Discovery provides new insights into the evolution of crabs and when they spread around the world
Looking at the ancient piece of amber, Javier Luque’s first thought wasn’t whether the crustacean trapped inside could help fill a crucial gap in crab evolution. He just, more or less, wondered what the heck is a crab doing stuck in fossilized tree resin?
“In a way, it’s like finding a shrimp in amber,” said Luque, a post-doctoral researcher in the Harvard Department of Organismic and Evolutionary Biology. “Talk about wrong place, wrong time.”
Luque spent three years trying to unravel the puzzle and, along with a team of international scientists, reported the findings on today (October 20, 2021) in Science Advances.
They say the 100-million-year-old piece of amber, recovered from the jungles of Southeast Asia, holds what’s believed to be the oldest modern looking crab ever found. The discovery provides new insights into the evolution of these crustaceans and when they spread around the world.
The 5-millimeter crab is the first-ever found in amber from the dinosaur era, and the researchers think it represents the oldest evidence of incursions into non-marine environments by “true crabs.”
True crabs (known as Brachyurans) stand in contrast to “false crabs” (called Anomurans) that aren’t technically crabs but are still sometimes called by the name (think hermit crabs or king crabs).
Previous fossil records, which mainly consist of bits and pieces of claws, suggested that nonmarine crabs came onto land and freshwater about 75 to 50 million years ago. This new discovery pushes that back to at least 100 million years ago, answering Luque’s initial question of what this crab was doing in the jungle and bringing the fossil record in line to long-held theories on the genetic history of crabs.
“If we were to reconstruct the crab tree of life — putting together a genealogical family tree — and do some molecular DNA analysis, the prediction is that nonmarine crabs split from their marine ancestors more than 125 million years ago,” Luque said. “But there’s a problem because the actual fossil record— the one that we can touch – is way young at 75 to 50 million years old… So this new fossil and its mid-Cretaceous age allows us to bridge the gap between the predicted molecular divergence and the actual fossil record of crabs.”
The researchers now believe that an event known as the Cretaceous Crab Revolution —when crabs (true or not) diversified worldwide and started evolving their characteristic, crabby-looking body forms — happened more times than previously thought. This new research brings the tally of when different crab species independently evolved to live outside their marine habitat to at least 12 separate times.
The new fossil was dubbed Cretapsara athanata, “the immortal Cretaceous spirit of the clouds and waters.” The name honors its age and South and Southeast Asian mythological spirits. The creature suspended in amber is instantly recognizable as a true crab, which makes sense since the researchers say it is the most complete fossilized crab ever discovered.The team, using micro-CT scans, was able to see in clear detail delicate tissues like the crab’s antennae, legs, and mouthparts lined with fine hairs, large compound eyes, and even its gills. Not even a single hair was missing, they said.
The study was a collaboration between Harvard and the China University of Geosciences, and included authors from 10 institutions including Yale University, Smithsonian Tropical Research Institution Panama, University of Alberta, UC Berkeley, Yunnan University, and the Royal Saskatchewan Museum.
The work is part of a larger National Science Foundation funded project with Javier Ortega-Hernández, an assistant professor in OEB and curator of invertebrate paleontology in the Museum of Comparative Zoology, Joanna Wolfe, a researcher Ortega-Hernández’ lab, and Heather Bracken-Grissom from Florida International University to investigate the evolution of crabs over 200 million years.
The fossilized amber specimen is housed at the Longyin Amber Museum in China. The piece was collected by local miners and in Myanmar and purchased legally in 2015. In the paper, the authors acknowledge the sociopolitical conflict in northern Myanmar and say they have limited their research to material predating the 2017 resumption of hostilities in the region. They hope acknowledging the situation in the Kachin State will serve to raise awareness of the current conflict in Myanmar and the human cost behind it.
Luque, who has been studying crab evolution for more than a decade, said he first became aware the specimen in 2018 and has been obsessed with it since. He hopes the finding will make people consider crabs deserving of another moment in the spotlight.
“They are all over the world, they make good aquarium pets, they’re delicious for those of us who eat them, and they’re celebrated in parades and festivals, and they even have their own constellation,” Luque said. “Crabs in general are fascinating, and some are so bizarre looking — from tiny little pea-shaped crabs to humongous coconut crabs. The diversity of form among crabs is captivating the imagination of the scientific and non-scientific public alike, and right now people are excited to learn more about such a fascinating group that are not dinosaurs. This is a big moment for crabs.”
Reference: “Crab in amber reveals an early colonization of non-marine environments during the Cretaceous” by Javier Luque, Lida Xing, Derek E. G. Briggs, Elizabeth G. Clark, Alex Duque, Junbo Hui, Huijuan Mai and Ryan C. McKellar, 20 October 2021, Science Advances.
Coconut crabs climb trees, so it’s not that weird?
Babu G. Ranganathan*
NOT MILLIONS OF YEARS OLD! Evolutionary dating (including radiometric dating) is not infallible science, is based on certain built-in assumptions, and has often been proven to be contradictory and inconsistent. Please read my popular Internet article, ARE FOSSILS REALLY MILLIONS OF YEARS OLD? Just google the title followed by my name.
There’s a lot of evidence that the fossil layers were not deposited by gradual floods, which would have required millions of years. Rather, the evidence strongly points to a one world-wide flood, just as the Bible teaches. This one world-wide flood fossilized species and unleashed tremendous forces that changed the geology and topography of the earth.
