The number of species is unknown – as of 2021 there are 48 species in 7 genera, but more species are being studied.
ðə nˈʌmbɚɹ ʌv spˈiːsiːz ɪz ʌnnˈoʊn æz ʌv tˈuː θˈaʊzənd twˈɛnti wˈʌn ðɛɹˌɑːɹ fˈoːɹɾi ˈeɪt spˈiːsiːz ɪn sˈɛvən dʒˈɛnɚɹə, bˌʌt mˈoːɹ spˈiːsiːz ɑːɹ bˌiːɪŋ stˈʌdid.