Definition of therian in English:

therian

noun

Zoology
  • A mammal of the major group Theria, which comprises the marsupials and placentals.

    • ‘In this way the ancestor of therian mammals came to possess a single generation of replacement teeth, which erupt when the jaw reaches a size large enough to accommodate them.’
    • ‘First, we point out that the loss of tooth replacement in marsupials is neither unusual among therian mammals nor highly correlated with the extended period of nipple attachment in any obvious manner.’
    • ‘The reproductive system of the therians (marsupial and placental mammals) is a complex variation on the egg-layer's basic tubular structure.’
    • ‘The evolutionary tree relating the mammalian species that share the amino-acid replacements dates back to the ancestral therian, 180 million years ago.’
    • ‘Fossils of therian mammals, which include the marsupials as well as the eutherians, may be recognized and distinguished by the number, morphology, and replacement pattern of their teeth.’

adjective

Zoology
  • Relating to or denoting therians.

    • ‘Thus, relative to the primitive therian condition, marsupials have a distinctive, derived pattern of reduced dental replacement.’
    • ‘As one might guess, the post-cranial skeleton is a mosaic of basal mammaliform and therian characters.’
    • ‘In this way the ancestor of therian mammals came to possess a single generation of replacement teeth, which erupt when the jaw reaches a size large enough to accommodate them.’
    • ‘The physiological site of the defect in these mice, the chorionic placenta, is found only in therian mammals.’
    • ‘Unfortunately, molar nomenclature was developed for therian mammals, and some of the terminology turns out not to work very well at this fundamental level.’

Pronunciation

therian

/ˈθɪərɪən/