Crabs, lobsters and shrimp now have a family tree dating 500 million years

APRIL 24, 2019

by Chrystian Tejedor, Florida International University

Researchers have for the first time traced the roots of crabs, lobsters and shrimp to create the family tree of crustaceans people love to eat.

The tree shows the 450-million-year evolution of these 10-legged decapods, when lobsters and crabs each diversified from a single evolutionary origin. Groups of shrimpevolved earlier.

The findings are part of a massive family tree project where researchers resolved the deep evolutionary relationships between crabs, shrimp and lobsters. The discoveries made by analyzing more than 400 genes from 94 species could also inform conservation policies to ensure their longevity.

"Understanding the origins of biodiversity across half a billion years in groups that are extremely ecologically and economically important is fascinating," said FIU marine sciences professor Heather Bracken-Grissom, the anchor author of the study. "This is extremely important since studying and preserving biodiversity needs to be at the forefront of our efforts in the biological sciences and across humanity"

The boom of diversification for crabs, lobsters and shrimp may coincide with the spread of modern reef-building corals, Bracken-Grissom said. It is possible the emergence of reef-building corals provided new habits for decapods to colonize and diversify, leading to the emergence of several new lineages after the mass extinction of life on Earth 250 million years ago.

While the study produced the largest amount of genetic information about decapods, more work remains to be done including the addition of more species to better understand species-level relationships. The researchers hope the newly generated genomic resources will be used by others interested in decapod crustaceans for years to come.

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