Friday, April 15, 2011

Blastoid with brachioles

Blastoids are a common fossil from Carboniferous aged rocks but rarely do they have their brachioles (feeding organs) preserved. This specimen, which I purchased on E-bay, has some brachioles preserved in near life positions.

Unlike Crinoids, Blastoids had very short cillia like arms (brachioles) that lined the edges of ambulacrul grooves (the five petal shaped areas) on the theca (body of the animal, similar to the crinoid calyx). This specimen has parts of those presevred with it which indicates a very rapid burial with little disturbance afterwards. Most blastoids are found without the brachioles because after the animal dies they fall apart at the joints and scatter in the currents.

1 comment:

  1. Nice. I've never seen one with the brachioles attached.