Locals had a name for it long before scientists did. Now, genetic analysis confirms Hemiscyllium dudgeonae is the tenth known species of walking shark.
Late one night in March 2025, marine biologist Christine Dudgeon was wading through a seagrass meadow in Milne Bay, Papua New Guinea — tired, torch in hand, searching for a shark she already knew. What she found instead was one nobody had formally described before.
The animal she spotted, moving along the seafloor in barely a metre of water, belonged to the genus Hemiscyllium — a group of small sharks that use their pectoral fins like limbs to walk across coral reef flats, often with most of their body exposed to air at low tide. Local communities in the region had long recognised these animals, calling them kadedekedewa — meaning “dog shark” or “lazy shark.”
But this individual looked different.
Dudgeon froze the shark by shining her torch directly at it — a standard defensive response in the species — then secured it using what researchers informally call the “flip and tuck”: turning the animal upside down and tucking its tail under one arm to prevent it from thrashing. She passed it to her colleague Jess Blakeway, waiting in a nearby boat.
Blakeway, also from the University of the Sunshine Coast in Queensland, Australia, immediately noticed something was off. While the nine previously known walking shark species are broadly similar in body size and shape — distinguished mainly by their skin patterns — this one carried markings unlike any of them. Where the expected species, H. michaeli, has a leopard-like spotted pattern, this animal was covered in small spots and dashes. “It reminded me of braille or morse code,” Blakeway said.
Over the following days, the team caught eleven more individuals at three nearby sites. Three were retained for further study; the remaining nine had tissue samples taken before release. Back in the laboratory, DNA analysis confirmed what the skin pattern had suggested: this was a genetically distinct species, not previously described by science.
The species has been formally named Hemiscyllium dudgeonae — after Christine Dudgeon herself — and published in the Journal of the Ocean Science Foundation.
A New Species, Already at Risk
H. dudgeonae is now the tenth known species of walking shark, all of which are found exclusively in Australia and New Guinea. Like the others, it feeds on small seafloor invertebrates, and its range appears to be confined entirely to the coral reefs of Milne Bay.
That restricted range is cause for concern. Papua New Guinea’s coastal ecosystems are under mounting pressure from habitat loss driven by coastal development, palm oil plantation expansion, and coral bleaching driven by climate change. The researchers believe H. dudgeonae may be the most endangered member of its genus.
“This species adds to Papua New Guinea’s extraordinary biodiversity, yet it faces local extinction without urgent conservation action,” Blakeway said.
The discovery is a reminder that new vertebrate species continue to be found but often in ecosystems that won’t wait for conservation to catch up.
Reference:
Journal of the Ocean Science Foundation. DOI: 10.5281/zenodo.20575429
