By Tsegaye Tadesse

ADDIS ABABA (Reuters) - An Ethiopian opposition party, whose leaders had been charged with treason, has lost the right to use its name after the country's election board decided on Wednesday to give the title to a splinter group.

"A political party led by Ayele Chameso is the sole owner of the Coalition for Unity and Democracy (CUD)," the National Ethiopian Election Board said in a statement.

In July, 37 CUD leaders were pardoned by Prime Minister Meles Zenawi after spending almost two years in a maximum security prison during a treason trial that ended in a conviction.

They had been arrested on charges of inciting their followers to riot after disputed elections in 2005 sparked two bouts of unrest in which 199 people were killed, 800 wounded and 30,000 arrested.

They are now divided into several groups and accuse each other of violating party rules.

"The former opposition leaders came under the CUD umbrella to challenge the dominant ruling party in the 2005 election," said one analyst who declined to be named.

"In the normal sense they are of different disciplines, ideas and programmes, they were never homogenous."

Hailu Shawel, who was chairman of CUD, suspended five top party leaders accusing them of plotting his overthrow.

Ayele's party is a splinter group of the former CUD but has no seat in parliament.

He asked 40 members of parliament who were elected under the CUD banner to join his group, but a spokesman for the group said they did not recognize Ayele's faction and would go to court to regain their old name.

Political analysts say the splinter groups have no option but to revert to party names they used before joining the coalition.