Regarding the difference of about 15,000 species, the text concludes: "It will require many detailed field surveys before it is possible to provide a reliable estimate of the total number of species ..."
ɹᵻɡˈɑːɹdɪŋ ðə dˈɪfɹəns ʌv ɐbˌaʊt fˈɪftiːn,zˈiəɹoʊzˈiəɹoʊ zˈiəɹoʊ spˈiːsiːz, ðə tˈɛkst kəŋklˈuːdz: "ɪt wɪl ɹᵻkwˈaɪɚ mˈɛni diːtˈeɪld fˈiːld sˈɜːveɪz bᵻfˌoːɹ ɪɾ ɪz pˈɑːsᵻbəl tə pɹəvˈaɪd ɐ ɹᵻlˈaɪəbəl ˈɛstᵻmət ʌvðə tˈoʊɾəl nˈʌmbɚɹ ʌv spˈiːsiːz ..."