The coelacanth, also known as the “living fossil,” has been a subject of fascination for scientists due to its unique anatomy that has remained largely unchanged since the extinction of the dinosaurs. A recent study published in Science Advances has revealed new insights into vertebrate evolution, shedding light on the cranial musculature of the African coelacanth (Latimeria chalumnae).

The researchers from the University of São Paulo (USP) and the Smithsonian Institution in the United States conducted a thorough examination of the fish’s anatomy, focusing on its cranial muscles. They discovered that only 13% of the previously identified evolutionary muscle novelties for the largest vertebrate lineages were accurate.

“Ultimately, it’s even more similar to cartilaginous fish and tetrapods than previously thought,” said Aléssio Datovo, a professor at the Museum of Zoology (MZ) at USP, who led the study. The researchers also identified nine new evolutionary transformations related to innovations in feeding and respiration in these groups.

Among the evolutionary novelties erroneously identified as present in coelacanths were muscles responsible for actively expanding the buccopharyngeal cavity, which extends from the mouth to the pharynx. However, the study showed that these supposed muscles in coelacanths were actually ligaments, which are structures incapable of contraction.

This discovery has significant implications for our understanding of vertebrate evolution, particularly regarding the cranial muscles of other large vertebrates. The researchers used three-dimensional microtomography images of the skulls of other fish groups to infer where the muscles found in coelacanths would fit, elucidating the evolution of these muscles in the first jawed vertebrates.

This study has shed new light on the evolution of vertebrate cranial musculature and highlights the importance of further research into this area. The discovery also underscores the significance of the coelacanth as a “living fossil,” providing valuable insights into the evolution of vertebrates that are not available from fossil records alone.

The study’s findings have far-reaching implications for our understanding of vertebrate evolution, and researchers intend to analyze similarities with the muscles of tetrapods, such as amphibians and reptiles, in future work.

Unveiling the Dinosaur’s Menu: A Fossilized Time Capsule Reveals the Sauropod’s Diet 100 Million Years Ago

A groundbreaking study published in the Cell Press journal Current Biology has shed light on the diet of one of the most fascinating creatures to have ever walked the Earth – the sauropod dinosaur. The research, led by Stephen Poropat of Curtin University, reveals that these gentle giants were herbivores and had a unique digestive system that relied heavily on gut microbes for digestion.

The study’s findings are based on an extraordinary discovery made in 2017 at the Australian Age of Dinosaurs Museum of Natural History. During an excavation of a sauropod skeleton from the mid-Cretaceous period, researchers stumbled upon a well-preserved cololite – a fossilized rock layer containing the dinosaur’s gut contents.

The analysis of the plant fossils within the cololite has confirmed several long-standing hypotheses about the sauropod diet. The research team found that these dinosaurs likely engaged in minimal oral processing of their food and instead relied on fermentation and their gut microbiota for digestion.

The variety of plants present in the cololite suggests that sauropods were indiscriminate bulk feeders, eating a range of foliage from conifers to leaves from flowering plants. This is supported by the presence of chemical biomarkers from both angiosperms and gymnosperms, indicating that at least some sauropods were not selective feeders.

The researchers’ findings have significant implications for our understanding of these massive herbivores and their role in ancient ecosystems. The study suggests that sauropods had successfully adapted to eat flowering plants within 40 million years of the first evidence of their presence in the fossil record.

In addition, the research team found evidence of small shoots, bracts, and seed pods in the cololite, implying that subadult Diamantinasaurus targeted new growth portions of conifers and seed ferns. This strategy of indiscriminate bulk feeding seems to have served sauropods well for 130 million years and might have enabled their success and longevity as a clade.

While this research has shed new light on the diet of sauropod dinosaurs, there are still limitations to consider. The study’s primary limitation is that the sauropod gut contents described constitute a single data point, which may not be representative of typical or adult sauropods’ diets.

This research was supported by funding from the Australian Research Council and has significant implications for our understanding of these fascinating creatures and their role in ancient ecosystems.

The fate of the West Antarctic Ice Sheet (WAIS) hangs precariously in the balance, with scientists warning that the next few years will be crucial in determining its future. A recent study published in Communications Earth & Environment has shed light on the alarming consequences of WAIS collapse, which could trigger a devastating four meters of global sea level rise over hundreds of years.

The researchers from the Potsdam Institute for Climate Impact Research (PIK), NORCE, and Northumbria University in the UK conducted extensive model simulations spanning 800,000 years to understand how the vast Antarctic Ice Sheet has responded to Earth’s climate fluctuations. Their findings revealed two stable states: one with WAIS intact, which is our current state, and another where the ice sheet has collapsed.

The primary driver of this collapse is rising ocean temperatures around Antarctica, which are mostly supplied by the ocean rather than the atmosphere. Once WAIS tips into the collapsed state, it would take several thousands of years for temperatures to drop back to pre-industrial conditions, reversing the damage.

“We have two stable states: one with WAIS intact and another where it has collapsed,” said lead author David Chandler from NORCE. “Once tipping has been triggered, it’s self-sustaining and seems very unlikely to be stopped before contributing to about four meters of sea-level rise. And this would be practically irreversible.”

The consequences of WAIS collapse would be catastrophic, with four meters of sea level rise projected to displace millions of people worldwide and wreak havoc on coastal communities.

However, there is still hope for a better outcome. Immediate actions to reduce emissions could avoid a catastrophic outcome, giving us a narrow window to act before it’s too late.

“It takes tens of thousands of years for an ice sheet to grow, but just decades to destabilise it by burning fossil fuels,” said co-author Julius Garbe from PIK. “Now we only have a narrow window to act.”