Thylacinus macknessi
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Infraclass: Marsupialia
Order: Dasyuromorphia
Family: Thylacinidae
Genus: Thylacinus
Species: T. macknessi
Binomial name
Thylacinus macknessi
Muirhead, 1992

Thylacinus macknessi lived during the early Miocene and is the oldest known member of the genus Thylacinus. It is named after Brian Mackness, a supporter of Australian vertebrate paleontology.

Thylacinus macknessi was a quadrupedal marsupial predator, that in appearance looked similar to a dog with a long snout. Its molar teeth were specialized for carnivory; the cups and crest were reduced or elongated to give the molars a cutting blade.

When the species was first described, only the posterior section of the jaw was known. Two years later in 1995 at the same fossil site, Muirhead and Gillespie found the anterior half of the specimen in a block of limestone. Its fossils have been found in north-western Queensland at the Riversleigh world heritage area at Neville's Garden Site.