Paleo 203 Midterm

Tetrapoda (informally, tetrapods)

Terrestrial vertebrates named for their four weight-bearing limbs. Includes all living and extinct amphibians, birds, mammals, and reptiles.

Amniota (informally, amniotes)

A clade of vertebrates that develop special membranes around their eggs, allowing them to cut reproductive ties with water. Includes all living and extinct birds, mammals, and reptiles.

Amnion

a membrane that surrounds an embryo which protects the developing young from drying out

Aquatic problem

The main theme of this course. Encompasses differences between air and water and the challenges terrestrial amniotes had to overcome to successfully live in the water.

Morphology

The shape and structure of an animal or any of the parts of its body.

Terrestrial

An organism that can carry out all aspects of its life on land.

Aquatic

An organism that can carry out all aspects of its life in water.

Semi-aquatic

An organism that requires both land and water environments to carry out all aspects of its life. Have long, smooth bodies, flippers, tail fluke and hind legs

Primarily aquatic

An organism that lives in the water, and is descended from ancestors that also lived in the water. Includes all living and extinct fishes.

Secondarily aquatic

An organism that lives in the water, but is descended from ancestors that live on land. Includes all living and extinct aquatic birds, mammals, and reptiles.

Pinniped

A member of the Pinnipedia- the group that includes seals, sea lions, and walruses.

Carapace

The bony shell across the back of an animal.

Plastron

The bony shell across the abdomen of an animal.

Crocodyliformes

(informally, crocodiles) A sub-group of the Crocodylomorpha containing all modern and some extinct crocodiles, alligators and gharials. Body armour, webbed toes, laterally compressed tails, Saltwater crocs use ocean currents to travel between Indonesian islands

Laterally compressed

When an object is flattened such that it is taller than it is wide.

Extant

Still in existence, currently living.

Extinct

No longer in existence, with no living members.

Thrust

The force that generates propulsion.

Appendicular skeleton

The bones that form the limbs and limb girdles. Includes all bones of the shoulders, arms, hips, and legs.

Appendicular locomotion

Motion generated by movement of the limbs. Have flippers or webbed feet to increase thrust and surface area

Flippers

Flatter bones, shorter radius, humerus, ulna, longer and numerous phalanges, covered in smooth flat tissue

Axial skeleton

The bones that form the mid-line of the body. Includes all bones of the skull, spinal column, and ribs.

Axial locomotion

Motion generated by movement of the spinal column. Developers caudal fluke to increase surface area

Flippers

Modified limbs that are adapted to manoeuvre in water.

Phalanges

The bones that form the individual segments of fingers or toes.

Caudal fluke

An expanded, soft-tissue fin supported by the last tail vertebrae. Vertical in marine reptiles, horizontal in marine mammals.

Collagen

A structural protein found in connective tissues of animals.

Caudal fin

An expanded vertical structure, completely supported by thin bones, but no vertebrae, that forms the tail of fishes.

Anguilliform locomotion

A form of axial locomotion in which the entire spinal column undulates, propagating waves of muscle contractions down the entire body. Low efficiency. Animals that use this form of locomotion tend to be long and skinny. Ex. Sea snakes and eels

Thunniform locomotion

A form of axial locomotion in which only the tail undulates. Maximum efficiency. Animals that use this form of locomotion tend to be torpedo-shaped. In high speed predatory fish, not body oscillation, crescent shaped fins and fluke. Ex. Tuna, dolphins

Carangiform locomotion

A form of axial locomotion in which only the back half of the spinal column undulates. Animals that use this form of locomotion tend to be spindle-shaped. ex. Seals, crocs, marine iguanas

Pitch

Up and down motion. One of three planes of motion in a 3D environment.

Roll

Movement where an object turns over on its forward-backward axis. One of three planes of motion in a 3D environment.

Yaw

Left and right motions. One of three planes of motion in a 3D environment.

Dorsal fin

An unpaired fin on the back of an animal which helps to stabilize them against rolling.

Drag

The force that resists the movement of an object through any medium. Increased by both density and viscosity of the medium.

Inertial drag

The force that resists the movement of an object by disturbing the flow of molecules around that object crates a space where the medium fills and pulls body backward. It is based on the density of the medium through which it moves. Needs fusiform body shape, smooth, elongate, decreased surface area, loss of hind limbs and external ears

Streamlined

A morphology that reduces resistance of a body moving through a medium by reducing the way it disturbs the medium. Minimizes inertial drag.

