herpetology exam 4

Where do lizards occur

Everywhere but Antarctica

What are common descriptions of lizards

1. High morphology

2. Tend to have 4 legs that stick outwards

3. Round bodies

4. Elevated heads on short neck

5. Long tails

6. Tongues that can protrude

What movement do lizards have

1. Diagonal gait

2. Bipedal running

3. Bipedal running on water

4. Climbing

5. Gliding

6. Swimming

7. Sand swimming

What is the problem with diagonal gait in lizards and how to solve it

Causes carriers constraint, where the diagonal movement pinches the lungs causing it hard to breath, get around it by gular pump for bigger lizards or bipedal movement for smaller ones

What stages are seen in bipedal water walking

1. Slap:hit the water

2. Stroke: swim the foot through the air bubbles

3. Recover: lick feet up before air bubbles collapse

What can lizards use to climb

1. Claws

2. Toe pads

3. Prehensile tail

What lizard can glide and how

The Draco lizards and they have skin flaps called petagium, they can grab and hold open to fly

How do some lizards swim through sand

1. Wedge shape head

2. Clear eyelids

3. Microscopic scale projection to stop friction

What are some lizard diets

Herbivores: least common like iguanas

Omnivore: not common like tegus

Carnivore:most common all other lizards

what senses do lizards use to hunt their prey

Mostly visual cues

Some use chemosensory

How do lizards catch and kill their prey

1. Biting

2. Sticky tongue

3. Venom

What types of venom can lizards have

1. Anticoagulant

2. Hypotension

3. Hypothermia

4. Intestinal cramping

5. hyperalgesia

What are the main classes of lizards

1. Dibamia (Legless insectivore lizards)

2. Gekkota

3. Scincoidea:skinks

4. Laterals: wall lizards and whiptails

5. Anguimorpha: glass lizards, alligator lizards, gala monsters, monitor lizards

6. Iguana: chameleon, anoles, iguanas

What is the lifespan and sexual maturity of lizards

It has large range from months to 70 years for life

it takes 9 months- 6.5 years for sexual maturity

Is sexual dimorphism present in lizards

only in some lizard species where males are bigger with larger crest and other ornamentation

What is territorialtiy

the defending of a territory within a home range as it has limited resources and better breeding chance

What species have more prominent territoriality

in species with male biased sexual dimorphism

What displays are present with lizard territorialty

1. push ups

2. head bobbing

3. mouth gapping

4. chasing and biting

What types of Courting rituals are present in lizards

1. Visual

2. chemical

3. tactile

4. vocalization

What visual cues are present in lizard courtship

1. color of head

2. color of lateral/ventral surfaces

3. color/size of dewlap and frill

4. head bobbing

5. push-ups

What can chemical signaling do for lizards

1. identify species

2. identify kinship

3. identify sex

4. identify sexual receptiveness

What tactile usage is used in lizard courtship

used to fight for dominance over a female or do it to protentional mates

1. bumping

2. biting

3. tearing limbs off (not for potential mates)

4. climb on

What lizards use vocalizations

Gekkotans use it and tend to be in chips and click sounds

What should be known about lizard mounting

1. male climbs onto female and bits her to hold onto her

2. males have hemipenis (two penis to insert)

3. can happen for hours or even days

What is mate guarding

males prevent other males from mating with a female

How is fertilization occured in lizards

internal

What is parthenogenesis

When asexual reproduction occurs with no male sperm and the mother makes full or partial clones of herself

What is Obligate parthenogenesis

When reproduction only occurs asexually for a particular species most likely caused by a hybridization event

What is facultative parthenogenesis

when the lizard have the ability to parthenogenesis but don’t have to, and has an unknown reason why its present

How do lizards lay thier eggs

Most of them are oviparous some are viviparity

What is Lecithotrophy

when nutrients is provided exclusively by the yolk

How do lizards make nest

most make them in damp soils, rotten logs, rock crevices, etc. with some being isolated nest and others being communal nest

What is the clutch size of lizards

can ranges from 1-50+ eggs spending of the species and size of female lizard

What is Viviparity

produce live young

What is Matrotrophy

nutrients are provided exclusively or partly by the mother, with some form of a functional placenta

What is Ovovivipartity

when a shell egg is held inside the mother until hatched by still only feed of the yolk

Why have viviparity pro and con

allows for better control over development of offspring and higher hatching rates, however can increase lizards weight and energetic requirements

