Police say Abdirahman Shirwac Aw-Saciid, head of the groups assassination squad, surrendered to authorities.
Despite facing a catastrophic combination of flooding and conflict, there is optimism in the African country - as climate editor Justin Rowlatt discovers.
Ethiopia agreed to lease 20km (12 miles) of coastline from Somaliland in exchange for recognition of its independence.
Three soldiers and five prisoners killed after armed inmates made an attempt to escape, says Somali army spokesperson.
More than 60 wounded in attack on popular seaside spot frequented by Somalis on weekends.
President Hassan Sheikh Mohamud has called a meeting of regional leaders.
Rift comes after Somaliland deal giving landlocked Ethiopia access to the Red Sea.
Mogadishu also shuts down Addis Ababas consulates in Hargeisa, capital of the Somaliland, and Garowe in Puntland.
MV Abdullah was sailing from Mozambiques capital Maputo to the United Arab Emirates when it was attacked.
The armed group considers the United Arab Emirates an enemy for its backing of the Somali government.