Our Oldest Ancestor: It's In The Bag

Dead Things iconDead Things
By Gemma Tarlach
Jan 30, 2017 9:00 PMNov 20, 2019 5:23 AM
Deuterostome-Saccorhytus-847x1024.jpg

Newsletter

Sign up for our email newsletter for the latest science news
 

Say hello to my little friend (and our great-granddaddy to the nth), Saccorhytus coronarius. Credit: S Conway Morris/Jian Han. Who's your daddy, give or take a few hundred million years? Researchers believe a 540-million-year-old creature unearthed in China is our oldest ancestor, and I can definitely see the family resemblance. Publishing today in Nature, the study introducing us to Saccorhytus coronarius places the tiny creature in the earliest days of the Cambrian Period, some 540 million years ago. Researchers discovered 45 specimens of the animal in limestone deposits in South-central China. The team classifies Saccorhytus as a deuterostome, one of the major groups of animals and the branch of the Tree of Life that includes vertebrates. Prior to Sir Sackybag here, the oldest deuterostomes found in the fossil record were around 520-525 million years old, though we can tell from their diversity that the actual lineage was established much earlier, during the Pre-Cambrian. Some deuterostome lines would evolve into things like starfish and sea cucumbers while others grew a backbone, evolutionarily speaking, and ended up as dinosaurs and fish and primates and such. If you're up on your ancient Greek, you may be wondering if deuterostomes ("second mouth") are supposed to have two mouths. Nope. It means the mouth is the second orifice to develop in the embryo, after the anus. In other words, yes, as deuterostomes we belong to the "assholes first" branch of the Animal Kingdom.

0 free articles left
Want More? Get unlimited access for as low as $1.99/month

Already a subscriber?

Register or Log In

0 free articlesSubscribe
Discover Magazine Logo
Want more?

Keep reading for as low as $1.99!

Subscribe

Already a subscriber?

Register or Log In

Stay Curious

Sign up for our weekly newsletter and unlock one more article for free.

 

View our Privacy Policy


Want more?
Keep reading for as low as $1.99!


Log In or Register

Already a subscriber?
Find my Subscription

More From Discover
Stay Curious
Join
Our List

Sign up for our weekly science updates.

 
Subscribe
To The Magazine

Save up to 40% off the cover price when you subscribe to Discover magazine.

Copyright © 2025 LabX Media Group