Paleo 200: Chapter 1 - Appearances and Anatomy

what is palaeontology?

• study of all prehistoric life.

• primarily coming from fossils.

what is a fossil?

• preserved evidence left behind by prehistoric organisms.

• literally means “dug up”.

what are bones made of?

• minerals which do not decay as easily as flesh and other soft tissues.

what are adaptations?

• traits that have evolved because they serve specific functions.

what are the four major functions of bones?

• passively resist gravity to maintain form.

• provide ridged framework for muscle attachment.

• provide protection and can be major components of horns and other weapons.

• store mineral reserves.

how can animals get minerals from bones?

• storage of calcium by growing bone deposit and increasing density of already existing bone.

what are vertebrates?

• animals that have two special kinds of skeletal adaptations: skull and vertebrae.

• group where dinosaurs belong to.

what are vertebrae?

• structures made primarily of bone.

• cartilage that surround portion of spinal nerve cord.

what do vertebrae interlock with each other to form?

• vertebral column.

what are animals that lack vertebrae called?

• invertebrates.

what can a skull provide?

• give palaeontologist great insight into dinosaur’s life.

what is the brain case?

• hollow chamber formed by multiple skull bones that houses the brain.

what pass through small openings that connect to brain?

• nerves.

what provide clues to dinosaur’s mental capabilities?

• the size and shape of brain case.

what are nares?

• pair of openings for nostrils.

what are orbits?

• pair of openings for eyes.

what are fenestrae?

• additional skull openings.

what is the laterotemporal fenestrae?

• fenestrae on lateral sides of skulls.

what is supratemporal fenestrae?

• fenestrae on top of the skull.

what is the antorbital fenestrae?

• located between each orbit and naris.

• may have made skull lighter or houses large sinus cavities.

what is the centrum?

• spool or disk shaped body of vertebra.

what covers the neural canal above the centrum?

• neural arch.

what is the opening in each vertebra?

• neural canal.

what are the vertebral processes?

• provide attachment surfaces for muscles and sometimes provide articulation surfaces for ribs.

what are the two types of vertebral processes?

• transverse process and spinous process.

what is a transverse process?

• extend from the lateral sides of vertebrae.

what is the spinous process?

• extends upwards from neural arch.

what is the cervical vertebrae?

• extra large openings for blood and nerve channels to support animals’s head.

• located in the neck.

what is the dorsal vertebrae?

• located in the back.

• tall spinous process and large rib articulation surfaces.

what is the sacral vertebrae?

• located in the hips.

• solid anchors for powerful leg muscles.

what happens when sacral vertebrae fuse with one another?

• sacrum is formed.

what is the caudal vertebrae?

• located in the tail.

what is underneath the caudal vertebrae bones?

• chevrons.

what purpose do chevrons serve?

• protect large blood and nerve channels.

• support tail muscles.

what are gastralia?

• smal ribs positioned across dino’s underbelly, underneath the ribcage.

what do dinosaurs, mammals, reptiles and amphibians belong to?

• tetrapods.

what are tetrapods?

• animals that evolve from ancient ancestors with four feet and limbs.

how are limbs of tetrapods connected to rest of skeleton?

• limb girdles.

what do forelimbs connect to?

• pectoral girdle.

what is the largest bone on each side of the pectoral girdle?

• scapula.

what are hindlimbs connected to?

• pelvic girdle.

what are the three bones that the pelvic girdle is composed of?

• ilium, ischium and pubis.

what is the ilium?

• upper hip bone where sacral vertebrae are fused.

what is the pubis?

• below ilium, positioned in front of the ischium.

what is the ischium?

• positioned behind pubis nearer the tail.

what is the acetabulum?

• depression or hole in pelvic girdle where hind limb articulates.

what is the largest bone in the forearm?

• humerus.

what are the bones between elbow and wrist?

• radius and ulna.

what are bones in the wrist?

• carpals.

what are the bones between wrist and fingers?

• metacarpals.

what are finger bones called?

