Age Of Dinosaurs Exam 3

Differences between Ankylosaurs and Nodosaurs

Ankylosaurs are more heavily armored with a club at the end of the tail and were more abundant in the late cretaceous; Nodosaurs have spikes and were more abundant in the early cretaceous

When did Ankylosauria live

Middle jurassic to late cretaceous

How large was Ankylosaurus

Medium to large - 2 to 10 meters long and 2-3 meters wide, weighing about 2 or 3 tons

What kind of food did Ankylosaurus eat

They were herbivores

Describe Ankylosaurs head

Small, low, and broad

What do we theorize about Ankylosaurs sense of smell

Because of the elaborate nasal passages, we think they may have had a good sense of smell

Describe Ankylosaurs jaw/snout

-leaf-shaped cheek teeth similar to stegosaurus

-Anterior jaw was toothless

-Snout ends in horny beak

Describe the general shape of Ankylosaurs' body

Wide and low; covered with round to rectangular armor plates

Describe Ankylosaurs' legs and feet

Robust legs with shorter front legs

Short and stout feet with hooves

Ankylosaurs' dorsal vertebrae...

Fused into a solid rod

Describe Ankylosaurs' pelvis

The ilia was greatly enlarged laterally and anteriorly which formed a shelf over the hips, abdomen, and legs

Describe Nodosauridae's body

Armored plates with spines

When did the nodosauridae peak

they peaked in the early and middle Cretaceous

Descirbe nodosauridae head

Relatively narrow skull that was not heavily armored, the skulls lack horns

Why are Pachycephalosaurs allied with Marginocephalia

Because of the shelf bone on posterior of the skull

Unique characteristic of Pachysephalosaurs

Greatly thickened skull bone

Two groups of Pachycephalosaur

Homalocephalidae and Pachycephalosauridae

How to tell the difference between Homalocephalidae and Pachycephalsauridae

Homalocephalidae has open supratemporal fenestra and a relatively flat skull; Pachycephalsauridae has closed supratemporal fenestra and a large domed skull

Characteristics of Pachycephalosaurs' limbs and how they walked

the hind limb was much longer than the forelimb; bipedal

Characteristics of Pachycephalosaurs' teeth and tendons

Simple herbivore teeth and ossified tendons in the back

Characteristics of pachycephalosaurs' pelvis, vertebre, and skull

Long low ilium in contact with 6-8 sacral vertebrae; Ridged vertebrae, locked into place; thick skull held downward with spine straight

ghost lineage

Portion of a phylogeny during which a taxon is known/thought to have existed but for which no fossil remains have been found

When did ceratopsians live

Late Jurassic to Late Cretaceous

Where did ceratopsians live

Asia and North America

What do ceratopsians have that is a Marginocephalian triat

Frill or shelf of bone at posterior of skull

Characteristics of a ceratopsians snout

Rostral bone - narrow snout ending in beak

Nostrils are high on the snout

Characteristics of a ceratopsian cheeks and mouth

Wide cheek bones with assumed fleshy cheeks; highly arched roof of mouth

Psittacosaurus means...

parrot lizard

When did Psittacosaurus live

Early Cretaceous

Where did Psittacosauria live

Asia

Characteristics of Psittacosauria skull

Short snout, narrow, parrot-like beak

Posterior skull slightly overhangs the front of the neck

Teeth found with gastroliths

When did Neoceratopsia live

Late cretaceous

How do Neoceratopsia compare to Psittacosaurus

Bigger head, bigger frill, just bigger

More robustly built

More quadrupedal

Sharply keeled rostrum

When did protoceratopsidae live

Early to Late Cretaceous

Characteristics of Protoceratopsidae size

Small(1-3m)

Characteristics of protoceratopsidae limbs

fore and hind limbs similar length; robust limbs; stouter feet

Characteristics of protoceratopsidae skull

Sharp, parrot-like beak with wide cheeks

Modest sized frill

No horns, nostrils small

When did ceratopsidae live

Late cretaceous

Where did ceratopsidae live

North America

What kind of biome did ceratopsidae prefer

Coastal lowlands

Characteristics of Ceratopsidae size

Large (4-8m, up to 6 tons)

Characteristics of Ceratopsidae skulls

Huge skulls that are about 1/4 the length of the organism

Largest brains relative to body size among quadrapedal dinosaurs

Large nostrils

Large frills

Variety of horns or bumps on nose, forehead, and frill

Triceratops head and tail characteristics

Sharp, pointed beak

3 horns - two long on frill and short one on snout

frill

dental battery like hadrosaurs

powerful jaws

short tail

How did Triceratop's anatomy support their big heads

The first four of their neck vertebrae were fused

Differences between chasmosauridae and centrosaurines

Chasmosauridae had large orbital horns where centrosaurines had large nasal horns

Chasmosauridae had large frills and centrosaurines had small frills

Chasmosaridae had long low faces and centrosaurines had shorter, deep faces

What characteristic identifies the marginocephalians

Shelf of bone on the back of the skull

What characteristic identifies thyreophorans

Keeled dermal armor

Lesothosaurus

One of the earliest ornithischians

Characteristics of Lesothosaurus jaw

Jaw ending in beak

Teeth finely serrated and chisel shaped; adapted for herbivory

Characteristics of Lesothosaurus limbs

Extremely long hind limbs, good for running

Short front limbs with clawed fingers that could grasp

Heterodontosauridae lived when

Early Jurassic

What dinosaur could the characteristics of Heterodontosauridae be compared to (as in they are similar)?

