The vast majority of sharks swim to move around, but some specific species can use more unique means of transport. This is the case of walking sharks, that is to say sharks using their fins as limbs to move on the seabed. And recently, four new species of walking sharks have been discovered by Australian marine biologists.
Unlike their larger cousins, members of these newly discovered species of walking sharks spend their time wandering gently along coral reefs on four flat fins. Or, at least, that's what they were doing when the researchers spotted them in the shallow waters of northern Australia.
In an article published in the journal Marine & Freshwater Research , marine biologists declared that the four new itinerant shark species were the most recently evolved shark species known, having developed after having separated from their common ancestor on closer about 9 million years ago.
Walking sharks: unique characteristics for a definite evolutionary advantage
" With an average length of less than one meter, walking sharks pose no threat to humans, but their ability to withstand oxygen-poor environments and to walk on their fins gives them a remarkable advantage over their prey, small crustaceans and molluscs ”explain the researchers. |
| Walking sharks have unique characteristics compared to their closest relatives. Credit: Mark Erdmann |
These unique characteristics are not shared with their closest relatives, whip sharks, or more distant relatives in order of carpet sharks, including whale sharks. The four new species almost doubled the total number of known walking sharks, bringing the total to nine. the researchers said they live in the coastal waters of northern Australia and the island of New Guinea and occupy their own separate region.
Better understand the evolution of walking sharks
“ We estimated the link between the species on the basis of comparisons between their mitochondrial DNA which is transmitted through the maternal line. This DNA codes for mitochondria, which are the parts of cells that convert oxygen and nutrients from food into energy for cells . ”The data suggest that the new species evolved after sharks moved away from their original population, became genetically isolated in new areas, and developed into new species.
This video shows a walking shark moving on the ocean floor:
| Bibliography: Walking, swimming or hitching a ride? Phylogenetics and biogeography of the walking shark genus Hemiscyllium Christine L. Dudgeon A H , Shannon Corrigan B , Lei Yang B , Gerry R. Allen C , Mark V. Erdmann D E , Fahmi A F , Hagi Y. Sugeha F , William T. White G and Gavin J. P. Naylor B Marine and Freshwater Research https://doi.org/10.1071/MF19163 |
Tags:
Plants & Animals