Ectillaenus katzeri is an extinct genus of trilobite which lived during the Ordovician period, specifically from the Llanvrinian series, dating it to around 466 to 461 million years old. Very little is known overall about the species, as is the case with many European trilobite specimens, however, what can be said is that the specimen here is near complete, its head is whole and present, although it appears to lack eyes, this appears to be common with this species, it is possible they are delicate and do not fossilise well. The glabella is also very large and wide, more so than other trilobites, the thorax segments are all present as well as the semi circular flat tail. The specimen measures 45 x 35 mm in size and has a typical rusty yellow colour. Supplied in a card tray with a label, this ectillaenus katzeri comes from Rokycany Drahouš, Barrandian area, Czech Republic.