Fossils, cells point to early appearance of the brain

Excerpt:
“…the kinds of inferences from comparative developmental studies such as [Arendt’s] are, right now, the only speculative route back into time,” Strausfeld says.
See also: All in the (bigger) family
Excerpt:

…new insights about what it took for an ancient crustacean to give rise to insects.

The new insights mentioned in an earlier article by Elizabeth Pennisi have since linked nutrient-dependent microRNAs and adhesion proteins to supercoiled DNA in the context of the physiology of reproduction and what appears to be nutrient-dependent protection from virus-driven genomic entropy.
Inferences from the fossil record seem to be far too speculative in the context of what is known about how the epigenetic landscape is manifested in the physical landscape of DNA via nutrient-dependent changes in base pairs and RNA-mediated amino acid substitutions.
The nutrient dependent amino acid substitutions are fixed in organized genomes long before the molecular mechanisms of ecological adaptation are manifested in morphological phenotypes. That fact suggests further speculation about how the fossil record may or may not be linked to any morphological phenotypes or to any behavioral phenotypes across hundreds of millions of years is somewhat inappropriate.
For example, the nutrient-dependent morphological phenotypes of bacterial that reportedly “re-evolved” their flagella over the weekend.

The “re-evolved” flagella must also have been linked to the pheromone-controlled physiology of their reproduction.  That fact suggests a problem with the fossil record that dates back to bacteria living in ocean sediments that appear to have not changed their morphological phenotypes in ~2 billion years.
See: Sulfur-cycling fossil bacteria from the 1.8-Ga Duck Creek Formation provide promising evidence of evolution’s null hypothesis
See also: Natural Selection on the Olfactory Receptor Gene Family in Humans and Chimpanzees
Co-author Svante Pääbo in known for his expertise on the primate fossil record and co-author Yoav Gilad has published other works that compare human and chimpanzee olfactory receptor gene repertoires. The comparisons exemplify how “Feedback loops link odor and pheromone signaling with reproduction” via as few as one nutrient-dependent RNA-mediated amino acid substitutions in the cell types of humans and chimpanzees compared to gorillas. Co-author Doron Lancet is the senior author of Deficiency of Asparagine Synthetase Causes Congenital Microcephaly and a Progressive Form of Encephalopathy. It was reported as:  Rare gene mutation sheds light on protein’s role in brain development.
Excerpt:

Long considered a “non-essential” amino acid, asparagine synthesis may actually be crucial for normal brain development and function.

See also: Dobzyansky (1973) Nothing in Biology Makes Any Sense Except in the Light of Evolution
Excerpt:

…the so-called alpha chains of hemoglobin have identical sequences of amino acids in man and the chimpanzee, but they differ in a single amino acid (out of 141) in the gorilla. ( p. 127)

My comment: Serious scientists continue to report their findings in the context of what is known to others about biologically-based cell type differentiation. They are Combating Evolution to Fight Disease with claims like this one:

The evolutionary biologist Theodosius Dobzhansky famously noted that “nothing in biology makes sense except in the light of evolution,” but perhaps, too, “nothing in evolution makes sense except in the light of biology.” Although the latter might be an exaggeration, an important gap is being filled by molecular understanding of the genesis of variation that confers the ability to evolve.

My comment: The molecular understanding of the genesis of variation that confers the ability to evolve is obviously explained in the context of the nutrient-dependent physiology of reproduction. That molecular understanding has escaped the notice of biologically uninformed theorists who are still trying to link the fossil record and cell types via natural selection and evolution.