The Utility of Geometric Morphometrics to Elucidate Pathways of Cichlid Fish Evolution

Michaela Kerschbaumer,Christian Sturmbauer

doi:10.4061/2011/290245

Michaela Kerschbaumer, Christian Sturmbauer

Open Access

https://doi.org/10.4061/2011/290245

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Abstract

Fishes of the family Cichlidae are famous for their spectacular species flocks and therefore constitute a model system for the study of the pathways of adaptive radiation. Their radiation is connected to trophic specialization, manifested in dentition, head morphology, and body shape. Geometric morphometric methods have been established as efficient tools to quantify such differences in overall body shape or in particular morphological structures and meanwhile found wide application in evolutionary biology. As a common feature, these approaches define and analyze coordinates of anatomical landmarks, rather than traditional counts or measurements. Geometric morphometric methods have several merits compared to traditional morphometrics, particularly for the distinction and analysis of closely related entities. Cichlid evolutionary research benefits from the efficiency of data acquisition, the manifold opportunities of analyses, and the potential to visualize shape changes of those landmark-based methods. This paper briefly introduces to the concepts and methods of geometric morphometrics and presents a selection of publications where those techniques have been successfully applied to various aspects of cichlid fish diversification.

Highlights

Cichlid fishes are the most species-rich family of all teleost fishes, and their diversity is centered in the Great East African Lakes where more than 2000 species [1] evolved within the past five to six million years [2]
Geometric morphometric methods have been established as efficient tools to quantify such differences in overall body shape or in particular morphological structures and found wide application in evolutionary biology
This paper briefly introduces to the concepts and methods of geometric morphometrics and presents a selection of publications where those techniques have been successfully applied to various aspects of cichlid fish diversification

Summary

Introduction

Cichlid fishes are the most species-rich family of all teleost fishes, and their diversity is centered in the Great East African Lakes where more than 2000 species [1] evolved within the past five to six million years [2]. While riverine ecosystems tend to be relatively speciespoor [17,18,19]—with the exception of the large South American rivers and perhaps the Zambezi system [20]— lakes comprise extremely species-rich communities Their hotspot of biodiversity clearly lies in the three Great East African Lakes, Victoria, Malawi, and Tanganyika, where an International Journal of Evolutionary Biology estimate of 1800–2000 species, that is, 60% of the total cichlid diversity, are centered in species flocks [7]. Seehausen [21] listed 27 lacustrine radiations of cichlid fishes in Africa alone As in all these lakes cichlid fish invariably form the most species-rich teleost lineage, they consistently outcompeted other fish groups when colonizing newly emerging lacustrine ecosystems [3]. Later we outline the opportunities to tackle important evolutionary questions via GM methods

Overview on Geometric Morphometric Techniques

Application of GM to the Study of Cichlid Evolution

Findings

Conclusions and Outlook