 The phalangeal count for archosaurs is 2-3-4-5-3; many archosaur lineages have a reduced number of digits, but have the same phalangeal formula in the digits that remain.In other words, paleontologists assert that archosaurs of different lineages tend to lose the same digits when digit loss occurs, from the outside to the inside.The three digits of dromaeosaurs, and "Archaeopteryx" have the same phalangeal formula of I-II-III as digits I-II-III of basal archosaurs.