ZOO 145 1ST LEC EXAM

Herpetology

the scientific branch of zoology

dedicated to the study of

amphibians and reptiles.

• The word comes from the

Greek word herpeton, which

means "creeping animal" or

"reptile”

Amphibians:

Frogs, toads,

salamanders, newts, and

caecilians.

Reptiles:

Snakes, lizards,

turtles, tortoises, crocodilians,

and tuataras

• Behavior and Ecology:

• Anatomy and Physiology:

• Conservation:

• Medical Uses:

• Invasive Species:

Key Areas of Study in Herpetology

Behavior and Ecology:

How these cold-

blooded (ectothermic) animals regulate

their body temperature, interact with

their environment, and hunt.

Anatomy and Physiology:

Internal

systems, skin structures, and unique

evolutionary adaptations.

Conservation:

Protecting vulnerable

species and studying how habitat loss

and climate change affect populations.

Medical Uses:

Researching snake and

reptile venoms to create helpful

pharmaceutical drugs and antivenoms.

Invasive Species:

Non-native species,

their dispersal and impacts

9,082

There are (..) recognized

amphibian species in the world,

according to tracking data from

the AmphibiaWeb Database.

8,012 species (about 88% of the total)

Frogs and Toads (Anura) have (..) species in the world

837 species

Salamanders and Newts (Caudata) have (..) species in the world

233 species

Caecilians (Gymnophiona) have (..) species in the world

12,000

There are about (..) known living species of reptiles on

Earth.

Reptiles

Scientists divide these animals

into four main groups

according to The Reptile

Database and Wikipedia's

Reptile Entry

Squamata (Lizards and snakes)

Testudines (Turtles and tortoises)

Crocodilia (Crocodiles, alligators, caimans, and gharials)

Rhynchocephalia (Tuatara)

four main groups of reptiles

Squamata (Lizards and snakes):

This is the largest

group. It includes thousands of

species of snakes, geckos,

iguanas, and worm lizards.

Testudines (Turtles and tortoises):

This group features

animals with hard, protective

shells built from their ribs.

Crocodilia (Crocodiles, alligators, caimans, and gharials):

This group

contains large, semi-aquatic

predators with powerful jaws.

Rhynchocephalia (Tuatara):

A

rare group includes only one

surviving species. It is found

exclusively in New Zealand and

looks like a lizard, but belongs to

a totally different ancient lineage.

Class Amphibia

• (Gr. amphi, both or double + bios, life) amphibians

• Ectothermic tetrapods, bony endoskeleton

• Respiration by lungs, gills, or skin

• Mostly oviparous, some undergo metamorphosis

• Development through larval stage or direct

amphibians

• Skin moist, containing mucous glands, lacking scales

• some with poison glands

• mesonephric kidneys - urea

• Mesolecithal eggs with jelly-like membrane covering

(anamniote)

chromatophores

• Pigment cells in skin of amphibians

3 chambered heart, with double circulation

how many hearts does amphibian have?

10 pairs cranial nerves

how many pairs cranial nerves does amphibians have?

Order Apoda (Caecilians)

Order Caudata (Salamanders & Newts)

Order Anura Frogs & Toads

orders under amphibians

Order Apoda

Caecilians

• Legless amphibians

• worm-like body

• Burrowing habit

• inhabits loose soil, litter or near streams

• Annuli rings

• Eyes reduced, tail short

• Tadpole larva or direct dev’t or viviparous

Order Caudata

Salamanders & Newts

• Tailed amphibians

• Limbs & tail present

• No claws or nails

• Paedomorphic - Axolotl

• Salamanders

• Giant Salamander - Largest amphibian

• Newts – more aquatic

• Sirens & Amphiniumas

examples of order caudata

Order Anura

Frogs & Toads

• Tailless amphibians

• Tadpole larva or none - direct development

• Web or pads on digits

• Males with vocal sac

• Toads with parotid gland – Bufo marinus

• Goliath Frog – largest

• Posion- arrow frog

• Arboreal Tree frog

examples of Order Anura

Class Reptilia

• (L. repere, to creep)

