Prehistoric Critters Change View of Mammal Evolution

Three extinct squirrel-like species were identified from Jurassic-era fossils in China.

By Molly Sharlach | September 12, 2014


Fossils of squirrel-like animals found on a farm in northeastern China have features that indicate they were true mammals. The creatures, which lived about 160 million years ago, constitute a new clade, Euharamiyida. Their similarity to older fossils in the group Haramiyida suggests that mammals arose more than 200 million years ago, during the Late Triassic. Scientists from the American Museum of Natural History (AMNH) in New York City and the Chinese Academy of Sciences published their analysis of the fossils this week (September 10) in Nature.

Although bits and pieces of haramiyids were first discovered in the 19th century, and more complete skeletons were recently uncovered, it’s still unclear whether haramiyids were mammals. The new, related fossils have a three-boned middle ear that is unique to mammals, lending evidence to the idea that haramiyids were among the earliest mammals.

“For decades, scientists have been debating whether the extinct group, called Haramiyida, belongs within or outside of Mammalia,” study author Jin Meng, a curator in the AMNH Division of Paleontology, said in a press release. “Previously, everything we knew about these animals was based on fragmented jaws and isolated teeth. But the new specimens we discovered are extremely well preserved. And based on these fossils, we now have a good idea of what these animals really looked like, which confirms that they are, indeed, mammals.”

The largest of the three species, Shenshou lui, probably weighed about 10 ounces, while the smallest was only the size of a house mouse. The fossils suggest that the slender animals spent time in trees, and had hands and feet adapted for grabbing branches. Their resemblance to present-day squirrels is a result of convergent evolution, as they belong to a lineage that diverged from that of modern mammals long ago.

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September 14, 2014

RE: Their similarity to older fossils in the group Haramiyida suggests that mammals arose more than 200 million years ago, during the Late Triassic.

Everything known about RNA-mediated events suggests and then shows via experimental evidence that ecological variation leads to ecological adaptations more quickly than neo-Darwinian theories suggest occurs via mutations and natural selection.

A single RNA-mediated nutrient-dependent amino acid substitution is all it takes for chromosomal rearrangements to rapidly lead to reproductive isolation and ecological speciation without the mutation-initiated natural selection that supposedly leads to the evolution of biodiversity via some unknown evolutionary event or events (accumulated mutations) that occurred over millions of years.

Is anyone else paying attention to facts that link interactions between pre-mRNA and proteins to the fine-tuning of alternative splicings and the de novo Creation of new functional proteins with no need to create additional genes? Guess what the de novo Creation of new proteins does without affecting existing proteins.

I've been guessing since 1996 (with co-authors) that the Creation of new proteins enables the chromosomal rearrangements that lead to reproductive isolation and biodiversity of morphological AND BEHAVIORAL phenotypes via nutrient-dependent pheromone-controlled RNA-mediated ecological adaptations in species from the single-celled eukaryote Oxytricha trifallax to multicellular primates (e.g, a northern white-cheeked gibbon).

Evolutionary theorists (except Dobzhansky) guessed wrong, and they should consider accepting the biological facts about RNA-mediated events in the context of ecological adaptations. It makes sense for everyone since Dobzhansky to accept the facts about amino acid substitutions. He was right about the difference one amino acid substitution makes in chimps, gorillas, and humans.

Until evolutionary theorists can describe an evolutionary event that might link the morphology AND behavior of one nutrient-dependent differentiated cell type in any individual of any species to the evolution of another nutrient-dependent differentiated cell type in an individual of another species, they should accept Dobzhansky's Creationist views and abandon the neo-Darwinian nonsense about mutations, natural selection, and the evolution of biodiversity.

Dobzhansky had something to say about that, too. "...the only worthwhile biology is molecular biology. All else is "bird watching" or "butterfly collecting." Bird watching and butterfly collecting are occupations manifestly unworthy of serious scientists!"

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