Wikipedia
Pattamkattiyar or Pattangkattiar is a small caste in the Tirunelveli and Tuticorin district of Tamil Nadu, India. They are called Katesar Pattamkattiyars of Tirunelveli and they are not a subcaste but a caste itself duly approved by government of India.
They have seven sub-divisions known as Keelai. People in the same Kelai do not get married.
In the Pattamkattiyar society, the maternal uncle's responsibility is more than the parents' responsibility.
Some of the Pattamkattiyars of Tirunelveli, Ramanad and Tuticorin were converted by St. Francis Xavier and other priests starting from 1536.
Their mangalsutra/thali worn during marriage are similar to Pillai. Their marriage customs find similarity with Brahmins and Pillais. with the passing of time, the Pattamkattiyars separated themselves from rest of the Pandiyan community and they formed an individual caste with their own customs.