From “Lone Star Regiments in Gray” by Ralph Wooster:

1st Texas Cavalry, Arizona Brigade:
“On Feb 21, 1863, Marauder ordered that 3 regiments be formed from the small, incomplete battalions. He authorized...Baird ...to organize a 4th...”

The 1st regiment of the Arizona brigade, commanded by Col Peter Hardeman, ....was ordered to North Texas...later assigned to Gano’s brigade....”

...a small Texas brigade that arrived in Indian Terr. In autumn of 1863. ...consisting of the 30th Texas...the 1st Texas Cavalry, Arizona Brigade, commanded by Col Peter Hardeman....was originally under the direction of ..Bankhead.... Just prior to the brigade’s assignment to Indian Territory, Bankhead was replaced by ..Gano.

...{previous to above]..Peter Hardeman was promoted to Colonel and regimental command, Edward Riordan was made Lt Col, and Michael Looscan became mMjor. [footnote says: “The 1st Cavalry, Arizona Brigade was sometimes referred to as the 31st Texas Cavalry” and cites Sifakis, and also New Handbook of Texas.]

...The Cabin Creek raid was the last large operation of Gano's brigade...Gano, whose left arm was shattered...at Cabin Creek, left the brigade...Command of the unit...passed to Edward Gurley of the 30th Texas, who was the senior colonel. When Gurley received a leave...Peter Hardeman assumed temporary command." [footnote cites: "Suffering to Silence" and "Official Records 52, 1029-30."]

31st Texas Cavalry-T.C. Hawpe
“..22nd and 34th regiments were joined at Ft. Smith by the 31st...”[1862]
Hawpe was the organizer and colonel of the regiment, G.W. Guess...named Lt Col, and F.J. Malone was chosen Major....

From “Texas In The War” edited by Harold Simpson from an original compilation by Gen Marcus Wright:

“1st Cavalry Regiment, Arizona Brigade-
Wm P Hardeman Col
Peter Hardeman, Lt Col, Colonel
Edward Riordan, Lt Col

Alexander Terrell, Major [note says: “After the firing on Ft Sumpter, Terrell was appointed a major in the 1st Texas Cavalry regiment, Arizona Brigade. He then served as Lt Col of his own cavalry battalion and later Colonel of his own regiment, sometimes referred to incorrectly as the 34th Texas Cavalry Regiment.”]

Michael Looscan, Major [footnote says: ...”During the early part of the conflict, he served as a major with the 31st Texas cavalry Regiment. Later he served as adj gen on the staff of John R. Baylor and then IG on the staff of Gen Maxey...”

31st Texas Cavalry Regiment [Dismounted]
Col Hawpe
Lt Col Guess
Major Malone
Major Peak
and in parenthesis [Major Looscan]”

Perhaps, while Looscan served on the staff of General Maxey, he may have been temporarily assigned to act in command of the 1st Texas, Arizona Brigade with his staff rank of Major. Prior to that, it appears he had briefly served as Major of Hawpe’s 31st Texas..

And speculating once again, this common thread of Looscan with these 2 separate regiments, just might account for the sometimes misrepresentation of the 1st Texas Cavalry, Arizona Brigade as the 31st Texas.

But, I don’t see how it was ever possible for these 2 separate regiments to have ever been consolidated, or even serving together. Only in the last few weeks of the war did they come near to serving together, and then most likely only on paper. This was during the wholesale dismounting of cavalry regiments and the formation of new infantry brigades and a new division as a result. For those few weeks, they may have been assigned to the same new division of infantry and newly dismounted cavalry regiments.