1
$\begingroup$

I imagined a hypothetical species of squamate from the Anguimorpha clade. They are my dragons. They are a rare example of viviparous nonmammalian tetrapod. However, like all anguimorphan squamates, they have the ZW sex determination system.

The only real life species I know that are viviparous all have the XY sex determination system: therians (viviparous mammals), and Carcharhiniformes (ground sharks).

I know that, in the XY sex determination system, which is used by mammals, sharks, termites, dipterans, and some plants (such as cannabises, and grapevines), being female is the default sex, and the father is the parent that determines the sex of the offspring (there are male sperms, and female sperms). At the opposite, in the ZW sex determination system, which is used by birds, anguimorphans, axolotls, lepidopterans, Schistosoma flatworms, and some plants (such as wild strawberries, purple willows, pistachios, and the world's oldest angiosperm, the great Amborella trichopoda), being male is the default sex, and the mother is the parent that determines the sex of the offspring (both female turkeys and female Komodo monitor lizards sometimes reproduce by parthenogenesis, and their offspring is always male, because having two W chromosomes and zero Z chromosome is lethal) (there are female ovums, and male ovums).

So, I wonder if a viviparous species with the ZW sex determination system is realistic.

$\endgroup$
1
  • 3
    $\begingroup$ ??? Lots of reptiles are viviparous. There is even a common species of lizard which has the cute scientific name Lacerta vivipara. And guess what, it uses the ZW sex determination system. (Actually, more like Z₁Z₂W, but close enough.) $\endgroup$
    – AlexP
    Commented Mar 9, 2023 at 6:38

1 Answer 1

10
$\begingroup$

Some real-world reptiles are viviparous, so it is entirely reasonable that the ZW sex determination system does not preclude viviparity.

In fact, the Anguimorpha sub-order already contains viviparous species, making viviparity even more realistic.

$\endgroup$

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .