The team observed the tropical marine creatures using their fins to walk across the sea floor, a motion rarely seen in sharks and one that affords them a strong advantage over the smaller creatures they prey on.
Dr Christine Dudgeon from the University of Queensland said a 12 year study into the sharks was a joint effort with Australia's science agency the CSIRO, Florida Museum of Natural History, the Indonesian Institute of Sciences, and Indonesian Ministry of Marine Affairs and Fisheries.
The discovery of the four new species brings the total number of known types of walking sharks to nine, but Dudgeon said researchers believe there are even more walking sharks waiting to be discovered.
"Walking sharks" are considered the newest "lineage of sharks" on Earth, the study says.
Dr Dudgeon said they live in coastal waters around northern Australia and the island of New Guinea, and occupy their own separate region.
The four new shark species belong to the genus Hemiscyllium. "These unique features are not shared with their closest relatives the bamboo sharks or more distant relatives in the carpet shark order including wobbegongs and whale sharks".
Four species of walking shark have been identified, nearly doubling the number of known species to nine.
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"This DNA codes for the mitochondria, which are the parts of cells that transform oxygen and nutrients from food into energy for cells".
The rich biodiversity can partially be explained by tectonic plate movement during the Miocene epoch (circa 23.03 to 5.3 million years ago), which is thought to have completed Australia and New Guinea's move north after its breakaway from the supercontinent Gondwana. The aim of this research is to examine the eating habits of walking sharks closely.
Sharks as a group have actually been around for about 400 million years.
Co-author of the paper, Mark Erdmann of the Conservation International, an US-based nonprofit environmental organization, said in a press release that "We found the sharks, which use their fins to "walk" around shallow reefs, only split off evolutionarily from their nearest common ancestor about 9 million years ago, and have been actively [spreading] into a complex of at least nine walking sharks ever since".
Genetic data suggests the different species evolved after they separated from the original population, spread to new areas and became isolated.
The study, published this week in Marine & Freshwater Research, says all nine species are small, "restricted to the Indo-Australian Archipelago" and show little inclination to move beyond that region.