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)