With huge eyes, big claws, paddle-shaped legs and lobster-like shells, scientists have named a newly discovered species as "the strangest crab that ever lived".
F Ossils found in Colombia have revealed the new evolutionary branch of swimming crabs that lived about 95 million years ago.
The small creatures allegedly reminded paleontologists of glockenspiel from Greek mythology with a lion's head, a goat's body and a serpent's tail – due to their mixed features, very similar to those of other marine arthropods. 19659006] We tell you what is true. You can form your own view.
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Called Callichimaera perplexa which means "confusing beautiful chimera", after its unusual mash-up of features, it is the earliest example of a floating arthropod with paddle-like legs since extinction of sea scorpions more than 250 million years ago.
It was discovered by an international research team led by paleontologist Javier Luque of the prestigious American Yale University.
" Callichimaera perplexa is so unique and alien that it can be considered as a platypus of the crab world," said Dr. Luque. "It indicates how novel forms evolve over time and become so different."
He added, "Usually we consider crabs as large animals with wide carapaces, strong claws, small eyes in long eyestalks, and small-eyed tails stowed under the body. Well, Callichimaera opposes all of these "grumpy" features, forcing us to rethink our definition of what makes a crab a crab. "
The fossilized creatures from which they were extracted The Andes in Colombia once lived in one in the Cretaceous shallow coastal sea.
Researchers have found over 70 soft-shelled specimens along with hundreds of other crustaceans such as shrimp and lobster.
The unique Callichimaera perplexa crab had fin-like legs that allowed it to swim, and large eyes that were thought to hunt in the night (Oksana Vernygora, University of Alberta)
while the fossils are no bigger than a coin. Dr. Luque explained that their exceptional level of conservation enabled researchers to detect subtle details such as their paddle-like legs and large eyes, suggesting that the crabs spent their life swimming instead of crawling like today's crabs today.
Dr. Luque said Callichimaera's "unusual and sweet" appearance, including its small size, large unimpeded eyes, curved claws, leg-like mouthparts, exposed tail and long body, are typical features of pelagic crab larvae.
He said that this suggests that some of the larval features seen in the species could be maintained and enhanced in miniaturized adults through changes in timing and rates of development.
This process is called "heterochrony" and is supposed to lead to the development of new body parts.
"It is very exciting that today we have completely new branches in the tree of life from a distant past, especially from regions such as the tropics, which, although today they are hotspots of diversity, are places who we least know about their past, "said Dr. Luque. "It's an incredible amount of detail, and we've been able to reconstruct it as it did yesterday."
The high quality of the fossils has even enabled the researchers to create a detailed 3D model of the crab.
"It is common to find novel body shapes in older rocks, such as the Paleozoic, when life exploded into many new forms," Dr. Luque. "This mid-Cretaceous discovery shows that there are still surprising discoveries of new, weird organisms waiting to be discovered in the tropics. One wonders, "What else is there to discover?"
The study appears in the journal Science Advances .