A Radiolaria from the Arbuckle Mountains and Criner Hills Upper Devonian and Mississippian
Six to nine pairs of caveal ribs with ladder-shaped vane on outer side of each rib; rib pairs delicate except one sturdy pair (bearing terminal rib spines) along anterior a.t.; first three to five rib pairs long, well- developed and last two to three rib pairs short, poorly-developed; patagial ring surrounds frame; six extensions long, straight, tribladed; a.p. curving dorsally.
Skeletal framework having small-sized central trangular frame formed by straight i.t., slightly curved a.t., and moderately curved b.t. (convex sides outwards) with b.t. : i.t : a.t. ratio = 1.0 : 1.0: 0.80. Six completely developed rod extensions, surrounding central triangular fram, lying on a plane of central skeletal frame. All extensions moderate in length, spine-like with pointed tips; straight with exception of distal part of a.p. which points dorsally upwards.
Triradiate part having trhree narrow ridges alternating with three wide grooves with ridges and grooves exhibiting slight to moderate twisting along extension axis.
Discovered by Dr. John Schwartzapfel, University of Texas at Dallas.
Named after Mark A. Herkommer, Willis, Texas (formerly Richardson, Texas).