Albertosaurus older "Gorgosaurus libratus" (sometimes called "Albertosaurus libratus"; see below). These two species are the only described albertosaurines; other undescribed species may exist. Thomas Holtz found "Appalachiosaurus" to be an albertosaurine in 2004, but his more recent unpublished work locates it just outside Tyrannosauridae, in agreement with other authors. The other major subfamily of tyrannosaurids is the Tyrannosaurinae, which includes "Daspletosaurus", "Tarbosaurus" and "Tyrannosaurus". Compared with these robust tyrannosaurines, albertosaurines had slender builds, with proportionately smaller skulls and longer bones of the lower leg (tibia) and feet (metatarsals and phalanges). Below is the cladogram of the Tyrannosauridae based on the phylogenetic
Roll the Bones rated it as one of the band's best ever songs partly due to its different texture than the rest of the album. The band was optimistic about its musical form, but faced the problem of overworking its arrangement because all the parts sounded good to them. In the end, they learned that by stripping the song back resulted in a stronger track. "Roll the Bones" was named after a science fiction story by Fritz Lieber that Peart had read some fifteen years prior titled "Gonna Roll the Bones". Though the story had no influence on the music or its message,