Get your nerd on

If you want to get your nerd on, deep in the paleontological weeds, keep reading. Otherwise my explanation of this recent fossil find won't interest you in the least.

 

You've been warned......

 

Meet Saccorhytus, at 540million years old, he is believed to be humans' oldest deuterostomic relative. This remarkably detailed fossil was found recently in China and "deuterostome" means "two mouths".

 

At only 1mm big, he probably lived inbetween grains of sand in the oceans. What makes him special is we believe that he was the first to break away evolutionarily from the dominant protostomic creatures based on how their earliest gestational cleavages took place, radially or spirally.

 

Up to that point, spiral cleavage in the early stages of gestation limited where germ cells ended up, meaning that the mature creature probably took in food and excreted waste through a single opening. But with radial cleavage, the options for germ-cell development were limitless and the anus and mouth openings formed at opposite ends of the blastula with the rudimentary gut formed in-between.

 

All chordates, and more specifically all verterbrates, like humans, snakes, and chickens, have a common ancestor from long ago at the end of the pre-Cambrian era.....excitingly, Saccorhytus is believed to be him.

 

Here are helpful pictures of the fossil, an artist's concept of the creature, and what Earth looked like during that time.