Results from a principal coordinates analysis (PCo2 versus PCo1)
of spectrographic cross-correlation (SPCC–PCo)
(Cortopassi and Bradbury,
2000) of 166 vocalizations from six species of toadfishes. Sounds
analyzed included harmonic hoots from the boatwhistle vocalizations of B.
trispinosus (filled blue squares), H. didactylus (filled red
circles), O. beta (open green circles), O. phobetron (open
purple squares), O. tau (open blue triangles) and the hum of P.
notatus (filled orange triangles). Due to their temporal similarity to
toadfish boatwhistles, `growls' of P. notatus (filled yellow
diamonds) were also analyzed.