The fossil layers in the real world are not even found in the sequence taught in evolutionary textbooks. There are many places where fossils of complex creatures are found beneath simpler ones, and there are fossils of mixed species existing in the same stratum which classic evolutionary textbooks teach should have been separated by millions of years. Of course a biblical world-wide flood would generally have buried and fossilized marine animals first with amphibians, reptiles and mammals to follow. Evolutionists have interpreted all of this into an evolutionary scenario spanning millions of years.
There is absolutely no proof of macro-evolution in the fossil record. The fossils of all species are found complete (not partially-evolved) with no evidence of actual transition from one kind to another. There are no fossils of fish, for example, with part fins, part feet to show that transition occurred from fins to feet. Besides this, partially-evolved species would be unfit for survival while waiting to be completed over millions of years.
ONLY LIMITED EVOLUTION (micro-evolution or evolution within biological “kinds”) is genetically possible (such as the varieties of dogs, cats, horses, cows, etc.), but not macro-evolution, or evolution across biological “kinds,” (such as from sea sponge to human). All real evolution in nature is simply the expression, over time, of already existing genes or variations of already existing genes. For example, we have breeds of dogs today that we didn’t have a few hundred years ago. The genes for these breeds had always existed in the dog population but never had opportunity before to be expressed. Only limited evolution or adaptation, variations of already existing genes and traits, is possible. Nature is mindless and has no ability to design and program entirely new genes for entirely new traits.
NEW SPECIES: Although new species can come into existence, they don’t carry any new genes. They’ve become new species only because they can’t be crossed back with the original parent stock for various biological reasons. A biological “kind” allows for new species but not new genes. Nature has no ability to invent new genes for new traits. Only limited variations and adaptations are possible in nature, and all strictly within a biological “kind” (i.e. varieties of dogs, cats, etc.).
THE FEW “INTERMEDIATE” (SO-CALLED TRANSITIONAL LINKS) IN FOSSILS claimed by evolutionists are highly disputed, even among the evolutionists. If macro-evolution really occurred there should be billions of indisputable intermediate fossils, not a few disputable ones. There’s not one example of a so-called transitional link that all evolutionists can agree on, not one.
What about the duck-billed platypus? It has traits belonging to both birds and mammals, but even evolutionists don’t argue that it’s a transitional link between birds and mammals.
Some evolutionists use similarities of traits between species as an argument for transitional forms. This is not a good argument because the traits they cite are complete, fully-formed, and fully functional, not in any true process of transition from one type of structure into another.
Genetic information, like other forms of information, cannot arise by chance, so it is more logical to believe that genetic and biological similarities between all forms of life are due to a common Designer who designed similar functions for similar purposes. It doesn’t mean all forms of life are biologically related!
What about natural selection? Natural selection can only “select” from biological variations that are possible and which have survival value. It doesn’t produce genes or biological traits. That’s why it’s called natural “selection.”
Many people have wrong ideas of how evolution is supposed to work. Physical traits and characteristics are determined and passed on by genes — not by what happens to our body parts. For example, if a woman were to lose her finger this wouldn’t affect how many fingers her baby will have. Changing the color and texture of your hair will not affect the color and texture of your children’s hair. So, even if an ape’s muscles and bones changed so that it could walk upright it still would not be able to pass on this trait to its offspring. Only changes or mutations that occur in the genetic code of reproductive cells (i.e. sperm and egg) can be passed on to offspring.
What about the new science of epigenetics? Epigenetics involves inheritable factors which can turn genes on, but epigenetics doesn’t alter the DNA code itself.
Modern evolutionists believe and hope that over, supposedly, millions of years, random mutations in the genetic code of reproductive cells caused by environmental radiation will generate entirely new genes for natural selection to use. This is total blind and irrational faith on the part of evolutionists. It’s much like believing that randomly changing the sequence of letters in a romance novel, over millions of years, will turn it into a book on astronomy! That’s the kind of blind faith macro-evolutionists have.
Mutations are accidents in the genetic code, are mostly harmful, and have no capability of producing greater complexity in the code. Even if a good accident occurred, for every good one there would be hundreds of harmful ones with the net result, over time, being harmful, even lethal, to the species. At best, mutations only produce further variations within a natural species. Even so, mutations are not the best explanation for variations within a natural species.
How could species have survived if their vital tissues, organs, reproductive systems, etc. were still evolving? A partially evolved trait or organ that is not complete and fully functioning from the start would be a liability to a species, not a survival asset. Plants and animals in the process of macro-evolution would be unfit for survival. For example, “if a leg of a reptile were to evolve (over supposedly millions of years) into a wing of a bird, it would become a bad leg long before it became a good wing” (Dr. Walt Brown, scientist and creationist) Survival of the fittest actually would have prevented macro-evolution (evolution across biological kinds!)
All the fossils that have been used to support human evolution have been found to be either hoaxes, non-human, or human, but not non-human and human.
The fossils show that all life came into existence as complete and fully-formed from the beginning, which is only possible by creation.
Visit the author’s latest Internet site: THE SCIENCE SUPPORTING CREATION (This site answers many arguments, both old and new, that have been used by evolutionists to support their theory).
Author of the popular Internet article, TRADITIONAL DOCTRINE OF HELL EVOLVED FROM GREEK ROOTS
*I have given successful lectures (with question and answer period afterwards) defending creation before evolutionist science faculty and students at various colleges and universities. I’ve been privileged to be recognized in the 24th edition of Marquis “Who’s Who in The East.”
You literally talked about scientists “blindly following” facts and research and you are hear preaching doctrine and bible thumping your false theologies on us to accept some magical sky wizard B L I N D L Y.
Hi pot, meet kettle.
Here* because auto correct is stupid.
You’d really Old Bay to go with these.