• Ectothermic tetrapods possessing lungs

• Skull with single occipital condyle

• No larval stage, lungs no gills, 3 chambered heart

• Limbs paired, usually with 5 digits with claws

Reptiles

• Skin dry lacking mucous glands, covered by horny epidermal scales

• Paired metanephric kidneys, uric acid waste

• 12 pairs cranial nerves + nervus terminalis

• Eggs covered with calcareous or leathery shells

• Embryonic membranes – chorion, amnion, allantois

Order Crocodylia

Crocodiles & Alligators

• Archosauria

• Primitive armoured aquatic reptiles

• Hardened osteoderms

• 4-chambered heart

• Claws & Webs on digits

• Gharials

• Crocodiles

• Caimans

• Alligators

Order Testudinata

Turtles

• Fused vertebra & ribs form upper carapace

• Modified gastralia forms lower plastron shell

• No teeth, horny beak

• Sea Turtles

• Tortoises

• Terrapins

• Soft shelled Turtles

• Snapping Turtles

Order Rhynchocephalia

• Tuatara Sphenodon

• Primitive, living fossil

• No eardrum, skull 2 arch

• New Zealand

• Suborder Amphisbaenia

• Worm-lizards

• Burrowing small limbs

• Eyes & ears covered

Order Sqaumata

Suborder Lacertilia - Lizards

• Limbs present, well

developed or reduced

• Agamids & Iguanas

• Chameleons

• Geckoes

• Skinks & Blind lizards

• Snake lizards & Whiptails

• Night & Sand lizards

• Beaded lizards & Anguids

• Monitor lizards

Order Squamata

Suborder Ophidia - Snakes

• Limbs absent on elongated trunk & neck

• Fang with venom gland or constriction

• Pythons & Anacondas

• Blind snakes

• Colubrids - harmless

• Cobras & Sea snakes

• Pit -Vipers

• Long wide snout is an advantage – to increase the volume in front to ambush prey

• Long snout is associated with utilization of sudden sideward movement to catch prey

• Extension of facial region of the snout in amphibians – an evolutionary step

• Freeing the pectoral girdle from its attachment to the rear of the skull – a functional neck

• Fishes cannot turn its head, it must bend its body – due to skull attachment to pectoral girdle

Evolution of Amphibian characters

in an aquatic habitat

• Naked moist skin – keep moist & permeable with mucus from mucous glands

• Anamniotes – retained a gelatinous egg

• Most have external fertilization in water

• Amphi Bios – A Double Life

• Free-swimming aquatic larvae– tadpoles

• Paedomorphic amphibians – retain gills

• Nictitating membrane – built in goggles

• Lateral undulations of body for swimming

Evolutionary linkages of

amphibians with water

Lemanuran, Scoptanuran, Acosmanuran

types of Tadpoles

Aquatic Caecilians (Order Apoda)

• Legless amphibians

• Lateral undulations of body for swimming

Order Urodela

– tailed amphibians

• Elongated body with short functional limbs

• Lateral undulation of body and tail to swim

• Retain undulating movement on land with legs

• Aquatic salamanders have reduced limbs and laterally depressed caudal fin or fleshy tail fin

• Digits are short and have little or no webbing

• Some salamanders give birth to live young, release aquatic larvae in water

paedomorphosis & reduction of lungs

Two trends that occur repeatedly in salamanders & newts

Paedomorphic Urodelans

Paedomorphosis is widespread and several families have solely paedomorphic forms

• Retention of larval characteristics – some useful for aquatic life

• Retain external gills

• Retain functional lateral line system

• Absence of eyelids and larval

Congo Eel - Amphiumas

Loose gills after metamorphosis but retain other

larval characteristics – flattened fin on tail

Family Cryptobranchidae (hidden gill) – hellbender

and giant salamanders

• Loose gills after metamorphosis but retain other

larval characteristics – flattened fins on tail

• Paedomorphic and permanently aquatic

Sirens - Siren

• Retain external gills throughout life

• Flattened fins on tail and reduced limbs

Mudpuppy - Necturus

• Retain external gills throughout life and flattened fins

on tail

Texas Blind Salamander – Typhlomolge

European Olm - Proteus

• Retain external gills throughout life and flattened fins

on tail

• Troglodyty – adapted to life in caves & sinkholes

• Lack eyes & pigmentation, extremely long legs

• Flattened snout to probe under pebbles for food

Red-spotted Newt Notophthalmus viridescens

• North America – complex life cycle

• Aquatic adults lays eggs that hatch into tadpoles

• Aquatic larvae spend months on home pond

• Metamorphose into terrestrial form - red eft

• Efts spend 6-7 years in moist forest floor

• Second metamorphosis into aquatic adults

• Develops smoother skin and flat fleshy

Order Anura: Frogs & Toads

• tailless amphibians

• Specialized pelvis & long hind legs deliver a powerful thrust – jumping & swimming

• Webbing on extended digits on both forelimbs and hindlimbs

• Eggs laid in aquatic habitats – as gelatinous mass, in strings, attached to plants or rocks, or encased in foam nest above surface

Surinam Toad (Pipa)

• Completely aquatic, flattened body and webbed feet

• Upward loop at amplexus, male fertilizes released eggs caught on his belly

• Downward loop, male presses eggs to females back to attach eggs on female’s skin (thick & soft at breeding season)

