Trimerus delphinocephalus Trilobite

Here is a trilobite found by a KYANA Geological Society (www.kyanageo.org) member on a field trip some years ago. It is a Trimerus delphinocephalus (Green) from the Silurian Period. It was found in the Waldron Shale layer in Clark County, Indiana.

This image shows the trilobite in two pieces: part of the head and thorax/back. Maybe it was a molt. See this link for different picture of this same specimen: http://www.kyanageo.org/Fossils/silurian/arthropoda/trimerus_delphinocephalus.jpg

Here is a link that shows another from the same area but it appears fully intact: http://weekstrilobites.com/Trimerus.htm

Trilobite Trimerus Side View

The side view of a Trimerus delphinocephalus found in Clark County, Indiana in the Waldron Shale layer. The creature lived in the Silurian Period. Two more images of this animal can be found in the Fossils of Ohio book on page 108, figures 10 and 11.

Back Side of Trimerus Trilobite

Here is the back thorax of a Trimerus type trilobite from the Silurian period. It is described in more detail on page 98 of the Fossils of Ohio book. According to that description, these trilobites could get to 20 cm in length. This one about 4-6 cm wide. The creature had small eyes about about 13 segments for the thorax.