Repro in reptiles and fish

Question 1

Describe the male reptile repro anatomy

Answer 1

Intra-abdominal testes
R testis cranial to L testis
No accessory sex glands

Question 2

Label the male reptile repro anatomy

Answer 2

Question 3

Describe the phallus in reptiles

Answer 3

Hemi-penes: lizards, snakes
Penis: chelonians
Keratinised spines

Question 4

Describe the function of hemi-penes in reptiles

Answer 4

Only use one at a time during copulation (one is retracted) in case of damage
Retracted by retractor muscles after copulation

Question 5

What is the function of the spur in snakes reproduction?

Answer 5

help to hold on to female during copulation

Question 6

Describe the sexual segment in squamates

Answer 6

In the distal convoluted tubules of kidney
Cells change in breeding season:
- cuboidal-> columnar
- 2-4x increase in size
Large eosinophilic granules secreted into lumen
Kidneys look larger, paler and smoother during breeding season

Question 7

What are the theorised functions of the sexual segment in squamates?

Answer 7

separate urine/semen at copulation
Copulatory plug

Question 8

Describe reptile ovarian anatomy

Answer 8

ovaries paired
R larger than L (L undeveloped in some species)

Question 9

Describe the anatomy of the oviduct in reptiles

Answer 9

Empties in cloaca: genital papillae
Secretes albumin -> shell
Includes:
- ostium
- aglandular segment
- magnum (albumin added)
- shell gland
- vagina

Question 10

What are pre-vitellogenic follicles in reptiles?

Answer 10

Follicles that have been produced but haven’t had the yolk added to them

Question 11

What are the stages of reproduction in reptiles?

Answer 11

Oocyte development - pre-vitellogenic follicle development
Vitellogenesis - yolk production
Oocyte maturation
Ovulation
Oviposition/parturition

Question 12

What is parthogenesis in reptiles?

Answer 12

form of reproduction in which an egg can develop into an embryo without being fertilised by a sperm
30 species of lizard

Question 13

Describe fertilisation in reptiles

Answer 13

Occurs in cranial oviduct
Sperm is viable at body temp
Sperm stored for months, years until environment is appropriate for fertilisation

Question 14

What are oviparous reptiles?

Answer 14

egg-laying
all chelonians
most squamates

Question 15

What are viviparous reptiles?

Answer 15

live-bearing
20% of squamates

Question 16

What are the types of viviparity in reptiles?

Answer 16

Lecithotrophy:
- egg in tract until hatching
- hatch at time of parturition

Matrotrophy:
- livebearing
- chorioallantoic placenta
- RARE

Question 17

How long is gestation in viviparous species of reptiles?

Answer 17

1.5-6 months
Hard to determine as fertilisation time unknown due to sperm storage

Question 18

How long is the incubation period for oviparous reptile species?

Answer 18

incubation 1-2 months typically
Can be up to >270 days

Question 19

What are the hormonal roles involved in chelonian reproduction?

Answer 19

FSH: ovarian growth, follicular development
LH surge: ovulation
Oestrogen
Progesterone

Question 20

What are the hormones involved in squamate reproduction?

Answer 20

1 gonadotropin
FSH-like compound
No LH equivalent
Oestrogen
Progesterone

Question 21

What are the roles of oestrogen in reptiles?

Answer 21

yolk development
seasonal breeders - high in early season

Question 22

What is the role of progesterone in reptiles?

Answer 22

High during gestation (viviparous species)
High after ovulation
Ovulatory surge in chelonians (similar to birds)

Question 23

What are the breeding stimuli in reptiles?

Answer 23

Temp change
Humidity
Day length (melatonin and pineal gland)
Presence of a mate (induced ovulators)
Environment

Question 24

What is follicular stasis in reptiles, the causes and treatment?

Answer 24

Follicles produced but not ovulated
Accumulate -> inflammation -> infection -> rupture -> leakage
Causes:
- inappropriate diet/husbandry
- lack of brumation/hibernation
- lack of mating or presence of male
- stress
- illness
Treatment:
- not ill - correct husbandry
- ill - spay

Question 25

Describe sex determination in snakes

Answer 25

Genetic Female heterogamety Male ZZ Female ZW

Question 26

Describe sex determination in lizards and chelonians

Answer 26

Genetic Highly variably Male heteromorphic (XX/XY) Female heteromorphic (ZZ/ZW) Homomorphic sex chromosomes

Question 27

Describe temp dependent sex determination in reptiles

Answer 27

Incubation temp determines sex Many chelonians, some lizards Lizards: - high temp = male - low temp = female Chelonians: - high temp = female - low temp = male Some chelonians and lizards: - extreme low or high temps = female - intermediate temp = male

Question 28

Describe lizard sexual dimorphism

Answer 28

Males often have ornamental anatomy e.g., horns, spikes

Question 29

Describe chelonian sexual dimorphism

Answer 29

Females: flat plastron, short tail Males: concave plastron, long tail

Question 30

Describe the sexing methods of squamates

Answer 30

Manual eversion of hemipenes/popping - not recommended Hydrostatic eversion of hemipenes - not recommended Cloacal probing Endocrinology - breeding season hormones Ultrasonography - presence of eggs Endoscopy

Question 31

Describe male fish repro anatomy

Answer 31

Paired intra-abdominal testes Sperm carried by ductus deferens to: - bladder - common urinary duct - genital pore Fish semen = milt

Question 32

Describe female fish repro anatomy

Answer 32

Gymnovarian: - oocytes into coelom -> oviduct remnants Cystovarian: - ovarian ducts (not oviducts)

Question 33

What are the stages of reproduction in female fish?

Answer 33

Question 34

Describe oviparous/egg laying fish species

Answer 34

most fish external fertilisation

Question 35

Describe vivparous/live bearing fish species

Answer 35

Fewer offspring than egg layers Internal fertilisation Lecithotrophy: - nutrition from yolk sac - fertilised eggs stay in body of parent Matrotrophy: - placenta-like structure - very rare

Question 36

Describe fish repro endocrinology

Answer 36

Pituitary gland releases GTH-I and GTH-II GTH-I: - FSH-like - vitellogenesis - gonadal development - +ve feedback => GTH-II release GTH-II: - LH-like - oocyte maturation - ovulation - progestins

Question 37

Describe fish sex determination

Answer 37

Genetic dependent: - male XY - female ZW Temp dependent

Question 38

What environmental factors affect fish reproduction?

Answer 38

photoperiod Temp Presence of opposite sex Currents/tides Proximity to spawning area

Question 39

What affects the onset of sexual maturity in reptiles?

Answer 39

diet can 'push' onset of sexual maturity with diet

Question 40

Describe the type of breeding in reptiles

Answer 40

Seasonal: - temperate/subtropical - spring, after hibernation - tropical - wet season