• Eggs sink into soft skin & covered in small capsule, toadlets hatch from capsules

Barbourula busuangensis

Aquatic endemic, webbed feet

Peruvian Lake Frog & African Clawed Frog

• Skin folds absorb more oxygen in oxygen-poor

waters of Lake Titica, Peru due to

eutrophication

• Xenopus laevis is commonly bred as a

laboratory animal, with long clawed digits

• Modern amphibians have glandular skin, lacks scales & permeable to water

• Glandularity & permeability = evolutionary backwater of amphibians

• Must remain in moist microhabitats because they lose water rapidly

• Valuable as bio-indicators of environmental health

• Indicators for state of aquatic ecosystems

Water relations of amphibians

Giant Marine Toad Bufo marinus

is one of a

few amphibians that tolerate sea water

Rana (Fejevayra) cancrivora

can tolerate brackish water estuaries & mangroves

dilute body fluids

Internal osmotic pressure is lower in

amphibians, due to

Lonely Marine Toad

From low sodium content, but can tolerate a

doubling of sodium concentration

• Plesiosaurs

• Mosasaurs

• Ichthyosaurs

Extinct Aquatic Reptiles

Tortoise

elephantine feet & dome-shaped carapace

Turtles

webbed feet or flippers & flattened carapace

pleurodire turtles

No truly terrestrial (..) (unlike cryptodire tortoises) – most aquatic forms

African Pond Turtles

• Some pleurodire turtles like (..) only move overland from pond to pond

• can raise ends of plastron to close off opening of shell like Mud & Box turtles

Freshwater Turtles

• Inhabit rivers, streams, lakes and ponds

• Semi-aquatic turtles periodically leaves water to forage or a bit more terrestrial – some box turtles

• Thick limbs with flattened feet & claws

• Some turtles are more aquatic, aside from egg-laying - permanently aquatic

• Wide flattened webbed feet reduced claws

Terrapins & Sliders

moderately streamlined, have large webbed feet, can swim actively thru water, but also basks above water

less streamlined

Turtles that crawl on the bottom of a body of water are (..) than those that swim

Snapping turtles

rely on large size for protection

Aquatic turtles

• have low carapaces that offer little resistance to movement thru water

• still lays eggs on land

Soft-shell Turtles: Trionychidae

• Streamlined body & large webbed feet are specialized for fast swimming

• More aquatic, greater agility in water than sliders, terrapins and mud turtles

• Snorkel on nostrils & long neck to reach water surface & seize prey easily

• Ossification of the shell is slightly reduced & lightweight, carapace with fleshy cover

• lie in ambush for prey buried

Alligator Snapping Turtle (Chelydridae)

• are ambush predator, uses concealment & prowl along bottom of ponds & shallow rivers.

• Like Mud & Musk Turtles, more sedentary & less streamlined shell & reduced plastron

• Tongue shaped like worm and wriggled – lure prey close to open mouth, very strong jaws

• rely on large size to protect them, as much as 60 cm & nearly 100 kg

Matamata Turtle (South American Pleurodire)

• most bizarre freshwater turtle

• Carapace flat with keels & webbed feet

• Very long neck & snorkel for nostrils to reach water surface for air, but keep body submerged

• Ambush predator – uses concealment

• Flaps of tissue on head & neck not only obscure the outline of the turtle, but are sensitive to minute water movements produced by nearby fish – sensory adaptations for prey capture

Snake-necked Pleurodires Turtles (Chelidae)

• with flat oval carapace & webbed feet (neck longer than body)

• Have extremely long slender necks that can reach water surface for air, but keep body submerged

• Nostrils & eyes near dorsal tip of head

Side-necked Turtles

have lateral S-shaped bend, the neck is withdrawn into the shell

Marine Turtles

• Streamline dorso-ventrally compressed shell

• Tear-drop shaped carapace, smooth flat scutes

• Head, tail and limbs non-retractable into shell

• Long oar-like flippers, remnant of reduced claw

• Excrete copious urine

• Elongated lungs, nostrils projected dorsally

• Males with longer tails for mating

• Females bury round eggs in sandy beaches

• Most specialized aquatic turtles (Cryptodires)

Lachrymal salt glands

• “Tears” secreted in marine turtles are from?

