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.

Deep-sea fish have long been a mystery, but new research is shedding light on their importance in Earth’s carbon cycle. Scientists at the University of Miami Rosenstiel School of Marine, Atmospheric, and Earth Science have discovered that deep-dwelling mesopelagic fish, which account for up to 94% of global fish biomass, excrete carbonate minerals at rates comparable to shallow-water species.

The study focused on the blackbelly rosefish (Helicolenus dactylopterus), a deep-sea species living at depths of 350-430 meters. The researchers found that these fish form and excrete intestinal carbonate, also known as ichthyocarbonate, which helps maintain internal salt and water balance in saline environments. This process plays a critical role in marine carbon cycling.

The study’s lead author, Martin Grosell, explained that it was unclear whether mesopelagic fish produced carbonate like shallow-water fish do or at what rate. However, the research confirms that they do produce carbonate at rates similar to those of shallow-water species. The blackbelly rosefish was found to excrete approximately 5 milligrams of ichthyocarbonate per kilogram per hour, aligning with predictions from thermal and metabolic scaling models.

This study fills a major gap in our understanding of ocean chemistry and carbon cycling. With mesopelagic fish playing such a significant role, their contribution to carbonate flux – and how it might change with warming oceans – deserves greater attention. The findings also underscore the importance of ichthyocarbonate in the ocean carbon cycle, especially given the vast, underexplored biomass of the mesopelagic zone.

The study’s authors say that these results offer strong support for global models of fish-derived carbonate production, which had assumed but not verified that mesopelagic species contribute at similar rates. Mesopelagic fish aren’t just prey; they’re chemical engineers of the ocean.

This research opens new avenues for studying deep-sea carbon dynamics and may improve Earth system models, which are sophisticated computer models that incorporate interactions between physical, chemical, and biological processes, such as biological carbon production and export. The study was published in the Journal of Experimental Biology on July 15, 2025.

The discovery of new compounds in millipede secretions has opened up exciting possibilities for drug development and the treatment of neurological diseases. A team led by chemist Emily Mevers has found complex structures in these secretions that can modulate specific neuroreceptors in ant brains, leading to disorientation in the ants.

These newly discovered structures, called alkaloids, fall into a class of naturally occurring compounds that have been studied for their potential pharmacological applications. The Mevers team named them andrognathanols and andrognathines after the millipede species, Andrognathus corticarius, found on Virginia Tech’s Blacksburg campus.

Mevers’ research focuses on leveraging the chemistry of underexplored ecological niches, such as the millipede, for drug discovery. Her team collected millipedes from Stadium Woods and used various analytical tools to identify the compounds contained in their defensive glands. These secretions are released by the millipedes to ward off predators while also sharing their location with their kin.

The broader implications of this research are significant, as much about millipedes remains mysterious, including their specific habitats, numbers, diets, behaviors, and chemistry. Mevers is collaborating with millipede expert Paul Marek in the entomology department to fill in these gaps and explore potential applications for future medications.

In a previous study, Mevers and Marek examined a millipede native to the Pacific Northwest and discovered that related alkaloids interacted potently and selectively with the Sigma-1 neuroreceptor. This interaction suggested that this family of compounds may have useful pharmacological potential for treating pain and other neurological disorders.

The new alkaloids discovered in this study are actively secreted from the Hokie millipede when it is physically disturbed, causing disorientation in ants, a presumed natural predator. A subset of these compounds possesses similar interactions with the Sigma-1 neuroreceptor, further supporting their potential for drug development.

With these complex compounds in hand, the next step is to synthesize them in larger quantities and evaluate their biomedical applications. According to Mevers, “These compounds are quite complex, so they’re going to take some time to synthesize in the lab.” Once larger quantities are available, Mevers will be able to better study their properties and potential in drug development, potentially leading to new treatments for human pain relief.