Hypodicranotus striatulus trilobite hypostome from the Verulam

One of the nice things about the middle Ordovician aged (Katian/Mohawkian stage) Verulam formation is the abundance or Trilobite remains. Most times they are whole specimens, like the Flexicalymene I found, but more often they are the scattered bits of the skeleton left after a molt. Below is one such piece which is a Hypostome from a trilobite called Hypodicranotus striatulus.

The Hypostome is thought to be one of the mouth parts on a trilobite. Some research suggests that they used them like claws in order to hold prey in place while feeding or that they were an integral part of the feeding apparatus.

The website Trilobites.info has a great page here that discusses Hypostomes and their varied shapes as well as how they were attached to the cephalon of trilobites.

Harvard's website has a great set of pictures of a whole specimen, click here, as well as some of the Hypostomes from the Walcott-Rust quarry in NY.

You can check out another Hypostome from a Hypodicranotus in the gallery of my friend Kevin on the Fossil Forum here. Thanks to Kevin for IDing the specimen for me.