Input (grade 13): The eleven known fossil imprints of conodont animals depict an eel-like creature with 15 or, more rarely, 19 elements forming a bilaterally symmetrical array in the head.
Output (grade 10): Eleven fossil imprints of conodont animals are known. They depict an eel-like creature with 15 or, more rarely, 19 elements forming a bilaterally symmetrical array in the head.