Dasyurids occur in virtually every terrestrial environment at all altitudes in mainland Australia and some offshore islands, mainland New Guinea, and some islands between Australia and New Guinea. In Australia, species diversity of the smaller species is higher in arid regions than in the more mesic coastal and sub-coastal areas of the east, southeast, and extreme southwest, while the converse is true for the larger dasyurids (more than 17 oz [500 g]), quolls, and devils). Species richness of small dasyurids reaches its highest density in the spinifex hummock grasslands of arid central Australia (average 5.3, maximum eight species) and is correlated with structural complexity of the habitat that allows niche separation. Population density, on the other hand, reaches highest levels in coastal forest and heath among the smaller species, and is uniformly low in the arid zone. With the disappearance of the chuditch (Dasyurus geoffroii), there are no larger dasyurids in the arid zone. The island of Tasmania supports the largest assemblage of larger dasyurids (three species, historically four) following the historic and prehistoric extinction of three of these species from mainland Australia. Dasyurid distribution within New Guinea is poorly documented.

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