Arthropods—brine shrimp, hawk moths, and many other invertebrate animals—have a nervous system made up of a brain, nerve cord, and other nerves. Researchers have gained insights about this system in ancient arthropods from traces found in various fossils. For example, in a study of two fossils of the extinct arthropod species Mollisonia symmetrica, Javier Ortega-Hernández, James Weaver, and team observed clear signs of a nerve cord. They also saw possible indications of a synganglion, a brain-like mass of nerves. Researchers hope to identify more features of the nervous systems of prehistoric arthropods as additional fossils are found.