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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 |