FNR 24150

Final

Why did amphibians move to land?

- Unexploited food and niches because aquatic niches were occupied; lack of large terrestrial predators; low oxygen levels in warm water and unlimited oxygen on land

What are the three main diversifications of reptile and amphibian phylogeny and when did they diversify?

- Ichthyostega (Paleozoic Devonian); Leptospondyli (Paleozoic Carboniferous); Temnospondyli (Paleozoic Carboniferous)

What radiation created the groups of amphibians we see today and when did it occur?

- Lissamphibian radiation during the Late Permian (Paleozoic) into the Mesozoic

What is the most remarkable feature of Tiktaalik?

- Front pair of fins with wrist-like structures

Which fossil was the first tetrapod with a proper neck?

- Tiktaalik

Which fossil is called the “roof fish”?

- Ichthyostega

Describe Eryops

- Crocodile-like early amphibian

Which fossil had a boomerang-shaped head?

- Diplocaulus

Which fossil is called the “frogmander”?

- Gerobatrachus

What are characteristics of Gerobatrachus?

- Two fused ankle bones, intermediate backbone, large tympanum, wide frog-like skull

When did the split between frogs and salamanders occur?

- 240–275 million years ago

Which fossil is called the “proto-frog” and was the first fossil frog?

- Triadobatrachus

Which fossil is the earliest true frog?

- Vieraella

Differences between Vieraella and Triadobatrachus

- Triadobatrachus: sacral vertebrae, small pelvis, separate tibia and fibula, 13–14 presacral vertebrae; Vieraella: urostyle, large pelvis, fused tibiofibula, 9 presacral vertebrae

Characteristics of Paleobatrachus

- Completely aquatic swamp-dweller; preserved soft tissue from volcanic gases; resembles modern Xenopus

What type of fertilization do salamanders mostly use?

- Internal fertilization

Which salamander groups do not have internal fertilization?

- Sirenidae and Cryptobranchidae

Defining characteristic of Sirenidae

- Lack hind limbs

Why is Sirenidae considered paedomorphic?

- Entire life aquatic and adults retain external gills

Habitat of the lesser siren

- Shallow water including swamps, ditches, and ponds

Cryptobranchidae species largest to smallest

- Chinese giant salamander, Japanese giant salamander, Hellbender

Why are Cryptobranchidae considered paedomorphic?

- Fully aquatic with paddle-like tails

Habitat of the hellbender

- Cold, fast-moving rivers and streams

Species under Proteidae

- Mudpuppies

How are Proteidae paedomorphic?

- Fully aquatic with external gills

Habitat of mudpuppy

- Rivers, streams, and lakes; hides under rocks and debris

Species under Ambystomidae

- Mole salamanders

Habitat of mole salamanders

- Hide in burrows and migrate to ponds for breeding

Describe aggregate pond breeding

- Mass migrations triggered by rain and temperature; males outnumber females; short breeding period

Largest salamander family and proportion

- Plethodontidae; about two-thirds of all salamander species

Defining characteristic of Plethodontidae

- Nasolabial grooves

Which salamander family has direct development?

- Plethodontidae

Habitat of plethodontid salamanders

- Terrestrial, aquatic, arboreal, or fossorial

Species under Salamandridae

- Newts

Define aposematic coloration

- Bright coloration advertising toxicity

Which salamander family uses aposematic coloration?

- Salamandridae

Which family has tetrodotoxin and an unken reflex?

