The former principal officer of the House representing Akoko Edo I, Mr. Kabiru Adjoto, was elected as the new Speaker.
Three other members were said to have appended their signatures to increase the number to 19.
The new leadership of the House also said that Okonoboh, his deputy, Mrs. Elizabeth Ativie; and the former Majority Leader, Mr. Foly Ogedengbe, had been suspended for three months.
But Ogedengbe described the impeachment as illegal, adding that the House did not form a quorum.
The House had only reconvened after 26 days of break for oversight functions when the incident occurred.
It was gathered that on the resumption of plenary, Emmanuel Agbaje, read a letter of a vote of no confidence on the floor of the House.
The member representing Etsako West II, Mr. Sylvanus Eruaga, was said to have asked Okonoboh to vacate the exalted seat, a development that led to a fight among some of the lawmakers in the chambers.
Okonoboh was, however, said to have left the seat after much pressure, leaving Eruaga to sit as Speaker pro tempore.
Efforts by another member of the House, Magnus Igbas, to prevent the removal of Okonoboh was said to have been heavily resisted by some of his colleagues, who also descended on him.
It was also learnt that Adjoto was later elected as the new Speaker after he was nominated by Eruaga.
The Assembly workers were locked out while the impeachment lasted.
There was also a heavy presence of security operatives around the premises to prevent a further breakdown of law and order.