The researchers completed a painstaking comparison of seven uncategorized fossil specimens with previously identified fossils and bone samples from around the world to describe the new species. Their finding makes a case for the use of the elbow portion of the humerus — in addition to teeth — to identify fossils of large saber-toothed cats whose massive forearms enabled them to subdue their prey.

The newly identified cat weighed an average of around 600 or so pounds and could have managed to kill prey weighing up to 6,000 pounds, the scientists estimate, suggesting that their findings provide evidence for another giant cat, one of the largest in Earth history.

“We believe these were animals that were routinely taking down bison-sized animals,” said study co-author Jonathan Calede, an assistant professor of evolution, ecology and organismal biology at The Ohio State University’s Marion campus. “This was by far the largest cat alive at that time.”

Calede completed the study with John Orcutt, assistant professor of biology at Gonzaga University, who initiated the project. Orcutt found a large upper arm bone specimen that had been labeled as a cat in the University of Oregon Museum of Natural and Cultural History collection when he was a graduate student, and collaborated with Calede on the years-long effort to figure out what kind of cat it could be.

They have determined that the new species is an ancient relative of the best-known saber-toothed cat Smilodon, the famous fossil found in the La Brea Tar Pits in California that went extinct about 10,000 years ago.

The Oregon specimen was excavated on the traditional lands of the Cayuse, a tribe joined with the Umatilla and Walla Walla in the Confederated Tribes of the Umatilla Indian Reservation. In recognition of its origin, Calede and Orcutt collaborated with the Tamástslikt Cultural Institute to name the new species Machairodus lahayishupup. Machairodus is a genus of large saber-toothed cats that lived in Africa, Eurasia and North America, and in the Old Cayuse language, Laháyis Húpup means “ancient wild cat.”

The study is published today (May 3, 2021) in the Journal of Mammalian Evolution.

Orcutt and Calede found similar uncategorized upper arm fossil specimens at the Idaho Museum of Natural History, where a big cat forearm was accompanied by teeth — generally considered the gold standard for identifying new species — as well as at the University of California Museum of Paleontology and Texas Memorial Museum.

“One of the big stories of all of this is that we ended up uncovering specimen after specimen of this giant cat in museums in western North America,” Orcutt said. “They were clearly big cats. We started with a few assumptions based on their age, in the 5 1/2 to 9 million-year-old range, and based on their size, because these things were huge.

“What we didn’t have then, that we have now, is the test of whether the size and anatomy of those bones tells us anything — and it turns out that yes, they do.”

The largest of the seven Machairodus lahayishupup humerus fossils available for the analysis was more than 18 inches long and 1.7 inches in diameter. By comparison, the average modern adult male lion’s humerus is about 13 inches long.

The researchers hypothesized that if an isolated forearm bone were useful in telling species apart, that would be true among the big cat species alive today. Calede and Orcutt visited numerous museums in the U.S., Canada and France to photograph forearm specimens of lions, pumas, panthers, jaguars and tigers, as well as fossils of previously identified extinct big cats.

Calede used software to place landmark points on each digitized sample that, when drawn together, would create a model of each elbow.

“We found we could quantify the differences on a fairly fine scale,” Calede said. “This told us we could use the elbow shape to tell apart species of modern big cats.

“Then we took the tool to the fossil record — these giant elbows scattered in museums all had a characteristic in common. This told us they all belonged to the same species. Their unique shape and size told us they were also very different from everything that is already known. In other words, these bones belong to one species and that species is a new species.”

The researchers calculated estimates of the new species’ body size based on the association between humerus size and body mass in modern big cats, and speculated about the cat’s prey based on its size and animals known to have lived in the region at that time: rhinoceros were particularly abundant, as well as giant camels and giant ground sloths.

The teeth from the Idaho Museum of Natural History came from the lower part of the jaw and did not include the saber-shaped canines, but provided additional evidence that the fossil belonged to the Machairodus genus, which gave its name to the machairodontines — the technical name for a saber-toothed cat, Orcutt said.

