Original description: Test relatively small, conical, with well-developed horn. Cephalis small, conical, covered with layer of microgranular silica. Thorax and abdomen with short, massive, and irregular costae between one or two rows of pore frames. Post-abdominal chambers comprised of long continuous costae, with one or two rows of pore frames between two adjacent costae. Post-abdominal chambers increasing in width more rapidly than increasing in length as added.
Original remarks: Hsuum acutum n. sp. can be distinguished from other Hsuum spp in this report by having a test with apical end very pointed in nature, and by having short, massive, and irregular costae on its earlier chambers.
Etymology: Acutus-a-um (Latin, adj.) pointed.
Full reference: K. Y. Yeh. 1987. Taxonomic Studies of Lower Jurassic Radiolaria from East-Central Oregon. National Museum of Natural Science Special Publications 2:1-169
Sister taxa: Hsuum altile, Hsuum amabile, Hsuum arabicum, Hsuum arenaense, Hsuum belliatulum, Hsuum brevicostatum, Hsuum cuestaense, Hsuum feliformis, Hsuum gratum, Hsuum lucidum, Hsuum lupheri, Hsuum matsuokai, Hsuum maxwelli, Hsuum mclaughlini, Hsuum mirabundum, Hsuum modicum, Hsuum mulleri, Hsuum optimum, Hsuum parasolense, Hsuum parvulum, Hsuum plectocostatum, Hsuum robustum, Hsuum rosebudense, Hsuum rutogense, Hsuum tamanense
Type specimen: NMNS (000083). Its type locality is Suplee-Izee area, OR-600A, which is in a Toarcian marine tuff/limestone in the Hyde Formation of Oregon.
Ecology: passively mobile planktonic omnivore