A “fish-prawn” hybrid creature known as the armored searobin has been filmed walking backward along the ocean floor for the first time. The peer-reviewed study, published July 30, in Ocean-Land-Atmosphere Research, details the discovery made by researchers from Sun Yat-sen University and the Southern Marine Science and Engineering Guangdong Laboratory in Zhuhai. The team captured the footage in the northern South China Sea using deep-sea diving vehicles.
Deep-Sea Footage Captures the Armored Searobin Walking Backward
Decoding the Anatomy of Scalicus engyceros
Scientifically classified as Scalicus engyceros, the armored searobin belongs to a family of fishes defined by specialized free pectoral-fin rays. Han Tian, the primary author and a doctoral researcher at the School of Marine Sciences at Sun Yat-sen University, notes that the species features a striking shrimp-fish hybrid appearance. This distinctive look earned it the “fish-prawn hybrid” moniker in U.S. local media. While formal descriptions of searobins date back to Albert Günther in 1872, direct observation of their underwater locomotion had previously remained unconfirmed.
Sideways Shuffling and Explosive Leaps on the Benthos
The new video documentation confirms the speculation that searobins use their free pectoral-fin rays to walk across the benthos. According to Tian, the fish can move both sideways and backward—a movement profile previously unobserved in other fish species. Beyond this steady walking gait, the creature retains shrimp-like fin rays and a tail that facilitate explosive, jerky leaps when threatened.
Rake-Like Barbels and Sensory Probes
Survival in the deep ocean demands specialized tools. Outward-extending barbels on the searobin resemble a farmer’s rake. These physical structures function as sensory probes, allowing the fish to dig directly into surface sediment and efficiently locate prey.
Shedding Light on Peristediid Adaptations
During expeditions in the northern South China Sea, scientists documented three live peristediid fish species: Scalicus engyceros, Paraheminodus murrayi, and Peristedion liorhynchus. Observations showed that these organisms rolled their eyes in response to the light beams of approaching deep-sea vehicles. This reaction indicates that their large eyes retain some sensitivity to light. Building on these findings, researchers plan to use these in situ observations to construct a new framework for understanding benthic fish adaptive evolution, alongside the co-evolution of walking locomotion, rake-shaped appendages, and deep-sea foraging strategies.