Wikipedia
Pachylemur is an extinct, giant lemur most closely related to the ruffed lemurs of genus Varecia. Two species are known, Pachylemur insignis and Pachylemur jullyi, although there is some doubt as to whether or not they may actually be the same species. Pachylemur is sometimes referred to as the giant ruffed lemur, because although it and the living ruffed lemurs had similar teeth and skeletons, Pachylemur was more robust and as much as three to four times larger. DNA studies have confirmed a sister group relationship between these two types of lemur. Like living ruffed lemurs, Pachylemur specialized in eating fruit, and was therefore an important seed disperser, possibly for tree species with seeds too large for even ruffed lemurs to swallow. In the spiny thickets of southwestern Madagascar, they were also likely to have dispersed seeds evolved to attach to fur and be carried away. Unlike ruffed lemurs, the fore- and hindlimbs of Pachylemur were nearly the same length, and therefore it was likely to be a slow, deliberate climber. However, both used hindlimb suspension to reach fruit on small branches below them.
Like other lemurs, Pachylemur was only found on the island of Madagascar, and its subfossil remains have been found primarily at sites in the central and southwestern parts of the island. Fragmentary and indeterminate remains have also been found in northern Madagascar. Pachylemur once lived in diverse lemur communities within its range, but in many of these locations, 20% or fewer of the original lemur species remain. Pachylemur went into decline following the arrival of humans in Madagascar around 350 BCE. Habitat loss, forest fragmentation, and bushmeat hunting are thought to have been the reasons for its disappearance. Pachylemur is thought to have gone extinct between 680–960 CE, although subfossil remains found in a cave pit in southwestern Madagascar may indicate that it survived up until 500 years ago.
Pachylemur remains were first described in 1895 by French zoologist Henri Filhol and were originally included in the genus Lemur, along with the ring-tailed lemur and other close relatives currently classified within the family Lemuridae. In 1948, French paleontologist Charles Lamberton placed the species in the subgenus Pachylemur, which was recognized as a genus by 1979. However, due to earlier uses of the name Pachylemur, the priority of an alternative genus name proposed by Guillaume Grandidier in 1905, and errors in Lamberton's 1948 description of the genus, the availability of the name under the rules of zoological nomenclature was considered questionable. In 2011, a petition was filed with the International Commission on Zoological Nomenclature to preserve the name.