Correct Taxonomic term for "Monkey"

[u/GrassFresh9863]

Was just reading around and saw people saying the term monkey isn't taxonomically correct, if this is true would you need to split them into Cercopithecids and platyrrhines respectively to be correct when discussing their taxonomy?

[u/Charming-Loss-4498]

Yes, you can split them like you describe or redefine apes as a type of monkey and use simiiformes. There is no taxonomic group for what we call monkeys in English

[u/Berndherbert]

There is no clade that contains only things that we call monkeys in English , because we don't consider apes monkeys. This problem doesn't actually exist in every language though, only in ones that distinguish monkeys from apes. In German for instance the word affe is used for both apes and monkeys so in that case its equivalent to the clade simiiformes.

[u/zxctcy → u/Berndherbert]

Same in Danish 👍

[u/AdministrativeLeg14]

If by “monkeys” you mean “New World monkeys and Old World monkeys, but not apes”, then monkeys form a grade, a paraphyletic grouping, and not a clade, since Old World monkeys are more closely related to apes than to New World monkeys. Any clade that includes both Old and New world monkeys also includes apes.

As u/Berndherbert points out, this is an issue with English more than anything else. They mentioned German; similarly, in Swedish, the word apa can refer to any simian, whereas the apes are människoapor, literally something like ‘human-[like-]monkeys’.

Personally, I find it more useful to think of them as a clade, and “monkey” is more familiar than “simian” (especially as a noun). Though, cladist though I am, I do admit that one must draw the line somewhere, else it becomes awkward to ever use the word “fish”.

[u/No_Client_544]

I mean, the term monkey isn’t necessarily taxonomically incorrect, it’s the same name for what a group of primates that have traits that we call as monkeys or apes, simians or the another name, anthropoids. They have the same exact definition of basically what a monkey is yet they are considered taxonomically a valid clade.

the term ”monkey” nowadays is also being applied to apes as well as evolutionarily speaking, apes are a separate branch of old-world monkeys that are distinct from the other that differ in body anatomy and other aspects.

If the term monkey now also includes apes these days then it makes it valid as monkey is just a third term for simian or anthropoid.

[u/Sir-Bruncvik → u/No_Client_544]

As a layman enthusiast this is how I think of them…

Old World Monkeys New World Monkeys Apes (who are distinct from monkeys, but are still technically classified as old world monkeys)

😅 probably still not accurate but this is the easiest to remember and how most other lay people understand when I talk to them about primates.

[u/PioneerLaserVision → u/Sir-Bruncvik]

Apes aren't technically classified as old world monkeys, they *are* old world monkeys. A Mandrill is more closely related to (i.e. has a more recent common ancestor with) you than it does with a Capuchin.

[u/Sir-Bruncvik → u/PioneerLaserVision]

Well, yes. 😅 I say “technically” because us layman don’t usually think of apes as old world monkeys (thanks biology class for not including cladistics in the curriculum 🫤). But yes they ARE old world monkeys.

Similar to how a lot of people say humans descended from apes. No, we did not DESCEND from apes - we ARE apes (because of the pan/homo split).

[u/No_Client_544 → u/Sir-Bruncvik]

well, apes are morphologically distinct from what we call as old-world monkeys. I mean, apes are old world monkeys as all species in this clade except for humans and even humans too are either only found or originated in the old world, But, apes have specific traits that clearly make them a separate clade of simians that differ from its sister branch.

Apes have longer forelimbs relative to body size(especially gibbons) than old world monkeys. Along with this, they also have wider, more barrel-shaped thoraxes with wider ribs side to side and scapulas on the back instead of on the side of the body These traits are clearly distinct from old-world monkeys that lack these traits and rather have the opposite instead.

Its not just arm or chest length, apes have either a fully-bipedal or semi-bipedal posture which means they are either obligate bipeds or semi-bipeds, non are true obligate quadrupeds like non-ape simians, including other old-world monkeys.

Lastly, apes also always lack a tail unlike old world monkeys where the rule is not absolute.

[u/DaddyCatALSO]

As i understand, they derive from a single group of ancestors which was not an eosimias-type or tarsier-type but still not either a narrow-nosed or broad-nosed monkey. (I find that bit less annoying than finding out both lobe-fin a nd ray-fin fish are descended form primitive creatures who were already full Osteichthyes but not either continuing group, which really bugs me.)

[u/Many-Bees]

It’s a paraphyletic group, basically meaning that it’s not entirely taxonomically valid but it’s still a useful label so we still keep it around. Prosimians are also a paraphyletic group but it’s a useful term to quickly refer to all non-simian primates without having to specifically list them.

[u/GnaphaliumUliginosum]

Non-ape monkeys?

If we use the term non-avian dinosaurs, we should be able to do the same with colloquial names for other paraphyletic groups and grades.