Like this study set? Create a free account to save it.

Sign up for an account

Already have a Quizlet account? .

Create an account

Rib Modifications

A tetrapoda synapomorphies
Cervical ribs are short
Thoracic ribs are elongated the connected to a sternum
Lumbar ribs are short or absent
Sacral ribs are connected to pelvic girdle and are immobile

Two Skeletal modifications that allow for greater mobility of the skull

Atlas: first cervical vertebra is modified on its anterior surface to form atlantal cotyles which are two cup-shaped structures that form joints with occipital condyles
-Development of 2 occipital condyles on the posterior end of the skull

Tetrapoda Synapomorphies

Pentadactly, possession of 5 digits
Modified Pectoral and Pelvic girdle
Two Skeletal Modifications
Rib modifications
Dermal body armor is greatly ruduced or absent
Muscular tongue
Middle ear components

Anuran Characteristics

-Specializations of the body for jumping
-Tail loss in adult
-Eyes large and placed well forward on the head.
-Variation of of body form based on locomotion type and habitat
- Arboreal species have pads with discs that secrete viscous (sticky) solutions
-Toothless dentary
-Most anurans have catapult-like mechanism to project the tongue which has a sticky substance to trap prey
-Keratinous beaks and denticles on larval mouthparts

Gymnophiona Reproduction

Internal fertilization accomplished by the male copulatory organ

25% of species are oviparous and females coil around eggs

75% of species are viviparous and matrotrophic

Yolk is absorbed first
Fetuses scrape the oviduct for "uterine" milk. Other species the offspring are born and they scrape the mother's outer layer of skin for nutrients

Some fetuses have gills
Terrestrial - branched gills
Aquatic - saclike gills

Amphibia Synapomorphies

Papilla amphibiorum
Green rods
Levator bulbi muscle structure
All amphibians have mucous glands and poison
Pedicellate teeth
Three-chambered heart

Urodela Reproduction

Male salamanders perform variety of courtship displays for females

During courtship, pheromones play an important role in attrracting mates and stimulating the endocrine activity
Stimulate pheromone release by salamanders by direct contact

Internal fertilization is performed by a spermatophore

Spermatophore - sperm packet with a sperm cap and gelationous base

Most salamanders are _oviparous_, but a few species are _vivaparous_. Some species lay only a few _eggs_ , while other species lay _masses_ of eggs.

Ichthyostega Synapomorphies

Ribs at base of tail for swimming
Robust paddle like hindlimbs
Ear specializations for hearing under water
Distinct thoracic and lumbar regions of the spine
Robust overlapping ribs
Bendable weight supporting elbow

Tiktaalik Synapomorphies

Well developed gills
Poorly ossified vertebrae
Very long body
Fish like characteristics
Large overlapping ribs
Pectoral fin could bend
- Suggests they could bear some weight out of the water


intermediate between fish and tetrapods

What has the head of a crocodile and the gills of a fish?



...early tetrapod that was mostly aquatic in nature
short ribs, wrists, and ankles making it incapable to bear weight on land


...early tetrapod with modifications for living in both an aquatic and terrestrial life


ribs at base of tail for swimming
robust paddle like hindlimbs
ear specializations for hearing under water
distinct thoracic and lumbar regions of the spine
robust overlapping ribs
bendable weight supporting elbow

Modified Pectoral and Pelvic girdle

allows for the weight of the body to be transferred to the limbs
-supracleitherum is absent causing the connection to the skull to be lost
-scapula is enlarged for attachment of limbs
-pelvic girdle is greatly enlarged


possessions of five digits


having four limbs: 2 connected to the pelvic gridle 2 to pectoral girdle

Two Skeletal Modifications

that allow for greater mobility of the skull: Atlas, modified to form atlantal cotyles which form joints with two occipital condyles

Dermal body armor

synapomorphies greatly reduced in tetrapoda

Muscular tongue

synapomorphy; allows for feeding out of the water

Middle ear components

synapomorphy tympanum and Stapes allow for transmission of sound


tympanum and Stapes allow for transmission of sound

Papilla amphibiorum

a special sensory area in the sacculus of the inner ear that allows them to detect sound below 1000Hz
Amphibia Synapamorphy


Two bones in the inner ear that are sometimes fused and are involved in transmitting sound
Amphibia Synapamorphy

Green rods

a special type of retinal cell
Amphibia Synapamorphy

Levator bulbi muscle structure

-the muscle structure is a thin sheet in the floor of the orbit that is innervated by the 5th cranial nerve
-causes the eyes to bulge outward, thereby enlarging the buccal cavity.
-Amphibia Synapamorphy

Pedicellate teeth

teeth in which the crown and base are composed of dentine and are separated by a narrow zone of uncalcified dentine or fibrous connective tissue
-Amphibia Synapamorphy

Three-chambered heart

which consists of two atrium and one ventricle
-Amphibia Synapamorphy

Skin Structure

moist permeable skin that allows for cutaneous respiration
-Amphibia Synapamorphy

How Do Mostly Terrestrial Amphibians Keep Moist?