Lesothosaurus; Lesothosaurus came before Heterodontosauridae evolution-wise

Heterodontosauridae defining features of the face

Tusks used for defense, display, and/or feeding

Hypsilophodontidae size

Small to medium (2-4m)

Hypsilophodontidae legs characteristics

Legs of a bipedal runner

Hypsilophodontidae jaw characteristics

Beak on both jaws

Chewing improved because the jaw moved back and forth

When did Hypsilophodontidae live

Middle Jurassic to Late Cretaceous

When did Dryomorphs live

Middle Jurassic to early Cretaceous

What are the Dryomorphs in the fossil record

Transitional morphologies between Hypsilophodonts and Iguanodonts

Dryomorphs characteristics of teeth

They lose the premaxillary teeth (as compared to Hypsilophodonts)

How do the Dryomorphs number of bones compare to their ancestors

Increase of cervical and sacral vertebrae and reduced number of phalanges in the 3rd finger

Were the dryomorphs more quadrapedal or bipedal

Compared to the Hypsilophodonts (ancestors) they were more quadrepedal but they are more bipedal than iguanodonts (which follows them in the fossil record)

When did Iguanodonts live

Late Jurassic to Early (maybe late) cretaceous

How large were Iguanodonts

Large; up to 10m long, 5m tall and 2-3 tons

Heavy body with massive hind legs, heavy shoulders and fore limbs

Iguanodonts characteristics of limbs and feet

Broad feet with 3 toes ending in hoof-like tips

Fused wrist bones

Iguanodonts head characteristics

Large head with long snout ending in horny beak

long neck

Iguanodonts body characteristics

Ossified tendons along backbone from shoulder to mid tail (stiff body)

Why were baby ornithopods bipedal and the adults quadrepedal

Babies were lighter and didn't require the support of as much weight and were able to run

When did Hadrosauridae live

Middle cretaceous to late cretaceous

Where did Hadrosauridae live

dominantly North America and Asia

Hadrosauridae jaws characteristics

Broad snout ending in horny beak

Jaws deep and strongly muscled

Up to 1500 teeth in the jaws at any given time

How did Hadrosauridae walk

quadrepedal, maybe faculatatively bipedal

Hadrosaur limbs characteristics

Front limbs medium length

No thumb

2nd and 3rd fingers long and ending in hooves

4th and 5th fingers long with no hooves

Size of hadrosaur

relatively large (7-10m, 3-6 tons)

Characteristics of hadrosauridae spine

8-10 sacral vertebrae, ossified tendons along the spinal column

What are the differences between the two groups of Hadrosaurs

Hadrosaurines: "primitive" morphology had flat skulls, large nasal openeings, and were duck-billed

Lambeosaurines had more robust limbs, narrower snout, smaller nasal opening, and crests on the skull

Hadrosaur teeth are possibly analogues to

Equine, elephant, or rodent teeth

Trampling of the ground and close cropping of vegetation by migrating herds of ornithopods may have aided the evolution and spread of which plant group

Angiosperms

Plants of the Triassic

Ferns and seed ferns

Cycads, cycadedoids, conifers, and ginkos

Plants of the Jurassic

Seed ferns extinct

Less common ferns and cycads

conifers

Plants of the Cretaceous

Flowering plants progressively take over from the mid-Cretaceous to the late Cretaceous then 50/50 at the end of the cretaceous

Maiasaura means

The good mother lizard

What is the leading theory for Lambeosaurine crests

Noise makers for group communication or courtship

Ways to recognize sexual dimorphism in the fossil record

If two morphs are found in the same deposits (age and region)

If the juveniles are all the same but the adults have 2 distinct morphologies

If the distinct morphologies have approximately a 50:50 ratio

Sauropodomorpha lived when

Late Triassic to the Late Cretaceous

Sauropodomorpha head characteristics

The heads were very small relative to their bodies

Sauropodomorpha neck and tail characteristics

Long slender tail with 50 or more caudal vertebrae and a neck with at least 10 cervical vertebrae

Sauropodomorpha limb characteristics

Short feet

Large dew claw

Primitively hind limb longer than fore limb

Sauropodomorpha teeth characteristics

Spatulate or peglike teeth

Where were prosauropods found

North America, South America, Europe, Africa, Asia, Austrialia, Antarctica

Where were Sauropods found

North America, South America, Africa, Europe, Asia

Eoraptor

An early theropod or an early member of the sauropodomorph clade?

Prosauropods as compared to Sauropods

Smaller and more slender than sauropods with relatively long back and tail; Sauropods were generally larger and more robustly built than prosauropods

Prosauropods Characteristics of skull and jaw

Small skull with deflected anterior mandible

Coarsely serrated, elongate lancolate or spatulate teeth with no evidence for cheeks

Prosauropods neck characteristics

Long neck with at least 10 cervical vertebrae

Prosauropods limb characteristics

large dew claw (claw on first digit)

Elongated femur

Greatly reduced 5th and 4th toes

Facultative biped?

Plateosaurus

Example of prosauropods

When did prosauropods live

Late Triassic to Early Jurassic

When did Sauropods replace the prosauropods

Early Jurassic

What is the indication that Prosauropods did not give rise to sauropods

Their feet; Sauropods all have 5 toes and prosaurpods do not; thus they are not ancestral to the sauropods