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Marsupials/Placental
Comparison between marsupials (metatherians) and placental mammals.
Question | Answer |
---|---|
Braincase is small relative to body size. Minimally developed neocortex. No corpus callopsum. | Marsupials |
Braincase is large relative to body size. Largely developed neocortex. Corpus callopsum present. | Eutherians |
Auditory bullae (generally) absent. | Marsupials |
Auditory bullae present. Formed from tympanic bone. | Eutherians |
Large jugal bone. Jugal and squamosal bones articulate with dentary bones in the mandibular fossa. | Marsupials |
Jugal bone does not articulate with dentary bones in the mandibular fossa. | Eutherians |
Angular process inflicted 90 degrees. | Marsupials |
Dental formula 5/4, 1/1, 3/3, 4/4 = 50. Teeth (mostly) non-deciduous. | Marsupials |
Dental formula 3/3, 1/1, 4/4, 3/3 = 4. Teeth (excluding molars) deciduous. | Eutherians |
Epipubic bones occur in both sexes. | Marsupials |
Scrotum anterior to penis. Baculum not present. | Marsupials |
Scrotum posterior to penis. Baculum sometimes present. | Eutherians |
(Often) contains marsupium that encloses teats. | Marsupials |