The Wondiwoi tree-kangaroo is a mammal species in the genus Dendrolagus. It was known until recently from a single specimen which was collected in 1928. The only known specimen is a male weighing. D. mayri was located in the Wondiwoi Peninsula of West Papua at an elevation of within montane forest. It is thought that the Wondiwoi tree-kangaroo could occupy an area of. Global Wildlife Conservation, the wildlife conservation charity, lists the Wondiwoi Tree Kangaroo as one of their "25 Most Wanted Lost Species".
In July 2018, what may prove to be the first ever photographs of the species were taken by British naturalist Michael Smith. Smith was investigating Vireya rhododendrons in an unexplored area of the Wondiwoi ranges and photographed a 'dorianus type' tree kangaroo at an altitude of approximately 1,600 metres. Scent marks, tree kangaroo scat and claw marks at the base of trees made by climbing tree kangaroos were found from 1,700m to 2,000m in steep montane forest. Local hunters, who frequently kill Grizzled tree kangaroos in lowland forest, rarely if ever visit the forest above 1,500m because of the difficult terrain, lack of water sources and dense bamboo thickets. Australian zoologist and conservationist Tim Flannery, who described four species or subspecies of tree kangaroo including the Dingiso, was reported as saying "Everything in the pictures is consistent with the only known specimen. It is an extremely significant find, the least known of tree roos and almost the most poorly known macropodid. To find it existing in good numbers in 2018 is astonishing." "I was amazed when I saw the photos. I had spoken to Ernst Mayr, the collector of the only previously known specimen, but could get little additional information. I believe it has gone unspotted for so long because it's restricted to a single, small mountain range."
Status
Long thought to be extinct or critically endangered, the IUCN Red List listed the species as Critically Endangered because "if the species still exists the population must be very small and probably in decline due to hunting pressures. Although the area has not been well-sampled, there have been a few visits to the area with no reports of this species." In 2018, a British amateur botanist photographed what is believed to be a living specimen of the Windiwoi tree-kangaroo in the mountains of New Guinea. The species status of Dendrolagus mayri is uncertain. Some authorities refer to all 'dorianus type' tree kangaroos as subspecies of Doria's tree kangaroo, including Colin Groves, who published a major revision of the taxonomy of the genus in 1982. More recent DNA analysis indicates, however, that the members of the dorianus group deserve species status, although Dendrolagus mayri itself was not included in the study.
