Crab nebula of life

February 14, 2014

Researchers Chu, et.al., have constructed the most complete and extensive crab sequence dataset to date. Their recalibrated crab gene tree using DNA and mitochondrial sequences from 140 species and 58 crab families provides some important new insights into the timing and diversity of crab evolution.

Crabs—those sometimes pesky, hard-shelled beachcombers—are a highly diverse animal, with some 7,000 species found in oceans, lakes and on land, varying in size from the diminutive pea crab (millimeters) to the giant 4 meter-wide Japanese spider crab.

Chu, et.al., have constructed the most complete and extensive dataset to date. Their recalibrated crab gene tree using DNA and mitochondrial sequences from 140 species and 58 crab families provides some new important insights into the timing and diversity of crab evolution.

The research team's estimates confirm the fossil record of most living crab families and superfamilies first arising during the late Cretaceous and early Tertiary (60-100 mya), at the same time when dinosaurs ruled the Earth. They also demonstrated that freshwater crabs were derived early in the evolution of true crabs and are shown to have at least two independent origins. Molecular methods estimate that freshwater separated from their closest marine relatives after the break-up of Pangaea (~200 mya).

The study refines many crab evolutionary issues, and provides a new, comprehensive resource for scientists to further investigate the molecular underpinnings responsible for body forms shapes and functions among the various .

Explore further: Furry-clawed Asian crabs found in Delaware and Chesapeake Bays

Related Stories

New 'strawberry' crab species found off Taiwan

January 5, 2010

(AP) -- A marine biologist says he has discovered a new crab species off the coast of southern Taiwan that looks like a strawberry with small white bumps on its red shell.

Horseshoe crabs are one of nature's great survivors

January 24, 2012

It may look like something out of a science fiction movie, but the horseshoe crab is definitely real. In fact it is one of nature’s great survivors, lasting through 3 of the Earth’s major extinction events.

Which came first, hermits or kings?

August 27, 2013

Heather Bracken-Grissom, marine sciences professor in the FIU Department of Biological Sciences, has helped answer one of the most debated questions among evolutionary biologists: Did the hermit crab evolve into the king ...

Recommended for you

How a single molecule turns one immune cell into another

July 30, 2015

All it takes is one molecule to reprogram an antibody-producing B cell into a scavenging macrophage. This transformation is possible, new evidence shows, because the molecule (C/EBPa, a transcription factor) "short-circuits" ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.