he assigned to Archaeoindris belonged to a juvenile. Although some later authors considered Lemuridotherium a synonym of Archaeoindris, it was not until 1988 that Martine Vuillaume-Randriamanantena provided a definitive proof. Vuillaume-Randriamanantena also established associations between the postcrania and crania of Archaeoindris, summarized what is known about the postcranial skeleton, and documented the strong similarity with the genus Palaeopropithecus. Anatomy and physiology Though similar to Palaeopropithecus, Archaeoindris was significantly larger and more robust. Archaeoindris was one of the largest primates to ever evolve, and was the largest-known strepsirrhine primate, weighing an estimated . It was roughly the size of an adult male gorilla, which was first noted by Lamberton. Since its discovery, size estimates have varied from "larger than a human" to "possibly the largest primate ever". In a study by Jungers from 1990, the area of its molar teeth predicted a mass of , while the femoral head diameter predicted a mass of . In 1995, Laurie Godfrey estimated a mass of using the midshaft circumferences of the humerus and femur. Based on multiple regressions of the cortical area of the femur in 2008, Jungers and colleagues generated the current best estimate of with a possible range of . These estimates were considered to be more accurate since the harder cortical bone in the midshaft of the femur supported an animal's weight, and its thickness better correlated with the animal's mass than the midshaft diameter (which includes both hard cortex and spongy bone). The only fossil primate that was probably larger than Archaeoindris was Gigantopithecus blacki, a close relative of orangutans. Like all three species of Palaeopropithecus, Archaeoindris exhibited derived traits not seen in the two other less specialized genera of sloth lemur. These traits included deflated auditory bullae and paired protrusions of bone around the nasal opening consisting of part of the premaxilla and the nasal bones. Its skull was wider than that of Megaladapis, but shorter, measuring . Its face was shorter than that of Palaeopropithecus, with its eyes directed further forward. The neurocranium (braincase) was small and elevated relative to the face, unlike Palaeopropithecus. Postorbital constriction (narrowing of the skull behind the eye sockets) is pronounced. The skull also bore a low, broad sagittal crest (a ridge of bone on the top of the skull to which jaw muscles attach) and robust but smaller nuchal crests (ridges of bone on the back of the skull to which