The microfossils that I recovered from drill core of the lower Chamberlain Formation are mostly made up of relatively large (i.e., greater than 120 micrometers in size) pluricellular aggregations of smaller cells. Symplassosphaeridium is a form taxon that matches these top level attributes quite nicely. The specimen shown here actually looks like it is made up of two smaller aggregations, each composed of cells that are all consistently about 3 micrometers in diameter, with no visible external envelope around the larger aggregate colony.

Symplassosphaeridium is a geochronologically wide-ranging taxon, and it’s unclear exactly which features might be most salient for extracting useful biostratigraphic and paleobiological information. However, its co-occurrence in the Chamberlain Formation with other pluricellular forms such as Coniunctiophycus and Synsphaeridium might provide a clearer indication that the fossiliferous lower Chamberlain was deposited in very shallow water, as I outlined in my recent GSA Special Paper (Adam et al., 2016).

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s