Ebook Diet, Habitat, And Ecomorphology Of Cichlids In The Upper Bladen River, Belize
Cichlids are among the most species-rich and diverse families of freshwater fishes, with a range in the Eastern Hemisphere extending throughout Africa and parts of the Middle East, including Madagascar, Sri Lanka, and along the southern coast of India. In the Western Hemisphere, cichlids occur from southern Texas to Argentina. Within the Perciformes, cichlids are placed in the suborder Labroidei, a large assemblage containing over 1800 species, or 5-10% of all living fishes. Members of this suborder possess highly derived pharyngeal jaws, a configuration referred to as the “labroid pharyngeal jaw”. Recent research suggests that the labroid pharyngeal jaw had important evolutionary consequences that have prompted significant diversification within the group, as it has allowed for development of diverse trophic behavior (for examples see:Greenwood 1978, Liem 1986, Gobalet 1989, Liem 1991).
Life history and other ecological attributes vary greatly among cichlids across their global range. In the Neotropics alone, studies have revealed a great diversity in cichlid ecology, morphology and behavior (Lowe-McConnell 1991, Winemiller et al.1995). This great diversity, in addition to providing evidence of rapid evolution, is the reason why cichlids provide a valuable resource for studies of speciation and adaptive radiation (Meyer 1987, Farias et al. 1999).
Adaptive radiation is morphological and ecological diversification within a lineage undergoing rapid phylogenesis, and the phenomenon has been studied extensively based on cichlid species flocks in the Great Lakes of Africa. Adaptive radiation occurs when an ancestral lineage evolves into multiple species with different traits that allow This thesis follows the style and format of Ecology.them to inhabit a variety of different environments or niches (Schluter 2002). Trophic differentiation presumably caused or accompanied radiation into various ecological niches (Liem 1991). Cichlids of the Neotropics have undergone impressive speciation as well, however, in a different pattern and representing a much older diversification than those of African lakes (Kullander 2003, Lopez-Fernandez et al. 2005). Among the extensive trophic diversification undergone by Neotropical cichlids (Myers 1966,Stiassny 1991, Winemiller et al. 1995), the Heroines are considered to be the mosttrophically diverse cichlid group (Hulsey et al. 2004) and specialize on a wide variety of distinct prey groups ranging from insects, algae, and detritus to evasive prey such as fish and crustaceans (Eaton 1943, Valtierra-Vega and Schmitter-Soto 2003, Waltzek and Wainright 2003).
Ecomorphology plays a central role in the study of adaptive radiation. Ecomorphology is an approach that examines ecological characteristics or performance functions of morphological features. The ecomorphological paradigm infers that morphological features are adaptive, i.e. they evolve and diversify due to competition,predation or other biotic interactions (Bock 1990). Using morphological traits to predict species or community patterns of food and habitat use is one avenue of ecomorphological studies (Wainwright and Richard 1995).
Studies of fish ecomorphology are particularly informative, because fishes exhibit extensive morphological and ecological diversity and relationships between form and function have been well established for many easily measured traits (Motta et al. 1995).Evolutionary ecology and ecomorphology have been investigated extensively for the family Cichlidae (Lowe-McConnell 1969, Lowe-McConnell 1991, Kullander et al. 1992,Norton and Brainerd 1993, Winemiller et al. 1995, Jepsen et al. 1997, Kornfield and Smith 2000, Ruber and Adams 2001). It has been suggested that Central American cichlid assemblages show greater ecomorphological diversification than African cichlid assemblages in rivers containing comparable numbers of species. One possible reason for adaptive radiation among Central American cichlids may be an evolutionary history lacking competition and predation from other freshwater fish families containing large numbers of taxa, as found in Africa and South America (Winemiller 1991, Winemiller et al. 1995).
CONTENTS
ABSTRACT
DEDICATION
ACKNOWLEDGEMENTS
TABLE OF CONTENTS
LIST OF FIGURES
LIST OF TABLES
INTRODUCTION
Background
Objectives
METHODS
Study area
Habitat
Diet
Morphology
Multivariate analysis
RESULTS
Species-specific findings
Ecomorphology
Niche partitioning, niche overlap and morphological diversification
DISCUSSION AND SUMMARY
LITERATURE CITED
VITA
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