Saccomorpha stereodiktyon Golubic, Radtke, Campbell, Lee, Vogel et Wisshak, 2014

Diagnosis: Complex system of borings composed of (a) bifurcated and segmented tunnels underneath and parallel to the substrate surface (shells), producing (b) numerous simple upright branches penetrating the interior of the shell, and (c) terminal swellings. The segments of the horizontal network are straight, gradually widening in direction of growth and forming distal conical nodes, where horizontal and vertical branches originate. Swellings are spherical later becoming elongated toward the interior of the shell or growing irregular protrusions. Smaller protrusions at the bottom of the swellings form separate connections to the substrate surface. The casts of deeply penetrating upright tunnels carry an upward diverging widening where they pass the organic lamellae of the bored shell and may extend to the opposite surface of the substrate.

Remarks: Because of similarity in positioning of terminal sporangial swellings, the trace has been in the past confused with Saccomorpha terminalis Radtke, 1991.