title: The fifth element (of Lucy's sacrum): Reply to Machnicki, Lovejoy, and Reno.
authors.affiliation: New York University. sawilliams@nyu.edu.
authors.forename: Scott A
authors.initials: SA
authors.lastname: Williams
authors.affiliation: Stony Brook University. Gabrielle.Russo@stonybrook.edu.
authors.forename: Gabrielle A
authors.initials: GA
authors.lastname: Russo
mesh_terms: D000818:Animals; D000885:Anthropology, Physical; D005580:Fossils; D015186:Hominidae / Q000033:anatomy & histology*; D012447:Sacrum / Q000033:anatomy & histology*