Scimitar-toothed cat

The Scimitar-toothed phenotype is a tooth variant present in saber-toothed cats. Typical genera in the Felidae family include Homotherium or Machairodus. Compared to the usually massively built dirk-toothed phenotype, apparent in Smilodon, Megantereon and Barbourofelis (just to list a few). Their upper canines were smaller than those of equally sized cats that had the dirk-tooth phenotype, but they had serrated edges.[1][2] The scimitar-toothed phenotype is not a taxonomic group and has evolved in many different families across mammals.

Uses
This tooth form was used to assist in the hunting of herbivorous megafauna. With its hyper sharp and serrated form it was perfect for ripping flesh off of downed prey. Sadly if this tooth would come into contact with bone it could get caught, serrations worn off, or even completely broken thus leaving the organism without a food source, leading to starvation and death.

Evolution
There is a large debate going on about how both the scimitar-tooth and the dirk-tooth evolved in felines and other mammals. the two sides of the debate revolve around whether it was derived from a sexual dimorphic trait or if it was completely natural selection that drove the creation of these phenotypes. The argument for sexual dimorphic origins stems from the fact that in mammals sexual dimorphic traits manifest as tools for males to compete for females. It is believed that the scimitar-tooth and the dirk-tooth were originally only in males for use in competition but then with the rise of mega-herbivores it became favorable for females to take up the trait as well. [6] The natural selection side of the debate argues that the scimitar and dirk-tooth both evolved because of the unfilled niche of predation of mega-herbivores so the trait evolved to take advantage of said niche. There still needs to be a lot more research before this debate is settled.