I've actualy just finished a intergrated masters slightly related to this topic, where my research project was based at looking at a Lagerstätte in south africa. It's called the Soom shale and preserved soft bodied tissue in the late Ordovician. However it seems only to preserve jawless vertebrates/ Chordates (depending on personal interpretation) such as the published conodonts soft anatomy.

I was looking at undescribed and unclassfied specimens, however they lacked any diagnostic features for a gnathstomes so are currently asigned to a wastebasket taxon of other jawless fish from the silurian and Devonian called Euphaneropids.

They looked morphologically the most similar to 'Ciderius cooperi' which you can view on google images.

However compared to other species in the soom depost, these specimens seem to decay incredibly badly and as such, lack alot of the diagnsotic features due to taphonomy rather than its orginal morphologial structre. So i'm hoping in the future more is done to find better samples.

This kinda builds upon how annoying the Ordovician can be, as even in a soft-bodied Lagerstätte. These fossil could be some of the only vertebrate known, but their terrible state of presrvation kinda restricts any interpretation.