The case most frequently insisted on by palaeontologists of the apparently sudden appearance of a whole group of species, is that of the teleostean fishes, low down, according to Agassiz, in the Chalk period.
古生物学家最常坚持的一整群物种明显突然出现的案例是硬骨鱼类,根据阿加西的说法, 在白垩纪。