Somers released an open letter on Friday, the same day as the four prospective directors sent a letter to shareholders, in which he described them as "fanatics" and stated that the minutes from the last two years showed recent boards had been "totally unfit".
That was perceived as a dig at one of the four, Malcolm Murray, who was chairman until May and left the board in July following a fractious relationship with the Charles Green consortium which took control in June 2012.
Somers claimed under-fire finance director Brian Stockbridge deserved gratitude for "holding things together" and denied claims about the pay of public relations contractor Jack Irvine.
A statement from the four, who include former oldco Rangers director Paul Murray plus Scott Murdoch and Alex Wilson, read: "He started by making great play of having never heard of Charles Green, Imran Ahmad nor Craig Whyte.
"You would have thought that a man who made a big deal of having been to big European nights at Ibrox, would at least have had a passing knowledge of central characters in our club's recent history.
"He then talked of having read board meeting minutes from the last two years which show a 'lack of professionalism and worse' and concluded that the boards have been 'unfit'. We agree with him and that is why we have been campaigning for change.
"He went on to say that it was a 'mystery' to him that members of these boards should be put up for re-election but yet he has two such members on his board at the moment.
"Is he now recommending to shareholders that they should vote against Brian Stockbridge and James Easdale?"
The statement added: "If he had taken time to read the minutes properly he would have noted that Paul Murray was not even on the board over the time period he refers to and he would also note that Malcolm Murray and Phil Cartmell, two of the non-executives, were voted off the board for challenging the lack of corporate governance and financial transparency in the club.
"It is not entirely surprising to us that Mr Somers seems to be a bit vague on the detail on the basis that this is the same man who when we asked him how he had come about being appointed said that 'he couldn't really remember'.
"Mr Somers then went on to defend Brian Stockbridge and Jack Irvine.
"In the same breath he talked about improving communication with the fans. What a ludicrous statement.
"As the chairman of the club he has had many opportunities to engage with his customers over the last month and he has chosen not to.
"Had he taken the time to listen and engage rather than adopt a siege mentality he would have quickly found out that the fans want truth and transparency not spin and bluster. They also want the removal of Brian Stockbridge and Jack Irvine.
"Mr Somers finished his rant by describing our group as 'fanatics'. If a fanatic is someone who, for no personal gain, stands up for his club's interests after two years of some of the worst corporate behaviour in modern history then we plead guilty as charged."
The statement challenged Somers to prove he is "truly independent" by disclosing who is behind the Blue Pitch and Margarita shareholdings; get his board to commit to pledges they made in their 'Rangers Constitution'; stop "defending the indefensible with Brian Stockbridge and Jack Irvine"; be "transparent" on his appointment; and to meet the fans and explain his vision.
The statement finished: "If you do that then people will start believing that you are independent. Until then it is just words."
The Rangers Supporters Trust also issued a challenge to Somers.
A statement read: "The comments from the chairman are deeply troubling and we call for an urgent meeting so that he can acquaint himself with the reality of the feelings of the support. We cannot run a club by press releases written by highly-paid spin doctors.
"In the current dire financial predicament the club finds itself in, the job of an impartial chairman should be to consider the views of the vast swathes of shareholders who have not been impressed by the performance of the company; and the concerns of the supporters who fund the club.
"We are disappointed that Mr Somers has not yet seen fit to meet with representatives of the support and we feel it is imperative that such a meeting takes place before the AGM."
The board will be decided at the annual general meeting on December 19, when accounts which showed a £14.4million operating loss in the first 13 months of trading will be discussed.