances are you have to work at the beach, sleep at the beach, eat at the beach and brush your teeth there, too.

Hey there! My name is Michaela and I am a cat-lady, sci-fi-nerd and hobby illustrator, who gets paid to hang out on tropical beaches a lot – how is that possible, you ask? Well… I got lucky.

The first time I got lucky was when I was eight years old and announced to my flabbergasted parents that I had decided to become a paleontologist like my hero at the time: Dr Alan Grant (also known as “guy with the cool hat in Jurassic Park”). My parents, who did not have the opportunity to go to university themselves and had never heard of paleontology, would have been perfectly justified to believe that my career goals were nothing to be taken seriously and move on, but they did not. Instead, they bought piles of dinosaur books, spent countless hours in museums and corrected everyone who confused paleontology with archeology with admirable patience. I was still set on becoming a paleontologist 11 years later, when I first set foot in the geoscience department of University Bonn. It is certainly not my parents’ fault that I didn’t.

The image shows a broad river flowing through a deep valley with high but not very steep, rocky walls. A bright blue sky in the background, no vegetation except for some palm trees by the water and bright sunlight indicate a desert environment. The water is calm, completely clear and shallow, the ground is covered in light grey gravel. A girl is standing knee deep in the water looking at a smoothened cliff that is twice as tall as she and boarders the river. The cliff is almost white and consists of well-rounded gravel in different sizes that is held together by a white matrix. The girl wears long, green pants, a dark T-Shirt and a cap that casts a shadow over her face. She points at something on the cliff to show it to a guy standing a few meters behind her.
Sedimentology is the study of rocks that were broken down into smaller pieces and transported on the surface of the planet by wind, gravity, and water. Here, I look at a river sediment in Oman that was turned into hard rock by a natural cement.

The second time I got lucky has to do with the fact that becoming a paleontologist in Germany requires you to become a geologist first. It only took a couple of rock identification classes for me to realize that yes, dinosaurs are amazing, but evolution is only one of the natural processes that shape our planet, and the others are even more fascinating to me. I had never thought about mountains being crumbled into tiny pieces by weather and time, these pieces then being transported by wind and rivers into the ocean, while being reshaped again and again, before they come to rest somewhere along the way. As a sedimentologist you look at the pieces of rock that are shuffled around on the planet’s surface and make them your own personal window through time. Sedimentary rocks let you study rivers that rushed by millions of years ago or watch coral reefs grow and die and regrow in a millennial cycle. By the time I finished my bachelor’s degree I was hooked. I still have a cool dinosaur model on my desk, but sedimentary rocks are what is on my mind, what pays my bills (sometimes) and what got me into another field of science with a very relevant application: sea level research.

A strongly fractured, uneven surface of brown and crumbly-looking rock fills most of the image that was taken from a heightened position. On top of the rock stands a smiling girl in fieldwork attire. She has her hair in a ponytail, arms akimbo and a broad grin on her face. One corner of the background shows a rough, blueish-green ocean with big waves breaking on a rocky platform in white foam.
Me on a beach in South Africa, happy about a freaky beachrock that I just discovered. The rocks that I am standing on formed within the last 77 years, before that it was just a sandy beach.

This brings me to the third time I got lucky. This one really did not feel like luck at the time. In 2016, I got rejected for three possible projects for a master thesis and thus one day stumbled into the office of the new professor at the department, who had nothing to do with sedimentology. I stood in the doorframe a little desperate and ready to take whatever the man would offer. This professor, who would later become my PhD supervisor and close friend, offered me an opportunity to study sea level change at the coastline of Oman – turns out you can squeeze sedimentology into any project.

Sea-level and coastal research became the focus of my scientific journey and Oman somewhat of a second home. For my masters and PhD, I studied beachrock. That is essentially beach sand that turned into hard rock, because a natural cement forms in between the individual grains of sand. Think of it as a bunch of sand and gravel glued together by carbonate, the white stuff that forms in your kettle or washing machine. Beachrocks are not only very cool, but also useful when we are trying to understand how sea level changed in the past and make assumptions on how it is going to change in the future. Climate driven global sea level rise might be something you are familiar with, but that is only part of the story. Yes, global sea level is rising, but the land might move as well. In some areas it is sinking, making global sea level rise an even bigger problem, in other areas the land is uplifting, mitigating the effects of global sea level rise. Beachrocks can help to understand what is happening on one individual stretch of coastline, giving coastal communities the chance to adapt and me the chance to hang out on tropical beaches a lot. While on the beach, I study the sedimentological characteristics of the beachrock and take samples. The samples are then taken to the lab – either to determine their age or to use a microscope to look at the cement between the grains.

