Herpetology

Tetrapoda

“bony fish”

Appeared during Paleozoic

What is the best known transitional tetrapod?

Panderichthys

• pectoral, pelvic appendages

• could prop itself up

What are traits of Tiktaalik that contributed to the transition from aquatic to terrestrial?

• basic wrist bones and rudimentary fingers

• spiracles on head that suggested gills AND lungs

• more robust rib cage

• functional neck

• occipital condyle

What are changes in sense organs that contributed to the transition from aquatic to terrestrial?

• loss of lateral line

• eyes shift to allow arial observations

• dual challenge nasal passage - allowed directional smell

• middle ear hearing structures appear

• jaw adapted to conduct sound to inner ear

What are physical changes that contributed to the transition from aquatic to terrestrial?

• 3 chambered heart

• limb and girdle bones changed to support body

• spinal column changed to become sturdy but flexible

• fish spiracle in amphibians

• tympanic membrane formed across notch in skull

What is the fish spiracle?

vestigial gill slit

What are problems territrial living presented that needed physiological changes?

• support/movement not being supported by water

• water loss

• respiration

• feeding

What are changes that occurred in support/movement?

• suspension of internal organs and vertebral column

• reorganization of the skull

What are changes that occurred with the skin to prevent water loss?

• 5-7 layers thick

• protective layer minimizes abrasion

What are changes that occurred with the skin of amphibians to prevent water loss?

• skin glands that produce mucous

• protective secretions

• minimal depth of epidermis

What is buccal pumping?

The mouth acts as the diaphragm

• nostrils open, buccal cavity expands

• nostrils close, buccal cavity contracts and pushes air into lungs

• lungs expand

• buccal expands and lungs contracts

• nostrils open, buccal cavity contracts

What three modern groups are part of Lissamphibia?

• frogs

• salamanders

• caecilians

What is are uniting factors for the members of Lissamphibia?

• All three have smooth skin (liss means smooth)

• cutaneous respiration

• pair of sensory papillae in inner ear

• two sound transmission channels in inner ear

• specialized visual cells in retina

• pedicellate teeth (two part)

  • the base and the crown

  • teeth are replaced as they wear down

  • two types of skin glands

What are traits required for reptiles to become fully terrestrial?

Reproduction and development without water —> internal fertilization

Why are amphibian eggs typically laid in water?

They lack multicellular membranes or shells

What are some forms of amphibian parental care?

• carrying larvae

• nesting chamber

• transportation

• egg guarding

• “raising” young

What is unique about the mating strategy of Rhinella proboscidea?

Males mate with dead females after extracting eggs from female’s body

How can environmental cues affect metamorphosis?

It can affect the rate of metamorphosis and size

environmental cues can increase hormones to stimulate growth and development

What is the most common form of fertilization for salamanders?

Internal

What is the order name for newts and salamanders?

Caudata - tailed amphibian

What region are most caudates found?

Northern Hemisphere

Are most caudates viviparous or oviparous?

Oviparous

What can affect larval body shape of salamanders?

habitat type

What are modes of feeding for salamanders?

• Jaw prehension

• suction feeding

• tongue protraction

Are salamanders more likely to cannibalize relatives or non-relatives?

non-relatives

What are some metamorphosis changes that occur in salamanders?

tail fins reduce

skin becomes thicker

gill slits close

lungs develop

teeth become pedicellate

What are the two classifications of salamander that are exceptions to the most common form of fertilization?

• suborder Cryptobranchidae

• family sirenidae

Which two classifications of salamander do not undergo metamorphosis changes?

Paedomorph and Neoteny

What does Neoteny mean?

“required”, standard of the species

What does Paedomorph mean?

Morphological choice

What is the developmental process for most salamander species?

larva —> metamorphosis —> adult

What is the developmental process for most newt species?

larva —> metamorphosis 1 —> “eft” (terrestrial) stage —> metamorphosis 2 —> adult (aquatic)

What is included in Anura?

Frogs and toads

What region is most diverse with anurans?

the tropics

About ½ known species in New World

Do most anurans have internal or external fertilization?

external

Is the hypothesis that mouth structure varies with diet supported?

There is little information to support it

What is the spiracle and what is it affected by?

exit for respiratory water

can vary by species and habitat

What are adaptations of frog skeletons that help with saltation?

< 9 presacral vertebrae

Caudal vertebrae fused into urostyle

variation in pectoral girdle

What is the urostyle in frogs?

a long bone formed by fusion of the caudal vertebrae located at the base of the spine during metamorphosis

How does the urostyle help frogs when jumping?

It acts as a shock absorber and strengthens the pelvic girdle when jumping

What are the three types of chromatophores amphibians and reptiles have?

Melanophores - bottom layers

Xanthophores - top layer

Iridophores - middle layer

What colors do each of the chromatophores contain?

Melanophores - brown/black

Xanthophores - red/yellow

Iridophores - contains crystals that create iridescence

What is Ecdysis in reptiles?

Shedding after fluids form in the stratum intermedium

Do snakes have the same ciliary muscles and scleral ossicles that lizards do?

No

What are microdroplets?

oil droplets in cone cellS

What are common defense mechanisms of snakes?

Crypsis, camouflage, bright colors

What are methods of snakes used after being detected?

flee, musk, gape, rattle, strike

Most boas have infrared receptors that provide temperature maps were?

interlabial pits

What is the reproductive strategy of Boidae?

live bearing

Cranial infrared receptors are located in the loreal pits of most species of which order?

Viperidae/Crotalidae (pitvipers)

What is the term given for reptiles with the ability to drop their tail?

Caudal autonomy

What are osteoderms and in which sect of reptiles do they occur?

Boney plates covered with keratinous skin, crocodilia