Tree 6 m. Leaves membranous, brittle, (ellipsoid-)oblong, 15-23 by 6-9 cm, base (short) cuneate, apex acute(-acuminate); Inflorescences, male and female flowers not seen. Fruit solitary, ovoid-ellipsoid, 4.5-5 by 3.5 cm, apex ± pointed, hairs dense, mealy, rusty, 0.1 mm;
Asia-Tropical, W Papua Barat present, mountains of northern Bird's Head: Tamrau Range endemic
Malesia: W Papua Barat (endemic to the mountains of northern Bird's Head: Tamrau Range).
Myristica tamrauensis is a species within a group of related species with, e.g., M. brassii, M. duplopunctata, M. millepunctata, M. neglecta, and, more remotely, M. cucullata, all characterized by leaves of medium or large size classes, with blackish dots on the lower leaf surface, and by fruits with a thick pericarp. Myristica tamrauensis is known only in fruit. Mature male flowers are known only from M. brassii, M. duplo-punctata, and M. neglecta. The present species has the marked, contrasting lateral nerves on the lower leaf surface in common with M. brassii (Central New Guinea), but that species has more coriaceous leaves and sessile inflorescences.