The photograph shows a magnified image of four sand grains and the empty space between them. A scale in the corner shows that the grains are between 200 and 400 microns in diameter. The grains have smoothed surfaces and show different colors: transparent pale blue, transparent pale green or black with a grainy texture. The empty space between the grains is black. A 50 to 100 microns thick rim surrounds the grains. It has a greyish color and looks like a palisade fence with pointy tips reaching into the empty pore space. The individual grains do not touch but their rims overlap, holding them together.
Beachrock under the microscope. The empty space between the sand grains is filled by a natural cement that first forms as a rim around each grain and will later fill up the entire pore space turning loose sand into hard rock within years.

Right now, I am (sadly) neither at a beach nor in a lab, but at a desk in Germany preparing for my PhD defense and applying for postdoc positions – a tedious task that involves a lot of rejection. I don’t think there is a career in science without tedious tasks, be it repetitive lab work, marking piles of exams or never-ending application forms to fill out. Nevertheless, science allows me to keep my inner child alive, it allows me to follow my curiosity, all while making a contribution that helps coastal communities deal with the threat of sea level rise. I don’t know if I’ll get lucky one more time and be allowed to do this for a few more years, but I certainly hope so. One thing that I wish I had known from the beginning is that people are more important than the academic disciplines they belong to – looking back I would always choose a mentor outside my specialty with whom I have a great connection over the greatest expert in my field who does not care about me.

Update: By the time this is posted, I successfully defended my PhD thesis and started a Postdoc position in Heidelberg, Germany, where I get to teach sedimentology (yay) and work on a grant proposal for studying the incorporation of trash into beachrock on the Bahamas (even bigger yay)!!

The image shows four smiling people in fieldwork attire standing next to a one-humped camel. All four are wearing sandals and scarves wrapped around their heads. Three of them are girls and one is a bearded man, who is slightly older than the others. One of the girls is stroking the camel’s neck. The scarves and loose hairs of the girls are flapping in the wind, which seems to be quite strong. The background is a desert landscape with high dunes and a couple of fences but no vegetation. The sand is bright red. The sky is grey with dust, indicating a mild sandstorm.
Me, two other PhD-students from our lab and my supervisor Gösta at a field trip in the Wahiba Sands in Oman. Pro tip for everyone pursuing a career in science: choose your lab based on the people not on the prestige, the lab gear or the expertise… you can get all of these elsewhere. A good relationship with the PI is irreplaceable.

Invasive Mice Pose Risk of Extinction to Albatross Species

Cryptic population decrease due to invasive species predation in a long-lived seabird supports need for eradication

Steffen Oppel, Bethany L. Clark, Michelle M. Risi, Catharine Horswill, Sarah J. Converse, Christopher W. Jones, Alexis M. Osborne, Kim Stevens, Vonica Perold, Alexander L. Bond, Ross M. Wanless, Richard Cuthbert, John Cooper, Peter G. Ryan

Summarized by Michael Hallinan

What data were used? This study uses data collected on the breeding population of Tristan Albatross (Diomedea dabbenena) from 2004 to 2021 on Gough Island, in the southern Atlantic Ocean, where they almost exclusively live. All adult birds were marked and identified using metal rings for identification across annual visits during breeding season. This resulted in 4,014 albatross having encounter histories, and a very high probability that any breeding individual will have been detected if the nest had not failed early as they are faithful to their breeding sites. In addition to population metrics the number of nests per study area was recorded.

Methods: From the population size and demographic data an estimation of population trajectory, annual survival probability, and probability of returning to breeding grounds were calculated. These models were used to create population projections under three different scenarios. One scenario where mouse predation of the hatchlings did not change average breeding success and survival, one where mouse eradication lead to an increase in annual breeding success, and one where gradual increase of mouse predation decreases adult survival by 10%

Results: Generally, between 2004 and 2021 albatross breeding pairs didn’t seem to decrease statistically significantly. However, when also considering immature and non-breeding birds there was a detectable decrease in the global population of ~1% per year. Since albatross survival was quite high, this long-term decrease seems to be explained by low breeding success which is later investigated in the three scenario projections. Within these projections, under scenario A (where mouse predation stayed the same) the population steadily declined up through the model. Under scenario B (where successful mouse eradication occurred) the albatross population experienced an increase to 1.8-7.6 times its current size by 2050. Lastly, under scenario C (where no mouse eradication occurred and impacts worsened) the population declined significantly by 2050 with less than 2000 birds remaining.  

