Lemur of mouse lemurs, the gray mouse lemur ("M. murinus"), golden-brown mouse lemur ("M. ravelobensis"), and Goodman's mouse lemur ("M. lehilahytsara") were considered the same species until recently, when genetic tests identified them as cryptic species. The lemur dentition is heterodont (having multiple tooth morphologies) and derives from an ancestral primate permanent dentition of . Indriids, sportive lemurs, the aye-aye, and the extinct sloth lemurs, monkey lemurs, and koala lemurs have reduced dentitions, having lost incisors, canines, or premolars. The ancestral deciduous dentition is , but young indriids, aye-ayes, koala lemurs, sloth lemurs, and probably monkey lemurs have fewer deciduous teeth.
I Should Have Known Better It was not released as a single at that time. In 1976, it was released as a B-side to "Yesterday". In the US, "I Should Have Known Better" was released on 13 July 1964 as the B-side to "A Hard Day's Night" and reached number 53 in the "Billboard" Hot 100, and number 43 on the "Cash Box" chart. As part of the film contract, United Artists acquired album rights for the American market. The company released a soundtrack album on 26 June 1964 with eight Beatles songs and four instrumentals. "I Should Have Known Better" was performed in the