Mammals marsupials

Marsupials (6/19) These present no known instances of loss or reduction. The Metatheria (Australian and South American marsupials) differ little in the layout of their VN complex from those of the higher placental mammals (Eutherians) (Broom, 1896 Kratzing, 1984 Poran, 1998). Attention to Australasian forms has until recently predominated [Kratzing, 1978, 1982 and 1984(a)-(c) Salamon, 1996]. A few genera... 

A clear demarcation of the external nose in marsupials and many eutherian mammals presents as a hairless area of skin surrounding the nostrils and the inter-narial space and can include the median part of the upper lip. This typically pigmented zone — the rhinarium — is... 

The early VN neurones migrate by various routes and in mammals become organised into two layers, each with distinct functional attributes (Chaps. 2 and 6). Amongst marsupials, the sensory cells of an opossum appear at about one-week post-conception (Jia and Halpem, 1998). Despite their extremely altricial developmental pattern, the bandicoots dendrites produce sensory processes (Fig. 4.5) on the lumenal border of the VNO at 35 days postnatal, which in the Northern Bandicoot (Isoodon macrourus) is about 50% of pouch life (Kratzing, 1986). 

Russell E. (1984). Social behaviour and organisation of marsupials. Mammal Rev 14, 101-154. 

Australian mammals, various 1.6-20.0 mg/kg BW Lethal to 8 species of marsupials and 5 species of rodents 9... 

The vomeronasal system, also known as the accessory olfactory system, consists of chemoreceptors, organized into the VNO, the vomeronasal nerve, its terminal, the accessory olfactory bulb, and more central pathways. First described by Jacobson in 1811, the VNO has been studied intensely. We now know how stimuli reach it and what behaviors it mediates. The VNO occurs in amphibians, reptiles, and mammals. Among mammals, it is best developed in marsupials and monotremes. In birds it only appears during embryogenesis. The VNO and its function are best known for squamate reptiles, particularly snakes, and rodents and ungulates among the mammals. 

The aA-crystallin gene has its own taxon-specific feature. In some placental and marsupial mammals the aA-crystallin gene contains an extra, alternatively spliced, exon in the first intron.3-46-47 The sequence of the human aA-crystallin gene revealed the presence of a silent, pseudoexon copy of the sequence.48 It thus seems that the insert exon arose in a distant common ancestor of mammals but has lost expression in many descendant species. A phylogenetic examination of this part of the aA-crystallin gene has begun47... 

Marsupial rats and mice are small mammals with a uniformly dark, brownish coat, often with a whitish belly, and they have a superficial resemblance to placental rats and mice. Most species are nocturnal predators that feed on insects and other small prey. The larger species, such as marsupial rats, feed on smaller marsupials, birds, and reptiles, and introduced rodents. In a sense, marsupial mice fill the ecological roles played by the smallest placental predators on other continents, for example, shrews, while the marsupial rats are ecologically similar to larger small predators, such as weasels. 

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