Are Primates over-split?

Genus-level splits tend to come after phylogenies can be robust enough to know that the taxa diverged a significant amount of time ago, rather than from other perceived differences, hence a greater agreement nowadays than in the past. It's still subjective, as that cut-off is arbitrary.

 

The Tapanuli orangutan and Cross river gorilla isn't a good example to give. Even before Tapanuli orangutan was discovered to be distinct, scientists and everyone into orangutans knew that both species of orangutans were endangered. Western gorillas were considered endangered four years before cross-river gorillas were considered to be an actual subspecies.

This is not to say that splitting is unnecessary, but it could be excessive at times (such as aotids, but's that's just my opinion)

 

Of course!!! They just follow the absurd modern revolutionary taxonomy, that affects not only primates but every group in the animal kingdom.
Plant kingdom too, but here botanists tend to not over-spilt species, but to over-spilt only genus and upper taxa.

 

Yes, primate genera are also oversplit.
For example in tarsiers, 3 former species were turned into 3 genera, and former subspecies and local forms into species.

Several wrong arguments are used. One is that some certain genetic difference means that it is a species, and that animals closest to each other must hybridize more often than more distant to each other. Neither is true for closely related primates. There are examples of hybridizing lineages which are not each other closest relatives.
Another false argument is picking the lowest borderline: two most closely related species mean that all other animals with the same or larger difference are automatically different species, too. I even saw somebody arguing about primates using example of ducks.

And, of course, thanks to oversplitting of primates, practically all primatologists and all users of Zoochat are hybrids between Homo sapiens, Neandertal man and often Denisovian man.

 

I would have thought this would also apply to people who are not primatologists and who do not use Zoochat.

 

Exactly.

 

That is an interesting point, but I should add that there is a need for some spliting and a need for this being reflected in zoo husbandry and general conservation management whether ex-situ or in-situ.

For example, hybridization between species is really a problem for a number of primates species like the buffy tufted marmoset and buffy headed marmoset here in Brazil (or apparently for a number of lemur species for that matter in Madagascar).

Yes, granted hybridization can occur naturally and sporadically between these species in certain areas where the species ranges meet in the habitat interface of Cerrado with Atlantic rainforest for example (in regards to buffy tufted marmoset and black eared marmoset).

However, there is absolutely no question that the level of hybridization we are seeing now has been caused entirely by the twin anthropogenic drivers of introduction of invasive marmosets via the illegal pet trade and massive habitat modification / urbanization of the Atlantic rainforest ecosystem.

Historically these species which we know now through molecular analysis to be distinct species (though there was a relatively recent divergence) were all lumped together and treated as subspecies of the common marmoset. This was because of the erroneous belief that they were not distinct species but merely a subspecies or even a race / population.

As a result of this misconception at a primate centre here in Brazil there was a colony of buffy tufted marmosets kept which were even being actively bred with common and black eared marmosets back in the 1970's. Needless to say, this was an absolutely insane ex-situ management strategy but not as much was known then as is currently known now so really quite forgiveable under the circumstances.

*I should add that the buffy tufted marmoset hybridized colony sadly died out so it didn't genetically impact captive populations which in the case of aurita are recently formed anyway.

 

Both of these get at the crux of where I always find myself in these discussions, which is wondering if there would be a great benefit in having an organization or international panel with the authority to establish global scientific standards on what evidence was sufficient to split or lump taxonomic units. If different scientists are using different definitions of what a species even constitutes, there is always going to be wide disagreement when it comes to taxonomy - which can have meaningful impacts on conservation and management policy, as well as other fields of science such as biomedical research.

So I take this to be that many of the current splits are based on findings of genetic differences between different populations and sub-populations? Do you (or anyone) know to what extant the reproductive isolation of these populations or functional disadvantages to re-mixing are being taken into account? Otherwise it wouldn't take much genetic distinction between two populations to make a claim to having identified a new "species" - regardless if that's the right conclusion to reach.

 

There seem to be some anomalies about the way primates are classified, as hybrids have been produced from distantly related species.

On a technicality, there is no way that a Rhesus macaque and vervet monkey could ever produce young, but they did.

Other hybrids include crab-eating macaques and mandrills, Allen's swamp monkeys and grivet monkeys, pig-tailed macaques and sooty mangabeys and Rhesus macaques and Hamadryas baboons.

Could some of these species be more closely related than has been suggested?

 

Hi. Some weeks ago, based on the agreement of primates being over split according to your responses, I decided to investigate and read some papers with the goal of creating a more compromised list of species, and I decided to start with the New World Monkeys (with callithrichs, precisely). However, I haven't found any convincing information about some groups (like marmosets), as it seems that practically all primatologists decided to use a phylogenetic species concept approach based on pelage colour and other morphological features, and no molecular analysis when describing new species... I'm stucked.

So, I'd like to hear what do you think about marmosets and tamarins, are they over split too? For example, I found that in the 70's Hershkovitz, who I believe didn't use a phylogenetic species concept approach, considered only four species of marmosets: Callithrix jacchus, Mico argentatus, Mico humeralifer, and Cebuella pygmaea (as we know them today). But to me, lumping all Atlantic forest marmosets in only one species seems radical, considering how different they look. It also seems, based on what I have read, that they do not form a cline, and even though there is some hybridization in the contact zones, these are narrow areas meaning that there is at least some kind of resistance to fully fuse with one another. But, on the other hand, all the atlantic forest marmosets seems to have diverged very recently, as some DNA analysis have found very little differences between them. And the Mico marmosets... They are way more complicated to understand.

So, maybe some advices could be helpful on to how to procede . (As a note: this is mostly a hobby, as I find taxonomy very interesting despite sometimes being kind of frustrating)

 

Article about another monkey-hybrid :

https://static1.1.sqspcdn.com/stati...5+Saks.pdf?token=Qm4utk9kUbnMy9Cd0O32nNRw5+I=