Hulitherium
Hulitherium tomasetti is an extinct zygomaturine marsupial that lived in New Guinea during the Pleistocene. The species name honours Berard Tomasetti, a Catholic priest in Papua New Guinea, who brought the fossils to the attention of experts.
Discovery
While excavating a bank to widen the Pureni Mission airstrip in Wabag, New Guinea, to comply with new regulations, the Huli workers unearthed fossils in 1967. They reportedly were frightened by their discovery as bones in their culture are associated with the ancestors, so the material was somewhat damaged by their inquisitive prodding until they were brought to the attention of Father Bernard Tomasetti, who recognized the significance. Geologists Paul Williams and Michael Plane subsequently headed field expeditions in the area beginning in 1969 in search of more remains.Among the material was the partial skeleton of a diprotodontid, catalogue number CPC 25718, comprising: a well-preserved skull, several detached teeth, a fragment of the mandible, some cervical vertebrae, an almost complete humerus, and some fragments from a femur and tibia. In 1986, mammalogist Tim Flannery and Plane described it as Hulitherium tomasetti, the generic name honouring the indigenous Huli people for discovering the creature, and specific name Father Tomasetti who ensured it was brought to scientific eyes.
A log discovered in the same bed as the holotype was carbon dated to roughly 38,600 ± 2,500 years ago. The Pureni site is a marine limestone sequence stretching from the Late Oligocene to the Pliocene, until it was filled in by lava about 850,000 years ago by Mount Iumu during the Middle Pleistocene. Infrequent volcanism in the area continued from Mount Rentoul, Mount Sisa, and Doma Peaks. The most recent deposits dating to the Holocene consist of peat, clay, and ash.
Anatomy
In either half of the upper jaw, Hulitherium has three incisors, no canines, one premolar, and five molars. As for the lower jaw, it is only known that it has a premolar and five molars on either side. The first incisor was the largest, and the second the smallest. Hulitherium has an unusually high-arched palate. The snout is quite narrow and has an almost-oval-shaped cross-section. The frontal bone juts up suddenly from the snout, and there is a depression on its midline. The eye sockets are placed fairly low on the skull, about above the P3 socket. There is a weak sagittal crest running along the midline of the braincase. The pterygoid bones were probably enlarged.The atlas is somewhat more reinforced than might be expected for its skull size, though the occipital condyles are unusually short relative to other marsupials. Another cervical vertebral centrum was preserved, measuring only, which may indicate Hulitherium had a short neck.
The only elements of the forelimb known are a single right humerus and a poorly preserved distal radial fragment. The proximal humerus as 180° of articulating surface in the anteroposterior direction, indicating considerable mobility especially in that direction. Its middle portion is remarkably narrow, only at its smallest laterally and at its smallest anteroposteriorly. The two condyles of the humerus at the elbow joint also have 180° of articular surfacing, much like in kangaroos rather than other diprotodontids.
The elements of the hindlimb known are a single left femur, a gracile right tibia, and what is probably a fibular fragment. Unusually for diprotodontids, the femoral neck is greatly reduced, so that the femoral head lies directly on top of the femoral shaft and sticks out of the femur quite pronouncedly, which may have enhanced the mobility of the hip.