''Shuyu'' is an

extinct Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...

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 ...

of early jawless vertebrate from the Early or Middle

Silurian The Silurian ( ) is a geologic period and system spanning 24.6 million years from the end of the Ordovician Period, at million years ago ( Mya), to the beginning of the Devonian Period, Mya. The Silurian is the shortest period of the Paleozo ...

period (late Telychian to early Wenlock stages). It is the basalmost known eugaleaspidiform

galeaspid Galeaspida (from Latin, 'Helmet shields') is an extinct taxon of jawless marine and freshwater fish. The name is derived from ''galea'', the Latin word for ''helmet'', and refers to their massive bone shield on the head. Galeaspida lived in shallo ...

and it lived in what is now northwestern

Zhejiang Province Zhejiang ( or , ; , also romanized as Chekiang) is an eastern, coastal province of the People's Republic of China. Its capital and largest city is Hangzhou, and other notable cities include Ningbo and Wenzhou. Zhejiang is bordered by Jiangs ...

, Southeast

China China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's most populous country, with a population exceeding 1.4 billion, slightly ahead of India. China spans the equivalent of five time zones and ...

. It is known from more than 20 headshields and at least 20 of them include three-dimensionally preserved neurocrania. The specimens of ''Shuyu'' were collected from the lower part of Maoshan Formation, located in Changxing District. ''Shuyu zhejianensis'' was first assigned by Pan, 1986 to a species of '' Sinogaleaspis''. The genus was first named by Zhikun Gai, Philip C. J. Donoghue, Min Zhu, Philippe Janvier and Marco Stampanoni in

2011 File:2011 Events Collage.png, From top left, clockwise: a protester partaking in Occupy Wall Street heralds the beginning of the Occupy movement; protests against Libyan dictator Muammar Gaddafi, who was killed that October; a young man celebrate ...

and the

type species In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specimen ...

is ''Shuyu zhejianensis''.Electronic supplementary material
/ref>

References

Prehistoric jawless fish genera Galeaspida Fossil taxa described in 2011 Prehistoric animals of China Silurian jawless fish {{silurian-animal-stub