eutheria उदाहरण वाक्य
उदाहरण वाक्य
- For example, Metatheria also includes the non-marsupial ancestors of the marsupials, after their divergence from placentals; Eutheria includes the non-Placental ancestors of placentals, after their divergence from marsupials.
- The names Prototheria, Metatheria and Eutheria ( meaning " first beasts ", " changed beasts ", and " true beasts ", respectively ) refer to the three mammalian groupings of which we have living representatives.
- The Australosphenida hypothesis remains controversial; for example, there seems to be a presence of lingual cingula in various non-australosphenidan mammals and some work has shown the possibility of Eutheria being the sister group to Australosphenida, without monotremes.
- The term "'eu-FEDS "'was first described in 1997 by Gary F . Clark et al . as " the human fetoembryonic defense system ", and later renamed to apply more broadly to all members of the taxon Eutheria.
- those extant mammalian infraclasses each have a set dental formula; the Eutheria ( placental mammals ) commonly have three pairs of molars and four premolars per jaw, whereas the Metatheria ( marsupials ) generally have four pairs of molars and between three or two premolars.
- Euarchontoglires is now recognized as one of the four major subclades within the clade Eutheria ( i . e ., placentalia ( placental mammals ) ), and it is usually discussed without a taxonomic rank but has been regarded as a cohort, magnorder, or superorder.
- In 2007, Guillermo Rougier and colleagues described another australosphenidan, " Henosferus ", from the Jurassic of Argentina; they argued against a relationship between Eutheria and Australosphenida ( Figure 3, top ), but were ambivalent about the placement of monotremes within Australosphenida.
- The researchers hypothesize that the divergence of Metatheria from Eutheria occurred in Asia no later than 125 million years ago, followed by the evolution of deltatheroidian-like taxa in Asia and North America about 120-100 million years ago and then the Paleocene diversification of relatives to the crown marsupials in South America.
- Initially treated as subclasses, Metatheria and Eutheria are by convention now grouped as infraclasses of the subclass Theria, and in more recent proposals have been demoted further ( to cohorts or even magnorders ), as cladistic reappraisals of the relationships between living and fossil mammals have suggested that the Theria itself should be reduced in rank.
- The traditional " theria hypothesis " states that the divergence of the monotreme lineage from the Metatheria ( marsupial ) and Eutheria ( placental mammal ) lineages happened prior to the divergence between marsupials and placental mammals, and this explains why monotremes retain a number of primitive traits presumed to have been present in the synapsid ancestors of later mammals, such as egg-laying.