Archisymplectes is an enigmatic worm from the Essex portion of the Mazon Creek Deposit.
It is always preserved as just a color difference within the concretion.
Specimens are nondescript preserving a basic worm shaped body without segmentation or any other obvious structures.
Some specimens preserve an everted proboscis.
This proboscis is what led the original author to classify it as a Nemertean or ribbon worm.
There are no clear Nemerteans known in the fossil record ho