He appears to have been chief ollamh of Connacht, and thus presumably that of the Síol Muireadaigh. However, the entry in the Annals of Connacht is somewhat ambiguous:
"It was in this year that the reign of the ollavs Dubshuilech and Dunlang O Mailchonaire came to an end, and Tanaide Mor son of Duinnin son of Nede son of Conaing Buide O Mailchonaire took his seat in the Ollav's Chair of the province of Connacht. In the words [of the poet]: 'Tanaide the teacher, a learned ollav, son of Duinnin, spent forty famous years on the floor of Liss Lerthaile.'"[1]
The possibility therefore exists that Dubsúilech and Dunlang held the post jointly during their lives. Their successor was a son of a previous Ollamh, Dúinnín Ó Maolconaire.
References
General
Annals of Connacht, ed. and tr. A. Martin Freeman (1944). Annála Connacht: The Annals of Connacht (A.D. 1224-1544). Dublin: DIAS. (Edition and translation available from CELT)
Mac Dermot of Moylurg: The Story of a Connacht Family Dermot Mac Dermot, 1996.
A New History of Ireland VIII: A Chronology of Irish History to 1976 - A Companion to Irish History Part I edited by T.W. Moody, F.X. Martin and F.J. Byrne, 1982. ISBN0-19-821744-7
The Celebrated Antiquary Nollaig O Muralie, Maynooth, 1996.
Irish Leaders and Learning Through the Ages Fr. Paul Walsh, 2004. (ed. Nollaig O Muralie).