''Hemiarthrum setulosum'' is a

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

chiton Chitons () are marine molluscs of varying size in the class Polyplacophora (), formerly known as Amphineura. About 940 extant and 430 fossil species are recognized. They are also sometimes known as gumboots or sea cradles or coat-of-mail s ...

in the

family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

Hanleyidae ''Hanleya'' is a genus of chiton, polyplacophoran molluscs known from Oligocene and Miocene fossils; it is represented today by a number of species including ''Hanleya sinica, H. sinica'' Xu 1990 (China), ''Hanleya brachyplax, H. brachyplax'' (B ...

, the only member of the

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

''Hemiarthrum''. Hemiarthrum setulosum represent one of the five major clades of chitons that are living. Hemiarthrim setulosum has an incomplete lateral tract in the nerve ring. They are the only known species to have an incomplete one. Sumner‐Rooney, Lauren, and Julia D. Sigwart. "Do chitons have a brain? New evidence for diversity and complexity in the polyplacophoran central nervous system." Journal of morphology 279.7 (2018): 936-949.

References

Hanleyidae Monotypic mollusc genera {{Chiton-stub