This is an endangered species of sifaka, one of the lemurs endemic to certain rainforests in eastern Madagascar.
This species is one of the world's largest living lemurs, with a total adult length of ~105 cm (41 in.), half of which is tail.
Russell Mittermeier, one of the contemporary authorities on lemurs, describes the diademed sifaka as "one of the most colorful and attractive of all the lemurs", having a long and silky coat.
P. diadema is also known by the Malagasy names simpona, simpony and ankomba joby.
The term "diademed sifaka" is also used as a group species designation formerly encompassing four distinct subspecies.
Reference: Wikipedia