Fuxianhuia protensa is an ancient arthropod from the Yunnan Province of China that has scientists rethinking the evolutionary history of insects. There are two main theories about the ancestor from which insects descended. One belief is that a class of water-dwelling crustaceans known as the malacostracans shared a common ancestor with modern insects. Other scientists think that insects come from the same family tree branch as a class of small, mostly freshwater, crustaceans; the branchiopods. Until the recent discovery of the 520-million year-old arthropod Fuxianhuia protensa, most evidence pointed towards the branchiopod theory because most known arthropod fossils have more primitive brains similar to branchiopods. F. protensa, which dates back to the Cambrian period, shows that more ancient arthropods did indeed have brains that were specialized beyond the basic brain layout of older arthropod ancestors. Nicholas Strausfeld, a neurobiologist at the University of Arizona, worked with Xiaoya Ma from the Natural History Museum in London in the analysis of F. protensa. They utilized a technique known as neurocladistics, in which ancestral relationships are inferred based on the morphology of the nervous system, to delve deeper into Fuxianhuia’s history. He believes F. protensa is evidence that insects probably did derive from a malacostracan ancestor. The Chinese fossil has a more complex brain similar to that of malacostracans; its brain is laid out in a similar fashion to that of a malacostracan brain. It also has advanced features such as crossing nerve fibers between multiple optic lobes and a brain made up of three fused segments (versus the two that comprises a branchiopod brain). The fundamental components of the brain and the non-specialized parts of the nervous system, however, are similar across the board: arthropods, malacostracans, branchiopods, and even humans all share the same basic circuitry that makes us thinking organisms.

Find out more about Fuxianhuia protensa at sci-news.com.

The scientific paper can be found in the journal Nature.

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