Shuyu zhejiangensis (P'an, 1986) Gai et al., 2011
Systematics: Agnatha Galeaspida Eugaleaspidiformes
Size: 15 cm long
Type Horizon and Locality: Middle or Early Silurian, Maoshan Formation (Late Llandovery or Early Wenlock), Changxing District, Zhejiang Province, China
Type Specimen: Holotype (headshield)
Originally described as a species of Sinogaleaspis, this small galeaspid received a new generic name in 2011, Shuyu which means in Chinese Pinyin "dawn jawed fish". The internal cranial anatomy of this jawless fish was investigated by synchrotron x-ray tomography revealing that unlike in lampreys and hagfish, some evolutionary prerequisite that lead to the origin of jaws were already present in these primitive fish.
References:
Gai, Z., Donoghue, P. C., Zhu, M., Janvier, P., & Stampanoni, M. (2011). Fossil jawless fish from China foreshadows early jawed vertebrate anatomy. Nature, 476(7360), 324.
August 6, 2017
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