[Show abstract][Hide abstract] ABSTRACT: Intermediate forms in the evolution of new adaptations such as transitions from water to land and the evolution of flight are often poorly understood. Similarly, the evolution of superfast sonic muscles in fishes, often considered the fastest muscles in vertebrates, has been a mystery because slow bladder movement does not generate sound. Slow muscles that stretch the swimbladder and then produce sound during recoil have recently been discovered in ophidiiform fishes. Here we describe the disturbance call (produced when fish are held) and sonic mechanism in an unrelated perciform pearl perch (Glaucosomatidae) that represents an intermediate condition in the evolution of super-fast sonic muscles.
The pearl perch disturbance call is a two-part sound produced by a fast sonic muscle that rapidly stretches the bladder and an antagonistic tendon-smooth muscle combination (part 1) causing the tendon and bladder to snap back (part 2) generating a higher-frequency and greater-amplitude pulse. The smooth muscle is confirmed by electron microscopy and protein analysis. To our knowledge smooth muscle attachment to a tendon is unknown in animals.
The pearl perch, an advanced perciform teleost unrelated to ophidiiform fishes, uses a slow type mechanism to produce the major portion of the sound pulse during recoil, but the swimbladder is stretched by a fast muscle. Similarities between the two unrelated lineages, suggest independent and convergent evolution of sonic muscles and indicate intermediate forms in the evolution of superfast muscles.
Frontiers in Zoology 11/2011; 8(1):31. · 2.30 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Underwater ambient noise was surveyed along the shallow-water banks in the regions adjacent to the estuaries of seven major rivers on the west coast of Taiwan. Attention was paid only to the sounds which were considered to be emitted by soniferous fishes. Eight sound types were recorded from the study areas. They were compared to the hand-held disturbance sounds of nine soniferous species captured in the coastal waters of Taiwan in order to determine the origins of the sounds found in the wild. There were few cases of high matches. The sea catfish was treated as the producer of the high-frequency sound commonly occurring in these areas.