The occurrence of early vertebrate fossils (mainly Silurian and Devonian fishes) in Yunnan, southwestern China has been known for almost a century. But only during recent decades have these fishes received the detailed systematic studies and drawn much attention on account of their diversity and the relatively early geological horizons at which they occurred. 
    The Silurian vertebrate faunas are known from several localities in Qujing, eastern Yunnan, from sequences which are predominantly near-shore marine and range from the Wenlock to the pridoli in age. An arthrodirelike fish from the Yuejiadashan formation (Wenlock) of the Xundian County represents one of the earliest representatives of placoderms and might throw some lights on the origin and early evolution of placoderms. The early forms of antiarch placoderms are also known from this region. The microvertebrate fossils, in association with brachiopods, trilobites and conodonts, include thelodonts, acanthodians and bony fishes, and provide a taxonomic database for the biostratigraphic correlation. 
    The Devonian vertebrates are known from over twenty localities throughout Yunnan. On the paleogeographic setting, these fossil sites can be referred to two early vertebrate provinces: the South China Province in the east and the Sibumasu Province in the west. The Early Devonian fishes are mainly from the South China Province and show the strong endemism with galeaspid agnathans and yunnanolepid placoderms. The discoveries of Early Devonian Youngolepis, Diabolepis, Kenichthys, Psarolepis, Achoania, and Styloichthys highlight the importance of Yunnan as a source of early sarcopterygians, and suggest that South China may be the place of origin of the Sarcopterygii (tetrapods, coelacanths, lungfishes and related groups). They also provide the crucial evidences for the origin and early evolution of the Osteichthyes (bony fishes and their descendants). By the Emsian, the verterbrate faunas of Yunnan appear cosmopolitan as the diversity of the endemic groups such as galeaspids and yunnanolepids suddenly decreases. The detailed taxonomic descriptions of the Devonian vertebrates from Yunnan over the last forty years, lead to a major increase in the database of described early vertebrate fossils, which are biogeographically and biostratigraphically useful.