Feeding specializations in Late Triassic fishes

Abstract

The ichthyofauna of the Zorzino Limestone represents an important proof of the richness and variety
reached by bony fishes during the Norian and, at the same time, it testifies the beginning of the faunal
transition which will be realized during the Jurassic. The thousands of specimens and the extraordinary quality
of preservation found in the fossiliferous levels of this unit allowed, in the last years, not only to follow such
a crucial moment in the evolution of vertebrates, but also to reconstruct the mode of life and the trophic
adaptations reached by the different groups, living in the depositional basins. As evidence of this peculiar
evolutionary period, the large predators at the highest trophic levels are still represented by ’primitive’ basal
actinopterygians; on the contrary, the most derived neopterygians specialized in durophagy, a trophic niche
previously almost unexploited by actinopterygians. Within the main trophic categories, anyway, we can find
different morphological specializations, which probably allowed the fishes to exploit most of the available
trophic resources.