Meeting Abstract

83.1  Friday, Jan. 6  Using fractals to describe morphology and ontogeny of lateral line canals of Xiphister (Cottiformes: Stichaeidae), with comparisons to other stichaeids CLARDY, Todd; Virginia Institute of Marine Science tclardy@vims.edu

Fishes of the family Stichaeidae, commonly known as pricklebacks, are a diverse group of about 37 genera and 76 species distributed in intertidal and continental slope waters of the North Pacific, Arctic and North Atlantic Oceans. A peculiar characteristic of some stichaeid genera is the presence of multiple, complexly branching trunk lateral line canals. This condition is rare among teleostean fishes and is found in members of only twelve other families. In this presentation, I describe the morphology of the trunk lateral line system of the two species of Xiphister using a fractal approach. Both species each have seven trunk lateral line canals, which are supported by dermal, ring-like ossifications. Lateral line systems in Xiphister were traced from cleared and stained specimens (32.4-170.1 mm SL) and their fractal dimensions were measured using the box/count method. This method calculates the complexity of a 2-dimensional object and yields values ranging from one (simple) to two (complex). At small sizes, trunk lateral lines in Xiphister are poorly developed resulting in low fractal dimensions (1.1-1.3). As Xiphister increase in size, branching of trunk lateral lines increases resulting in greater complexity and higher fractal dimensions (1.4-1.5). The implications of increasing fractal dimension of lateral line systems in Xiphister will be discussed, and comparisons to other fishes with multiple trunk lateral lines will be made.