Dufugan 1st Earl of Angus - Father?

The Wikipedia reference appears to contradict it too:
Dubacan of Angus (Medieval Gaelic: Dubacan mac Indrechtaich) is usually regarded as one of the earliest attested Mormaers. He is mentioned as Dubucan filius Indrechtaig mormair Oengusa (i.e. "Dubucan son of Indrechtach, Mormaer of Angus") in the Chronicle of the Kings of Alba, and it is told that he died along with his lord, Amlaib, son of Caustantín II at the Battle of Brunanburh (c. 937).

There is another Dubacan, called Dufagan comes in a spurious foundation charter for Scone Abbey. The latter has no province name, but he is often called Mormaer or Earl of Angus because he shares the same name as Dubacan son of Indrechtach.

Dubacan is considered a probable ancestor of Gilla Brigte of Angus. It is possible that Dubacan was succeeded by a man called Cuncar, although there is no information about their exact relationship.

https://en.wikipedia.org/wiki/Dubacan_of_Angus

A look at the Unresolved Data Conflicts on this profile, suggest that it's a mash-up of the two men mentioned above.
As 3 of the 4 original profiles were for Dufagan NOT Earl of Angus - I'm going to resolve the data conflicts to reflect that.

I can still find no sources that suggest he is the son of Constantine though.

It seems to me that the presently posited child of this profile: Gille Brigte mac Dufugan, 2nd Earl of Angus - 2nd Earl Of Angus, is more likely to be the child of the 'Dubucan son of Indrechtach, Mormaer of Angus' mentioned above.
I will leave that for the profile's managers to discuss and decide.

Justin Durand has provided a late source that has tradition name Dufugan the son of "Macduff"

Summary of Sibbald, copied from http://www.geni.com/discussions/151727?msg=1058200

1. The 1st Earl is Macduff, who "commanded the king's army against the rebels in Mar, and enjoyed the privilege was granted to him." In an earlier passage Sibbald's editor explains that the holding of a parliament by Malcolm III immediately after his accession rests entirely on the authority of Boeth. The editor thinks it was not properly a parliament, but he says Malcolm III introduced the English title of Thane, which would have been familiar to him because he was educated at the English court. "Hence Duncan Macduff became Thane of Fife, of which he before was chief, (by what title is not known) ...." [Note the name Duncan for Macduff.]

2. The 2nd Earl is Dufagan, Macduff's son, who witnessed Alexander I's charter to Scone: "The name of Dufagan shows him to be the Earl of Fife, 'tho Fife be not mentioned there : for there is no designation of the other Earls there mentioned as assenters, by their province, only their name is set down, and after that Comes." A footnote says, "The genealogists differ about the number and order of the descendants of Macduff, and the individuals from whom different families descended. The editor feels no inclination to enter into these disputes."

3. The 3rd Earl is Constantine, who is mentioned in the charter of Edelrad. Sibbald does not connect him to the earlier earls. He died 1129.

According to the ancestry that was provided to me by my late Aunt who investigated our ancestry Dufagen MacDuff was the father of Constantine MacDuff 3rd Earl of Fife, died 1129. It will take me a while to find my Aunts original paperwork at this time.

I have listed Duncan Mac Duff, Maormor of Fife, born about AD 1000.

Dufagan MacDuff, styled Earl of Fife.

Constantine MacDuff, Styled 3rd Earl of Fife died 1129

Gillimichael MacDuff, 4th Earl of Fife, died 1139

Duncan MacDuff 5th Earl of Fife, Regent of Scotland 1153, died 1154.

Seach MacDuff Founder and first chief of Clan MacIntosh Died 1179

The only improbability is that *he* spelled it "Dufagan". That's a later, and inaccurate, English transcription of the Gaelic "Dubhagan" or "Duibhgenn" (both referring to darkness, probably of hair).

Rather like Duff is a later, and inaccurate English transcription of Dubh.

It seems we need a militia to go door-to-door and make sure all the modern MacDuffs conform to the Gaelic spelling. Then, let's enlist librarians in our cause. They can go through all the copies of Shakespeare and reform his spelling as well. And, we need a time machine so we can go back and teach Dufagan to read and write so we can make him use the proper spelling ;)

:-P

Dufagan mac Indrechtaich, 1st Mórmaer of Angus looks like a duplicate of one of the original mash-up profiles above.
I would suggest that he is this "Dubacan of Angus (Medieval Gaelic: Dubacan mac Indrechtaich) is usually regarded as one of the earliest attested Mormaers. He is mentioned as Dubucan filius Indrechtaig mormair Oengusa (i.e. "Dubucan son of Indrechtach, Mormaer of Angus") in the Chronicle of the Kings of Alba, and it is told that he died along with his lord, Amlaib, son of Caustantín II at the Battle of Brunanburh (c. 937)."https://en.wikipedia.org/wiki/Dubacan_of_Angus

and that, once he's been detached from the Dufagan who is (by 'tradition') Mormaer of Fife, there needs to be some proof that he really is the brother of Gillemichiel, Mormaer of Fife, as he is prsently shown. Jason Scott Wills can you come and take a look and tell us what you think too?

The Gille Míchéil MacDuff, Earl of Fife - above presently shown as 1st Earl of Fife, cannot be that either. Private User can we drag you over here to watch that we untangle in a way that works for you too? :-)

We've got three mysterious entries in the "Book of Deer" relating to a "Mac-Dubbacín" or "Mac-Dobarcon", or two people with very similar names.

"Domnall son of Mac-Dubaicín quenched all the grants in favour of Drostán in return for giving him his goodwill. Cathal quenched his toísech's dues on the same terms, and gave a banquet for a hundred every Christmas and Easter to God and to Drostán. Cainnech son of Mac-Dobarchon and Cathal gave Altrie of the cliff of the birch-tree of the river-bend(?) as far as the birch-tree between the two Altries. Domnall and Cathal gave Ednie to God and to Drostán. Cainnech and Domnall and Cathal quenched all the grants in favour of God and of Drostán from beginning to end, from mormaer and toísech till Doomsday. And the blessing of the Lord on every mormaer and every toísech who shall comply with it, and to their descendants after them."

Precisely how these three men were related is an exercise in speculation, especially since "Cathal", although at one point specified as "toisech", is never provided with a parental or ancestral name.

"Cainnech" may very well be the father of "Gartnait son of Cainnech" in the following section, which would imply that he was mormaer of Buchan prior to Gartnait.

The question remains whether "mac Meic-Dubbacín/mac Meic-Dobarcon" represents a strictly paternal name, or the more generic "descendant of Dubbacín/Dobarcon". In the latter case we may have a succession to the mormaerdom of Buchan: Domnall > Cainnech > Gartnait (> Colbán, see section VI).