THE CARCINIZATION PROCESS AS A MEDIATOR TO SEXUAL DIMORPHISM AND MORPHOMETRIC VARIATIONS CLINES: ECOPEOGRAPHY IN DECAPODA
Allometry ; Macroecology ; Crustacea ; Phenotype ; Procrustes Coordinates ; Sexual fitness ; Latitude
Decapoda can have a variety of elongated “body forms” with excellent swimming, asymmetrical, and symmetrical compressed in rigid carapace. These are called ‘shimp-like’, ‘lobster-like’, ‘squat-lobster-like’, ‘pagurus-like’ and ‘crab-like’, in this study called Carcinotype. This is a reflection of the Carcinization process, a series of modifications that resulted in the compression of body plans. This does not represent a clear phylogenetic bias, it occurred in parallel in several lineages, probably associated with the occupation of vacant niches of benthic habitats in the past. Adaptive convergence processes within rates are poorly investigated and their mechanisms on a macroscale, such as Rensch's Rule (the correlation of sexual dimorphism of size with mean size, in monophyletic taxon) and Bergmann’s Rule (positive relation between latitude and mean body size, in endothermic animals). Thus, through regressive models with data obtained by a systematic review and data collected (evaluated by the geometric morphometry tool – variables: Centroid size, Form and Shape). 101 families of Infraordem Brachyura (Crab-like) has been reviewed, 14 families with eligible information. Relation between males and females accept the Neutrality of Rensch's Rule. The Size Sexual Dimorphism magnitude and Females Size showed Neutrality of Rensch's Rule. Between Average Population Size and Latitude, there was a tendency to corroborate the Bergmann’s Rule. And in the Size Sexual Dimorphism and Latitude, a positive bias was visualized. The information involving magnitude as a response variable (Centroid Sexual Dimorphism, Shape SD and Form SD) showed very similar results both in general models and in the trends for each Carcinotype, the Bergmann’s Converse. Ectotherms have a metabolic limitation based on the balance of body size, amplitude of the metabolic rate and the optimal thermal rate. The Interplay of the Bergmann’s Rule and Rensch’s Rule is a clinal approach to the Rensch’s Rule. This suggests that some traits vary systematically with latitude, with the Rensch’s Rule being visualized in its degree of magnitude among populations and its general tendency in the species or lineages in question. In general, trends in different directions were evident, but the bias between Carcinotypes was not always conclusive.