(Below are details from the Kamakoti peetam website Kamakoti.org acharya parampara)
Sri Sivanandendra Chidghanendra Saraswati : He was a Karnataka Brahmin and the son of one Ujjvala Bhatta. His poorvasrama name was Iswara Vatu. His predilections were towards Sivaadvaita. He attained mukti at Vrjddhachala on Sukla Dasami in the month of Jyestha of the cyclic year Virodhikrit (172 AD).
The pic below is a carving from one of the pillars which I believe depicts the acharya .
A new pic of the adhishtanam which I re visited last Sunday