The Annals of the Four Masters record Maelsechlainn with this terse entry: "Maelseachlainn, son of Tadhg, son of Maelruanaidh, lord of Magh-Luirg, was slain by the men of Breifne and Tighearnan Ua Ruairc."
References
"Mac Dermot of Moylurg: The Story of a Connacht Family", Dermot Mac Dermot, 1996.