Paranthropus was an offshoot of human evolution that lived alongside us ~2 million years ago. Despite
However, it turns out that name may have been a bit premature. Not only because didn’t they eat many nuts, but their teeth aren’t all they cracked up to be (haha, get it?).
This twist comes from a study on the southern species of this lineage, Paranthropus robustus. Researchers found their teeth were riddled with defects, to the point where the authors, Towle and Irish, concluded it couldn’t have been an accident. P. robustus actually evolved weak teeth1.
The pitfalls of Nutcracker Man
The defects in question are a series of tiny pits covering the crowns of most P. robustus teeth. On the surface, these wouldn’t be anything to worry about. However, they can provide a home for plaque and other things, dramatically raising the risk of dental
Not the sort of thing you want to happen if you’ve got a reputation as a nutcracker.
We know the pitfalls of these defects (haha) because they do sometimes occur in people. Typically, they’re the result of stress during growth, like lack of food or ingesting nasty compounds, mucking with the development of the tooth. Basically, these stresses turn off the cells making the enamel, leading to these holes in it1.
However, Towle and Irish weren’t sure that this could explain the defects they
The weirdness of Paranthropus‘ defects
The genetics of nutcracker man
After all of this, Towle and Irish were faced with a bit of a paradox. Paranthropus teeth had defects that looked like they stemmed from malnutrition, but nothing else about them fitted with that explanation. They were just too common and consistent.
Fortunately, that weirdness could hold the answer. After all, genetics can make things common and consistent. Could these pits be the result of evolution? Perhaps mutations made them much more vulnerable to these defects cropping up.
Now, it might seem weird to think a species would evolve a tendency towards defects. However, it’s worth remembering that evolution isn’t some
These are technically called “pleiotropic effects”, and humans are riddled with them.
In the context of Paranthropus, the evolved big
So, nutcracker man serves as yet another reminder that not every trait in human evolution is there for a reason. Sometimes, evolution is just messy.
- Towle, I. and Irish, J.D., 2019. A probable genetic origin for pitting enamel hypoplasia on the molars of Paranthropus robustus. Journal of Human Evolution, 129, pp.54-61.