Bertha is a female Kentrosaurus that was one of the main character in season 2.
Bertha first appeared in the first episode of season 2 as the prey of the Dilophosaurus, Silas. However Silas lost the element of surprise and retreated into the brush, leaving Bertha in peace to continue her feeding. She made her final appearance in episode 11 of season 2 where she was brought down by Silas, Delta, and Dongi.
(To be added)