Hominini

The Hominini (hominins) are a group of primates that includes modern humans and their closest living relatives. This group belongs to a larger family called Homininae, which also includes gorillas. Today, the Hominini consist of two genera: Homo, which includes humans, and Pan, which includes chimpanzees and bonobos. Gorillas, while closely related, are classified separately.

The word Hominini was first used by a scientist named Camille Arambourg in 1948. He combined two older groups to create this new classification. Over time, scientists have learned more about how these animals are related through their genes. We now know that humans, chimpanzees, and gorillas share a more recent common ancestor with each other than with orangutans.

Orangutans used to be grouped with chimpanzees and gorillas, but they are now placed in a different family called Hominidae, which includes all the great apes. Gorillas are now considered their own tribe within Homininae. Even with all this research, some scientists still debate the exact groupings. Humans are the only living members of a group called Australopithecine, which also includes many extinct relatives close to humans.

Terminology and definition

Further information: Human taxonomy

The Hominini are a group that includes humans and chimpanzees. Sometimes, scientists talk about them in different ways. One way is to include both humans and chimpanzees in Hominini. Another way is to only include humans and their ancient relatives in Hominini, leaving chimpanzees in a separate group. These different ways of grouping help scientists discuss and study these animals better.

The word "hominin" usually refers to this group, but some scientists use it to mean only humans and their ancient relatives, not chimpanzees. This can make things a bit confusing, but it helps experts talk about specific parts of human and chimpanzee history.

Cladogram

A cladogram is a diagram that shows how different groups of animals are related through their shared ancestors. This particular cladogram focuses on the superfamily Hominoidea, which includes apes and humans. It highlights the Hominini group, which consists of two main types: the Panina, which includes chimpanzees, and the Australopithecina, which includes early human relatives known as australopithecines.

Genetic studies and fossil records tell us that these ape-like ancestors split from Old World monkeys around 25 million years ago. The subfamily Homininae, which includes gorillas and the Hominini, shares a common ancestor that lived about 15 million years ago. One well-known early genus from this time is Sivapithecus, which lived between 12.5 million and 8.5 million years ago and had different teeth and body structures compared to today’s orangutans.

cladogram shows the clade of superfamily Hominoidea and its descendant clades, focused on the division of Hominini (omitting detail on clades not ancestral to Hominini). The family Hominidae ("hominids") comprises the tribes Ponginae (including orangutans), Gorillini (including gorillas) and Hominini, the latter two forming the subfamily of Homininae. Hominini is divided into Panina (chimpanzees) and Australopithecina (australopithecines). The Hominina (humans) are usually held to have emerged within the Australopithecina (which would roughly correspond to the alternative definition of Hominini according to the alternative definition which excludes Pan).

Genetic analysis combined with fossil evidence indicates that hominoids diverged from the Old World monkeys about 25 million years ago (Mya), near the Oligocene-Miocene boundary. The most recent common ancestors (MRCA) of the subfamilies Homininae and Ponginae lived about 15 million years ago. The best-known fossil genus of Ponginae is Sivapithecus, consisting of several species from 12.5 million to 8.5 million years ago. It differs from orangutans in dentition and postcranial morphology. In the following cladogram, the approximate time the clades radiated newer clades is indicated in millions of years ago (Mya).

Evolutionary history

Further information: Chimpanzee–human last common ancestor

Early humans and chimpanzees shared a common ancestor that lived between eight and four million years ago. Scientists have found very few fossils that show direct links to modern chimpanzees. The first fossil chimpanzee was discovered in Kenya in 2005 and is dated to between 545 and 284 thousand years ago.

Humans and chimpanzees share about 99% of their DNA. The earliest members of the human genus, Homo, likely evolved from a group called australopithecines around 4.4 to 3 million years ago. Some fossils, like Orrorin tugenensis from 6.2 million years ago, have led scientists to question this idea. Scientists study fossils to determine if they might be ancestors of humans by checking if they are closely related to humans and could have led to our species.

List of known hominin species

Here is a list of known hominin species, which are early relatives and ancestors of modern humans. Some of these species are still around today, like chimpanzees and us, humans!

• Sahelanthropus tchadensis
• Orrorin tugenensis
• Ardipithecus kadabba
• Ardipithecus ramidus
• Australopithecus anamensis
• Australopithecus afarensis
• Australopithecus deyiremeda
• Australopithecus garhi
• Kenyanthropus platyops
• Australopithecus africanus
• Australopithecus sediba
• Paranthropus aethiopicus
• Paranthropus boisei
• Paranthropus robustus
• Pan troglodytes (extant)
• Pan paniscus (extant)
• Homo habilis
• Homo rudolfensis
• Homo ergaster
• Homo erectus
• Homo antecessor
• Homo heidelbergensis
• Homo naledi
• Homo neanderthalensis
• Homo denisova
• Homo sapiens (extant)
• Homo floresiensis
• Homo luzonensis