Redlichiida

A number of different feeding methods have been suggested for trilobites including filtering particles from the water and predatory or scavenging habits. If you consider the overall shape of a trilobite, those that were more streamlined could move through the water faster, allowing them to catch other animals. Redlichids are generally streamlined and were most likely predatory.

A small plate called the hypostome is present on the underside of some trilobites just behind the mouth. In trilobites that filter fed the hypostome was not attached to the rest of the exoskeleton in a natant condition. In predatory trilobites, the hypostome was stronger to allow manipulation of food against the plate and movement was vertical to push bulky food through the gut. The hypostome for these types are trilobites is called either counterminant, where the front of the plate lines up with the domed glabella on the exoskeleton above, or impendent, where the front of the glabella is much further forward. Redlichida have a counterminant hypostome which again suggests they were predators.