Clionolithes alcicornis (Vogel, Golubić et Brett, 1987)

Microboring; substrate calcareous; tracemaker invertebrate?

Emended diagnosis. Branches diverge from the flat and elongated main trunk, spreading radially and in one plane, often in straight lines, ramifying in varying density at angles between 40° and 115° without forming anastomoses, tapering toward pointed tips. Often with a distinctive cuspate texture and fine filaments scattered over the entire surface, but most numerous on the edges and sides of the branches.

Diagnosis. - Rosette-shaped repeatedly branched systems up to 2 mm (1.41 f 0.34 [16]) in diameter (Fig. 6A). Branches diverge from the main trunk spreading radially, curved in a characteristic clawlike fashion (Fig. 6B), at angles ranging from 40" to 115" (72 2 17 [50]). The main trunk is 75- 190 pm (142 f 40 [7]) wide. The primary branches range from 53 to 136 ~III (95 2 19 [a]), the secondary branches from 31 to 66p111 (51 2 11 [50]), and the tertiary branches from 12 to 45 pm (26 2 9 [37]) in diameter. They have smooth and rounded surfaces, and are circular in cross section. The branches taper toward pointed tips. There is a significant decrease in diameter from primary to secondary and tertiary (distal) branches, and the diameter between individual branching points remains constant or decreases. The branching varies in density, without anastomoses. The main aperture to the surface was not detected.