@article {611,
	title = {Convergence is Only Skin Deep: Craniofacial Evolution in Electric Fishes from South America and Africa (Apteronotidae and Mormyridae)},
	year = {2022},
	month = {Jun-14-2022},
	abstract = {<p><jats p="">Apteronotidae and Mormyridae are species-rich clades of weakly electric fishes from Neotropical and Afrotropical freshwaters, respectively, known for their high morphological disparity and often regarded as a classic example of convergent evolution. Here we use CT-imaging and 3D geometric morphometrics to quantify disparity in craniofacial morphologies, and to test the hypothesis of convergent skull-shape evolution in a phylogenetic context. For this study we examined 391 specimens representing 78 species of Apteronotidae and Mormyridae including 30 of 37 (81\%) of all valid genera with the goal to sample most of the craniofacial disparity known in these clades. We found no overlap between Apteronotidae and Mormyridae in the skull-shape morphospace using PCA and a common landmark scheme, and therefore no instances of complete phenotypic convergence. Instead, we found multiple potential instances of incomplete convergence, and at least one parallel shift among electric fish clades. The greatest components of shape variance in both families are the same as observed for most vertebrate clades: heterocephaly (i.e., opposite changes in relative sizes of the snout and braincase regions of the skull), and heterorhynchy (i.e., dorsoventral changes in relative snout flexion and mouth position). Mormyrid species examined here exhibit less craniofacial disparity than do apteronotids, potentially due to constraints associated with a larger brain size, ecological constraints related to food-type availability. Patterns of craniofacial evolution in these two clades depict a complex story of phenotypic divergence and convergence in which certain superficial similarities of external morphology obscure deeper osteological and presumably developmental differences of skull form and function. Among apteronotid and mormyrid electric fishes, craniofacial convergence is only skin deep.</jats></p>
},
	issn = {2517-4843},
	doi = {10.1093/iob/obac022},
	url = {http://dx.doi.org/10.1093/iob/obac022},
	author = {Ford, Kassandra L and Peterson, Rose and Bernt, Maxwell and Albert, James S}
}
@article {609,
	title = {Is the medium the message? Functional diversity across abiotic gradients in freshwater electric fishes},
	year = {2022},
	month = {Mar-28-2022},
	abstract = {<p><jats title="">Abstract</jats> <jats p="">Evolutionary transitions across abiotic gradients can occur among habitats at multiple spatial scales, and among taxa and biotas through a range of ecological and evolutionary time frames. Two diverse groups of electric fishes, Neotropical Gymnotiformes and Afrotropical Mormyroidea, offer interesting examples of potentially convergent evolution in aspects of morphological, physiological, and life history traits. We examined biogeographical, morphological, and functional patterns across these two groups to assess the degree of convergence in association with abiotic environmental variables. While there are superficial similarities across the groups and continents, we found substantially more differences in terms of habitat occupancy, electric signal diversity, and morphological disparity. These differences likely correlate to differences in biogeographical histories across the Neotropics and Afrotropics, biotic factors associated with aquatic life and electric signals, and sampling issues plaguing both groups. Additional research and sampling are required to make further inferences about how electric fishes transition throughout diverse freshwater habitats across both microevolutionary and macroevolutionary scales. We find little evidence that abiotic gradients in the freshwater habitat medium have driven convergent evolution of functional traits in these two continental radiations of electric fishes.</jats></p>
},
	issn = {1540-7063, 1557-7023},
	doi = {10.1093/icb/icac010},
	url = {http://dx.doi.org/10.1093/icb/icac010},
	author = {Ford, Kassandra L and Albert, James S}
}
