Mud creature — with ‘rectangular’ body — found in Australia bay is new species
As the tide recedes from the Bay of Rest, mud flats lined with mangrove trees are left exposed.
It’s a dichotomy of environments as the seafloor shifts from an underwater habitat to part of the land.
It’s also the home of a species new to science.
During research expeditions through the Western Australia Museum, a new species of crab was found to be living in these mud flats, according to a study published Oct. 13 in the peer-reviewed journal ZooKeys.
The Bay of Rest mangrove crab, or Parasesarma otiense, can be identified by its particularly “rectangular” and broad carapace, or body, according to the study.
The surface of the body is “smooth and shiny” and covered in various mottled patterns, ranging from dark brown with white patches in males to a nearly orange color in females, photos of the new species show.
The crab’s ambulatory legs, or one of the legs used for walking, are “relatively long” in comparison to other related species, researchers said.
The species has eyestalks that are longer than they are wide that protrude from the front flat face of the carapace, according to the study.
There are nine known species of Parasesarma found in Australia’s mangroves, half of which are found on the east and west coasts, researchers said.
Mangroves exist in the intertidal zones of warm rivers, estuaries and bays, growing in the sediment brought to the coast by the freshwater rivers and tides, according to the Australia Department of Agriculture, Fisheries and Forestry.
Mangroves cover 2.2 million acres of land in Australia and include 41 different tree species, the department said.
“More than half of the world’s mangrove species are found in Australia,” the department said.
Mangrove ecosystems are essential for coastlines because of their ability to provide shelter for animals, prevent erosion of the coast, protect against storms and filter pollutants from the water, according to The Nature Conservancy.
The Bay of Rest is on the northwestern coast of Australia, in the Western Australia territory.
The research team includes Adnan Shahdadi, Andrew M. Hosie, Ana Hara and Benny K. K. Chan.
This story was originally published October 16, 2025 at 12:50 PM with the headline "Mud creature — with ‘rectangular’ body — found in Australia bay is new species."
