Meeting Abstract
P3.106 Sunday, Jan. 6 Diversity of Adult Lateral Line Morphologies is not Explained by Differences in Neuromast Patterning in Two Lake Malawi Cichlids BECKER, EA*; SCOTT, R; WEBB, JF; University of Rhode Island; URI; URI emily_becker@my.uri.edu
The diversity found in the lateral line (LL) system of fishes has been attributed to differences in the pattern and timing of development. However, few studies have compared LL development in closely related species characterized by divergent adult morphologies. LL development occurs in three phases: neuromast differentiation and patterning, neuromast maturation (changes in size, shape), and canal morphogenesis. Thus, we asked – during which phase(s) of LL development do interspecific differences in adult lateral line morphology become apparent? We used fluorescent mitochondrial dyes to visualize hair cells in order to describe cranial neuromast distributions in ontogenetic series (hatch through >100 dpf) of two Lake Malawi cichlids, Aulonocara stuartgranti (widened canals) and Tramitichromis sp. (narrow canals). Aulonocara grows faster and hatches with more canal and superficial neuromasts than Tramitichromis. Aulonocara has a full set of mandibular (MD) canal neuromasts well before they appear in Tramitichromis, but a full complement of neuromasts in the other cranial canals are present at an earlier age in Tramitichromis than in Aulonocara. Early appearance of MD neuromasts in Aulonocara may be related to their role in prey detection (Schwalbe, et al., 2012). Despite differences in adult LL morphology, larval Tramitichromis and Aulonocara have the same number and distribution of canal neuromasts, but Tramitichromis has more superficial neuromasts, which are found in the same linear series or clusters as in Aulonocara. Thus, these two species demonstrate the same initial patterning of neuromasts, but differences in adult LL morphology are due to the subsequent processes of superficial neuromast proliferation, canal neuromast maturation, and LL canal morphogenesis. Supported by NSF grant IOS-0843307 to JFW and NSF EPSCoR Cooperative Agreement #EPS-1004057.