Fusiform

An oblong morphology that tapers at both ends. Can be described as spindle-shaped or torpedo-shaped.

Viscous drag

The force that resists the movement of an object based on friction generated between the object and the medium it is moving through. Caused by the viscosity of the medium through which it moves. Needs smooth, hairless body

Lactic acid

An organic acid produced in muscles during strenuous activity when there is little oxygen available. Causes muscle fatigue and soreness. In crocs

Nares

Openings in the skull that allow for the passage of air from the nostrils to the windpipe.

Blowhole

Nostrils that have migrated to the top of the head in a marine mammal.

Neutral buoyancy

When an object has the same density as the medium that surrounds it. The object with neither sink nor float.

Pachyostosis

A condition in which bones become denser and larger due to increased growth of the denser outer layers of the bones. In manatees, penguins, early whale relatives

Osteosclerosis

A condition in which bones become denser, but not larger, due to increased mineralization usually in the spongy inner regions of the bones. In walrus and turtles

Gastroliths

A small stone swallowed by an animal to aid in digestion of tough materials and/or to contribute to neutral buoyancy. Sometimes called gizzard stones. In crocs and birds

Osmosis

A process in which water passes through a membrane from an area of low solvent concentration to an area of high solvent concentration. Equalizes the concentration between the two areas.

Salt gland

A special gland that concentrates salt from the blood so that it can be expelled from the body. On crocs tongue, under sea snake tongue, above sea turtle and bird eyes, connected to nostrils in marine iguanas (expel by sneeze)

Metabolism

The sum total of all chemical processes that occur within an organism in order to maintain life. Hard to maintain in water because water is a good heat conductor

Blubber

A thick layer of fat found on some marine mammals that is used as insulation.

Underhairs

The shorter, finer hairs close to the skin of a mammal. Function primarily as insulation. Traps heat near skin

Guard hairs

The outer layer of longer, coarser hairs on a mammal. Functions primarily as protection. Keeps water away from underhairs. Layer like shingles

Tapetum lucidum

A lining on the back of the eyes that reflects incoming light through the retina a second time, increasing the effectiveness of the eye in low light conditions. Seals, crocs, cats

Water properties related to sight

1. Density changes how light bends - bends less in water
2. Light doesn’t travel as far and diffracts
3. Only some spectrum of light is seen in greater depths - blue and green penetrate deeper, total darkness at 200m

Bone conduction

The transmission of sound waves from the surrounding environment to the inner ear through the skull bones. Uses vibrations, less distortion, secondarily aquatic adaptation

Hearing in water

Easier to hear in water, travel 5x faster

Echolocation

A type of sonar used by some animals to detect objects. The animal emits high-pitched sounds which bounce off of surrounding objects and back to the animal's ears, revealing the location of the objects.

Ecology

The relationship of an organism to other organisms and its physical surroundings.

Convergence

Where organisms facing similar ecological challenges evolve similar or indistinguishable solutions.

Paleoecology

(see ecology) The ecology of extinct organisms.

Marine Reptile clades

Ichthyoperygians, sauropterygians, mosasauroids

Basal

Belonging to the base of a lineage, usually with few of the specialized adaptations seen in later members of the group.

Derived

Belonging at or near the tip of a lineage, usually with many specialized adaptations not seen in ancestral forms.

When first tetrapods colonized

During Devonian

Temporal fenestrae

Holes in the side of a skull- the number of these holes determine major phylogenetic groupings.

Anapsid

Having no temporal fenestrae in the skull.

Synapsdid

Having one pair of temporal fenestrae in the skull.

Diapsid

Having two pairs of temporal fenestrae in the skull: the laterotemporal and supratemporal fenestrae.

2 diapsida lineages

Archosauromorpha, Lepidosauromorpha

Synapsida (informally, synapsids)

With the Sauropsida, is one of the two major divisions of amniotes. This group have only one temporal fenestra. Mammals are the modern representatives of this group.

Sauropsida (informally, sauropsids)

With the Synapsida, is one of the two major divisions of amniotes. This group has two temporal fenestrae. Crocodiles, lizards and birds, Parareptiles and diapsida

Orbit

The opening in the skull where the eye is located.

Parareptilia (informally, parareptiles)

With the Diapsida, is one of two major divisions within the Sauropsida. Has the anapsid skull condition.

