The top of the head was a “disk-shaped shield”
thisfossilteeth,China“” In the Xinjiang Uighur Autonomous Region in the northwestJunggar Basin(Junggar Basin) ”was discovered.
The skull, including the teeth, and the four cervical vertebrae (neck bones) that connect to the spine were recovered.
From the analysis of teeth and bones, this creature“Being aliveGiraffeRelatives ofIt turned out to be.
However, it is not a direct ancestor of giraffe, but belongs to another line of giraffids. (By the way, there are only two species of giraffes that are living today, giraffes and okapis.)
The research team gave the scientific name of this organism“Discokeryx xiezhi”I named it.
Disco is a “disk”, Kelix is a “horn”, and Siegy is a Chinese legendary unicorn.XiezhiMeans.
As a result of investigating the shape of teeth and isotopes contained in enamel, D. SiegyIt was an animal that eats grass in open land and changes its habitat depending on the season.It is concluded that.
Also, due to the size of the fossil,Body size is regarding the same as modern sheepWas estimated.
Has the long neck of a giraffe evolved by “breeding competition”?
On the other hand, the top of the head is shaped like a disk-shaped helmet, and the bones of the neck are also very thick and sturdy.
The disk part is the same as the bone component of a head-butting animal such as a bull.Protective layer of “keratin”It was covered with.
This is D. SiegyAdapted to a severe head impact, rival males head-butted each otherIndicates that.
According to the research team, the traits of head-butting between males are selected for sexual reasons surrounding females.
for that reason,D. Siegy’s disc-shaped skull and short, thick neck also evolved in the breeding race for females.I can think of it.
The team thinks this theory also applies to modern giraffes.
In other words, the giraffe’s long neck has evolved because it is advantageous in the collision between males over females.
The predominant hypothesis that has continued since Darwin’s time was that “a long neck was chosen because it is advantageous for getting overhead food.”
Sure, giraffes take advantage of their neck length to eat high-altitude vegetation, but on the other hand.“Necking” where males slam their long necks over femalesThe behavior is known.
For that reason, in recent years, the theory that “the long neck of a giraffe has evolved due to breeding competition” has gradually become influential.
In other words, it is possible that the ancestors of animals called giraffes have a habit of hitting their heads to fight and breed, which has promoted evolution in a direction favorable to this battle, such as the disk-shaped skull and neck length. It is.
And at some point in evolution, it may be the modern giraffe that long-necked males gained the upper hand in the battle for females, and their reproductive success led to the inheritance of longer-necked offspring. ..
Although it is still undecided which is correct with Darwin’s theory, the results of this study by D. Siegy support evolution through reproductive competition.
At the same time, the research team said, “It is quite possible that the giraffe’s extreme neck length was formed by both evolutionary pressures to some extent.”
By further excavating and researching fossils of the giraffid family, it will become clear why modern giraffes look like they are today.
