Trimerus

For the Italian islands, see Tremiti Islands.

Trimerus
Temporal range: Llandovery–Lochkovian
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 Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Arthropoda
Class: †Trilobita
Order: †Phacopida
Family: †Homalonotidae
Genus: †Trimerus
Green, 1832
Species:
†T. delphinocephalus
Binomial name
†Trimerus delphinocephalus
Green, 1832
Other species

See text

An isolated fossil cephalon from the trilobite Trimerus (Trimerus) delphinocephalus, missing some of the anterior portion. Collected from the Rochester Shale in Canada. Pores for setae are visible marginally.

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.[1]

  1. ^ Eldredge, Niles (1970). "Observations on burrowing behavior in Limulus polyphemus (Chelicerata, Merostomata), with implications on the functional anatomy of trilobites". American Museum Novitates (2436).