title: Evolution of opercle shape in cichlid fishes from Lake Tanganyika - adaptive trait interactions in extant and extinct species flocks.
abstract: Phenotype-environment correlations and the evolution of trait interactions in adaptive radiations have been widely studied to gain insight into the dynamics underpinning rapid species diversification. In this study we explore the phenotype-environment correlation and evolution of operculum shape in cichlid fishes using an outline-based geometric morphometric approach combined with stable isotope indicators of macrohabitat and trophic niche. We then apply our method to a sample of extinct saurichthyid fishes, a highly diverse and near globally distributed group of actinopterygians occurring throughout the Triassic, to assess the utility of extant data to inform our understanding of ecomorphological evolution in extinct species flocks. A series of comparative methods were used to analyze shape data for 54 extant species of cichlids (N = 416), and 6 extinct species of saurichthyids (N = 44). Results provide evidence for a relationship between operculum shape and feeding ecology, a concentration in shape evolution towards present along with evidence for convergence in form, and significant correlation between the major axes of shape change and measures of gut length and body elongation. The operculum is one of few features that can be compared in extant and extinct groups, enabling reconstruction of phenotype-environment interactions and modes of evolutionary diversification in deep time.
authors.affiliation: School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, NSW 2052, Australia.
authors.forename: Laura A B
authors.initials: LA
authors.lastname: Wilson
authors.affiliation: Zoological Institute, University of Basel, Vesalgasse 1, CH 4051, Basel, Switzerland.
authors.forename: Marco
authors.initials: M
authors.lastname: Colombo
authors.affiliation: Paläontologisches Institut und Museum, Karl-Schmid Strasse 4, CH 8006, Zürich, Switzerland.
authors.forename: Marcelo R
authors.initials: MR
authors.lastname: Sánchez-Villagra
authors.affiliation: Zoological Institute, University of Basel, Vesalgasse 1, CH 4051, Basel, Switzerland.
authors.forename: Walter
authors.initials: W
authors.lastname: Salzburger
mesh_terms: D000222:Adaptation, Physiological; D000825:Animal Structures / Q000033:anatomy & histology* / Q000502:physiology; D000818:Animals; D005075:Biological Evolution; D002063:Burundi; D023681:Cichlids / Q000033:anatomy & histology* / Q000145:classification / Q000235:genetics; D015023:Democratic Republic of the Congo; D017753:Ecosystem; D053476:Extinction, Biological; D005247:Feeding Behavior / Q000502:physiology; D060106:Lakes; D008962:Models, Theoretical; D010802:Phylogeny; D013045:Species Specificity; D013636:Tanzania; D013997:Time Factors; D015024:Zambia