, has turned herself in to authorities in Scotland and is facing extradition to Spain.
She arrived voluntarily at an Edinburgh police station on Wednesday before being formally arrested.
Spanish authorities have accused her of rebellion and misuse of public funds, and Spain's Supreme Court issued a European arrest warrant for her and a number of separatist leaders.
Ponsati's lawyer, Aamer Anwar, said she views the charges - which carry a maximum penalty of 30 years in jail - as "political persecution".
Former Catalan leader Carles Puigdemont, who faces similar charges, was taken into custody in Germany on Sunday.
Ponsati is a professor at the University of St Andrews in Scotland and fled Spain with Puigdemont after Catalonia's referendum on declaring independence from Spain in November 2017.
She faces an initial extradition hearing at the Edinburgh Sheriff Court later on Wednesday.
The University of St Andrews said it was deeply concerned about Ponsati's potential extradition.
"We believe there are legitimate arguments that Clara is being targeted for standing up for her political beliefs," the university said in a statement.
Scottish First Minister Nicola Sturgeon said her government would cooperate with Madrid, but added it supported the right of the Catalan people to determine their future.
Protests in Catalonia
The Catalan regional administration has been under direct rule by Madrid and news of Puigdemont's arrest sparked demonstrations in Barcelona, which ended in clashes with the police.
About 90 people were slightly injured during the protests, including 22 police officers.
On Tuesday, demonstrators blocked the main roads in Catalonia to protest Puigdemont's arrest and the jailing of nine other separatist leaders in Spain.
The Catalan parliament passed a symbolic motion on Wednesday affirming the right of Puigdemont to be re-elected to his old job.
It approved two resolutions put forward by separatist parties to defend "the political rights" of politicians who are in pre-trial custody or "in exile".
Pro-independence parties used their slim majority to approve the motion and continued their defiance of the central Spanish government.
Puigdemont, detained by German police at the border with Denmark, is currently awaiting his extradition trial.
A German court has ordered him to remain in jail while a decision is pending on an extradition request from Spain. Agencies