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INTRODUCTION
Most coral and rocky reef fishes have stage-structured life histories with two main distinct stages including a pelagic larval stage and a demersal stage (generally juveniles and adults; Gonçalves et al. 2002, Lecchini 2005, Hernández-Miranda et al. 2009). The settlement phase, which is the transition from the pelagic environment to the benthic reef environment is a key period, because during this phase fish often undergo a change in form and physiology to a mode suited for the new environment (McCormick and Makey 1997), which also produces changes in behaviour and feeding habits (Russo et al. 2007, Frédérich et al. 2008, 2012, Usmar 2012).
Fish morphology plays a major role in determining diet, because variations in morphology are assumed to underlie variation in feeding ability, and variation in the latter is expected to affect diet (Wainwright and Richard 1995). The assumed link between morphology and diet in fishes is provided by feeding performance (Norton 1991, Wainwright 1991, Motta and Kotrschal 1992, Costa and Cataudella 2007), because morphology influences the fish feeding abilities by limiting the prey that the individual it is able to capture and handle. Body size is important in diet shifts of fishes; as individuals grow, their feeding habits also change. Nonetheless, the shape of the feeding apparatus also changes throughout early development, and morphology plays a central role in determining the minimal, maximal and optimal prey sizes (Wainwright and Richard 1995).
Allometry is the pattern of covariation among several morphological traits or between measures of size and shape (Gould 1966). It can be used to summarize the developmental history of growing parts of an animal (Weston 2003) and contributes to the integration of morphological traits (Klingenberg 2016). Allometry, the variation in shape that is associated with variations in size, is widely characterized by multivariate regression of shape on size (log-transformed centroid size; Loy et al. 1998, Mitteroecker et al. 2004). Allometric variation can amount to a sizeable proportion of total shape variation, and can contribute substantially to overall integration of shape (Sidlaukas et al. 2011, Klingenberg 2016).
Geometric morphometric techniques are one way to visualize the patterns of allometric growth occurring during the transition from the larval to the settled phase, because this approach allows a mathematical quantification of the changes in...