Arambourg and Coppens (1967) is the publication that first proposed Omo 18-1967-18 as the holotype specimen for the new genus and species, Paraustralopithecus aethiopicus. This 1967 publication included an iimage, description and measurements. Arambourg and Coppens (1968) provided additional description and measurements of the holotype along with a fuller differential diagnosis.
Groves (1989) suggested that Arambourg and Coppens (1967) proposed the new name conditionally, and that the 1968 publication is the one that established the name. Indeeed Arambourg and Coppens (1967) ended with, "Nous le désignerons provisoirement sous le nom de Paraustralopithecus aethiopicus nov. gen., nov. sp." (p. 590), which certainly indicates a provisional assignment. However the relevant section of the Code (Article 15) refers to conditional propsoals, i.e. those that are made with "stated reservations" (ICZN Glossary) and it is not clear that the 1967 publication expresses reservations. That publication (1967) includes a footnote indicating that a registered letter was sent to the French Academie announcing the discovery. This would suggest the discovery and the name were not proposed conditionally, or with reservations. Furthermore Arambourg and Coppens (1968) concludes with the sentence, "Nous avons désigné cette forme archaïque sous le nom de Paraustralopithecus aethiopicus." (p. ) indicating with the past tense that the name had already been assigned (in 1967). In either case the name Paraustralopithecus aethiopicus is potentially valid, and the issue is what date is appropriate.
Groves (1999) discussed additional challenges and problems surrounding the designation of the name 'aethiopicus'.