- Salamandridae

Define tetrodotoxin

- Non-protein toxin used for chemical defense

Define unken reflex

- Defensive posture exposing toxic skin areas

Habitat of newts

- Forested habitats under logs, leaves, and rocks

Additional life stage of Salamandridae

- Red eft; terrestrial, diurnal, lasts 2–3 years

Differences between frogs and toads

- Frogs have smooth skin and long legs; toads have rough skin and shorter legs

Four types of anuran calls

- Advertisement, aggressive, courtship, release

Most common fertilization in anurans

- External fertilization

Defining characteristic of Scaphiopodidae

- Keratinized spade on hind feet

Why Scaphiopodidae are transitional

- Traits of both frogs and toads

Habitat of spadefoot toads

- Burrowers in tropical forests; estivate and breed in temporary ponds

Species under Hylidae

- Tree frogs

Defining characteristic of Hylidae

- Toe pads

Habitat of tree frogs

- Mostly arboreal; return to water to breed

Species under Bufonidae

- Toads

Describe Bidder’s organ

- Vestigial ovary on larval testes in Bufonidae

Which anurans have parotid glands?

- Bufonidae

Habitat of bufonids

- Terrestrial or fossorial; return to water to breed

Species under Ranidae

- True frogs

Characteristics of Ranidae

- Dorsolateral folds and webbed feet

Habitat of Ranidae

- Mostly aquatic

When did reptiles begin evolving and why?

- 320–310 MYA due to arid climates

Key reptile adaptations

- Larger brain, stronger jaws, scales, lungs, amniotic egg

Most important reptile

–amphibian difference - Amniotic egg

Three reptile evolutionary groups

Synapsids, Diapsids, Anapsids

Describe Casineria

- Early amniote with reptile and amphibian traits

First fossil with amniotic egg

- Casineria

Why is Hylonomus important?

- Earliest known reptile

Age of reptiles

- Mesozoic

Ruling reptiles

- Archosauromorphs

Archosauromorph descendants

- Crocodilians and birds

Lepidosauromorph descendants

- Lizards and snakes

Anapsid descendants

- Turtles

Synapsid descendants

- Mammals

Defining feature of Odontochelys

- Toothed shell and jaws

Most well-known turtle fossil

- Proganochelys

Largest turtle fossil

Archelon

Unique turtle evolution trait

Body plan unchanged over millions of years

Define temperature dependent sex determination

- Sex of offspring determined by incubation temperature of eggs

All chelonians lay eggs

- True

Species under Chelydridae and defining traits

- Snapping turtles; spiny shells and tails, reduced plastron, fully aquatic

Species under Kinosternidae and defining traits

- Mud and musk turtles; glands that produce musky odor

Species under Emididae and defining traits

- Basking, marsh, and box turtles; long-lived and diverse body shapes

Species under Trionychidae and defining traits

- Softshell turtles; no bony carapace, genetic sex determination

Define genetic sex determination

- Sex determined by chromosomes and not affected by temperature

Defining characteristics of lizards

- Movable eyelids and external ear openings

Species under Phrynosomatidae and defining traits

Spiny lizards; spines with wide range of morphology

- Bask from morning to midday; active and fast-moving foragers

Describe basking behavior

Species under Anguidae and defining traits

- Glass and alligator lizards; legless, osteoderms, tail autotomy

Define osteoderms

- Bony plates beneath the scales that provide stiffness and protection

Species under Teiidae and defining traits

- Whiptails and racerunners; very fast, some parthenogenetic, tail autotomy

Species under Scincidae and defining traits

- Skinks; osteoderms and tail autotomy

Largest lizard family

- Scincidae

Defining characteristics of snakes

- Legless, immovable eyelids, no external ears, Jacobson’s organ, reduced or absent left lung

Describe Jacobson’s organ

- Chemosensory organ using tongue flicking to detect chemical cues

Species under Viperidae and defining traits

- Pit vipers; venomous with loreal pit organs

Species under Natricidae and defining traits

- Water snakes; associated with aquatic environments

When does brumation occur?

- During cold weather

When does estivation occur?

- During hot, dry weather

Define ectothermic

- Primary heat source is external

Define endothermic

- Primary heat source is internal

Limiting factor affecting herp distribution

- Temperature

Three methods of heat exchange

- Radiation, convection, conduction

Smaller animals gain and lose heat faster

- True