Monotremata and Marsupialia

The order Monotremata comprises two families: Tachyglossidae, the echidnas, of which there are four extant species; and Ornithorhynchidae, the platypus (Ornithorhynchus anatinus). Marsupials covered in this chapter include wombats (Vombatidae), possums (Phalangeriformes), gliders (Petauroidae), dasyurids (Dasyuridae), bandicoots (Peramelemorphia), greater bilby (Macrotis lagotis), and opossums (Didelphimorphia). Apart from a few idiosyncrasies as outlined, obtaining diagnostic images of monotremes and marsupials is no different than domestic animals and other zoo and wildlife taxa. The monotreme gastrointestinal tract has a simple monogastric arrangement. Male monotremes are testicond with the two ovoid testicles suspended within the abdominal cavity caudal to the kidneys. The female reproductive tract of marsupials covered in this chapter, apart from bandicoots and the greater bilby, are typical of most marsupials. An adult zoo maintained bare-nosed wombat has been documented with US findings consistent with cystic endometrial hyperplasia and possible metritis.