<unk>  (or, more simply,<unk><unk>  are<unk>  whose lingual surfaces are scooped as a consequence of lingual marginal ridges, crown curvature or basal tubercles, either alone or in combination.<unk>  and Non<unk> .<unk>  are significantly common in Amerindians from North, Central and South America. They are also common in East and Central Asians, Hungarians, the Inuit and Aleut peoples of Northeast Asia and North America (including but not limited to the Inuit peoples of eastern Alaska, arctic Canada and Greenland). In European and African groups,<unk><unk>  upper<unk>  are uncommon or not present. There is a spectrum of the degree of<unk> ed-ness, ranging on a scale from 0 to 7 of spatulate<unk>  to<unk> ed<unk> . It was theorized that positive selection for<unk>  over the spatulate<unk>  are more commonly found in anthropoids within cultures that used their teeth as tools due to a greater structural strength in increased<unk> . However, more modern research suggests that instead genetics plays a role in the degree of<unk> ed-ness. In some instances,<unk>  can present a more pronounced version of this called double<unk><unk> . When present,<unk>  can indicate correlation among populations and are considered to be one of the non-metrical traits in osteology. Structurally resembling the<unk> , double-shovel-shaped<unk>  are distinguished by a more pronounced mesial ridge comparing to the distal ridge. Similarly, the grades for both<unk>  and the double<unk>  in females are significantly greater than that in males.<unk><unk>  dental characteristic are also observed in Homo erectus like the Peking Man and in Neanderthals, although the morphology of these<unk> ed<unk>  is distinct from the modern human form of<unk> ing. The morphology of Neanderthal's anterior teeth has been seen as an adaptation to the heavy use of their canines and<unk>  in processing and chewing food, and the use of their teeth for activities other than feeding.
Shovel-shaped incisors
Chattering teeth
Spotted lunulae
High-arched palate
Elfin facies
Maxillary hypoplasia
Condylar hypoplasia
Hippocratic facies