A shaded range line graph which presents observed breeding population and estimated total population from 2005 to 2021, as well as modeled total populations from 2021 to 2050. Breeding populations were consistently between 2000 individuals and 4000 individuals for this period with little variation outside of this range. The estimated total population however, begins at about 10000 individuals in 2005 and steadily decreases with some plateaus and peaks till about 8000 individuals in 2021. In addition, this graph then presents modeled data from 2021 to 2050 of each of the three scenarios. In scenario A (where no change occurs) the median population declines steadily from about 8000 to a little under 7000 individuals by 2050. In scenario B (where mice are successfully eradicated) the population experiences a median population increase up to just under 10000 individuals by 2050 but estimation errors result in a very wide credible interval which ranges from as high as approximately 17000 to a little under 8000 individuals in 2050. Lastly, in scenario C (where mice population increases and no eradication occurs) the median estimated population falls under 2000 individuals plus or minus 1000 by 2050.
This diagram shows observed population size on Gough Island between 2004 and 2021 (all data left of the dashed vertical line) where the black data points and regression represent the breeding population and the green line represents total estimated population size including unobservable immature and non-breeding birds.The three lines and intervals shown to the right side of the dashed line present the three scenarios through 2050. The lines represent the median values and the shading represents the 95% credible interval.

Why is this study important? The Tristan Albatross is classified as critically endangered based on a previous demographic analysis, finding that the species might go extinct within 30 years. This study creates a better projection for albatross population health under the three scenarios, which allows for significantly improved conservation efforts and a data-based sense of urgency regarding their conservation. 

The big picture: A series of Albatross population health and nest quantity data from 2004 to 2021 was recorded. It was used to model future population health development among three different scenarios regarding invasive mice predation on the albatross chicks. One where mice predation stayed the same, one where it got worse, and one where the mice were successfully being eradicated leading to increased albatross breeding successes.  If the mice were to be eradicated, albatross populations could experience a significant increase by 2050 with a population of up to 7.6 times today’s size. 

Citation: Ryan, Peter G. (2022/06/18). Cryptic population decrease due to invasive species predation in a long-lived seabird supports need for eradication. Journal of Applied Ecology, n/a, -. https://doi.org/10.1111/1365-2664.14218

Which trees are better suited for drought resistance and why?

Small and slow is safe: On the drought tolerance of tropical tree species

Joannès Guillemot, Nicolas K. Martin-StPaul, Leticia Bulascoschi, Lourens Poorter, Xavier Morin, Bruno X. Pinho, Guerric le Maire, Paulo R. L. Bittencourt, Rafael S. Oliveira, Frans Bongers, Rens Brouwer, Luciano Pereira, German Andrés Gonzalez Melo, Coline C. F. Boonman, Kerry A. Brown, Bruno E. L. Cerabolini, Ülo Niinemets, Yusuke Onoda, Julio V. Schneider, Serge Sheremetie, Pedro H. S. Brancalion

Summarized by Habiba Rabiu, a student of environmental geosciences at Fort Hays State University. Habiba is interested in all aspects of environmental science and conservation & sustainability. She would like to work in educating others about those topics. In her free time, she likes to read, write, and bake. 

What data were used? In this study, data concerning 601 tree species were examined. To determine what characteristics of a tree would make it more drought resistant, three qualities were assessed: resistance of xylem to embolism, which is the blocking of water from moving through the plant (designated as P50 by the authors), leaf turgor loss point or the ability of a plant to maintain turgor pressure and operate under water stress (TLP), and the hydraulic safety margin (HSM) which is the risk that a plant will experience hydraulic failure in the driest conditions it could normally face. HSM can also be defined as the difference between turgor loss point and resistance to embolism (HSM=TLP-P50).

