The terms ‘hominid’ and ‘hominin’ are frequently used in human evolution.
New definitions
The most commonly used recent definitions are:
Hominid – the group consisting of all modern and extinct Great Apes (that is, modern humans, chimpanzees, gorillas and orang-utans plus all their immediate ancestors).
Hominin – the group consisting of modern humans, extinct human species and all our immediate ancestors (including members of the genera Homo, Australopithecus, Paranthropus and Ardipithecus).
Previous definitions
Current use of the term ‘hominid’ can be confusing because the definition of this word has changed over time.
The term ‘hominid’ used to have the same meaning that ‘hominin’ now has. It was therefore a very useful term to designate the line leading to modern humans and was used when referring to various members of our human evolutionary tree.
‘Hominid’ has now been assigned a broader meaning and now refers to all Great Apes and their ancestors. This new terminology is being used in many scientific journals already, and it is only a matter of time (but possibly many years) before everyone catches up to using the new term.
The problem for students and teachers is that a lot of texts still use the old system and many internet sites also haven't caught up, even those of many reputable scientific establishments. So students/teachers will need to be aware that 'hominids' can mean two different things depending on how up-to-date a reference is with regard to incorporating these taxonomy/classification changes.
Why have these changes occurred?
‘Hominid’ and ‘hominin’ are derived from names used in the scientific classification of apes (including humans). By international convention, certain word endings are used for specific taxons or levels within this classification. For example, ‘family’ names always end in ‘-idae’ (eg Hominidae), ‘subfamily’ names end in ‘inae’ (eg Homininae) and ‘tribe’ (1) names end