Researchers have identified three new species of snailfish in the abyssal plains of the eastern Pacific Ocean, a discovery that underscores the vast amount of biodiversity remaining to be found in the deep sea. The finds, located at depths between 3,268 and 4,119 meters off the California coast, were made possible by advanced deep-sea submersibles and robotic technology. These new organisms provide a vivid reminder of how little is known about Earth’s largest and least-explored habitat.
The collaborative effort, involving scientists from several universities and the Monterey Bay Aquarium Research Institute (MBARI), has provided a clearer picture of life in extreme environments. Through a combination of modern genetic sequencing and detailed physical analysis, the research team officially described the new species, each possessing unique adaptations to survive under immense pressure and in near-freezing temperatures. The discoveries contribute significantly to the growing catalog of the snailfish family, Liparidae, which now includes more than 400 species found in oceans worldwide, from shallow waters to the deepest trenches.
New Additions to the Snailfish Family
The three newly described species each have distinct features that set them apart. One of the most visually striking is the bumpy snailfish, given the scientific name Careproctus colliculi. This small, pinkish-white fish has a rounded head, large eyes, and a unique, bumpy skin texture that inspired its name. It was observed near the seafloor about 100 kilometers offshore from Monterey Bay. Despite its memorable appearance, scientists have only one confirmed observation of this species, highlighting the rarity of such encounters in the deep ocean.
The other two species were discovered more than 200 kilometers away, near a long-term deep-sea research site known as Station M. The dark snailfish, Careproctus yanceyi, is entirely black and was named in honor of Paul Yancey, a biologist recognized for his extensive contributions to the field of deep-sea physiology. Sharing its habitat is the sleek snailfish, Paraliparis em, which has a long, dark, and laterally compressed body. Interestingly, these two species were collected during the same dive but are genetically and morphologically quite different, which demonstrates the hidden, or cryptic, diversity that can exist even within a small area of the abyssal zone.
Advanced Exploration Technology
The discovery of these new snailfish would not have been possible without sophisticated underwater technology capable of reaching and operating in the abyssal zone. The research team utilized multiple deep-sea vehicles to explore these remote environments. Two of the species, the dark snailfish and the sleek snailfish, were collected using the human-occupied submersible Alvin at a depth of around 4,119 meters. Alvin allows scientists to personally visit the deep seafloor, offering direct observation and precise sample collection capabilities.
The bumpy snailfish was collected during a separate expedition on MBARI’s now-retired research vessel, the Western Flyer, which deployed a remotely operated vehicle (ROV). ROVs like the Doc Ricketts are controlled from a surface ship and equipped with high-definition cameras and robotic arms, enabling researchers to survey large areas and collect specimens with great care. These technologies are critical for accessing environments where the pressure is thousands of pounds per square inch and temperatures are colder than a household refrigerator. The long-term observatory, Station M, has been instrumental in allowing scientists to regularly study deep-sea communities and changing ocean conditions over time.
A Multi-Faceted Identification Process
Morphological and Anatomical Analysis
Confirming that the three snailfish were new to science required a meticulous and multi-pronged approach. Researchers began with traditional taxonomic methods, including detailed microscopy to examine external features. They carefully counted physical characteristics such as fin rays and vertebrae, which are standard metrics for distinguishing between fish species. To gain a deeper understanding of the fishes’ internal structures without resorting to invasive dissection, the team employed micro-CT scans. This advanced imaging technique created high-resolution, three-dimensional models of the fishes’ skeletons and other internal features, revealing subtle but crucial differences between them.
Genetic Confirmation
While physical characteristics provided strong evidence, genetic analysis delivered the definitive proof. The scientists sequenced the DNA of the specimens, focusing on a specific mitochondrial gene known as COI, which is a standard marker used for species identification in animals. The genetic data confirmed that the three types of snailfish were distinct from one another and from any other known species. This combination of morphological and genetic evidence is now a cornerstone of modern taxonomy, especially for deep-sea organisms where species can sometimes appear superficially similar—a phenomenon known as cryptic speciation.
Expanding Knowledge of Deep-Sea Ecosystems
This research, published in the journal Ichthyology & Herpetology, highlights how much remains unknown about life on our own planet. Mackenzie Gerringer, a marine biologist at the State University of New York at Geneseo and the study’s lead author, noted the importance of continued exploration. “The deep sea is home to an incredible diversity of organisms and a truly beautiful array of adaptations,” Gerringer stated. “Our discovery of not one, but three, new species of snailfishes is a reminder of how much we have yet to learn about life on Earth.” The study also involved several undergraduate co-authors, providing valuable experience for the next generation of marine scientists.
Snailfish are a remarkably successful and adaptable family of fishes. They are characterized by large heads, gelatinous bodies, and narrow tails. Many species possess a suction disk on their bellies, which allows them to attach firmly to surfaces like rocks, the seafloor, or even other animals like crabs. This adaptation is seen in shallow-water species that curl up like snails when clinging to rocks, giving the family its name. Documenting deep-sea biodiversity is not just an academic exercise; it is critical for establishing a baseline to monitor the health of these remote ecosystems and detect any future changes. As human activities increasingly impact the ocean, understanding the full scope of its biodiversity is more important than ever.