Abstract
The lateral line system of fish has been implicated in contributing to many behaviours, including orientation, activity and feeding. The system is comprised of a series of interconnected organs (neuromasts) that may be either embedded in fluid filled canals in the dermal surface of the fish (canal neuromasts), or embedded on the skin of the fish (superficial neuromasts). The ratio of canal to superficial neuromasts has been demonstrated to vary with hydrological environment. The Gobiomorphus genus occupies a wide variety of hydrological environments and one species, Common Bully, has been demonstrated to exhibit habitat related variation in the lateral line system. This study examined the lateral line system of four Gobiomorphus species (Common, Bluegill, Redfin and Upland Bullies) through vital staining and histological methods. This demonstrated that the lateral line system varies with the hydrodynamic environment of each species, with high flow specialists having low neuromast counts and low flow generalists having high and variable neuromast counts. A consistent difference in superficial neuromast size was found across all species. Redfin Bullies were found to lack neuromasts within their canals. A feeding experiment in controlled aquaria conditions suggests that the capacity of these species to capture prey in the absence of light is related to the form of the lateral line system. Species with canal neuromasts caught more prey than those with solely superficial neuromasts, and those with a higher proportion of large superficial neuromasts were more successful at capturing prey compared to species with only superficial neuromasts. This study demonstrated the likely importance of the lateral line system in feeding in the Gobiomorphus genus. The role of differing feeding capabilities between species and how it relates to the distribution patterns of these species and across the wider genus is discussed.