“We’re quite confident it’s a saber-toothed cat and we’re quite confident it’s a new species of the Machairodus genus,” he said. “The problem is, in part because we haven’t necessarily had a clear image in the past of how many species were out there, our understanding of how all these saber-toothed cats are related to each other is a little fuzzy, particularly early in their evolution.”

Establishing that the humerus alone can be analyzed to identify a fossil cat has important implications for the field — saber-toothed cats’ “big, beefy” forearm bones are the most common specimens of fossil cats found in excavations, he said.

Only a reconstruction of the evolutionary history of saber-toothed cats can determine where this new species fits in, but Orcutt and Calede believe Machairodus lahayishupup existed early in the evolution of the group.

A discovery that this giant cat in North America existed at the same time similar animals lived around the world also raises another evolutionary question, Calede said.

“It’s been known that there were giant cats in Europe, Asia and Africa, and now we have our own giant saber-toothed cat in North America during this period as well,” he said. “There’s a very interesting pattern of either repeated independent evolution on every continent of this giant body size in what remains a pretty hyperspecialized way of hunting, or we have this ancestral giant saber-toothed cat that dispersed to all of those continents.

“It’s an interesting paleontological question.”

For the first time, an international team of researchers from the University of Rochester and Delft University of Technology in the Netherlands used 3D printers and a novel bioprinting technique to print algae into living, photosynthetic materials that are tough and resilient. The material has a variety of applications in the energy, medical, and fashion sectors. The research is published in the journal Advanced Functional Materials.

“Three-dimensional printing is a powerful technology for fabrication of living functional materials that have a huge potential in a wide range of environmental and human-based applications.” says Srikkanth Balasubramanian, a postdoctoral research associate at Delft and the first author of the paper. “We provide the first example of an engineered photosynthetic material that is physically robust enough to be deployed in real-life applications.”

HOW TO BUILD NEW MATERIALS: LIVING AND NONLIVING COMPONENTS

To create the photosynthetic materials, the researchers began with a non-living bacterial cellulose — an organic compound that is produced and excreted by bacteria. Bacterial cellulose has many unique mechanical properties, including its flexibility, toughness, strength, and ability to retain its shape, even when twisted, crushed, or otherwise physically distorted.

The bacterial cellulose is like the paper in a printer, while living microalgae acts as the ink. The researchers used a 3D printer to deposit living algae onto the bacterial cellulose.

The combination of living (microalgae) and nonliving (bacterial cellulose) components resulted in a unique material that has the photosynthetic quality of the algae and the robustness of the bacterial cellulose; the material is tough and resilient while also eco-friendly, biodegradable, and simple and scalable to produce. The plant-like nature of the material means it can use photosynthesis to “feed” itself over periods of many weeks, and it is also able to be regenerated — a small sample of the material can be grown on-site to make more materials.

ARTIFICIAL LEAVES, PHOTOSYNTHETIC SKINS, AND BIO-GARMENTS

The unique characteristics of the material make it an ideal candidate for a variety of applications, including new products such as artificial leaves, photosynthetic skins, or photosynthetic bio-garments.

Artificial leaves are materials that mimic actual leaves in that they use sunlight to convert water and carbon dioxide — a major driver of climate change — into oxygen and energy, much like leaves during photosynthesis. The leaves store energy in chemical form as sugars, which can then be converted into fuels. Artificial leaves therefore offer a way to produce sustainable energy in places where plants don’t grow well, including outer space colonies. The artificial leaves produced by the researchers at Delft and Rochester are additionally made from eco-friendly materials, in contrast to most artificial leaf technologies currently in production, which are produced using toxic chemical methods.

“For artificial leaves, our materials are like taking the ‘best parts’ of plants — the leaves — which can create sustainable energy, without needing to use resources to produce parts of plants — the stems and the roots — that need resources but don’t produce energy,” says Anne S. Meyer, an associate professor of biology at Rochester. “We are making a material that is only focused on the sustainable production of energy.”

