areas in the skulls of therizinosaurids (Erlikosaurus or Nothronychus mckinleyi) indicates that the tympanic systems would result in increased and optimal low frequency sound reception, possibly infrasound. Such is the case of N. mckinleyi, which had an average hearing frequency of 1100 to 1450 Hz and possible upper limits between 3000 and 3700 Hz. Features include not only extensive basicranial pneumaticity, but also the development of a basisphenoid bulla (hollow bony structure). In addition, the orientation of the horizontal semicircular canal relative to the horizontal orientation of the occipital condyle gave therizinosaurids a horizontal head posture that enabled binocular vision with overlapping visual fields. A vast majority of these senses were also well-developed in earlier coelurosaurs and other theropods, indicating that therizinosaurids inherited many of these traits from their small, carnivorous maniraptoran ancestors and retained the ancestral, carnivorous ear configuration to be used for their different and very specialized dietary purposes. Locomotion In 1964, Zakharov described and named the particular ichnogenus Macropodosaurus, which is represented by a series of four-toed footprints. These tracks were found in beds of the Cenomanian age at Tajikistan, noting that they were made by a bipedal four-toed dinosaur and the toes were webbed or at least, very fleshy. It is unlikely that these were made by a quadrupedal animal since no manual footprints were found in association. The footprints are about long and wide. Since the research of therizinosaurs started posterior to these findings, Zakharov was not able to determine the exact type of dinosaur. Sennikov in 2006 re-examined these footprints and concluded that a therizinosaurid-grade dinosaur could have made those tracks. He compared Macropodosaurus with the articulated feet of Erlikosaurus and the referred one from Therizinosaurus revealing that when articulated in a plantigrade position they fit in the morphology of Macropodosaurus. Therefore, he considered these tracks to be more associated with therizinosaurids and was one of the first in propose a plantigrade stance in therizinosaurids. An additional Macropodosaurus-grade footprint was discovered in Poland and first reported in 2008. This footprint is reminiscent of the tracks described by Zakharov and therefore assigned to Macropodosaurus sp. These tracks could indicate the presence of therizinosaurs in Europe. In 2017 Masrour with colleagues reported Macropodosaurus footprints in what is now Morocco. They are similar to the original description with some degree of semiplantigradism. However, several other footprints may indicate a more digitigrade stance. Such is the case the