I'm going to throw a curve ball and not talk about dinosaurs (crazy, I know), instead looking at another group who are far more recent and whose one of its members have had a far bigger impact in a much shorter amount of time. Apes are fairly well known, but there have been many questions about their origins, so let's take a look at when apes first appeared and how they radiated throughout the world.
What is an ape?
First up, let's clarify what an ape actually is. Within the group of primates, there is a infraorder named Simiiformes, or simians. Sounds complicated so far, but simians are the group that contain everything we would commonly refer to as monkeys and apes. Within this infraorder are the platyrrhini ('new world monkeys') and the catarrhini ('old world monkeys'). The 'old world monkeys' further contain two groups, though it was once a much more diverse group, now only contain the 'lesser apes' and the 'greater apes'.
Still with me? Good.
So, the 'lesser apes', or hylobatids, consist pretty much of gibbons while the 'greater apes', or hominids, contain the likes of gorillas, orangutans, chimpanzees and us humans. The two main differences between apes and monkeys are commonly, with apes lacking a tail and being generally larger. Other differences are present though, with apes having much more mobile shoulder joints, relatively bigger ribcages and being generally more intelligent.
For the sake of the question being posed, I will be talking mainly about the 'old world monkeys' (scientifically known as hominoids...don't misread that, it's different to hominids, which are the group within hominoids...again, bare with me).
But for the sake of context, let's go a little further back...
When did primates first appear?
The order of primates is a big one. members of this order that are still alive today include the aforementioned apes and monkeys, as well as tarsiers, lemurs and bush babies.
Us primates actually go back further than you might think. The earliest known pro-primate is a little guy named Purgatorius unio, who lived around 63 million years ago (only 3 million years after the extinction of the non-avian dinosaurs).
To be honest, there aren't many mammals that didn't originate from little, squirelly-looking things.
The oldest known proper primates cropped up around 10 million years later in Africa, which is where the majority of their diversification would take place to begin with. Of course, there are studies (such as phylogenetic studies) which actually estimate the origin of primates to be as early as the mid-Cretaceous, but we are yet to find hard fossil evidence for this.
When and where did apes diverge from them?
So, that brings us back to apes. So far, one of the earliest known fossil of a catarrhine that predates the divergence between hominoids and other old world monkeys is Aegyptopithecus zeuxis, from Egypt around 30 million years ago. It wasn't actually until 2010 that we got any closer to finding out the origin of apes specifically, when a genus known as Saadanius was found. Dated at around 29 million years ago, Saadanius was a catarrhine that has been found to share a common ancestor with hominoids.
After this guy though, the lineage of hominins (apes) specifically gets a little unsure. There are a few genera that seem to give us clues though. The first of these is Proconsul, which lived in Africa around 20 million years ago and shares some primitive traits with modern apes as well other groups of catarrhines, meaning this guy could be extremely close the divergence point. In fact, many scientists debate whether Proconsul was before or after apes splitting from the rest of the catarrhines.
A close relative from 14-15 million years ago was Nacholapithecus, from Kenya.
One of the earliest true apes, however, is Afropithecus from northern Kenya which lived 16-18 million years ago, showing that true apes seemed to split from the rest of catarrhines in the Northern/Eastern African area around 30 million years ago.
After that, apes diversified very quickly and reached far beyond Africa. One ape thought to have begun the radiation out of Africa is Kenyapithecus around 14 million years ago. After that, the rest is history, reaching Asia with orangutans and co. (including the massive Gigantopithecus blacki) and the rest of the world with one species in particular...
What about us?
One genus that did stay in Africa to begin with though. Around 4.2 million years ago a genus known as Australopithecus inhabited much of East and South Africa. This particular genus was especially smart and were actually documented as using stone tools. Around 3 million years ago, Australopithecus gave rise to a certain genus named Homo, a genus more commonly referred to as 'humans'.
Our particular species of Homo is called Homo sapiens, but, believe it or not, there used to be lots of different species around the globe. The include such characters as Homo neanderthalensis (neanderthals), Homo floresiensis (real life hobbits), Homo erectus (don't laugh) and the earliest known species, Homo habilis.
Australopithecus eventually went extinct around 1.9 million years ago and the various species of humans soon followed suit. The species Homo sapiens were different though, having evolved around 300,000 years ago in Africa. As to where we'll go next? Who knows...
Until next time!