Dog from multiple grey wolf populations, with the dingo and New Guinea singing dog "breeds" having developed at a time when human populations were more isolated from each other. In the third edition of "Mammal Species of the World" published in 2005, the mammalogist listed under the wolf "Canis lupus" its wild subspecies, and proposed two additional subspecies: ""familiaris" Linneaus, 1758 [domestic dog]" and ""dingo" Meyer, 1793 [domestic dog]". Wozencraft included "hallstromi" - the New Guinea singing dog - as a taxonomic synonym for the dingo. Wozencraft referred to the mDNA study as one of the guides in forming his decision.
Invasive species used to describe a non-native or introduced species that has become widespread (p. 136). However, not every introduced species has adverse effects on the environment. A nonadverse example is the common goldfish ("Carassius auratus"), which is found throughout the United States, but rarely achieves high densities (p. 136). Notable examples of invasive species include European rabbits, grey squirrels, domestic cats, carp and ferrets. Dispersal and subsequent proliferation of species is not solely an anthropogenic phenomenon. There are many mechanisms by which species from all Kingdoms have been able to travel across continents in short periods of time such as via