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.

The 2014-2016 marine heatwave along the Pacific coast of North America was unprecedented in its duration and severity. This prolonged event pushed temperatures to two to six degrees above historical averages, leaving an indelible mark on the region’s marine ecosystems. Researchers from the University of Victoria’s Baum Lab have compiled a comprehensive synthesis of 331 primary studies and governmental reports, shedding light on the far-reaching ecological impacts of this heatwave.

“The marine heatwave resulted in unprecedented ecological disturbance across thousands of kilometers of North America’s west coast,” says Samuel Starko, lead author and former UVic postdoctoral fellow. “Our comprehensive synthesis helps us better understand its overall impacts and how these fit into the broader context of other marine heatwaves.”

The consequences of this heatwave were multifaceted and far-reaching:

* 240 species were found outside their typical geographic range, with many swimming further north than ever before.
* Several species, such as the northern right whale dolphin and sea slug Placida cremoniana, were discovered over 1,000 kilometers north of their usual habitat.
* Kelp forests collapsed, and widespread declines in kelp and seagrass occurred.
* Sea stars, seabirds, and marine mammals experienced unprecedented mortality events.
* Temperature-linked diseases contributed to ecosystem collapse.

The impacts of this heatwave cascaded throughout the ecosystem, affecting everything from plankton to whales. The reduced abundance and nutritional quality of forage fish caused problems for predators, while plankton communities reorganized, and offshore oceanographic productivity was altered.

The economic costs were substantial, with hundreds of millions of dollars in losses due to the closure of multiple fisheries driven by changes in species interactions, disease proliferation, and habitat loss.

“As heatwaves become more frequent and intense under climate change, the 2014-16 Northeast Pacific marine heatwave provides a critical example of how climate change is impacting ocean life,” says Julia Baum, UVic marine ecologist and special advisor on climate. “This study underscores the urgent need for proactive, ecosystem-based marine conservation strategies and climate change mitigation measures.”

The research published in Oceanography and Marine Biology: An Annual Review was supported by funding from various organizations, including the Natural Science and Engineering Research Council of Canada.

Research in the Baum Lab supports the United Nations Sustainable Development Goals (SDGs) No. 11 (life below water) and No. 13 (climate action).

As Brazil’s Pantanal wetlands faced devastating wildfires in 2020, it seemed like a catastrophe for its unique wildlife. However, a recent study published in Global Change Biology reveals that the fires actually led to an increase in jaguar population density in the area, making it a potential climate refuge. The research team from Oregon State University and their Brazilian partners have been studying the jaguars since 2014, using camera traps and scat analysis to understand their behavior and habitat.

The study site, covering over 36,700 acres, is a protected area that experiences seasonal flooding. It’s home to a distinct population of jaguars that primarily feed on aquatic organisms rather than land-based animals. These big cats are also surprisingly socially tolerant, often sharing space with other jaguars. The researchers found that the 2020 wildfires and extreme drought drove an estimated loss of 17 million vertebrates across the Pantanal.

The study, led by Charlotte Eriksson, a postdoctoral scholar at Oregon State University, analyzed video footage from camera traps deployed before, during, and after the fires. They also collected nearly 175 jaguar scats to determine their diet. The findings suggest that the area may serve as a climate refuge, buffering the effects of extreme climate events.

Eriksson emphasized the importance of maintaining such refugia and implementing proactive fire management to protect these unique ecosystems. “Finding even more jaguars and other mammals in the study area following the 2020 wildfire and extreme drought suggests that it may serve as a climate refuge, buffering the effects of extreme climate events,” Eriksson said.

The researchers caution against generalizing their findings to other areas due to the site’s unique characteristics, including its protected status. However, they highlight the significance of preserving refugia like this one, which can provide crucial habitat for species struggling with the impacts of climate change.