The Sharpteeth only appear in Grandpa Longneck's story about why Pterano left the herd, and the grown ups were scared of them. After Grandpa Longneck's story about why Pterano left the herd, they do not appear in the rest of the movie. They are also the only Sharpteeth that appear in The Land Before Time Stone of Cold Fire.It is unkown what gender they are. Although they do not speak, they are voiced by Frank Welker.
It's possible that The Sharpteeth are the tertiary antagonists (although it's unkown if they are, becuase they don't appear much as the other characters in the film).
Just like the other villainous sharpteeth, they are even more dangerous than the other Land Before Time villains (although Chomper is not a villain because he's a friendly sharptooth, his parents reformed, and The Swimming Sharptooth from the fourth movie was a neutral character, and he defeats Dil in the cilmax of the film).