A 7-million-year-old fossil of an animal with a shorter neck than that of a modern-day giraffe holds evidence that the giraffe’s iconic neck evolved in stages, and lengthened over time, according to a new research.
Researchers call the fossil discovered in 1888 a ‘transitional’ fossil, which actually closes a gap in the evolution of giraffes, and it provides proof of how the animal evolved from one stage and into the other.
Nikos Solounias, lead researcher of the study and a professor of anatomy at the New York Institute of Technology (NYIT) College of Osteopathic Medicine, said that the animal’s neck has an intermediate length, meaning that it is in fact one of the missing links between giraffes and okapis.
According to Solounias, the fossils belong to the Samotherium major, an extinct genus of giraffe that lived during the Late Miocene in forested areas ranging from what is modern-day Italy to modern-day China. The Miocene (meaning “less recent”) is a geological epoch that extends from about 23.03 to 5.332 million years ago.
When the researchers first discovered the Samotherium major fossils, they did not give it much importance, until much later. As he was working on his doctoral thesis, Solounias first saw the fossils in Germany in the 1970s.
Solounias said that the neck bones of the Samotherium major were shorter than those of modern-day giraffes, but longer than the bones of the okapi (Okapia johnstoni) – which is the animal most closely related to the giraffe.
This year, Solounias and his colleagues looked at the neck bones of four Samotherium major, three okapis, and three giraffes (Giraffa camelopardalis). They found that on average, the necks of giraffes were 6.5 feet long (about 2 metres), compared with the necks of okapis that were about 1.9 feet long (60 centimetres), and the necks of Samotherium major which extended about 3.2 feet (one metre).
Judging by the results, it is clear that the length of the Samotherium major neck is somewhere between the length of the giraffe necks and the okapi necks. Researchers say that the angles and shape of the Samotherium major neck bones are also intermediate.
Melinda Danowitz, study first author and a medical student at the NYIT College of Osteopathic Medicine, said that Samotherium major is completely between the two other living species.
The researchers also found that Samotherium major held its head vertically much like a giraffe, and not horizontally, like a cow does.
However, it is important to note that the Samotherium major is not a direct ancestor of the giraffe, but rather a near direct ancestor, according to Solounias.
Donald Prothero, a research associate in vertebrate palaeontology at the Natural History Museum of Los Angeles County said that the discovery is very important because it proves once again that an animal does in fact evolve from another.
The findings were published November 25 in the journal Royal Society Open Science.