Level 1 — Absolute Beginner

Scientists found a new type of shark. This shark is special because it can walk. Most sharks only swim. This one uses its fins to walk on the sea floor.

The shark was found in Papua New Guinea. It lives in shallow water near coral reefs. It is small and has brown spots. Scientists named it Dudgeon's walking shark.

Scientists are worried about this shark. It lives in a very small area. If the area is damaged, the shark could disappear forever. They want to protect it.

shark

a large sea animal with sharp teeth and fins

walk

to move using legs or fins to step forward

fin

a flat body part that fish use to move in water

coral reef

an underwater structure made of coral where many sea animals live

shallow

not deep

spot

a small round mark or dot on a surface

protect

to keep something safe from harm

disappear

to stop existing or go out of sight

Level 2 — Elementary

Scientists have officially described a new species of shark that can walk on the sea floor. The shark, called Hemiscyllium dudgeonae or Dudgeon's walking shark, was discovered in Milne Bay, Papua New Guinea. It is the tenth known species in the walking shark family.

The shark is small and brown, with white spots and dashes that look like Morse code. It uses its paired pectoral and pelvic fins to push itself forward in shallow tidal pools. It is most active at night, when it hunts for small fish and crustaceans among coral and rocks.

Researchers are concerned because the shark lives in a very small geographic area near the Coral Triangle. This makes it especially vulnerable to threats like coral reef damage and rising sea temperatures. Scientists from Australia and the United States who described the species say it should be classified as endangered.

species

a group of living things of the same kind that can reproduce together

pectoral fins

the pair of fins located on the sides of a fish, used for steering and balance

pelvic fins

the pair of fins near the belly of a fish, used for stability

tidal pool

a shallow pool left by the sea when the tide goes out

crustacean

an animal with a hard shell and jointed legs that lives in water, such as a crab

Coral Triangle

a region in Southeast Asia and the Pacific known for its high marine biodiversity

vulnerable

in danger of being harmed or damaged

endangered

at serious risk of becoming extinct

Level 3 — Intermediate

A team of marine biologists from New South Wales Fisheries and the California Academy of Sciences has formally described a new species of epaulette or walking shark from the shallow reefs of Milne Bay, Papua New Guinea, naming it Hemiscyllium dudgeonae in honor of marine biologist Sheldon Dudgeon. The species, colloquially called Dudgeon's walking shark, is the tenth member of the Hemiscyllium genus and represents the first new walking shark formally described since 2013, though individuals were first informally observed during a night dive more than 25 years ago.

Like other members of its genus, H. dudgeonae propels itself across submerged rocks, coral rubble, and intertidal flats using a characteristic undulating gait driven by its paired pectoral and pelvic fins, a locomotion strategy that allows it to hunt trapped prey in shallow tidal pools where larger predators cannot follow. The shark reaches a maximum length of approximately 70 centimetres and is distinguished by a brown base colour overlaid with white spots and irregular dashes that researchers informally described as resembling Morse code.

The species' extremely restricted range within the Coral Triangle, the most biodiverse marine region on Earth, raises immediate conservation concerns. Researchers David Harasti and William Short, who co-authored the formal description in the Journal of Fish Biology, noted that such limited distribution is a classic precondition for vulnerability to habitat degradation, warming seas, and artisanal fishing pressure. They are advocating for an IUCN Red List assessment of Vulnerable or Endangered before the species is fully documented across its potential habitat.

epaulette shark

a common name for walking sharks in the Hemiscyllium genus, named for their shoulder-like markings

genus

a biological grouping of closely related species

undulating gait

a wave-like walking motion

intertidal

the zone between the high and low tide marks on a shoreline

restricted range

a very small geographic area where a species lives

habitat degradation

the deterioration of a natural environment, reducing its ability to support wildlife

artisanal fishing

small-scale, traditional fishing using simple methods

IUCN Red List

a global inventory of threatened species maintained by the International Union for Conservation of Nature

Level 4 — Advanced

The formal description of Hemiscyllium dudgeonae, published in the Journal of Fish Biology by David Harasti of New South Wales Department of Primary Industries and William Short of the California Academy of Sciences, elevates to ten the total number of recognized species within the Hemiscyllium genus. The species represents the first formal Hemiscyllium description since 2013 and was named in honour of marine biologist Sheldon Dudgeon, whose fieldwork in the Coral Triangle contributed substantially to the foundational understanding of walking shark ecology. Specimens were first informally encountered during night-dive surveys in Milne Bay more than 25 years before the description reached print, a lag that underscores the chronic underfunding of tropical elasmobranch taxonomy.

H. dudgeonae exhibits the genus-typical ambulatory locomotion that has made walking sharks subjects of evolutionary interest: using brachiation-like coordinated strokes of the pectoral and pelvic fins against substrate, individuals can traverse exposed intertidal rock and coral rubble during low-tide events, accessing prey concentrations in hypoxic micro-pools that exclude gill-breathing competitors. The species is distinguishable from its congeners by a brown dorsal ground colour overlaid with a markedly irregular pattern of white spots and dashes that bears a superficial resemblance to Morse code sequences, a character state absent in other Hemiscyllium members.

Conservation biologists immediately flagged the species as potentially imperilled. Its known distribution is restricted to a single sub-region of the Coral Triangle, an archipelagic zone that, while hosting extraordinary marine biodiversity, faces compounding anthropogenic stressors including coral bleaching driven by thermal anomalies, destructive fishing practices, and coastal sedimentation from deforestation. The authors call for an expedited IUCN Red List evaluation under either the Vulnerable (VU) or Endangered (EN) criteria B1 and B2, predicated on the species' area of occupancy likely falling well below the 500 km threshold. The case of H. dudgeonae exemplifies a broader taxonomic debt: species may be biologically extinct before science formally acknowledges their existence.

elasmobranch

the class of cartilaginous fish that includes sharks, rays, and skates

ambulatory locomotion

movement by walking, as opposed to swimming or crawling

brachiation

arm-over-arm swinging movement, here used analogically to describe fin-based walking

hypoxic

having very low levels of dissolved oxygen, as in isolated tidal pools

congener

another species within the same genus

anthropogenic

caused or influenced by human activity

thermal anomaly

an abnormal increase in ocean temperature, often associated with climate change