Herpetology Exam 2: lizards

Squamates

lizards and snakes

hemipenes

• male snakes have 2 copulatory organs, located in tail

• females don’t have

• hemipenial retractor muscles pulls everted hemipenis back inside

• like hollow balloon

• sulcus: shallow canal for path for sperm

• awns: little feelers, don’t know what for

Female eggs snakes

• released from ovary, follicles called “ova”

• enter infundibulum of the oviduct - where fertilization occurs

• shelled in the oviduct- called eggs

• can feel lumps of females

• most clutches laid 25-30 days after prelay shed

limb reduction

• fracture planes within vertebrae in lizards, between vertebrae in snakes

• partial regeneration in ilzards, not snakes

lizard reproduction

• 20% viviparous

• Obligate Parthenogenesis in 6 families & 1 snake

• temperature sex determination in 12 sp lizards, no snakes

obligate parthenogenesis

asexual reproduction

an asexual reproductive strategy where organisms exclusively reproduce through females, developing offspring without the involvement of a male or fertilization

snakes produce asexually

lizards

• 7,700 sp

• basal split (iquania & scleroglossa)

• teeth: chameleonsand agamids sisters have acrodont teeth

teeth

old world lizards

Agamidae (think aged …agamids…old world)

• 60 genera, 580 sp

• mod-large, terrestrial

• no limb reduction

• africa, southern asia, austrailia

chamaeleons

chamaeleonidae

• 200 sp

• most in madagascar

• color change: light, temp, emotions

• communication with conspecifics

  • unique skin with layers

  • crystals that quickly move around pignement

  • melanophores: (ouside) yellow/red —> blue —> white (inner)

• laterally compressed bodies, flat to walk on twigs

• zygodactylus feet, prehensile tail - gripping

• eyes move independently (accomidation to measure distance not angle like us - good focusing

• tongue: 2.5 length body, accelrator msucle on tepred hypoid

Iquana

iguanidae

• 38 sp, mod-lg size

• americas, galapagos, west indies, figi (new world tropics)

• young hang by adults: insectivores to vegetarian

  • eat feces of adults to innoculate gut with symbiotic bacteria from parents then switch to plants when stomach gets bigger

figi iquana

brachylophus

• rafting to get out to islands - flood

marine iguana

amblyribynchus cristatus

• blunt face, eat algae on rocks

the anoles

dactyloidae (think…she dact on on my loidae til i anoled)

• subfam of iguana

• 400 sp, mostly arboreal

• diurnal, sit and wait predators

• 1 egg per week, continuously breen

• males: dulaps on neck, do push ups

• have pigment, not structural color

green anole

anolis carolinensis

• florida and TX

brown anole

anolis sagrei

horned lizards

• west/midwest USA

• eats nonpoisonous ants

• squirt blood out of eye for defense

• colard lizard, new mexico

• basiliscus: iagarto de jesus risto, walk on water

Species that used to be iguanias

• Collard lizard

• basiliscus: mohawk

• igarto de jesus cristo: walks on water

wall climbing geckos

gekkonidae

• 1,000 sp, most of any lizard

• drab, nocturnal, no eyelid, soft skin

• vocal: click/chirp

• almost all oviparous, 1-2 hard shell eggs, good for transport

• defence: highly autotomic tail breaks easy, fragile skin flakes off easy

• pantropical

van der waal forces

surface area bc of hairs with microscopic hairs that share electrons and cling, have to ‘disengage’ to move

leopard gecko

• have eyelids

day gecko

• africa, madagascar, indian ocean islands

• bright green, with reds, blues, yellows

racerunners/whiptails

teiidae

• active, diurnal, 120+ sp

• long, streamline body, long tail and hindlimbs

• parthenogenesis in several

• racerunner

  • small, granular scales

  • high body temp, FAST

• N. america/S america

six-lined racerunner

Skinks

Scincidae

• > 1500 sp

• cosmopolitan

• smooth, shiny scales with osteoderms

• secrative dwellers/burrowers

• short limbs/some limbless

• babies have blue tails

• worldwide

  • islands, deserts, rainforest

• oviparous, guard eggs

  • 45% viviparous

• diurnal

oviparous vs viviparous

Oviparous animals lay eggs, while viviparous animals give birth to live young

Legless lizards

Anguidae (think… alligators are angry)

• 110 species, widespread

  • grasslands, cloud/rain forest

• diurnal, 70m - 1.3m

• tails autotomize (break off) easily, limb loss common

• Ophisaurus in midwest US

glass lizard

slender glass lizard

• tail 2/3 of body length

• snap off without being touches

Monitor lizard

varanidae (mrs. kipling monitors the vary crazy children)

• 75 sp

• active foragers, forked tongue

• Mrs. kipling

• huge

• serated teeth, slashing bites

• endangered, apex predators

  • don’t always kill prey, die of sepsis

  • regurgitate horns

Gila monster and beaded lizard

helodermatidae

• “sun skin”

• only venomous lizards - venom glands along mandibles, chew prey

• stout, fat tails, burrows

• eat eggs, mammals, birds, lizards

• central america