A taxonomic study of millipede genera, Orangutana Golovatch, 1996 and Gigantomorpha Jeekel, 1963 (Diplopoda, Polydesmida, Paradoxosomatidae), with description of four new species from Sabah, Borneo, East Malaysia

This taxonomic study focuses on the millipede genera, Gigantomorpha Jeekel, 1963, and Orangutana Golovatch, 1996, both in the family Paradoxosomatidae. The present investigation focuses on specimens collected in Sabah, Malaysian Borneo, a region known for its remarkable biodiversity. Two new species are described from the Crocker Range Park: Gigantomorpha alabensis Ng & Likhitrakarn sp. nov., and Orangutana koropungoi Ng & Likhitrakarn sp. nov. Another two new species come from the Kinabalu Park: Gigantomorpha sayapensis Ng & Likhitrakarn sp. nov. and Gigantomorpha mesilauensis Ng & Likhitrakarn sp. nov. Their descriptions highlight the neglected, yet vibrant millipede diversity in Sabah. The statuses of both Gigantomorpha and Orangutana are mentioned, their distribution map is presented, and an identification key to all species of Gigantomorpha is given.