Description: Rays about equal in length, medium of width, one ray usually slightly wider than the other, both rays terminating in large ellipsoidal tips. Width of tips about equal to length of ray shafts. Test comprised of small irregularly arranged polygonal pore frames without prominent small nodes at vertices. Several spines with circular cross-section and variable length occurring at distal surface of tips and sides of rays.
Remarks: Bistarkum rigidium Yeh, differs from B. bifurcum Yeh, by lacking bifurcate tips and by having a wider test.
Etymology: Rigidius-a-um (Latin, adj.) rigid.
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
Type specimen: NMNS (000045). 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
Total: 4 collections each including a single occurrence
Specimen images are retrieved through the ePANDDA API.
Click image to enlarge. Click to access iDigBio record.