Saturday , April 17 2021

the newly discovered Callichimaera perplexa is a wonderful, strange cancer



The newly discovered ancient species forces scientists to consider what exactly is considered cancer.

An international team of paleontologists from Yale University announced the discovery of a wealth of hundreds of well-preserved shells. Fossils include varieties of real shrimp, fork shrimp and, most exciting, a new branch of the evolutionary crab tree. The samples were found from Colombia and the United States, dating from the middle of the chalk (90 to 95 million years ago).

Stupid eyes with design

"Callichimaera perplexa is so unique and peculiar that it can be considered a bird in the cancer world," said Javier Luque, who led research efforts.

"It hints at how the Roma forms develop and become so diverse over time. Usually we mean crabs like big animals with broad caprices, strong claws, small eyes in long eyeglasses and a small tail tucked under the body." So, Callichimaera opposes everyone these features of "crabby" and encourages us to rethink our definition of what makes cancer cancer. "

Reconstruction.

Reconstruction of Callichimaera perplexa.
Figure credits J. Luque et al., 2019, Science Advances.

The team writes it Callichimaera perplexa is one of the earliest species of floating anthropods we once discovered, second only in the group of marine scorpions (who lived more than 250 million years ago). He was named chimera, a mythical creature whose body included features of several animals. His name and surname refers to the "confusion of the wonderful chimera".

The pattern, which Luke describes as "unusual and sympathetic", is definitely puzzling. The ancient cancer was fairly small, about a quarter of a size. There was also a striking pair of large, complex eyes – but without eye attachments. The folded claws, mouth-like legs, and the long body end in an exposed tail, end their appearance.

These last features are typical of larvae of pelagic crabs to date, the team writes. This suggests that the evolutionary connection connects with the ancient species. The team believes that these features were retained and reinforced in "miniaturized adults" through changes in time and rate of development. This process, called "heterochrony", is one of the mechanisms through which species develop new parts of the body.

"It is very exciting that we are constantly finding new branches in the tree of life from a distant past, especially from regions such as the tropics, which, although they are the hotspots of diversity today, are places we know at least in terms of their past diversity" , said Luc.

The newspaper "Exceptional Preservation of the Middle Cretaceous Sea Arthropods and Evolution of Roma Forms Through Heterochrony", published in the journal Progress in science.


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