A rare species of shark has been rediscovered in Papua New Guinea, nearly half a century after its last sighting.

The Sailback Hound Shark, known for its unusually large dorsal fin (Gogolia filewoodi), was first recorded by researchers in 1973. A pregnant female was captured in Astrolabe Bay, near the Gogol River, and this marked the only known instance of the species for many years.

Jack Sagumai and his team from the World Wildlife Fund Pacific gathered fisheries data from local communities, aimed at supporting the national action plan for sharks and rays. In March 2020, they were pleasantly surprised when they stumbled upon images of several small sharks close to the mouth of the Gogol River, all featuring the characteristic dorsal fin.

Initially, five of these sharks were identified as female. In 2022, another fisherman in the vicinity caught a male. Collaborating with William White from the Commonwealth Scientific and Industrial Research Organization in Australia, the team verified that these creatures were indeed the long-lost sailback houndsharks.

“When we heard that this species was so elusive, it was frustrating,” Sagmai said.

This marks the first scientific documentation of the species in over 50 years, though fishermen in Astrolabe Bay claim they regularly encounter these sharks. They report sightings near the mouth of the Gogol River while fishing primarily for drums, according to Sagmai.

“It appears to favor deeper waters and tends to associate with other fish when feeding near the river mouth,” he noted.

As these sharks are only located in a small area, they may represent a “micro-inhabiting” species with a very limited range in Astrolabe Bay.

“Alternatively, they may have once had a broader distribution across regions like Indonesia and Papua New Guinea,” suggested David Ebert from San Jose State University in California. This region also hosts similar micro-inhabiting species, such as bamboo and epaulette sharks.

Sagumai noted that information regarding the Sailback Hound Shark’s biology and population size remains sparse. Currently, two deceased specimens are housed at the University of Papua New Guinea, and the team plans to collaborate with researchers in Australia and Florida to conduct a DNA analysis of the sharks.

“These efforts will establish genetic baselines for future monitoring and inform conservation strategies,” he added.