ðə tˈaɪp spˈiːsiːz, ˈɛm. bɹˈɛvɪɹˌɑːstɹɪs wʌz nˈeɪmd ɪn wˈʌn θˈaʊzənd ˈeɪthˈʌndɹɪd twˈɛnti nˈaɪn æz ɐ spˈiːsiːz ʌv stˌɛnɪəsˈɔːɹəs bᵻfˌoːɹ bˌiːɪŋ nˈeɪmd æz ɐ sˈɛpɹət dʒˈɛnəs baɪ ðə dʒˈɜːmən pˌæliːəntˈɑːlədʒˌɪst kɹˈɪstʃən vˈɑːn mˈeɪɚɹ ɪn wˈʌn θˈaʊzənd ˈeɪthˈʌndɹɪd θˈɜːɾi tˈuː.
The type species, M. brevirostris was named in 1829 as a species of Steneosaurus before being named as a separate genus by the German palaeontologist Christian von Meyer in 1832.