Palaeos		Laurasiatheria
Vertebrates		Overview

Laurasiatheria: Overview

EUTHERIA
|--EUARCHONTAGLIRES
|?--CHIROPTERA
`--LAURASIATHERIA
   |?--INSECTIVORA
   `--Ferungulata
      |--+--FERAE
      |  `--Pholidota
      `--+--+--Phenacodontidae
         |  `--PERISSODACTYLA
         `--Eparctocyona
            |--+--Arctostylopida
            |  `--+--Mesonychia
            |     `--CETARTIODACTYLA  
            `--Bulbulodentata
               |--Hyopsodontidae
               `---MERIDIUNGULATA

Phenacodus, an early Tertiary Laurasiathere (Ferungulata - Phenacodontidae), about the size of a small sheep, and already specialised towards a herbivorous browsing lifestyle. Animals like Phenacodus may be close to the ancestry of perissodactyls and indeed resembled early horses like Hyracotherium (Eohippus). Artwork by Heinrich Harder (public domain)

Introduction

The Laurasiatheria are one of the four main clades of placental mammals, as revealed by molecular sequencing. Controversially, there are absolutely no morphological traits that define this taxon. However, a more restricted Laurasiatheria, the Ferungulata, is supported by both molecules and morphology, and so here we are on firmer ground. This diverse and important evolutionary lineage began with unspecialised, omnivorous, Paleocene mammals. By the end of the Eocene they dominated terrestrial faunas, and had already become specialise dinto various carnivore and herbivore niches. While other clades such as the Archontaglires (rodents and primates) and the Afrotheria (elephants and their kin) would also be important, it is the ferungulates that became the most diverse and characrteristic animals of teh age of mammals. MAK120717