Crab nebula of life

February 14, 2014

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,, 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 crabs 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 species.

Molecular Biology and Evolution (Oxford University Press)

Related Evolution Articles from Brightsurf:

Seeing evolution happening before your eyes
Researchers from the European Molecular Biology Laboratory in Heidelberg established an automated pipeline to create mutations in genomic enhancers that let them watch evolution unfold before their eyes.

A timeline on the evolution of reptiles
A statistical analysis of that vast database is helping scientists better understand the evolution of these cold-blooded vertebrates by contradicting a widely held theory that major transitions in evolution always happened in big, quick (geologically speaking) bursts, triggered by major environmental shifts.

Looking at evolution's genealogy from home
Evolution leaves its traces in particular in genomes. A team headed by Dr.

How boundaries become bridges in evolution
The mechanisms that make organisms locally fit and those responsible for change are distinct and occur sequentially in evolution.

Genome evolution goes digital
Dr. Alan Herbert from InsideOutBio describes ground-breaking research in a paper published online by Royal Society Open Science.

Paleontology: Experiments in evolution
A new find from Patagonia sheds light on the evolution of large predatory dinosaurs.

A window into evolution
The C4 cycle supercharges photosynthesis and evolved independently more than 62 times.

Is evolution predictable?
An international team of scientists working with Heliconius butterflies at the Smithsonian Tropical Research Institute (STRI) in Panama was faced with a mystery: how do pairs of unrelated butterflies from Peru to Costa Rica evolve nearly the same wing-color patterns over and over again?

Predicting evolution
A new method of 're-barcoding' DNA allows scientists to track rapid evolution in yeast.

Insect evolution: Insect evolution
Scientists at Ludwig-Maximilians-Universitaet (LMU) in Munich have shown that the incidence of midge and fly larvae in amber is far higher than previously thought.

Read More: Evolution News and Evolution Current Events is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to