Thanks. Guy....You're right-- the correct term is senatores pedarii (I read a note somewhere calling them "walking senators" which I then translated literally but incorrectly as senatores ambulantes).
There's at least two theories on the term-- curile senators (those who held high office) who arrived by cart (carrus) and sat in curile chairs vs the pedarii who arrived on foot...or from the fact that pedarii never got to speak but merely expressed support of the speaker by walking to his side. https://www.perseus.tufts.edu/hopper/text?doc=Perseus:text:2007.01.0072:book=3:chapter=18&highlight=pedarii
Another interesting treatment of the Senate during the Republic https://youtu.be/QcWqu0Ifxjc?si=bT4glKAbINhePaGa