spˈiːsiːz ɪn ðɪs dʒˈɛnəs wɜː tɹɐdˈɪʃənəli klˈæst ˌɪntʊ tˈuː skˈʌl ɡɹˈuːps: lˈɔŋɡaɪɹˌɑːstɹiːn lˈɔŋ, nˈæɹoʊ dʒˈɔːz ænd bɹˈɛvɪɹˌɑːstɹiːn ʃˈɔːɹt, bɹˈɔːd dʒˈɔːz.
Species in this genus were traditionally classed into two skull groups: longirostrine (long, narrow jaws) and brevirostrine (short, broad jaws).