The scan results confirmed the presence of four giraffe species, consistent with previous genetic analysis. (Photo credit: Murat Özgür Güvendik/Anadolu, Getty Images)
When paleontologist and zoologist Nikolaos Kargopoulos embarked on a research project two years ago to analyze the morphology of giraffe skulls, he believed that “giraffes are just giraffes.”
Kargopoulos traveled the world to 3D scan a huge dataset of giraffe skulls (515 to be exact) from African national parks, game farms, taxidermists, and museum collections.
“We didn't expect there to be such a clear difference in the shape of giraffe skulls. Before we took a closer look, we thought giraffes were just giraffes,” said Postdoctoral Researcher at the University of Cape Town (UCT). According to the Giraffe Conservation Foundation.
Kargopoulos is the lead author of the new UCT-led study, which further confirms that there are four distinct species of giraffes through the shape of their skulls. It was published in a magazine, pro swanDecember.
Nearly a decade ago, scientists discovered four species of giraffes, instead of just one as previously thought, based on genetics. Masai, northern giraffe, reticulated giraffe, and southern giraffe.
There were many theories about the differences in giraffe appearance, but it wasn't until UCT and the Giraffe Conservation Foundation launched a research project in collaboration with Spain's Autonomous University of Madrid, other European universities, and a number of partners from African governments that they analyzed this. There were no studies that did so.
The study's authors were not surprised that the study, using 3D geometric morphometric analysis, revealed distinct differences between male and female giraffe skulls.
Unexpectedly, the results confirmed the existence of four giraffe species, consistent with previous genetic analysis. The four species have different cranial morphologies, mainly related to the osseous bones (bone protrusions of the head).
The problem with giraffe skulls, Kargopoulos noted, is that because of their size, museums rarely have space to house more than five to 10 giraffe skulls.
“This meant that to collect as much data as possible, we had to work together and sample everything we could. At the end of the sampling, we had 515 skulls from 39 different sources. This required very efficient scheduling and a lot of coordination, given that we were able to scan.”
With only 117,000 giraffes left in the wild in Africa, the study's findings are crucial in “finally shedding light on the silent extinction of these gentle giants,” the authors said. said.
The world's tallest mammals are found in many countries in sub-Saharan Africa, but not all species are equally common, “as a result, some species are more common than others. are also in urgent need of protection,” Kargopoulos said.
“For example, there are fewer than 6,000 northern giraffes left in the wild, living in rather 'challenged' regions such as central and west Africa, while southern giraffes are relatively abundant, with around 50,000 individuals left in southern African countries. It lives near the head. Often under better protective management.
“Now that we know there are many different species of giraffes, it's become clear that some require much more urgent action than others.”
He said that while the International Union for Conservation of Nature (IUCN), the world authority on the state of the natural world, is “not an expert in taxonomy”, many people continue to look to it for guidance.
“The main issue impacting giraffe conservation is the fact that the IUCN has not yet formally classified giraffes into four species… but we are optimistic that this will change soon.”
Regulations and measures would then be applied individually to each giraffe species, allowing targeted conservation strategies to be applied.
Julian Fennessy, conservation officer at the Giraffe Conservation Foundation and co-author of the study, said in a statement: I confirmed this. It's time for the world, especially the IUCN, to stand up for giraffes and change the outdated giraffe taxonomy that some still cling to. ”
Conservation efforts need to target all four species, especially those with precariously low numbers, before it's too late, Fennessy added. “Science is science and facts are facts. We hope that any debate surrounding giraffe taxonomy will finally die down.”
The team's sampling involved acquiring a 3D model of the skull, which was performed using a 3D scanner and, in some cases, a CT scanner. Kargopoulos added that the research's original promoter, the Giraffe Conservation Foundation, saw the value and purchased such a scanner.
Geometric morphometrics is used to compare shapes. “We placed certain landmarks on the 3D object to compare the skulls. [using specialised software] When combined, the overall shape of the skull was recreated. ”
The software determines the coordinates (3D distance from the skull's centroid) of these landmarks and uses statistical tools to compare their exact locations across all skulls.
“Ultimately, we will be able to learn whether landmark locations differ between defined groups, such as sex, species, or age class.”
Geometric morphometrics has been used in biology for decades, but recently sampling and analysis tools have developed to a considerable extent, allowing complex tests that were previously impossible, Kargopoulos says. he pointed out.
There are many variations in giraffe skulls, especially the strong bones.
“If we dig deeper into the analysis, we find that there are small differences in many areas of the skull, such as the eye sockets, rostrum, and the back of the skull. However, the most striking differences between the four species are in the eyes, especially in the male. It is seen in the development of the central bony bone above.
There appears to be a clear tendency in the development of this osichone to follow geography and taxonomy.
“As you move from south to north, this oscicon gradually gets bigger.
“The two extreme giraffes are the southern giraffe, whose oscicone is essentially a wispy hill, and the northern giraffe, whose oscicone is very tall and pointy. The Masai giraffe and the reticulated giraffe occupy an intermediate position. Masu.”
The giraffe oscicon is important because it influences reproductive selection and thus evolution. Males with more developed bone bones look more intimidating and are more likely to win in a hand-to-hand fight between males, Kargopoulos said.
“Thus, not only are they more successful in claiming territory, but they are also more successful in their mating efforts with females. In this framework, the shape of the oscicone is an important aspect of giraffe anatomy. and influence the life and evolution of giraffes.”
The authors of this study are preparing additional scientific papers based on the data. “It's interesting how much you can learn just by looking at a skull,” he says.
