Meeting Abstract
Syngnathid fishes provide an unusual opportunity to examine dermal armor development throughout ontogeny and quantify the influences of sex-role reversals on the morphology of teleost fishes. Individuals of the Bay Pipefish, Syngnathus leptorhynchus (n=16), were filmed, CT-scanned, and measured to analyze swimming kinematics and dermal armor characteristics. These analyses indicate that individuals do not scale proportionally during ontogenetic growth in terms of body diameter, cross-sectional area of the body, or surface area of dermal armor. Instead, larger individuals have a more slender body shape with a much smaller cross-sectional area than is predicted by an isometric growth model. Further, swimming speed and estimated Reynolds number scales with total length to the power of 1.8 and 2.7, respectively. Thus, juveniles of S. leptorhynchus become proportionally faster as they grow in size, and swim at lower Reynolds Numbers than mature individuals. Mature Bay Pipefish adults, regardless of sex, have proportionally larger scales that cover a greater percentage of their body when compared with small juveniles. There are also distinct shape differences in the dermal armor between sexes; these differences are likely related to reproductive roles, because male brooding requires specialized bony structures along the abdomen and tail. In summary, body shape and dermal armor in S. leptorhynchus change with size and sex, and these variables likely influence the functional characteristics such as Reynolds number and swimming speed.
