Abas Hussein Abdirahman, 33, was killed in front of a crowd of some 300 people in the port town of Merka.
An official from the al-Shabab group said the woman would be killed after she has had her baby.
Islamist groups run much of southern Somalia, while the UN-backed government only control parts of the capital.
This is the third time Islamists have stoned a person to death for adultery in the past year.
Al-Shabab official Sheikh Suldan Aala Mohamed said Mr Abdirahman had confessed to adultery before an Islamic court.
“He was screaming and blood was pouring from his head during the stoning. After seven minutes he stopped moving,” an eyewitness told the BBC.
The BBC’s Mohammed Olad Hassan in Mogadishu says that if the woman is also killed, her baby would be given to relatives to look after.
Al-Shabab’s concern for the welfare of the child is touching.
The President of Somalia (or, what’s left of it) decried the stoning:
Meanwhile, President Sheikh Sharif Sheikh Ahmed has accused al-Shabab of spoiling the image of Islam by killing people and harassing women.
“Their actions have nothing to do with Islam,” said the moderate Islamist…
Bunk. Just ask the Iranians, who stone women and execute gays as prescribed by sharia law. Just ask the Saudis, who whip rape victims. Just ask the Jordanians, who refused to pass a law against honor killings because it would go against religion. (And they meant Islam, in case you didn’t guess.) It is part and parcel of Islam, as attested by the hadith in the Sahih Buhkari, one of the most revered collections of hadiths in Islam:
Narrated Ibn ‘Abbas:
‘Umar said, “I am afraid that after a long time has passed, people may say, “We do not find the Verses of the Rajam (stoning to death) in the Holy Book,” and consequently they may go astray by leaving an obligation that Allah has revealed. Lo! I confirm that the penalty of Rajam be inflicted on him who commits illegal sexual intercourse, if he is already married and the crime is proved by witnesses or pregnancy or confession.” Sufyan added, “I have memorized this narration in this way.” ‘Umar added, “Surely Allah’s Apostle carried out the penalty of Rajam, and so did we after him.”
(What is a hadith?)
The difference between “moderate” Islamists and full-throated Islamists is one of degree, not kind.
(hat tip: The Jawa Report)