Four new species of tropical sharks that use their fins to walk are causing astir in waters off northern Australia and New Guinea.

While that might strike fear into the hearts of some people, University ofQueensland researchers say the only creatures with cause to worry are smallfish and invertebrates.

The walking sharks were discovered during a 12-year study with ConservationInternational, the CSIRO, Florida Museum of Natural History, the IndonesianInstitute of Sciences and Indonesian Ministry of Marine Affairs and Fisheries.

UQ’s Dr Christine Dudgeon said the ornately patterned sharks were the toppredator on reefs during low tides when they used their fins to walk in veryshallow water.

“At less than a metre long on average, walking sharks present no threat topeople but their ability to withstand low oxygen environments and walk ontheir fins gives them a remarkable edge over their prey of small crustaceansand molluscs,” Dr Dudgeon said.

“These unique features are not shared with their closest relatives the bamboosharks or more distant relatives in the carpet shark order includingwobbegongs and whale sharks.”

The four new species almost doubled the total number of known walking sharksto nine.

Dr Dudgeon said they live in coastal waters around northern Australia and theisland of New Guinea, and occupy their own separate region.

“We estimated the connection between the species based on comparisons betweentheir mitochondrial DNA which is passed down through the maternal lineage.This DNA codes for the mitochondria which are the parts of cells thattransform oxygen and nutrients from food into energy for cells,” Dr Dudgeonsaid.

Hemiscyllium galei walks on a reef at night (credit MarkErdmann)

“Data suggests the new species evolved after the sharks moved away from theiroriginal population, became genetically isolated in new areas and developedinto new species,” she said.

“They may have moved by swimming or walking on their fins, but it’s alsopossible they ‘hitched’ a ride on reefs moving westward across the top of NewGuinea, about two million years ago.

“We believe there are more walking shark species still waiting to bediscovered.”

Dr Dudgeon said future research would help researchers to better understandwhy the region was home to some of the greatest marine biodiversity on theplanet.

The study was published in the CSIRO’s Marine and Freshwater Researchjournal (https://doi.org/10.1071/MF19163).

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