Meeting Abstract

36.8  Monday, Jan. 5  Phylogenetic variation of swimbladder disturbance sounds and morphology for twenty genera of doradoid catfishes with outgroup comparisons KAATZ, I. M.*; STEWART, D. J.; SUNY College of Env.Sci.Forestry; SUNY College of Env.Sci.Forestry imkaatz@yahoo.com

This is the first comprehensive phylogenetic survey of sound signal design in a clade of catfishes (Families Doradidae and Auchenipteridae). We described the swimbladder acoustic mechanism and disturbance sounds of catfishes representing 29 species in 24 genera. Outgroup taxa included mochokid, pimelodid, pseudopimelodid and aspredinid species. The acoustic parameters were: 1. waveform; 2. sound duration (5 – 5,727 ms); 3. dominant frequency (mean 71 – 520 Hz) and 4. acoustic behavioral effort = total time for all sounds per individual (mean 337 – 28,996 ms). Waveforms of most taxa were continuous "growls". Several species produced unique "buzz" groups, "foghorn" sounds, and "whistles" with harmonic shifts. Duration fell into two overlapping categories: "shorter" (mean 12 – 78 ms) with few or no sounds above 100 ms and "longer" (mean 124 – 730 ms) including sounds >100 ms. Duration was statistically significantly different within but not between doradid and auchenipterid families. Mochokids were significantly different from all families producing the longest sounds. Acoustic effort was lowest for basal families and derived doradids and highest for basal doradids and two auchenipterid species. We are testing hypotheses on the morphological correlates of this variation: a. swimbladder shape (round or cardioid to elongated ovoid, smooth edge vs. horns or diverticulae); b. swimbladder volume (length 0.4 – 4.5, width 0.5 – 3.3, depth 0.2 – 1.5 cm); c. shape of the bony "esa", elastic spring apparatus (disk- or plug-shaped); d. "esa" dimensions (width 0.8 – 12.5, height 0.8 – 11.1, thickness 0.18 – 1.47 mm); e. acoustic muscle mass (0.0026 – 1.2473 g) and f. muscle dimensions (origin-insertion 2.1 – 20.2 mm).