The researchers compiled data from previous meta-analyses on the TLP and P50 values of the chosen tree species. The species were further divided based on leaf habit, meaning whether they were evergreen or deciduous. Additionally, seven traits of the species were considered: leaf mass per area (LMA), leaf size, leaf nitrogen concentration (leaf N), leaf phosphorus concentration (leaf P), wood density, maximum height, and seed mass. The type of forest the species lived in, whether dry or moist, was also a factor that was considered.

Methods: To organize these data in a way that would allow classification of the tree species based on drought resistance, the researchers found two major axes (traits) that contributed to drought resistance. The most important factor (labeled the “fast-slow” axes) showed the difference in rate of resource attainment and processing between the tree species. The second most important factor was the “stature-recruitment” axes, which compared the relationship between preference for (that is more energy and resources are allotted to) growth and survival of individual plants, to preference for new seedling propagation.

LMA, wood density, and leaf N and leaf P concentrations are features that determine where the species falls on the fast-slow axes, while maximum height, seed mass, and leaf size indicate their position on the stature-recruitment axes. TLP and P50 values (plus the calculated HSM values) demonstrate how well the species respond to lack of water and the accompanying stress. Lower values of HSM, TLP, and P50 (which are expressed as negative numbers) indicate more drought resistance.

Results:  The research determined that TLP and P50 (blocking of hydraulic action and the ability of the plant to maintain water pressure) were more negative in dry forests, and evergreen species tended to exhibit more negative TLP and smaller TLP- based HSM (risk that a plant will experience hydraulic failure) in dry forests than deciduous forests. The species that had the more negative TLP/P50 values and smaller HSM values tended to be smaller (leaned more to the recruitment side of the “stature-recruitment” axes) and slower to get and use resources (leaning towards “slow” rather than “fast” on those axes). In other words, smaller and slower evergreen trees were more drought resistant, and dry forests were naturally better suited to survive water stress than moist ones. 

Both graphs have an x-axis showing the properties P50, TLP, HSM, and leaf habit. The y-axis shows a range of R² in percentages from 0 to 60. Graph (b) shows P50 at around 30%, TLP around 60%, HSM around 10%, and leaf habit around 2%. Graph (c) shows P50 at around 37%, TLP around 1%, HSM around 20% and leaf habit around 1%.
The R² value shows the strength of the relationship between the qualities shown on the x-axis and the subject of the graph. Graph (b) shows that TLP is strongly related to the fast-slow axes, while (b) and (c) show that P50 has a similar relationship with the fast-slow axes and the stature-recruitment axes.

Why is this study important? One significant takeaway from this study is that it shows that drought resistance is not an independent quality that can be assessed on its own, it’s a complex mix of many traits. Isolating which traits are possessed by the most drought-resistant trees is valuable information when contending with ecosystems that are becoming hotter and drier as global warming becomes a bigger threat.

The big picture: Planting trees to restore tropical forests could be a great tool to combat the ill effects of climate change. However, care has to be taken to ensure that the trees planted are equipped to deal with the increased temperature of the atmosphere and presence of greenhouse gasses that come with global warming. 

Citation: Guillemot, J., Martin- StPaul, N. K., Bulascoschi, L., Poorter, L., Morin, X., Pinho, B. X., le Maire, G., Bittencourt, P. R. L., Oliveira, R. S., Bongers, F., Brouwer, R., Pereira, L., Gonzalez Melo, G. A., Boonman, C. C. F., Brown, K. A., Cerabolini, B. E. L., Niinemets, Ü., Onoda, Y. Schneider, J. V., … Brancalion, P. H. S. (2022). Small and slow is safe: On the drought tolerance of tropical tree species. Global Change Biology, 28, 2622– 2638. https://doi.org/10.1111/gcb.16082

Using Dinosaur Models to Learn More About Their Behavior

Digital 3D Models of Theropod Dinosaurs for Approaching Body Mass Distribution and Volume

by: Matías Reolid, Francisco J. Cardenal , Jesús Reolid

Summarized by: Makayla Palm 

What data were used? This study picked physical dinosaur models from eight different genera, or groups of dinosaur species, to scan and create 3D computer models. These models were used, alongside measurements collected from previous studies on each genus, in order to infer how these dinosaurs may have hunted, moved, and lived. The eight genera in the study were: Coelophysis, Dilophosaurus, Ceratosaurus, Allosaurus, Carnotautus, Baryonyx, Tyrannosaurus, and Giganotosaurus

Methods: Each model was scanned by a 3D printer in order to make a digital image. After the eight models were scanned, data on body length, collected in other studies, was added to the models. information was used in order to calculate body mass, volume, and skull length. These calculations were then used to make three ratios: skull length/body length, surface area/volume, and length/mass. 

