Biology Reference
In-Depth Information
CHAPTER FIVE
Metamorphosis in Teleosts
Sarah K. McMenamin, David M. Parichy
1
Department of Biology, University of Washington, Seattle, Washington, USA
1
Corresponding author: e-mail address: dparichy@u.washington.edu
Contents
1.
Introduction and Definitions
128
2. Metamorphic Diversity in Teleosts
130
2.1 Marine teleosts
130
2.2 Diadromous teleosts
135
2.3 Freshwater teleosts
138
3. Endocrine Controls of Teleost Metamorphosis
140
3.1 Thyroid hormone
141
3.2 Non-TH mediators of metamorphosis
146
4. Local Mechanisms of Morphogenetic Changes
148
4.1 Flatfish cranial asymmetry
149
4.2 Skin
149
4.3 Pigmentation
150
4.4 Fin ray formation
152
5. Conclusions
153
Glossary
153
References
154
Abstract
Teleosts are the largest and most diverse group of vertebrates, and many species
undergo morphological, physiological, and behavioral transitions,
“
metamorphoses,
”
as they progress between morphologically divergent life stages. The larval metamor-
phosis that generally occurs as teleosts mature from larva to juvenile involves the loss
of embryo-specific features, the development of new adult features, major remodeling
of different organ systems, and changes in physical proportions and overall phenotype.
Yet, in contrast to anuran amphibians, for example, teleost metamorphosis can entail
morphological change that is either sudden and profound, or relatively gradual
and subtle. Here, we review the definition of metamorphosis in teleosts, the diversity
of teleost metamorphic strategies and the transitions they involve, and what is known
of their underlying endocrine and genetic bases. We suggest that teleost metamorpho-
sis offers an outstanding opportunity for integrating our understanding of endocrine
mechanisms, cellular processes of morphogenesis and differentiation, and the evolution
of diverse morphologies and life histories.
