Trimerus
| Trimerus Temporal range: | |
|---|---|
| Fossil of Trimerus (Trimerus) delphinocephalus from the Rochester Shale of North America, housed at the Oxford University Natural History Museum. | |
| Reconstruction of Trimerus (Trimerus) delphinocephalus from the Rochester Shale of North America. | |
| Scientific classification | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Arthropoda |
| Class: | †Trilobita |
| Order: | †Phacopida |
| Family: | †Homalonotidae |
| Genus: | †Trimerus Green, 1832 |
| Type species | |
| Trimerus delphinocephalus Green, 1832 | |
| Other species | |
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See text | |
Trimerus is an extinct genus of trilobite in the family Homalonotidae. Trimerus is one of North America's largest trilobites, reaching over 20 cm (7.9 in) in length. It had a thorax composed of 13 segments with weak trilobation, a large subtriangular head terminating in an expanded rostral plate, a two-pronged hypostome, and a triangular pygidium. It is known from all continents except for Antarctica. Its tiny compound eyes and the shovel-like anterior of the head suggests a burrowing lifestyle, and an exoskeleton marked with many small pores which, in life, probably housed hair-like sensory setae in life, allowed the trilobite to feel which portions of its body were covered with sediment.