Results: The three ratios calculated, skull length/body length, length/mass, and surface area/volume reveal information about these genera that wouldn’t be easily found by just observing the fossils, such as metabolism, eating habits, and overall roles in the ecosystem. The study first looks at the skull length/body length ratio. The larger a skull the dinosaur had, the larger and more expansive their jaws were. This is directly correlated to a higher demand for energy and higher body mass; a large skull was required to take down enough prey to fulfill energy demands. . If a dinosaur had a smaller skull, it was less equipped to take down larger prey, so this limits the kind of prey it had access to. In the case of Coelophysis, the oldest and smallest genus in the study, its skull/body length ratio infers that its small jaws were suited to smaller prey on land, but also small fish. In contrast, the larger theropods, Tyrannosaurus and Giganotosaurus, had the ability to hunt larger prey because of their large skull/body ratio. 

The next ratio observed was the length/mass ratio. This ratio considers differences in body plan that the skull/body length ratio does not. For example, Carnotaurus had a short skull in comparison to the other genera in the study, so it is the outlier in the group. However, the length/mass ratio accounts for its build, which recognizes its ability to hunt larger prey. Similarly, Baryonyx has one of the largest skull/body length ratios, but its long snout shape, similar to modern crocodiles, suggests it fed exclusively on fish and other swimming organisms, rather than large land-living prey. This ratio also sheds light on locomotion possibilities for these theropods. Allosaurus, a mid-size theropod, had longer arms than most other large dinosaurs like Tyrannosaurus. This suggests it may have used its arms when taking down large prey unlike its larger theropod comparisons, which are famous for their seemingly useless arms. 

The final ratio observed in this study is the surface area/volume ratio. This was used to study the efficiency of the dinosaurs to release excess heat, which has strong implications for metabolism. If an organism can release heat efficiently, it can have a higher metabolism, because high-metabolism organisms need that heat release. Researchers found that the smaller the dinosaur, the higher heat release, therefore a high metabolism and vice versa. This is consistent with the study’s findings on feeding habits. Coelophysis preyed on smaller organisms, but was probably able to do so more frequently. Tyrannosaurus hunted larger prey, but most likely needed to rest in between for significant periods of time because of its slower metabolism. 

A scatter-plot graph represents the different body mass and skull/body ratios of each theropod dinosaur genus . The overall trend is a positive exponential growth, which represents a consistent increase in these ratios over time, with Carnotaurus as the outlier because of its shorter skull shape. Coelophysis, the smallest of the studied genera, has the smallest body mass and skull-to-body length ratio and plots on the x-axis. Dilophosaurus, Ceratosaurus, Baryonyx, Allosaurus, Giganotosaurus and Tyrannosaurus all follow the curve of the graph and are listed here in order from smallest to largest skull to body length ratios. Carnotaurus, the outlier on the graph, has a point on the graph that lies close to the origin despite its slightly larger body mass.
This scatter plot displays each dinosaur’s body weight by skull-to-body ratio. As body weight increases, so does the skull/body length ratio. The outlier in the group is Carnotaurus, as its shorter skull gives it a smaller skull/body length ratio.

Why is this study important? This study allows observations of theropod dinosaurs to be made that would not be possible from studying just the bones. This data strengthens previous ideas about theropod behavior, such as larger dinosaurs need more energy and need to hunt larger prey. Therefore, their body structure is reflective of a creature able to take down the kind of prey it needs. This study also provides new information previously not available because of new data about metabolism and body surface area, such as a surface area/volume ratio, which indicates what dinosaur metabolism may have been. 

The big picture: This study of 3D scans of theropod dinosaurs infer information from new data by scanning to scale models. These data allow researchers to compare new measurements like surface area and volume to better understand what dinosaur metabolisms and body plans may have been like, which may confirm or reform what we already know about their roles in their respective environments. 

Citation: Reolid, Matías, et al. “Digital 3D Models of Theropods for Approaching Body-Mass Distribution and Volume.” Journal of Iberian Geology, vol. 47, no. 4, 2021, pp. 599–624., https://doi.org/10.1007/s41513-021-00172-1.