Reptile
Reproduction
Herpetoculture
Pensacola Jr College
Urogenital System
w In reptiles, begin the
complete separation of the excretory and reproductive systems in females
w Consider: why is this
necessary in relation to production of amniotic eggs?
Reptile Excretory
System
w Kidneys:
Smaller and more compact
than amphibians
True nephritic kidneys
Excrete uric acid generally,
a prerequisite for long term egg development
No loops of Henle in kidneys
w Salt glands in the head of
marine reptiles
Excretory System
(contd)
w Urinary bladder:
Present in tuatara, turtles,
most lizards
Absent in snakes and
crocodilians
w Cloaca:
Begins to form separations
of excretion and reproductive functions
Reptile
Reproductive System
w Gonads:
Paired, in abdominal cavity
Snakes/legless lizards: one
gonad anterior, one posterior
Snakes/lizards: gonads are
sacs with lymph cavities
Turtles/crocs/tuatara:
gonads are solid structures
Fewer Graafian follicles at
a time than in amphibians
Tortoise Repro
Tract
Snake Urogenital
Tract
Reproductive
System (contd)
w Ducts:
Separate from excretory
ducts
Oviduct: fertilization,
albumen gland, shell gland. May store sperm
for delayed fertilization
Mesonephric duct separates
from excretory ducts and becomes epididymis and vas deferens
w Hemipenes in many males
Reptile Egg
Structure
w Embryo
w Amnion= cushion membrane
w Yolk sac= nutrition
w Allantois= waste sac
w Chorion= membrane
immediately inside shell
w Shell: hard or leathery
Reptile Egg
Structure
Female Tortoise
X-Ray
Crocodile Egg
Mating/fertilization
w Always internal
fertilization
w Generally uses copulatory
organ, either penis or hemipenes
w Tuatara uses cloacal kiss
method
Embryo Development
w Most reptiles are oviparous
w Eggs larger and more easily
hidden in terrestrial environment, so can have fewer eggs than amphibians
w Some lizards and snakes are
ovoviviparous or viviparous
Development
(contd)
w Gestation period= duration
of embryo development within the female repro tract
w Incubation period= time
between depositing eggs outside and rupture of egg membranes
Length varies by temperature
Development
(contd)
w Sex of offspring dependent
on incubation temperature of clutch in many reptiles
w Pivotal temperature=
produces 50% of each sex
Turtles: males below the PT
Lizards: females below the
PT
Crocodilians: two PTs, males
in between the two
Parental
Investment
w In general, investment is in
egg production (yolk etc) and not in offspring care
w Eggs are hidden and left
w A few cold-climate snakes
stay and incubate
w Crocodilians guard clutch
Sexes of
Population
w Most are bisexual
w A number of lizard species
have parthenogenetic populations or whole species
w Some parthonogenetic females
mate with males of related species, result is triploid sterile offspring
Breeding Season
Control
w Tropics: control generally
by small temperature shifts or breed year round
w Non-tropics: control
generally by photoperiod, secondary affect of temperature
w Generally little rainfall
effect