The extinct omomyids, which are considered to be the most basal haplorhines, are believed to be more closely related to the tarsiers than to other haplorhines. The exact relationship is not yet fully established – Williams, Kay and Kirk (2010) prefer the view that tarsiers and simians share a common ancestor, and that common ancestor shares a common ancestor with the omomyids, citing evidence from analysis by Bajpal et al. in 2008; but they also note two other possibilities – that tarsiers are directly descended from omomyids, with simians being a separate line, or that both simians and tarsiers are descended from omomyids.