Conchocelichnus seilacheri Radke, Campbell et Golubic, 2016

Diagnosis: The identification of the trace depends on a combination of the following characteristics: cylindrical segments, clusters of ramifications, spindle-shaped and globular swellings, and thin projections. The clusters of ramifications separated by long stretches of unramified section of thin tunnels (Fig. 1).

Description: The trace is characterized by gradual increase in dimensions from its entering of the carbonate substrate to the development of bushes of larger filaments (which in the modern setting are formed by reproductive conchosporangial branches). The initial exploratory tunnels are 100–300 (mean ± SD: 121± 61)μm long and 2–4μm wide. The advanced stages of the “vegetative” parts of the system show frequent occurrences of spindle-shaped and spherical swellings, which are shorter and wider 20 to 60( 35±14)μm long and up to15μm wide, often in serial arrangements. Diameter of the tunnels is variable with narrow interconnection coinciding with crosswalls separating cell-like units, so that the changes in dimensions are diagnostic rather than theirabsolute size. Pit connections when preserved in the borehole casts are an important recognition property.