The ‘trilobite larvae’ known occurring in the South East Asian rain forests are neotenic females of the beetle genus Duliticola (Coleoptera:Lycidae). Some can glow in the dark!
Trilobites ("three-lobes") are extinct arthropods that form the class Trilobita. They appeared in the Early Cambrian period and flourished throughout the lower Paleozoic era before beginning a drawn-out decline to extinction when, during the Late Devonian extinction, all trilobite orders, with the sole exception of Proetida, died out. The last of the trilobites disappeared in the mass extinction at the end of the Permian about 250 million years ago (m.y.a.).
Trilobites are very well-known, and possibly the second-most famous fossil group, after the dinosaurs. When trilobites appear in the fossil record of the Lower Cambrian they were already highly diverse and geographically dispersed. Because of their diversity and an easily fossilized exoskeleton, they left an extensive fossil record with some 17,000 known species spanning Paleozoic time. Trilobites have been important in biostratigraphy, paleontology, and plate tectonics research. Trilobites are often placed within the arthropod subphylum Schizoramia within the superclass Arachnomorpha (equivalent to the Arachnata), although several alternative taxonomies are found in the literature.
Different trilobites made their living in different ways. Some led a benthic life as predators, scavengers or filter feeders. Some swam (a pelagic lifestyle) and fed on plankton. Most life styles expected of modern marine arthropods are seen, except for parasitism. Some trilobites (particularly the family Olenida) are even thought to have evolved a symbiotic relationship with sulfur-eating bacteria from which they derived food.