In the third edition of Mammal Species of the World published in 2005, the mammalogist W. Christopher Wozencraft listed under C. lupus 36 wild subspecies, and proposed two additional subspecies: familiaris (Linnaeus, 1758) and dingo (Meyer, 1793). Wozencraft included hallstromi—the New Guinea singing dog—as a taxonomic synonym for the dingo. Wozencraft referred to a 1999 mitochondrial DNA study as one of the guides in forming his decision, and listed the 38 subspecies of C. lupus under the biological common name of "wolf", the nominate subspecies being the Eurasian wolf (C. l. lupus) based on the type specimen that Linnaeus studied in Sweden. Studies using paleogenomic techniques reveal that the modern wolf and the dog are sister taxa, as modern wolves are not closely related to the population of wolves that was first domesticated. In 2019, a workshop hosted by the IUCN/Species Survival Commission's Canid Specialist Group considered the New Guinea singing dog and the dingo to be feral dogs Canis familiaris, and therefore should not be assessed for the IUCN Red List.