discussant

plural discussants

1. Someone involved in a discussion, especially a participant in a formal discussion or who has been assigned a particular role or topic.First known use 20th c.

   I would like to thank Cynthia Ruder, whose comments as panel discussant helped me to rework my original paper.

   2005, Julie A. Cassiday, “Kirov and Death in The Great Citizen”, in Slavic Review, volume 64, number 4, page 799n

   1 more example

   The prominence given to readers' responses to topical issues [...] made concrete the sense of belonging to a large, active, and opinionated community of discussants.

   2012, Faramerz Dabhoiwala, The Origins of Sex, Penguin, published 2013, page 319