The specific name of P. sagitta is the Latin word sagitta (arrow), in direct reference to the arrow-like shape.
ðə spəsˈɪfɪk nˈeɪm ʌv pˈiː. sˈædʒɪɾə ɪz ðə lˈætɪn wˈɜːd sˈædʒɪɾə ˈæɹoʊ, ɪn dᵻɹˈɛkt ɹˈɛfɹəns tə ðɪ ˈæɹoʊlˈaɪk ʃˈeɪp.