What is the Cold-Climate Hypothesis

Viviparity occurs in squamates because of cold climates and females had into internally incubate the eggs increasing hatching rates and higher survival rates

How is sex determined in lizards

In a complex way with both temperature and genetic determination and yolk allocation

What makes a male and female lizard genetically

Males are XY or ZZ and females are XX or ZW

What can temeprature do to sexes in lizards

it can determine the sex or even induce sex reversal

What is yolk allocation

eggs with more yolk create more females and less yolk make males

What is common in TDS lizard species

higher temps are males and lower temps are females. with some have an inverse but very few

Do lizards have parental care

not really only 1% and its always the females

What do the few females lizards do when protecting the nest

1. regulate egg hydrating by moving eggs and expanding the next

2. deter fungal infection

3. keep the eggs hide

4. guard the nest

5. guard the young (only occur in viviparous species)

How do lizards avoid predators

1. crypsis

2. Batesian mimicry

3. escape approach

4. threat display

5. epidermal scales

6. osteoderms

7. spines

8. chemical defense

9. thanatosis

10. tail display

11. tail autotomy

12. tail biting and looping

What is the conservation status of lizards

about 20% are extinct/ critical or vulnerable

30% haven’t even been evaulted or have enough data

all due to habitat loss, mining, pollution, invasive species, climate change

Where are snakes found

anywhere but Antarctica

Description of a snake

1. elongated limbless bodies

2. pectoral girdle and forelimbs are gone

3. Pelvic girdle and hindlimbs can be absent or very little present

4. 120-500 vertebrates

5. no tynpanum

6. left lung is reduced

What are the families of snakes

1. boidae

2. pythonidae

3. elapidae

4. viperidae

5. colubridae

Snake movement

1. lateral undulation

2. rectilinear

3. Concertina

4. sidewinding

5. Arboreal concertina

6. lasso locomotion

7. gliding

What is the diet of snakes

carnivores

What senses do snakes use to find prey

1. visual

2. chemical sensing (both nose and tongue)

3. Auditory ground sensing

4. Thermal sensing

5. underwater tactile sensing

6. Caudal luring

What are the difference in thermal sensing

Labial pits, which are in boas and pythons

Loreal pits seen in vipers

What are the four types of teeth seen in snakes

1. Aglyphous : no fangs (non venmous snakes)

2. Oplsthoglyphous: rear fangs and must chew to inject venom into prey (Colubrias)

3. Solenoglyphous : long hollow fangs with folding abilities (vipers)

4. Proteroglyphous: front fixed fangs that are short with venom grove with no folding (elaprids)

How do snakes kill larger prey

1. venom

2. constriction

What must be present to inject venom

1. venom producing glands

2. muscles to move venom

3. fangs to inject venom

4. ducts to get venom from glands to teeth

what is venom metering

Snakes can choose how much venom to inject into a prey

What is venom made up of

1. enzymes

2. polypeptides

3. ion compounds

What category does snake venom fall under

1. tissue destruction

2. neurological collapse

What toxic is used in tissue destruction

1. hemotoxic: attack blood and clotting

2. cytotoxic: attacks cells to create necrosis

3. myotoxic: paralysis muscles

What toxic is used in neurological collapse

neurotoxins

How do snakes consume their prey

1. through inertial feeding

2. toad popping

3. organ eating

4. skull/jaw unhinging for large prey

What sexual dimorphism is seen in snakes

1. Females are larger and heavier than males

2. males are larger than females in male-male combat species

3. males have longer tails

Do snakes have territorially

yes, but very rare

How do male snakes find reproductive female snakes

through pheromones

What are the stages of snake courting

1. tactile chase

2. tactile alignment

3. intromission coitus

What is a mating ball for snakes

When a large congregation of males surrounded a female and all attempt to mate with her

how does fertilization occur in snakes

internal

Is pathogenesis seen in snakes

yes, obligated only one species, while facultative is seen in many

what is brooding in snakes

females with stay with the nest and control the nest temp and some pythons go through shivering thermogenesis

How is gender determined in snakes

genetic

How do snakes advoid predators

1. crypsis

2. batesian mimicry

3. thanatosis

4. escape approach

5. threat display

6. tail autotomy (does not regrow)

7. musk

8. toxin sequestering

9. spitting venom

10. biting

What do snakes use to breath while eating

glottis

What % of food has to be consumed to be considered an herbivore or carnivore

90% for herbivore and 95% for carnivore