> >>In mammals, such as humans, vertebrae are grouped as cervical (neck), >thoracic > >(chest), lumbar, sacral and... however that fused remnant of the tail is >called; > > > >Isn't that the sacrum? > > > > Coccyx Bingo. I had forgotten the word :-] . Just interesting why the analogous features of frogs and birds are called urostyle and pygostyle.