• phalanges.

what is the largest bone in hindlimbs?

• femur.

what are the bones between the ankles and toes?

• metatarsals.

what are the bones in the toes called?

• phalanges.

what impacts how the tetrapod moves?

• limb proportions, or limb postures.

what happened when dinos walked?

• only their toes touched the ground.

what are the two major groups of dinos?

• saurischians and ornithischians.

what are saurischians?

• pubis downward and forward towards ribcage.

• lizard hipped.

what are ornithischians?

• special beak forming bone.

• pubis extended downwards and backwards towards tail.

• bird hipped.

what are the two groups of saurischians?

• sauropodomorph and theropods.

what are sauromodomorphs?

• large herbivores with elongated necks and small heads.

what was the early group of sauromodomorphs?

• prosauropods.

what are prosaurpods?

• first group of large bodied dinosaurs to evolve.

what are the later group of sauropodomorphs?

• sauropods.

what are sauropods?

• largest animals to ever walk the earth.

• column like legs.

• vertebrae: filled with complex air sacks which reduced weight.

• teeth: simple and peg like.

what are theropods?

• bipedal carnivorous saurischians.

• teeth: serrated and blade like and sharp hooked claws.

why do ornithischians have backwards pe

what do all ornithischians possess?

• beaks: herbivorous adaptation that helped chop off large mouthfuls of vegetation.

what are the five major groups of ornithischians?

• ornithopods, pachycephalosaurs,

what are ornithopods?

• lacked armour and walked bipedally or assumed bidepal stance.

  • ex. small antelope sized dinos.

what are the sub groups of ornithopods?

• iguanodonts and hadrosaurs.

what are iguanadonts?

• large ornithopods with spike shaped claw on each hand.

what are hadrosaurs?

• duck billed dinos.

• elaborate boney crests, large beaks in front of their mouth.

• dental batteries that are dense and tighly packed (side to side and backward and forward).

what are pachycephalosaurs?

• bipedal with short arms, stout and strong tails, armoured skull.

• thick, domed skull roofs and backwards pointing horns.

what are ceratopsians?

• large parrot like beaks and skulls that expanded in the rear.

• large bony frill or neck shield and large horns and dental batteries.

• quadrupedal and short tails.

what are stegosaurs?

• quadrupedal dinosaurs with rows of projecting osteoderm plates down back and tail.

• front legs shorter than back, enabled them to stand on hind legs.

what are osteoderms?

• bones that develop with skin and common component of animal armour.

what is an anklyosaur?

• most heavily armoured dinosaur.

• quadrupedal with short legs and wide ribcages.

• spikey back and club at end of tail.

what is an integument?

• body covering.

what is the first mummified dinosaur?

• hadrosaur.

what is keratin?

• tough but flexible material composes hair, feathers, fingernails, claws, beaks and horns.

what is the small theropod specimen with fossil feathers called?

• sinosauropteryx.

what dino was first reported to have feathers?

• yutyrannus: largest known feathered dino.

what dinosaur had feathers and filamentous integument?

• theropod dinosaurs.

what features did ceratopsians psittacosaurus have?

• long, stiff bristle like structures on tail.

what was the feature of tianyulong ceratopsian?

• covered in long filaments over most its body.

what was the features of kulindadromeus?

• bristle like filaments but branching, feather like structures.

what kind of osteoderms did anklylosaurs have?

• armour and tail club ends.

what kind of osteoderms did stegosaurs have?

• plates an spikes along back.

what kind of osteoderms with sauropods have?

• mineral reserves.

what are melanosomes?

• pigament cells within feather.

• influence shape and arrangment.

what do black and gray melanosomes result from?

• long and narrow melanosomes.

what do brown and reddish melanosomes result from?

• short and wide melanosomes.

what do white feathers indicate?

• no melanosomes.

what do shiny black and blue feathers indicate?

• narrow melanosomes, aligned in same direction.

what is a scipionyx?

• preserves mineralized remains of trachea, throat and intestines.