Systematics of the South American marsupial family Microbiotheriidae / Larry G. Marshall --.

Phylogenetic Relationships and Classification of Didelphid Marsupials, an Extant Radiation of New World Metatherian Mammals

“…Both groups inhabit wet-temperate Patagonian forests, but paucituberculates also occur in climatically similar montane habitats of the tropical Andes (Bublitz, 1987;Patterson and Gallardo, 1987;Albuja and Patterson, 1996;Hershkovitz, 1999;Lunde and Pacheco, 2003). Because microbiotherians and paucituberculates were more diverse and widely distributed in the Tertiary than they are today (Marshall, 1980(Marshall, , 1982bBown and Fleagle, 1993;Goin and Candela, 2004), these orders are appropriately regarded as relictual elements in modern faunas.…”

Molecular Systematics of Marsupials Based on the rRNA 12S Mitochondrial Gene: The Phylogeny of Didelphimorphia and of the Living Fossil Microbiotheriid Dromiciops gliroides Thomas

“…Dromiciops is considered a living fossil form because it is the sole representative of an extinct lineage, the microbiotheres, whose oldest fossil record is from the Paleocene of Bolivia (Marshall and de Muizon, 1988). Morphologically, Dromiciops differs from other mouse opossums in the presence of a pouch (in females) and the great development of the auditory bulla (Marshall, 1982). Karyotypically, female Dromiciops have a diploid number of 14 chromosomes, while males seem to have 13 (the Y chromosome appears to be absent; Gallardo and Patterson, 1987, although see Spotorno et al, 1997).…”

Suprafamilial relationships within marsupialia: Resolution and discordance from multidisciplinary data

“…Each of these monospecific extant families possesses a number of autapomorphies at the morphological level, and at least some of these are known also for Miocene fossil relatives of microbiotheriids (Marshall, 1982;Reig et al, 1987;Marshall et al, 1990) and notorycfids (Archer et al, 1991). Although portions of the dentition, jaws, and limbs are known for the Miocene notoryctids, they remain undescribed, and so it is unclear whether these tantalizing remains will provide clues to the australidelphian affinities of notoryctids.…”