Week 10 Vocab: Paleogeography and Plate Tectonics

The Crust

The outermost layer of the earth

consisting of the continents and ocean basins.

Alfred Wegener

Founder of the theory of plate tectonics.

Mantle

Highly viscous layer of the Earth; layer between the crust and the outer core; roughly 2900 km thick.

Lithosphere

Ridged outermost layer of the Earth; composed of the crust and the upper portion of the mantle.

Asthenosphere

The viscous layer of the upper mantle below the

lithosphere; between roughly 80 and 200 km below the Earth's surface

Inner Core

The innermost layer of the Earth; a solid mass composed of iron and nickel.

Outer Core

Layer of the Earth composed of molten iron and nickel; roughly 2270 km thick.

Plates

Pieces of the lithosphere affected by

convection currents.

Pangaea

Supercontinent, comprised of all the Earth's major

landmasses, that formed around 300 million years ago and began breaking up around 200 million years ago.

Panthalassa

The giant ocean that surrounded Pangaea.

Plate Tectonics

The movement of the lithosphere that provides the explanation for the drifting continents that Alfred Wegner theorized.

Diplodocids

A group of sauropod dinosaurs with long necks and long "whip-like" tails; lived during the Middle to Late Jurassic; examples: Apatosaurus, Diplodocus, Supersaurus

Macronarians

Group of Jurassic sauropods with robust bodies, front legs not noticeably shorter than their back legs, and that lack whip-lack tails. E.g. Brachiosaurus and Giraffatitan

Thyreophorans

Group of ornithischians with body armour. Includes e.g. Stegosaurs

Niche Partitioning

When similar animals avoid direct competition for

food resources, by exploiting different ecological niches e.g. predation vs scavenging

Ecological niche

An animal's role in the ecosystem; how it survives in that ecosystem.

Allosauroids

Large predators that originated in the Jurassic, with vertebrae that interlock more

rigidly, so their spines were held stiffer. Their

legs are also proportionately longer, suggesting

that they were faster than either megalosaurids

or ceratosaurids. E.g. Allosaurus

Coelurosaurs

Group of theropods that originated in the Jurassic, characterised by a long series

of sacral vertebrae, narrow hands, and tails with

back halves that are skinny, stiff, and

lightweight. the group from which birds arise.

Laurasia

Northern of the two supercontinents that were formed as Pangaea split in the Early Jurassic; comprised Asia, Europe, and

North America.

Gondwana

Southern of the two supercontinents that were formed as Pangaea split in the Early Jurassic; comprised Australia, Antarctica, Africa, South America, Madagascar and India.

Titanosaurs

Group of advanced sauropod dinosaurs; lived during the Late Jurassic to Late Cretaceous; globally distributed but most abundant in Gondwana; examples: Argentinosaurus,

Saltosaurus, Alamosaurus.

Carcharodontosaurids

A group of theropod dinosaurs with teeth that somewhat resemble those of modern sharks; lived during the Late Jurassic to Late Cretaceous; examples: Giganotosaurus, Carcharodontosaurus, Concavenator

Abelisaurids

A group of ceratosaurid theropods that thrived throughout Gondwana during the Middle Jurassic to Late Cretaceous; characterized by short forelimbs, small teeth, and ornamented skulls; examples: Carnotaurus, Majungasaurus, and Rugops.

Ankylosaurs

Heavily-armored quadrupedal ornithischian dinosaurs; examples: Ankylosaurus, Edmontonia, Polacanthus.

Nodosaurids

The second major group of

ankylosaurs. They lacked tail clubs, but some

have offensive weapons at the other end, in the

form of large osteoderm spikes that project

outwards from over their shoulders. E.g. Borealopelta

Ankylosaurids

The first major group of ankylosaurs.

The ankylosaurs with the famous tail clubs; also typically have large backwards-pointing horns at the rear of their skulls and a short rounded snout at the front.

Lambeosaurines

Advanced group of hadrosaurs with a big crest on their heads. Inside this crest is a complex and

hollow nasal passageway. E.g. Parasaurolophus

Hadrosaurines

Advanced group of hadrosaurs that lacked

complex sound amplifying crests. Some still did have small bony, or soft tissue crests. E.g. Edmontosaurus.

Marginocephalians

Diverse group of Laurasian dinosaurs that includes the ceratopsians and pachycephalosaurs. The name literally means "fringe heads" and refers to an overhanging lip of bone at the back margin of the skull.

Ornithomimids

Group of coelurosaurs that evolved a body plan similar to that of a modern ostrich or emu, but with long clawed forelimbs and a large tail.

Maniraptorans

Group of coelurosaurs that developed a highly specialized wrist bone called a semilunate carpal; includes birds, dromaeosaurs and oviraptorosaurs.

Dromaeosaurs

Group of maniraptoran theoropds with a large, sickle-shaped claw on each foot. E.g. Deinonychus

Oviraptorosaurs

Group of maniraptoran theropods that

adapted to a mostly vegetarian life and lost

their teeth in favour of large beaks. Many had cranial crests and fans of feathers on the ends of their tails.

Therizinosaurs

Bizarre group of maniraptoran theropods, with large hand claws, small skulls on the end of long necks and hind feet with four forward pointing toes. They also have a backwards-directed pubis and jaws with small herbivorous teeth in the back and a beak in the front.

Faunal interchange

When animals from one region can

move into another, leading to similar species in

both regions. E.g. Mongolian and W. Canadian dinosaurs.