such muscles are lacking in birds and crocodiles I think - although not so
sure of this in the case of crocodiles
In birds, the beak means that lips _cannot_ be present. Lip muscles are thus
_not_ "absent", but _"inapplicable"_ in birds, means, _unknown_ for the
purposes of phylogenetic bracketing. So, the EPB for nonavian dinosaurs
consists of the crocodiles and the lepidosaurs; the birds must be ignored.