Exam 1 - Comparative Anatomy

Gnathostomata Features

• Sclerotic Rings- boney ring in the eye

• paired pectoral appendages 

• cellular/dermal bone 

• dental tissues - dentin and enamel 

conodonts

• Extinct

• have tooth elements - made of apartite

• bone is not cellular

ostracoderms

• jawless fish

• Diverse Body Forms

• Body armor made of cellular bone

osteostracans

• paired pectoral fins

• closest living relative to jawed vertebrates

placoderms

• jawed fishes!!!!

• Armored 

• have dermal denticle plates (not real teeth) 

• five or fewer branchial arches 

Eugnathostomata

every other vertebrate

Eugnathostomata features

• teeth formed within a dental lamina

• chartlagious fish 

Chondrichthyes

• endoskeleton made of calcified cartilage

  • tessarae prismatic calcified cartilage 

• placoid scales and teeth made of dentin/enamaloid 

Chondrichthyes diverge into what two groups

• Elasmobrachii - sharks, skates, rays

• holocephali - Chimeras, ratfish 

Acanthodians

• spiney sharks 

• made of tessarae and cartilage 

• boney fish features too

  • enamel, not enameloid 

Osteichthyes break into two groups

• Actinoptergii - ray finned fishes

• Sarcoptergii - lobed finned fishes 

• Actinoptergii - ray finned fishes breaks into what other three groups 

• cladista (birchir and reed fish)

• acipenseriforms - means sturgeon form so sturgeons are a part of this group 

• Neoterogii - stands for new fin 

Neoterogii breaks into what other two groups 

• Holosteii- includes Gars and Bowfish 

• telostei - includes everything else 

Sarcopterygii - lobed finned fishes break into what other two groups

• actinista- coalocanths 

• dipnoi- lungfish (2 lungs) - paired swim bladders that can absorb oxygen 

lobbed fin means

muscular filled fin bases

tetrapodomorpha is united by their

nostrils

Tetrapodomorpha breaks into two groups

fishapods and tetrapods

fishapods still have their

fins

tetrapods have

front and hind limbs with digits

Batrachomorpha break into two groups

• Temaospondyils

• lepospondyil 

lissamphibia includes

• caudata (salamanders)

• Urdela (frogs and toads)

• Gymnophiona (caecilians) 

• caudata (salamanders)

• Urdela (frogs and toads)

• Gymnophiona (caecilians) 

these all have 

• same tooth shape 

• skin glands 

• skeletal features 

repilimorpha

all of the non - amphibians

amniotes have

an amnioitc egg with 4 extra embroyic layers

amniotes have how many groups

• synapsida

• reptilia 

synapsida include 

pelycosaurs, mammals and mammal like reptiles 

mammal like reptiles are

theraspids

theraspids includes

6 different groups of herbivores

cynodonta is the line that led to what

mammals

cynodonta charateristcs that are mammal like

• move towards 3 middle ear bones

• heterodont teeth (teeth differ in size and shape across the jaw) 

Mammalia united by synapomorphies

• mammary glands

• have 3 bones in the middle ear

• squamosal - Dentary Jaw joint 

3 mammalia groups

• monotremata - echidnas and platypus

• methatheria - marsupials 

• eutherians - placental mammals 

Reptilla (aka saurospida) includes

dinosaurs, turtles, birds, and alligators

parareptillia (extinct)

They are early reptiles

Eureptiles

everything else

Eureptiles have 3 groups

• Lepidosauria 

  • squamata includes snakes, lizards and amphibeanians 

  • rynchocephalia

    • includes tuttaria 

• Testudines includes turtles and tortises

• archosauria which includes birds and dinos 

Two new groups with 2 different ankle structures

• pseudosuchia

• Avemetatarsalia 

pseudosuchia includes 

crocodylmorpha 

• Avemetatarsalia includes 

pterosaurs 

• first bird to achieve powered flight 

theropoda gave rise to what

birds

echinoderms have what

five pole symmetry

examples of echinoderms

sea cucumbers, starfish, and sea urchins

chordate features

1. mid dorsal holo nerve cord

2. notochord 

3. muscular post anal tail 

what is the mid dorsal holo nerve cord

our spine

what is the notochord

our intervertebral disks

other features of chordates

1. pharyngeal gill slits

2. endostyle (similar to thyroid) 

3. segmentation 

4. bilateral symmetry 

protosomes have

spiral cleavage

deutersomes have

radial cleavage

deutersomes are

• echinodermata

• hemichordata 

echinodermata and hemichordata are

ambulacaria

protosomes

offset their cells in cleavage

deutersomes

stack their cells ontop of one another in cleavage

coelom is

the body cavity that contains the gut

zygote is 

a freshly fertilized egg

blastula 

hollow ball of cells 

gastula

hollow ball with a dent in it; organized into 3 cell layers

arcentron

primative gut

vertebrate features

1. neural crest cells

2. a head with neuralgenic placodes

3. tripartite brain (forebrain, midbrain, and hind brain)

4. vertebrae

neural crest cells form

meloctyes, schwann cells, smooth muscle cells

cyclostomata (class mynoxidea)

include hagfish

cyclostomata (class Petromyzontida)

include lamprey