The influence of size on body shape diversification across Indo‐Pacific shore fishes*

Abstract

Understanding the causes of body shape variability across the tree of life is one of the central issues surrounding the origins of biodiversity. One potential mechanism driving observed patterns of shape disparity is a strongly conserved relationship between size and shape. Conserved allometry has been shown to account for as much as 80% of shape variation in some vertebrate groups. Here, we quantify the amount of body shape disparity attributable to changes in body size across nearly 800 species of Indo‐Pacific shore fishes using a phylogenetic framework to analyze 17 geometric landmarks positioned to capture general body shape and functionally significant features. In marked contrast to other vertebrate lineages, we find that changes in body size only explain 2.9% of the body shape variation across fishes, ranging from 3% to 50% within our 11 sampled families. We also find a slight but significant trend of decreasing rates of shape evolution with increasing size. Our results suggest that the influence of size on fish shape has largely been overwhelmed by lineage‐specific patterns of diversification that have produced the modern landscape of highly diverse forms that we currently observe in nature.

Evolutionary and morphological patterns underlying carnivoran body shape diversity

“…1), indicating that older families simply had more evolutionary time to accumulate more disparate body shapes than younger families. Although my results somewhat follow predictions of a Brownian motion model (O'Meara et al 2006), previous empirical studies have found inconsistent relationships between phenotypic variation, clade age, phenotypic evolutionary rates, and species richness (e.g., Rabosky and Adams 2012;Sherratt et al 2014;Zelditch et al 2015;Friedman et al 2019). Together, these findings contribute to the continual discovery of the discrepancy between the variation of phenotypic traits and diversity of species (Martin and Richards 2019).…”

Appendicular skeletal morphology of North American Martes reflect independent modes of evolution in conjunction with Pleistocene glacial cycles

“…The independent evolution of shape and size has occurred in several other clades (e.g., Adams & Nistri, 2010;Botton-Divet et al, 2018;Friedman, Martinez, Price, & Wainwright, 2019;Law, 2019;Mitteroecker, Gunz, Bernhard, Schaefer, & Bookstein, 2004). Frequently, this independence is recognized through a lack of allometric signal and is hypothesized to act as a release from evolutionary constraints on morphology (Huxley, 1932;Simpson, 1944;Rensch, 1959;Gould, Lewontin, Smith, & Holliday, 1979;Gould, 2002;Voje, Hansen, Egset, Bolstad, & Pelabon, 2014).…”

Holosteans contextualize the role of the teleost genome duplication in promoting the rise of evolutionary novelties in the ray-finned fish innate immune system

“…Instead it is far more likely that the clustered organization of these and similar families of innate immune receptors have, and continue to provide the genomic substrate required to persist in the face of evolving pathogenic threats over several hundred million years of teleost evolution. The changes in pathogen driven selective pressures as ray-finned fishes have made evolutionary transitions to novel biomes such as saltwater to freshwater transitions (Yamanoue et al 2011; Nakatani et al 2011; Davis et al 2012), invaded new adaptive zones (Dornburg et al 2011; Burns and Sidlauskas 2019; Friedman et al 2019), or faced changes in climatic conditions (Near et al 2012a; Siqueira et al 2019), could be associated with pathogenic spread. Transitions such as these may explain the high within-lineage diversity of these receptor families.…”