Just yesterday I read a chapter on Madagascar in Chruchill’s series, The Second World War: The Hinge of Fate.
I don’t know if you can credit this victory to the effectiveness of marines. Chruchill considered the operation a great success because of excellent planning and execution. Using a far superior force against a weak colony composed of Vichy, African natives, and even Frenchmen who disliked Vichy was almost a sure win from the start.
Yes, marines are effective, but they are basically regular troops extensively trained for certain situations.
Any well-trained handful of men could have done the same job given the same circumstances.
I do not want to discredits the marines, but there is no reason why they should be counted separate or special compared to other infantry divisions.