Mark, who has been occupant of the seat since the return of democracy in 1999, was finally replaced by Comrade Abba Patrick Moro.
Moro, however, retained the seat for the Peoples Democratic Party.
Mark served as the Senate President in the 6th and 7th Senate but returned to the floor after the PDP lost majority to the opposition APC in 2015.
The retired soldier suffered another heavy blow when an appellate court nullified his election in 2015.
He narrowly escaped defeat to Daniel Onjeh of the All Progressives Congress, APC, during a rerun in February 20, 2016 and has since then remained inactive in the house.
Mark vied for the presidential primary election of his party but only managed to secure 35 votes.
During the electioneering campaign of the PDP in Benue South, he told the people that he was retiring and had anointed the former Minister of Interior to succeed him.
Speaking at a reception organized in his honour on Tuesday in Abuja, Moro promised to consolidate on the ‘good foundation’ laid by his predecessor.
“I told you during my campaigns that I would provide qualitative and quantitative representation, I promise I will never fail you,” he said.
Moro, a former Minister of Interior thanked his constituents for the mandate given to him. He called on everyone to join him to work together for the betterment of the senatorial district and Nigeria at large.
“Please join me, let’s work together for the good of Benue South and Nigeria at large,” Senator Moro added.