Another application of the material would be photosynthetic skins, which could be used for skin grafts, Meyer says. “The oxygen generated would help to kick-start healing of the damaged area, or it might be able to carry out light-activated wound healing.”

Besides offering sustainable energy and medical treatments, the materials could also change the fashion sector. Bio-garments made from algae would address some of the negative environmental effects of the current textile industry in that they would be high-quality fabrics that would be sustainability produced and completely biodegradable. They would also work to purify the air by removing carbon dioxide through photosynthesis and would not need to be washed as often as conventional garments, reducing water usage.

“Our living materials are promising because they can survive for several days with no water or nutrients access, and the material itself can be used as a seed to grow new living materials,” says Marie-Eve Aubin-Tam, an associate professor of bionanoscience at Delft. “This opens the door to applications in remote areas, even in space, where the material can be seeded on site.”

How will climate change affect the Earth’s ecosystems? How will biodiversity in different regions change? Such important questions about the future are difficult to answer. In order to do so, it is important to know how the individual species and their communities will react to changing precipitation conditions, for example. But despite numerous scientific experiments worldwide, we do not have synthetic, global answers to these questions. For example, experiments differ greatly in their methodology, such as whether they add small or large amounts of water. “These studies use different methods and are located in different regions of the world,” says first author Dr. Lotte Korell, a biologist at the UFZ. “And these studies yield contradictory results in many cases.” Together with her colleagues, she has therefore set out to derive a general understanding from the data collected worldwide. The focus was on how an increase or decrease in precipitation affects the plant diversity of terrestrial ecosystems.

In their search, she and her team found 23 usable publications, which presented results from 72 field experiments. With this data, they calculated various statistical variables that provided information about the biodiversity at the individual sites and related them to the increasing or decreasing amounts of rainfall.

“However, in such experiments, biodiversity depends on many factors,” says Prof. Dr. Tiffany Knight, last author of the study and ecologist at the UFZ, iDiv, and MLU. For example, the size of the experiment plays an important role. If you focus on only a single experimental plot, then you might see dramatic effects of treatments on biodiversity, as plots with less water have fewer plant individuals growing there, and thus fewer species. However, at least one individual of every species might be found in at the larger scale, and thus a lower effect of the treatment on biodiversity. Indeed, the researchers found that increasing dryness has a greater effect when it is considered at small compared to larger spatial scales. “Thus, in order to draw the right conclusions from the data, you have to take into account both the local climate conditions and the spatial scale of the experiments,” says Knight.

In this way, the researchers have identified a clear trend. In the drylands of the world, changes in precipitation levels have a much greater effect than in wetter regions.

Dry ecosystems currently occupy about 40% of the Earth’s land surface. It is not easy to predict what awaits these areas against the backdrop of climate change. Although climate models do predict increasing rainfall in some dry regions, the water shortage is likely to worsen in most of them.

According to the study, plant diversity is expected to increase where it becomes wetter. This is probably because the seeds of the species found there may have a better chance of germinating and becoming established.

However, in light of the projected expansion of drylands, this effect is likely to benefit only relatively few regions. According to the authors, this would lead to a noticeable decline in plant diversity. “Although the plants there have adapted to the challenges of their habitats over long periods of time,” says Korell, “at some point, even the most resilient survivor reaches its limits.” And with every species that dries up and can no longer germinate, biodiversity is reduced.

This could be bad news not only for the ecosystems but also for the inhabitants of the dry regions. After all, they account for about one third of the world’s population. Many of these people struggle to make a living from the land under the most difficult conditions. If biodiversity declines along with the rainfall, this is likely to become an even greater challenge. For Korell and her colleagues, this is another pressing argument for slowing climate change. “It is also important to protect the drylands particularly well,” says the researcher. The more these sensitive ecosystems are put under pressure from overgrazing and other stress factors, the more climate change is likely to affect plant diversity.