to a juvenile individual shows that the manual phalangeal formula is 2-3-3-3-3 as in mammals. This hand (as well as an incomplete foot) was first considered by Lieuwe Dirk Boonstra as belonging to the right side of the animal. Boonstra himself corrected this mistake later by correctly identifying these remains as the left hand and foot. He also thought that digit III had four phalanges. Tim Rowe and J.A. van den Heever later showed that this was not the case, this digit having three phalanges. The manus have a digit I (the innermost) much smaller than the others. The digits III to V are the longest, the digit V (the outermost) being the most robust. The foot is only partially known, but also has a smaller digit I. Based on more complete skeletons of the Russian anteosaur Titanophoneus, the limbs would be rather long with a somewhat semi-erect posture. The tail is longer than in herbivorous Tapinocephalids dinocephalians. Paleobiology Skull variations and agonistic behaviour The numerous skulls of Anteosaurus show a wide range of variation in cranial proportions and extent of pachyostosis. Most specifically the development of the postfrontal "horns" and the frontal boss is particularly variable between specimens. Some have both the "horns" and the boss massively pachyostosed, others have well-developed "horns" but a weak or nonexistent boss, and some others have a very weakly developed "horns" and boss. Even the heavily pachyostosed specimens show between them some variations. Some have "horns" relatively small compared to the boss, while others have postfrontal "horns" very massive. Some of these variations can be attributed to ontogenetic changes. In adults specimens the variations of the development of the frontal boss (to very weak to very strong) can be a sexually dimorphic feature, because in dinocephalians the frontal bosses have been implicated in head-butting and pushing behaviour. Various authors have suggested the existence of agonistic behavior in Anteosaurus based on head-butting and/or demonstration involving canines. According to Herbert H. Barghusen, Anteosaurus does not use its teeth during intraspecific combat because both animals were able of doing severe damage to each other with their massive canines and incisors. The alternative head pushing strategy reduced the risk of fatal injuries in both combatants. The contact area of the skull roof during head combat included the most posterior part of the nasal bones, part of the prefrontal, and the entire frontal and postfrontal on either side.