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Cretaceous

Paleogene 65.5 to 23.03 Million years ago

Neogene

Plate Tectonic Reconstructions

The Paleogene* sees the rapid filling of the environment following the K/T extinction. On land primitive mammals and birds began to spread rapidly.  In the seas plantontic foraminifera and nanofossils begin new evolutionary paths.  Most marine life resembles modern forms: the wonder of Cenozoic fossils is seeing recognizable organisms cast in stone, rather than the exotic, 'alien' life forms of the Mesozoic and Paleozoic Eras.

The fossils of the Paleogene encompass three Epochs: the Paleocene, the Eocene and the Oligocene. During the Paleocene (65-56 Mya) small mammals diversify on land. The first marine mammals appear during the Eocene (56-35 Mya), while large mammals appear on land. The Oligocene (35-23 Mya), saw the first appearance of the grasses, an immensely important group in subsequent ecologies. The anthropoid apes also appeared during this epoch. Additional information about the mammals of these epochs can be found in our Prehistoric Mammals of the Cenozoic exhibits.

Climatically there is a global warming episode at the Paleocene-Eocene boundary. Later in the Paleogene significant cooling trends aim the climate towards modern conditions.

*The term Paleogene is from Naumen’s “Paleogen Stufe” (1866) in which he combined the Eocene and the Oligocene.

Paleogene Animal (Metazoan) Fossils
Crustacea (ToL: Arthropoda<Ecdysozoa<Bilateria<Metazoa<Eukaryota)
	Crabs (Decapoda) continued to be common, and are represented by two Eocene specimens: Lobocarcinus-paulino wurtemburgensis (top and bottom views) and Harpactocarcinus punctulatus.
Echinoderms (ToL: Echinodermata<Deuterostomia<Bilateria<Metazoa<Eukaryota)
	Echinoids (Echinoidea [sea urchins and relatives]) are the common echinoderms. They are represented by a sea urchin, Echinolampas kleini, and a heart urchin, Eupatagus clevi.
Vertebrates (ToL: Vertebrata<Chordata<Deuterostomia<Bilateria<Metazoa<Eukaryota)
	Bony Fish (Osteichthyes): Ray-finned teleost fish fossils on display include a "death assemblage" of minnow sized fish and an Eocene Perch, Priscacara liops.
	Turtles (Turtles<Reptilia) (Testudines = Chelonia, etc.) are represented by a tortoise (Stylemys nebrascensis) shell and a water turtle shell piece on a freshwater snail plate.
	Birds (Aves<Dinosauria [Birds and Dinosaurs]<Reptilia) diversify, occupying the niches left by the pterosaurs. The collection's bird head, feather, and tracks are all of the Eocene Epoch.
	Mammals (Mammalia) are represented by a group of Oligocene fossils: the skull of an Oreodont, Leptauchenia nitia and a squirrel skull and jaw Ischyromys typus. Also displayed are the jaws of an Oligocene dog (Hesperocyon gregarius), a rabbit (Megalagus sp.) and an insectivore (Ictops dakotensis).
Mollusks (ToL: Mollusca<Lophotrochozoa<Bilateria<Metazoa<Eukaryota)
	Bivalves (Bivalvia) are represented by a cluster of Paleocene clams (Cardium sp.) in limestone.
	Gastropods (Gastropoda): Displayed are two halves of sliced nodule containing a Turitella sp. and two additional Turitella sp. in nodules. Also shown is a plate with an assemblage of fresh water snails and a turtle shell piece.
Paleogene Plant Fossils
Vascular Plants (ToL: Embryophytes [land plants] <Green Plants<Eukaryota)
	Conifers remained important, and are represented in the collection by a slab with paleocene redwood (Metasequoia and Sequoia) foliage.
	Angiosperms are represented by Eocene fossils of flowers, a willow leaf (Salix sp.), and a sweet gum (Liquidambar sp.) pod along with a modern specimen for comparison.

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Last modified 29 January 2007 | ©1998, HSU NHM