Life through the Paleocene
the demise of the dinosaurs at the end of the Cretaceous,
the stage was set for mammals and
to become the dominant land vertebrates. Although Paleocene bird fossils
are rare, mammals are well represented in Paleocene sediments. Insectivorans,
early relatives of true primates
creodonts, and primitive
herbivores (such as condylarths and early uintatheres)
inhabited the forests. The largest mammal, Pantolambda (a
primitive plant eater), was about the size of a small pony. The multituberculates,
small mammals with chisel-like front teeth that had evolved in the
Mesozoic, remained common in the Paleocene; rodents
appeared late in the Paleocene.
Although the majority of Cretaceous plant species did not survive
into the Paleocene, ferns were very abundant for a
brief period following the end-Cretaceous asteroid impact.
Subsequently, flowering plants and conifers
once again became more abundant during the early Paleocene. Paleocene
swamp forests from middle latitudes to the shores of the Arctic Ocean
were dominated by deciduous trees related to bald cypress. Drier-ground
vegetation supported members of the tea, laurel, and birch families,
among many others.
Through most of the Paleocene, fossil leaves show low amounts and
few types of damage caused by herbivorous insects. This suggests that
insect herbivores were slow to recover diversity and abundance following
the end-Cretaceous extinction. The diversity of insect
feeding marks on plants did not recover to Cretaceous levels until
the late Paleocene.