Extraordinarily thick-boned fish linked to the aridification of the Qaidam Basin

Scattered with numerous salt lakes and approximately 2700-3200 m above sea level, the giant Qaidam inland basin on the northern Tibetan Plateau has experienced continuing aridification since the beginning of the Late Cenozoic as a result of the India-Asia plate collision and associated uplift of the Tibetan Plateau. Previous evidence of aridification comes mainly from evaporite deposits and salinity-tolerant invertebrate fossils.

Vertebrate fossils were rare until recent discoveries of abundant fish. Among them, an unusual cyprinid fish, Hsianwenia wui, has an extraordinarily thick skeleton that occupied almost the entire body, apparently leaving little room for muscles, which is unknown among extant fish. We are studying how this could have happened and its implications to paleoenvironmental analysis.