Leatherback Turtle (Dermochelyidae)

• are more specialized for aquatic life – the shell has been reduced to a series of bony platelets embedded in tough skin

• Torpedo-shaped carapace, longitudinal ridges & round head makes it streamlined

• Large wide oar-like flippers for propulsion

• Largest turtle in the world, reaches shell lengths of > 2m & weighs > 500kg

• Pelagic turtle ranges far from land, feed on invertebrates & small fish

(Chelonidae)

• Hawksbill Turtle

• Green Sea Turtle

• True Sea Turtles like the loggerhead, the limbs have

evolved into flippers to “fly” underwater

• they feed on sponges and soft corals

• Green Sea Turtles feed on jellyfishes

Crocodilians

• Semi-aquatic primitive reptiles (Mesozic)

• Streamlined body - fusiform-shaped, elongate

• Long snout and flexible neck for prey capture

• Eyes and nostrils at top of head

• Webbed feet with claws for swimming & digging

• Thick waterproof scutes and osteoderms

• Laterally depressed tail for propulsion

• Undulating movement of body, limbs clipped

• Fish trap long snout, many teeth, flexible neck

Crocodiles

• are specialized for an aquatic life

• can breathe while only its nostrils are exposed above surface without inhaling water

• Nasal openings at tip of snout and secondary palate carries air passages to rear of mouth

• Flap of tissue arising from base of tongue can form a watertight seal between mouth & throat

• can inhabit coasts & estuaries

Alligator & Caimans (Alligatoridae)

• Freshwater only

• Except for Chinese Alligator, all species found in the New World

Crocodiles & False Gharials (Crocodylidae)

• Lives in freshwater lakes & rivers to coastal beaches,

estuaries & mangrove swamps

• Distributed widely in Indo-Pacific, with American Crocodile in New World

Gharials (Gavialidae)

• Freshwater only, a single species

• Once lived in large rivers from northern India to Burma – declined heavily

• Has the narrowest snout – specialization for feeding on fish, sudden sideward jerk

• Mandibular symphysis (fusion at anterior end of lower jaw) extends back to the level of 23rd to 24th tooth in the lower jaw

Crocodilians

• grow slowly once they reach maturity, it takes time to attain large size

• Not all are giants, some small species are

specialized for life in small bodies of water

Saltwater or Indo-Pacific Crocodile (Crocodylus porosus)

• Largest crocodile at > 7 m

Dwarf Caiman of S. America & Dwarf Crocodile of Africa

• Smallest crocodile at < 1 m

Aquatic Lizards

• Many terrestrial & arboreal lizards can swim for short

periods, but some are excellent swimmers & divers,

stay submerged for long periods

• Some are associated with streams, rivers, lakes &

flooded swamps, adjacent forests

• Most forage at waters edge or on rocks but still

spend more time above water

• No lizard species is known to be fully aquatic & most

appear to be semi-aquatic

marine iguana

Only the (..) iguana was known to have

specialized adaptations to its marine habitat

Arboreal Green Iguana

lizard that dive into rivers to

escape predators & stay submerged long period

Basilisk Basiliscus or JC Lizard

lizard that can swiftly run over the

water’s surface to escape predators using their feet

with fold along sides of toes

Large Caiman lizards

inhabits the flooded swamps of

the Pantanal in Bolivia, have thickened dorsal scutes

that mimics caimans

Waterside Skinks Tropidophorus

inhabit burrows in embankments of forest streams & rivers, usually

forage at the water line & can stay submerged for

long periods of time

Marine or Mangrove Skinks Emoia

are aquatic lizards that are excellent

swimmers & forage at inter-tidal areas for crabs

Leyte Sphenomorphus

are good swimmers, they inhabit forest streams on Leyte & Samar islands, but found nowhere

Marine Iguana – Amblyrhynchus cristatus

• Probably the most specialized aquatic (or semi-

aquatic) lizard to the marine habitat

• Unique to the Galapagos Islands, feeding largely on

tidal & subtidal seaweed, kelp or algae growing on

submerged rocks in the strong surf

• Excellent swimmer due to its rounded snout

• Using webbed feet, body undulations & laterally

flattened tails to swim (dive up to 15m)

• Able to submerge & feed for extended periods

• Spends much time basking to thermo-regulate &

glands in nasal cavity which excrete excess salt

Water Dragons Physignathus and Sailfin Lizards Hydrosaurus

• A few Agamid lizards (Agamidae) are associated with

water, inhabiting rivers, streams & lakes often near

forests

• Both are basically arboreal lizards that are able to

drop into water to escape & hide from predators,

stay submerge for long periods

• Some have laterally flattened tails with sails or

fringes – are excellent swimmers

Monitor lizards (Varanidae)

are voracious predators

of small vertebrates & invertebrates

• Streamlined slender & elongate body, relatively long

snout, neck & tail – but not specialized

• A modest amount of lateral flattening of the tail in a

few aquatic forms of monitors

• Malay Water Monitor – SE Asia

• River Monitor – Africa

• Komodo Dragon

examples of monitor lizards

Komodo Dragon

largest lizard, able to swim in the

sea to cross islands