The key driving forces in giraffe evolution have been revealed by fossils of a strange giraffoid.
The study was published in a journal.
The evolution of the giraffe's neck has been a mystery for years. Scientists never believed that high foliage was the reason for giraffe neck extension.
The long neck of giraffes may be the key to the giraffe evolutionary mystery as scientists realized that the long neck is used as a weapon in male courting.
The giraffes use their long swinging neck to hurl their heavy skulls against the weak parts of their competitors. The longer the neck, the more damage it causes.
IVPP researchers and their partners studied a giraffoid. Understanding how the giraffe's long neck evolved is one of the things this research contributes to. The neck size of male giraffes is related to social hierarchy and the evolution of long necks can be traced back to competition.
The fossils were found on the north side of the Junggar Basin. There was a full skull and four neck bones.
The development of a large ossicone in the middle of the mammal's head was one of the unique characteristics. The fossil's name was given due to the resemblance of the single ossicone to the one-horned creature from Chinese mythology.
The researchers said that the Discokeryx xiezhi have the most complex joints between the neck and head of any mammal. The team demonstrated that the skull and spine of Discokeryx xiezhi were adapted to high-speed head to head impacts. The structure was far more effective than other animals that are adapted to head impact. The best adapted to head impact might have been Discokeryx xiezhi.
The living giraffes and Discokeryx xiezhi are part of a super family. Wang Shiqi, the first author of the study, said that both the skull and neck have evolved in an extreme direction.
Several groups of ruminants were compared by the research team. They found that horn diversity in giraffes is much greater than in other groups, with a tendency towards extreme differences in morphology, thus indicating that courtship struggles are more intense in giraffes than in other ruminants.
The research team looked at the ecology and the niche it occupied. The Tibetan Plateau to the south was blocking the transfer of water vapor because the Earth was in a warm period.
According to MENG Jin, one of the authors of the study, discokeryx xiezhi was living in open grassland and may have migrated. The grassland environment was not as comfortable for animals as the forest environment. The environment may have been a factor in the violent fighting behavior of Discokeryx.
There was a similar environment at the time of the emergence of the new genera. The ancestors of giraffes had to adapt to changes in the environment around 7 million years ago. It is possible that giraffes developed a way of attacking their competitors by swinging their heads and necks. The giraffe's neck was shortened over a period of 2 million years as a result of this extreme struggle.
The niche of feeding on high foliage was well suited for Giraffa. Their ecological status was not as secure as that of other animals. As a result, the marginal ecological niche may have promoted certain types of courting.
More information: Shi-Qi Wang et al, Sexual selection promotes giraffoid head-neck evolution and ecological adaptation, Science (2022). DOI: 10.1126/science.abl8316. www.science.org/doi/10.1126/science.abl8316
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