The rise and fall of proboscideans? functional diversity

SANISIDRO, O.; BLANCO F.; ALBERDI M. T.; SAARINEN J.; CANTALAPIEDRA, J. L.; PRADO, J. L.

Valencia

Congreso; The Palaeontological Association - 63rd Annual Meeting; 2019

The Palaeontological Association

The history of the proboscidean lineage is one of success and decline. During their 60 myr of evolution, proboscideans evolved into a remarkable diversity of body sizes and cranio-dental adaptations, and have been common constituents of Cenozoic mammalian communities. Yet, today?s proboscideans represent but a tiny fraction of their past diversity. We examine the tempo and mode of their functional evolution using extensive fossil information and phylogenetic methods. Based on sixteen ecomorphological traits, we identify eight proboscidean functional types (FTs). During the early phase of their evolution (until ~40Ma) only two of such FTs appeared. It wasn?t after speciation and extinction rates taped off that the other six FTs evolved. The earliest Miocene witnessed the maximal functional disparity of the clade, as three new FTs appeared featuring zygolophodont and bunolamelar teeth with more cusps and lophs, as well as more derived patterns of mastication. The functional decay of the lineage started ~10Ma, with extinction progressively being more selective with respect to function. Functional attrition peaked in the last 2 myr, and just three FTs survived until 100 kyr ago. We pick the signal of differential speciation and extinction rates across the functional space.