Diapsida (informally, diapsids)

With the Parareptilia, is one of two major divisions within the Sauropsida. Has the diapsid skull condition.

Laterotemporal fenestra

The lower of two temporal fenestrae in the diapsid skull condition, found below and/or behind the eye.

Supratemporal fenestra

The upper of two temporal fenestrae in the diapsid skull condition, found above and/or behind the eye.

Archosauromorpha (informally, archosaurs)

Ruling reptiles. With the Lepidosauromorpha, is one of two major divisions of the Diapsida. Have an additional fenestra in front of the eye and on the jaw. Members include birds, crocodiles, dinosaurs and pterosaurs.

Lepidosauromorpha (informally, lepidosaurs)

Scaly Reptiles. With the Archosauromorpha, is one of two major divisions of the Diapsida. Members include lizards and snakes. No extra temporal openings

Mesosauridae (informally, mesosaurs)

Group of aquatic marine parareptiles from the Permian. Earliest known group of secondarily aquatic amniotes. Includes genera such as Mesosaurus. Slender body, long neck, elongated skull, dense bone, long hind limbs, laterally compressed tail, needle like teeth, paddle in sallow water, could NOT live in open ocean

Tanystropheidae

Includes Tanystropheidae and Dinocephalosaurus

Tanystropheidae

Lacks paddles, laterally compressed tail, long and stiff neck, snatch fish at lake edge

Dinocephalosaurus

Long neck and paddles, lived in ocean

Crocodylomorpha (informally, crocodylomorphs)

A clade of archosaurs characterized by the articulation of their ankles. Includes all living and extinct alligators, caimans, thalattosuchians, and crocodiles. Webbed feet, laterally compressed tail.

Thalattosuchia (informally, thalattosucians)

A group of fully aquatic crocodylomorphs from the Jurassic and Cretaceous. Includes genera such as Geosaurus.

Geosaurus

Paddle like forelimbs, tail fluke (controls propulsion in water column), reduced dermal armour (for neutral buoyancy), salt glands in orbit, layer eggs on land, lived in water

Protorosauria (informally, protorosaurs)

A very basal clade of archosaurs.

Tanystropheidae (informally tanystropheids)

A family of protorosars with very long necks thought to be semi aquatic. Includes genera such as Tanystropheus and Dinocephalosaurus.

Drepanosauridae (informally, drepanosaurs)

A family of protorosaurs with convergent adaptations to chameleons, feet and hands for tree climbing, huge claws, though one species, Hypuronector, is thought to be aquatic.

Hypuronector

Laterally compressed tail, like a newt, tail not good for trees but good for water propulsion, in lake deposits part of Drepanosauridae

Choristodera (informally, choristoderes)

A clade of aquatic diapsid archosauromorphs with uncertain phylogenetic relationsips. Convergent body plan to crocodylomorphs. Includes genera such as Champsosaurus. Lived in waterways in the mesozic, survived end-Cretaceous mass extinction, unknown extinction in Miocene epoch

Champsosaurus

Long narrow snout with conical teeth for fish, distant realities of crocodiles, pachyostotic ribs for neural buoyancy

Tangasauridae (informally, tangasaurids)

Lizard-like basal diapsids from the Permian of Madagascar. Includes genera such as Hovasaurus. 2 temporal openings but not archosauromorph of lepidosauromorph, long flattened tail

Hovasaurus

Found with gastroliths, dense bones, semi aquatic, unclear ecology, part of Tangasauridae

Atopodentatus

An unusual genus of semi-aquatic reptiles of unknown relationships (probably related to sauropterygians, with a zipper-like split up the front of its face that was filled with needle like teeth, possibly for filter feeding and sieve in mud. Long bodies, short limbs but strong enough for terrestrial.

Odontochelys

A basal turtle genera, oldest fossil with a plastron, teeth and no carapace. Had teeth, Triassic of china, marine sediments

Turtles

Anapsid skull, derived diapsids, debated Parareptiles, related to crocodylomorpha, originated as aquatic amniotes, later returned to freshwater and terrestrial

Archelon

The largest marine turtle that ever lived, growing to lengths of more than four metres.

Cephalopoda (informally, cephalopods)

A class of molluscs characterized by their tentacles. Includes extant members such as octopus, squid and nautilis; and extinct members such as ammonites and belemnites.

Ammonites

A sub group of extinct cephalopods very common in the Mesozoic oceans that typically had spiral shells with ridges. Eat small prey in water column, like nautilus