Johanson and colleagues formally named the species Afarensis of the genus Australopithecus in 1978.

Between 1992 and 1994 White and his team discovered the first Ardipithecus ramidus fossils in the Middle Awash area of Ethiopia. They named their discovery Ardipithecus ramidus (‘ramid’ means ‘root’ in the Afar language of Ethiopia and refers to the closeness of this new species to the roots of humanity, while ‘Ardi’ means ‘ground’ or ‘floor’). White devised the genus name Ardipithecus to distinguish this new genus from Australopithecus. 

The first Ardipithecus ramidus fossil found was dated to 4.4 million years BP on the basis of its stratigraphic position between two volcanic strata. 

The authors provide evidence that Ardipithecus may be the beginning of the evolutionary pathway that eventually led to hominids. This pathway was distinct from the evolutionary pathway that led to extant African apes.

"Ar. ramidus, first described in 1994 from teeth and jaw fragments, is now represented by 110 specimens, including a partial female skeleton rescued from erosional degradation. This individual weighed about 50 kg and stood about 120 cm tall. In the context of the many other recovered individuals of this species, this suggests little body size difference between males and females. Brain size was as small as in living chimpanzees. The numerous recovered teeth and a largely complete skull show that Ar. ramidus had a small face and a reduced canine/premolar complex, indicative of minimal social aggression. Its hands, arms, feet, pelvis, and legs collectively reveal that it moved capably in the trees, supported on its feet and palms (palmigrade clambering), but lacked any characteristics typical of the suspension, vertical climbing, or knuckle-walking of modern gorillas and chimps. Terrestrially, it engaged in a form of bipedality more primitive than that of Australopithecus, and it lacked adaptation to “heavy” chewing related to open environments (seen in later Australopithecus). Ar. ramidus thus indicates that the last common ancestors of humans and African apes were not chimpanzee-like and that both hominids and extant African apes are each highly specialized, but through very different evolutionary pathways" (Conclusion of the authors' introduction). Digital facsimile from academia.edu at this link.

Order of authorship in the original publication: White, Asfaw, Beyene, Haile-Selassie...

(Thanks to Juan Weiss for this reference and its interpretation.)