Mucous glands, Kidneys, Behavior to reduce water loss and increase water uptake

Mucous glands

distributed all over the body of amphibia and produce mucopolysaccharide compounds

Amphibia kidneys

produce urine hyposmolal to the blood, so that the urine is in the bladder is dilute and water can be reabsorbed from the urine

Poison Glands

- found on dorsal surfaces and defense poses expose those surfaces
- Toxicity ranges from producing unpleasant sensation to death

- bright warning coloration to let predators know they are toxic

Poison dart frogs obtain their lethal compounds from...

the beetles and ants they consume

Aposematic coloration

Aposematic coloration

bright warning coloration to let predators know they are toxic

Batesian Mimicry

a non-toxic or palatable species mimics the coloration of a toxic or unpalatable species

Batesian Mimicry

Jordan's (Plethodon jordani) & Mountain Dusky (Desmognathus ochrophaeus)

Three Distinct Orders of Amphibia

Urodeles (Caudata)

Urodeles (Caudata)


Urodeles (Caudata)


frogs and toads




Urodela Characteristics

Elongate with four functional limbs
Walking-trot gait


adult retention of larval or juvenile traits: urodela characteristic

Paedomorphs retain

Tooth and bone patterns
Absence of eyelids
Functional lateral line system
External gills


sperm packet with a sperm cap and gelationous base
seen in Urodela

Plethodontid Salamanders

Lungless Salamanders


Family of Salamanders

Plethodontid Salamanders Characteristics

Lack of lungs, Nasiolabial grooves, dear enemy recognition

Nasiolabial grooves

Nasiolabial grooves

help direct pheromones to the chemoreceptors of the vomeronasal organ used for courtship and territorial behaviors

Plethodontid Territorial Behavior

Dear Enemy Recognition

Dear Enemy Recognition

recognizing territorial neighbors that are less threatening, thus decreasing its territorial aggression to reduce energy expenditure

Anuran Specializationsfor jumping:

Urostyle - posterior vertebrae fused into a solid rod
5-9 Pre-sacral vertebrae
Elongated Illium (part of pelvis)
Hindlimbs longer then forelimbs
Fusion of tibia and fibula
Fusion of radius and ulna
Elongated ankle bone

Two Anuran Mating systems

Explosive breeding
Prolonged breeding

Prolonged breeding

breeding season may extend for several months

Explosive breeding

breeding season is very short

Anuran Vocalizations

Advertisement calls used in courtship and territorial behavior


process in which the male Anuran uses his legs to clasp the female

In most anurans, fertilization is


Axillary amplexus

male Anuran clasps female's pectoral region

Inguinal amplexus

male Anuran clasps female's pelvic region


tadpoles increase in size with little change in form


hind legs appear and growth of the body continues at a slower rate

Metamorphic climax

fore legs emerge and the tail regresses

Gymnophiona Synapamorphys

-Absence of girdle and legs
-Eyes are greatly reduced and sometimes covered by skin or bone
-Annuli - conspicuous dermal folds that reflect body segmentation
-Pair of protrusible tentacles on each side of snout
-Protrusible copulatory organ in males


conspicuous dermal folds that reflect body segmentation

Chytrid Fungi

this is most likely the major cause for population decline and extinction. A fungus that can penetrate the skin of amphibians and interferes with their cutaneous respiration causing the amphibian to die

Anuran Characteristics

tail lost in adults
eyes large and forward on head
toothless dentary
catappult mechanism tongue sticky substance to trap prey
keratinous beaks and denticles on larval mouthparts

Gymnophiona reproduction

internal fertilization by male copulatory organ
25% are oviparous females coil around eggs
75% vivaparous and matrotrophic

Vivaparous matrotrophic gymnophiona

yolk is absorbed first
fetuses scrape the oviduct for uterine milk. other species offspring are born and scrape the mothers outer layer of skin for nutrients
some fetuses have bills terrestrial (branched) aquatic (sacklike)

Please allow access to your computer’s microphone to use Voice Recording.

Having trouble? Click here for help.

We can’t access your microphone!

Click the icon above to update your browser permissions and try again


Reload the page to try again!


Press Cmd-0 to reset your zoom

Press Ctrl-0 to reset your zoom

It looks like your browser might be zoomed in or out. Your browser needs to be zoomed to a normal size to record audio.

Please upgrade Flash or install Chrome
to use Voice Recording.

For more help, see our troubleshooting page.

Your microphone is muted

For help fixing this issue, see this FAQ.

Star this term

You can study starred terms together

Voice Recording