PaleoDB taxon number: 165853
Original description: Cephalis small, dome shaped, with short, well-developed horn. Horn circular in axial section. Thorax and abdomen closely spaced, trapezoidal in outline. First post-abdominal chamber inflated in larger subellipsoidal outline and terminating in a narrow tubular extension. Tubular extention tapering distally. Cephalis, thorax, and abdomen sparsely perforate, covered with layer of microgranular silica. Mesh work of first post-abdominal chamber and tubular extension comprised mainly of pentagonal and hexagonal pore frames. Size of pore frames decreasing apically and distally with largest pore frames at central portion of post-abdominal chamber. Pore frames thi n in rims and sides.
Original remarks: Katroma angusta, n. sp., differs from K. infiata, n. sp., by having a smaller, narrower test with shorter horn.
Etymology: Angusta-a-um (Latin, adj.) narrow.
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: Katroma aurita, Katroma bicornus, Katroma brevitubus, Katroma clara, Katroma elongata, Katroma hullae, Katroma inflata, Katroma inflatio, Katroma irvingi, Katroma milloti, Katroma neagui, Katroma pinquitudo, Katroma regina, Katroma sinetubus, Katroma tetrastyla, Katroma westermanni
Type specimen: NMNS (000121). Its type locality is Suplee-Izee area, OR-589D, which is in a Toarcian marine mudstone/limestone in the Snowshoe Formation of Oregon.
Ecology: passively mobile planktonic omnivore