| 论文摘要 |
The iconic saurichthyid fishes (‘lizard fish’) are specialised predators in the aquatic realm of Early Mesozoic era. After a rapid diversification in the Middle Triassic, they seemingly shrank their geographical distribution from a global pattern to that mainly confined to Euramerican region and exhibited increasing rarity in the freshwater environment since the Late Triassic. Here, we report a new species of Saurichthys from the Late Triassic freshwater deposits of the Junggar Basin, northwestern China. This new species Saurichthys sui sp. nov. is characterised by a mosaic of primitive and derived features in Saurichthys: large circumorbital bones and spiracular plate, a vestigial opercle and pectoral fins devoid of fringing fulcra. This feature combination supports the hypothesis that the freshwater system might have served as the refugium of some basal saurichthyid species. Saurichthys sui represents the first record of large predatory fishes in the Triassic Junggar Basin and indicates the establishment of a trophically complex lacustrine ecosystem there. Together with the co-occurring fossil insects and plants, Saurichthys sui, showing some affinities to its congeners from central Asia and North China, implies some biogeographical links of the fossil localities of non-marine Saurichthys on the continents north to PalaeoTethys during the Middle-Late Triassic. |
