A team from USC found the Eotiaris guadalupensis in the collections of the Smithsonian Institution from the Glass Mountains of west Texas, where it had been buried in a rock formation that dates back to 268.8 million years at its youngest.”This fossil pushes the evolution of this type of sea urchin from the Wuchiapingian age all the way back to the Roadian age,” said David Bottjer, professor at the USC Dornsife College of Letters, Arts and Sciences, and senior author of a paper announcing the find that appeared in Nature Scientific Reports on October 21.
Eotiaris guadalupensis is a cidaroid, one of the two main types of sea urchins found in today’s oceans. The other group, the euechinoids, evolved wildly varying body types and accounts for almost all sea urchins alive today. Cidaroids, by contrast, look pretty much the same as they did millions of years ago. Both evolved from an ancestral group of echinoids known as the Archaeocidaridae, which are now extinct.
The divergence of the two groups marks a major — and relatively abrupt — shift in the genetic organization of sea urchins.
“It’s not just the color of a moth’s wing changing,” said Bottjer, referring to the classic example of the peppered moth in England that, in the post-Industrial Revolution’s sooty skies, began to appear in a darker color. “We’re looking at tightly intertwined networks of genes that change together to cause major morphological differences.” More.
Hmmm. Curious that the Darwin icon, the peppered moth, is acknowledged to be trivial as soon as something possibly real appears.
Yet isn’t the peppered myth in all the textbooks? Well, stay tuned.
Maybe the actual purpose of textbooks is to reduce critical thinking, and encourage acceptance of official views, in th hope that information will turn up that supports them?
See also: Stasis: Life goes on but evolution does not happen
Note: Should a billionaire interested in “evolution” hire a team to go through all that stuff down in the Smithsonian’s basements? Didn’t we once find the Cambrian explosion down there? “Oh wait, Darwin! Let’s think this one out … what if … ?
Follow UD News at Twitter!
Here’s the abstract:
Echinoids, or sea urchins, are rare in the Palaeozoic fossil record, and thus the details regarding the early diversification of crown group echinoids are unclear. Here we report on the earliest probable crown group echinoid from the fossil record, recovered from Permian (Roadian-Capitanian) rocks of west Texas, which has important implications for the timing of the divergence of crown group echinoids. The presence of apophyses and rigidly sutured interambulacral areas with two columns of plates indicates this species is a cidaroid echinoid. The species, Eotiaris guadalupensis, n. sp. is therefore the earliest stem group cidaroid. The occurrence of this species in Roadian strata pushes back the divergence of cidaroids and euechinoids, the clades that comprise all living echinoids, to at least 268.8?Ma, ten million years older than the previously oldest known cidaroid. Furthermore, the genomic regulation of development in echinoids is amongst the best known, and this new species informs the timing of large-scale reorganization in echinoid gene regulatory networks that occurred at the cidaroid-euechinoid divergence, indicating that these changes took place by the Roadian stage of the Permian. Open access – Jeffrey R. Thompson, Elizabeth Petsios, Eric H. Davidson, Eric M. Erkenbrack, Feng Gao, David J. Bottjer. Reorganization of sea urchin gene regulatory networks at least 268 million years ago as revealed by oldest fossil cidaroid echinoid. Scientific Reports, 2015; 5: 15541 DOI: 10.1038/srep15541
Not a whole lot on YouTube re cidaroids, but there’s this: