Evidence for a Grooming Claw in a North American Adapiform Primate: Implications for Anthropoid Origins

AMNH 143612/143640 preserves a semi-articulated Notharctus foot in which AMNH 143612-03 can be assigned to digit two and exhibits the cited study’s comparative grooming-phalanx morphology.

Notharctus is bounded here by the semi-articulated AMNH 143612/143640 foot from Bridger B, Wyoming, within an approximately 50–48.5 Ma locality interval; its digit-two anatomy does not establish a global genus range or crown-anthropoid ancestry.

Maiolino and colleagues treat the semi-articulated AMNH 143612 and AMNH 143640 foot as Notharctus for a ray-specific phalangeal comparison; this attribution and comparison do not establish crown-primate membership or direct ancestry.

The profiled Notharctus foot is bounded to AMNH 143612 and AMNH 143640 from the Bridger Formation in Wyoming; this specimen provenance does not establish a complete genus distribution.

The cited Notharctus foot study tests phalangeal function rather than diet, habitual habitat, observed locomotion, population body size or ecological guild; those fields therefore remain unresolved in this profile.

AMNH 143612 and AMNH 143640 preserve a semi-articulated foot with ray-specific proximal and intermediate phalanges used to infer a digit-two grooming claw; grooming behaviour itself is not observed.