The leading trade unionist Richard Leonard emerged as the favoured candidate of the left as a number of other prominent Labour figures ruled themselves out of the contest.
Last night it looked as though the battle for the succession would come down to a two-horse race between Mr Leonard and frontbencher Anas Sarwar, although neither politician had formally declared their intention to stand.
Mr Leonard is a former GMB organiser with strong left-wing credentials, who would command widespread support from trade unionists in the event of a leadership election.
“What’s important is that we get someone that moves the party forward and who’s in tune with the Corbyn agenda,” said one prominent left-winger, who believed union backing could see Mr Leonard get the job.
Mr Sarwar, a former Scottish Labour deputy leader, is the party’s health spokesman and would hope for the support of Labour moderates when the Scottish party chooses its seventh leader in little over a decade.
Speculation that Mr Sarwar would throw his hat into the ring intensified when it was reported on social media that he had met with his fellow front-bencher Jackie Baillie at a Cash and Carry in Glasgow.
Ms Dugdale insisted that her resignation had not been triggered by pressure from Corbyn supporters. However she had been subject to criticism from left wingers within the party prior to her resignation late on Tuesday night.
The Campaign for Socialism (CFS) had claimed Ms Dugdale had held back Labour at the General Election and tacitly turned voters towards the Conservatives.
Yesterday a spokesperson for CFS, which promotes socialism within Labour, said: “The party must now look to the future and towards the exciting and engaging politics that Jeremy Corbyn’s election as UK leader has delivered.
“The radical and transformational manifesto of For the Many, Not the Few offers a blueprint for the kind of socialist politics that can revitalise Scotland and bring people back to Labour who have abandoned us in recent years. To achieve that our next leader must work closely with Jeremy Corbyn and build upon the remarkable gains of the General Election in June.”
Mr Leonard’s name entered the frame after Mr Corbyn’s most prominent Scottish ally Neil Findlay ruled himself out of any contest.
Mr Findlay, a Lothian MSP who ran in a previous Scottish leadership contest and who ran Mr Corbyn’s leadership campaign in Scotland, said he would not be standing.
He said: “I will not be putting put my name forward in this election. I wish Kezia and those who may seek to succeed her the very best for the future.”
Scottish Labour deputy leader Alex Rowley also said he would not be standing, despite many assuming that he would want the job.
The Mid Scotland and Fife MSP, who supported Mr Corbyn for the UK leadership, said the next Labour leader must be ready to replace Nicola Sturgeon as First Minister and he had “no ambition” to step into Ms Dugdale’s shoes.
“Whoever becomes the next leader of the Scottish Labour party should be focussed on ensuring that they become the next First Minister of Scotland - I’m absolutely clear on that and I think we can do that. I’ve no ambition to be the First Minister of Scotland - it’s never something that I saw myself doing.”
Mr Rowley will lead the party until a replacement is found. Pat Rafferty, Unite Scotland regional secretary, said whoever becomes leader must “work in harmony” with Mr Corbyn and backed Mr Rowley’s interim leadership warning against rushing into choosing a successor.
Scottish Labour’s executive committee will meet on Saturday 9 September to consider the timetable and process for selecting their next leader. The voting arrangements adopted in the event of a contest have yet to be decided. But previous elections have been on a one-member-one-vote basis involving paid up members, registered supporters and trade union members.
There was a 30,000-strong electorate when Ms Dugdale won the leadership in 2015.