 In 1998 interpreted as a reduced hyposphene-hypantrum complex, a system of secondary vertebral joints shown by many theropods, it was by the 2011 study seen as a pair of attachment points for tendons, as identified in 2006 in "Compsognathus".Exceptionally, with the thirteenth vertebra the two rib joint processes, the parapophysis and the diapophysis, are positioned at the same level.The five sacral vertebrae have not yet fused into a real sacrum.