pura sudama-namasid adya sundara-thakkurah
Sundarananda Thakur was previously one of the twelve Gopals known as Sudama.
(Gaura-ganoddesha-dipika 127)
Sundarananda is counted amongst the branches of Nityananda Prabhu.
Sundarananda is Nityananda’s branch, a true servant. Nityananda joked with him in the Vrindavan mood.
(Chaitanya Charitamrita 1.19.23)
Sundarananda is an ocean of sacred rapture. He is chief amongst the associates of Nityananda Prabhu.
(Chaitanya Bhagavat 3.5.728)
His home was in the village of Maheshpura in Jessore district. Maheshpura stands on the Vetravati River, fourteen miles east of the Majdiya railway station. Only his place of birth remains there at present. 
"I worship Sundarananda Thakur in great hope who made a kadamba flower bloom on a lime tree." (In the image: Kadamba flowers on the liem tree).
His Deities were named Radha-Vallabha and Radha-Ramana. Their priests later moved these Deities to Saidabad and installed a wooden Deity in Maheshpura.
Sundarananda never married and thus has no descendants. Descendants of his disciples continue to maintain the site in Maheshpura. Some relatives of his established a Temple in Mangaladihi in Birbhum district.
Sundarananda possessed great mystic powers. He made kadamba flowers bloom on a lime tree, which he later used in the service of Radha-Ramana, as is stated in the Vaishnava-vandana:
"I worship Sundarananda Thakur in great hope who made a kadamba flower bloom on a lime tree."
On another occasion he dove into a river and pulled a crocodile out. He resembled Nityananda Prabhu in being a savior of the most fallen.
His disappearance took place on the full moon day of Karttik month.
[Excerpted from “Shri Chaitanya: His Life & Associates” by Shrila Bhakti Ballabh Tirtha Maharaj]