Key inn ovations may allow lin eages access to new resources and facilitate the invasi on of new adaptive zon es,potentially influencing diversificati on patter ns.Many studies have focused on the impact of key inno v...Key inn ovations may allow lin eages access to new resources and facilitate the invasi on of new adaptive zon es,potentially influencing diversificati on patter ns.Many studies have focused on the impact of key inno vations on speciation rates,but far less is known about how they influe nee phe notypic rates and patterns of ecomorphological diversification.We use the repeated evolution of pharyngognathy within acanthomorph fishes,a commonly cited key innovation,as a case study to explore the predicti ons of key inn ovation theory.Specifically,we in vestigate whether transiti ons to phary ngognathy led to shifts in the rate of phenotypic evolution,as well as shifts and/or expansion in the occupation of morphological and dietary space,using a dataset of 8 morphological traits measured across 3,853 species of Acanthomorpha.Analyzing the 6 evolutionarily independent pharyngognathous clades together,we found no evidence to support pharyngognathy as a key innovation;however,comparisons between individual pharyngognathous lineages and their sister clades did reveal some consistent patterns.In morphospace,most pharyngognathous clades cluster in areas that correspond to deeper-bodied morphologies relative to their sister clades,whereas occupying greater areas in dietary space that reflects a more diversified diet Additi on ally,both Cichlidae and Labridae exhibited higher univariate rates of phenotypic evolution compared with their closest relatives.However,few of these results were exceptional relative to our null models.Our results suggest that transitions to pharyngognathy may only be advantageous when combined with additional ecological or intrinsic factors,illustrating the importance of account!ng for lineage-specific effects when testing key innovation hypotheses.Moreover,the challenges we experienced formulating informative comparisons,despite the ideal evolutionary scenario of multiple independent evolutionary origins of pharyngognathous clades,illustrates the complexities involved in quantifying the impact of key innovations.Given the issues of lineage specific effects and rate heterogeneity at macroevolutionary scales we observed,we suggest a reassessment of the expected impacts of key innovations may be warranted.展开更多
基金a National Science Foundation grant DEB-1556953/1830127 to S.A.P.and P.C.W.
文摘Key inn ovations may allow lin eages access to new resources and facilitate the invasi on of new adaptive zon es,potentially influencing diversificati on patter ns.Many studies have focused on the impact of key inno vations on speciation rates,but far less is known about how they influe nee phe notypic rates and patterns of ecomorphological diversification.We use the repeated evolution of pharyngognathy within acanthomorph fishes,a commonly cited key innovation,as a case study to explore the predicti ons of key inn ovation theory.Specifically,we in vestigate whether transiti ons to phary ngognathy led to shifts in the rate of phenotypic evolution,as well as shifts and/or expansion in the occupation of morphological and dietary space,using a dataset of 8 morphological traits measured across 3,853 species of Acanthomorpha.Analyzing the 6 evolutionarily independent pharyngognathous clades together,we found no evidence to support pharyngognathy as a key innovation;however,comparisons between individual pharyngognathous lineages and their sister clades did reveal some consistent patterns.In morphospace,most pharyngognathous clades cluster in areas that correspond to deeper-bodied morphologies relative to their sister clades,whereas occupying greater areas in dietary space that reflects a more diversified diet Additi on ally,both Cichlidae and Labridae exhibited higher univariate rates of phenotypic evolution compared with their closest relatives.However,few of these results were exceptional relative to our null models.Our results suggest that transitions to pharyngognathy may only be advantageous when combined with additional ecological or intrinsic factors,illustrating the importance of account!ng for lineage-specific effects when testing key innovation hypotheses.Moreover,the challenges we experienced formulating informative comparisons,despite the ideal evolutionary scenario of multiple independent evolutionary origins of pharyngognathous clades,illustrates the complexities involved in quantifying the impact of key innovations.Given the issues of lineage specific effects and rate heterogeneity at macroevolutionary scales we observed,we suggest a reassessment of the expected impacts of key innovations may be warranted.
