life. Both maxilla and premaxilla were toothed and some species of therizinosaurids had specialized, recurved dentaries such as Segnosaurus and possibly Neimongosaurus. Braincases are known from three therizinosaurids: Erlikosaurus, Neimongosaurus and N. mckinleyi. Unfortunately, the braincase of Neimongosaurus has not been described nor illustrated. The braincases are directed to the bottom, co-ossified with well-developed sideways oriented paroccipital projections, highly pneumatized and had a prominent central foramen. The dentition is another featured trait in therizinosaurids which differs from all theropod groups. At least two different tooth morphologies are observed among therizinosaurids; the first is represented by relatively homodont, oval to lanceolate-shaped teeth with moderate coarse denticles (serrations) on the crowns (upper exposed part). This type of dentition is better represented by the complete, three-dimensional holotype skull of Erlikosaurus which features the mentioned characters. Two isolated teeth are known from Nothronychus and they are lanceolate-shaped, symmetrical, have moderate denticles, and strongly resemble those of Erlikosaurus. Furthermore, they seem to derive from the dentary based on comparisons with the latter. The preserved holotype dentary tip of Neimongosaurus preserves an erupted tooth that is lanceolate-shaped with small coarse serrations, falling within this type of dentition. Another type of dental morphology is the one seen on the highly specialized Segnosaurus. In this taxon, the teeth are very heterodont, leaf-shaped with relatively less denticles that are prominently developed being bigger than in the previous therizinosaurids. These denticles are composed of numerous folded carinae (cutting edges) with denticulated front edges, creating a roughened and shredding surface near the base of the tooth crowns. Most therizinosaurids appear to have had a low tooth replacement rate or not able to loose them at all. Postcranial skeleton In therizinosaurids, the shoulder girdle was robustly specialized than in other maniraptorans and less bird-like. The scapula (shoulder blade) was very straight and flattened at the upper end being fused to the coracoid bone, forming the scapulocoracoid. Near the region of the scapulocoracoid suture, on the coracoid, a large foramen is present. The coracoid is a wide and broad element that is slightly convex and thickened near of the scapulocoracoid suture. The humerus (upper arm) was exceptionally robust and flexible with wide lower ends as seen on the humeri of the therizinosaurids Nothronychus and Therizinosaurus. Not only that but the biceps muscle was prominently well-developed in Therizinosaurus. In Segnosaurus, the deltopectoral crest (deltoid muscle attachment) was strongly built. The antebrachium was relatively straight