what kind of animals are trilobites
Trilobites are an extinct group of arthropods (jointed-legged animals) known from more than 10,000 fossil species. The group Trilobita existed from early in the Cambrian Period (520 million years ago) until the end of the Permian Period (250 million years ago).The name Trilobita is derived from the three (tri-) lobed structure of the exoskeleton, which has a raised central lobe (or axis) and a pair of side lobes, called pleurae.efore the first trilobite with its legs fossilised was described in 1870, it was already well established that Trilobita belonged to the Arthropoda. Arthropods are the most species-rich animal phylum living today, and have been the most diverse group of multicellular animals since the Early Cambrian.