Table 1. Spectral features of DF1 and DF2 across Xenopus species.
Average values (Standard Error). DF1: lower dominant frequency, DF2: higher dominant frequency. Additional broadband frequencies present at the attack of each sound pulse are not summarized here because they are not sustained. For both DF1 and DF2, the Q-value is the bandwidth at −6 dB divided by the peak frequency. Musical interval descriptors were assigned if the value of DF2/DF1 fell within 0.02 of a small integer ratio (e.g., 2:1 = Octave, 3:2 = Fifth, 4:3 = Perfect 4th, 5:4 = Major Third, 6:5 = Minor Third).
| Species | N | DF1 hz (SE) | DF1 Q-Value (SE) | DF2 hz (SE) | DF2 Q-Value (SE) | DF2/DF1 Ratio (SE) | Musical interval |
|---|---|---|---|---|---|---|---|
| X. pygmaeus | 3 | 1591 (40) | 16.6 (0.8) | 2124 (54) | 18.1 (2.6) | 1.34 (0.009) | Perfect 4th |
| X. ruwenzoriensis | 1 | 1937 | 21.6 | 2575 | 27.8 | 1.33 | Perfect 4th |
| X. amieti | 3 | 2043 (107) | 22.4 (1.3) | 2715 (152) | 27.2 (2.4) | 1.33 (0.005) | Perfect 4th |
| X. boumbaensis | 3 | 2475 (16) | 27.6 (0.2) | 3291 (29) | 33. 9 (0.4) | 1.33 (0.004) | Perfect 4th |
| X. allofraseri | 1 | N/A | N/A | N/A | N/A | N/A | Harmonic stack |
| X. andrei | 3 | 2062 (30) | 20.8 (1.5) | 2759 (51) | 26.7 (2.7) | 1.34 (0.006) | Perfect 4th |
| X. itombwensis | 3 | 1179 (32) | 12.4 (0.6) | 1573 (38) | 15.3 (2.1) | 1.33 (0.006) | Perfect 4th |
| X. wittei | 3 | 1319 (35) | 13.9 (0.7) | 1545 (38) | 15.0 (1.1) | 1.17 (0.003) | Non-consonant |
| X. vestitus | 2 | 1609 (2) | 17.7 (0.1) | 2150 (2) | 23.3 (0.3) | 1.34 (0.003) | Perfect 4th |
| X. lenduensis | 3 | 1595 (28) | 17.4 (0.2) | 2131 (33) | 22.8 (0.2) | 1.34 (0.004) | Perfect 4th |
| X. largeni | 2 | 929 (45) | 10.0 (0.2) | 1387 (59) | 14.7 (0.4) | 1.49 (0.010) | Perfect 5th |
| X. gilli | 3 | 2114 (45) | 22.7 (1.3) | 2641 (62) | 28.7 (1.3) | 1.25 (0.003) | Major Third |
| X. poweri | 3 | 1714 (28) | 19.1 (0.4) | 2159 (38) | 22.7 (0.1) | 1.26 (0.004) | Major Third |
| X. laevis Nigeria | 3 | 2029 (17) | 22.5 (0.2) | 2481 (22) | 26.6 (0.2) | 1.22 (0.004) | Minor Third |
| X. victorianus | 3 | 1891 (78) | 21.3 (0.9) | 2295 (102) | 22.4 (1.5) | 1.21 (0.005) | Minor Third |
| X. petersii | 3 | 2124 (24) | 23.6 (0.3) | 2576 (22) | 27.7 (0.3) | 1.21 (0.004) | Minor third |
| X. laevis Malawi | 3 | 1482 (80) | 15.8 (0.3) | 1831 (75) | 17.3 (0.7) | 1.24 (0.016) | Major Third |
| X. laevis South Africa | 3 | 1879 (21) | 16.0 (0.9) | 2154 (9) | 18.9 (2.2) | 1.15 (0.008) | Non-consonant |
| X. borealis | 3 | 1253 (5) | 13.9 (0.1) | 2504 (11) | 27.8 (0.4) | 2.00 (0.000) | Octave |
| X. muelleri | 2 | 1107 (29) | 12.2 (0.5) | 2262 (23) | 16.0 (6.1) | 2.04 (0.032) | Octave |