This is on Mesa's pilot recruitment page.
Captain Seniority Hire Date By Crew Base:
DFW: January 19, 2018
IAD: June 15, 2018
IAH: April 13, 2018
PHX: July 21, 2017
SDF: April 27, 2018
So the most junior CA at IAH has less than a year at Mesa, and is an E175 CA?