Marine biologists have described a new species of the shark genus Heterodontus from northwestern Australia based on six whole specimens and a single egg case.
Heterodontus is a small genus of sharks within the family Heterodontidae of the order Heterodontiformes.
First discovered in Australia in the 18th century in the form of the Port Jackson shark, it now includes 10 scientifically recognized species.
All Heterodontus species are relatively small, with the largest species reaching 1.65 m (5.5 feet) in length.
They are commonly known as bullhead sharks or horn sharks.
They first appeared in the fossil record in the Early Jurassic epoch, well before any of other Galeomorphii, a group that includes all modern sharks except the dogfish and its relatives.
They occur in warm-temperate and tropical continental waters of the western Indian Ocean, western and eastern Pacific, but are absent from the Atlantic and from oceanic insular waters.
These are sluggish, rare to uncommon night-active sharks, slowly swimming and crawling on rocky, kelp-covered and sandy bottom. Some species at least favor rocky crevices and caves, where they spend the day resting.
These sharks are oviparous, producing eggs in unique, large, spiral-flanged egg cases. At least two species lay eggs in specific ‘nesting’ sites. Eggs may take over five months to hatch, and young hatch at a large size, over 14 cm (5.5 inches).
They primarily feed on benthic invertebrates. Sea urchins are a favorite food, but crabs, shrimp and other crustaceans, abalone, top shells and other marine gastropods, oysters, polychaetes, sipunculid worms and more rarely small fish are also eaten.
Some Heterodontus sharks are encountered by divers, who have commonly harassed them.
Although regarded as harmless, these sharks can and do snap when provoked and occasionally pursue and bite their tormentors.
“The Heterodontiformes is a unique shark order comprising a single family and single extant genus,” said lead…
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