Meeting Abstract
The mechanosensory lateral line system (LL) of fishes mediates the detection of low frequency water flows of biotic and abiotic origin. In bony fishes, it is comprised of two types of receptor organs: 1) Canal neuromasts (CNs) in pored canals within a subset of dermatocranial bones and in the LL scales. 2) Superficial neuromasts (SNs) that occur singly, in lines or in clusters on the skin. Several methods have been used to visualize neuromasts, but recently, in vivo staining using fluorescent mitochondrial stains (e.g., 4-di-2-ASP) has revolutionized our ability to simultaneously image the distribution of all CNs and SNs on a fish (including dramatic proliferations of 100’s – 1000’s of SNs). We used 4-di-2-ASP and SEM to document SN distribution and morphology in neon tetras and allies (Fam. Characidae) and in a neon goby (Fam. Gobiidae) and to determine the size, shape and axis of best physiological sensitivity (hair cell orientation) of SNs in these taxa. We also reviewed available data on SN morphology and distribution in a range of fish taxa (Ostariophysi, Salmoniformes, Stomiiformes, Gobiiformes, Pleuronectiformes, Acanthomorpha more generally). We used these data to seek “rules” that define variation in SN morphology and the structural (and functional) organization of the lines, clusters, and large dense fields (patches) of SNs among fishes. Collectively, these data demonstrate that the distribution of SNs has been underestimated among fishes thus demanding a new context in which to address their functional role in flow sensing among fishes. Funded by URI Office of Undergraduate Research and Innovation (EJM), NSF GRFP (AEJ) and NSF Grant 1459224 (JFW).
