Abstract
AbstractThe vast majority of reef fishes, including damselfishes, have a pelagic larval stage that ends when any surviving larvae swim to a reef to settle. An extremely rare alternative lifestyle is ‘larval brooding’, where both parents protect larvae on the reef for months until they disperse nearby. The monophyletic clade of larval brooders includes two generaAcanthochromisandAltrichthys. In examination of the skeletons of these damselfishes, we found that all species of damselfish that brood larvae on the reef have a uniquely increased precaudal vertebral count, while all typical damselfishes have an invariable vertebral count with a greater proportion of caudal vertebrae. To explore the significance of the vertebral differences, we measured body proportions of larval brooders vs relatives with the typical pelagic larval stage. We found increased body cavity area and reduced muscle area in the larval brooderAcanthochromis polyacanthus. Furthermore, populations ofAcanthochromisthroughout its range have evolved significantly different proportions. In a comparison of known larval swimming ability among reef fishes, the larval brooders performed most poorly. We propose that when larval brooding evolved, relaxed selection on larval swimming performance allowed a shift in body proportions to favor a larger body cavity and altered axial patterning. Enlarged body cavity gives a fitness advantage as females could hold more of the large eggs and increase clutch size.
Publisher
Cold Spring Harbor Laboratory
Reference37 articles.
1. Altrichthys, a new genus of damselfish (Pomacentridae) from Philippine seas with description of a new species;Revue française d’aquariologie (Nancy),1999
2. Arvedlund, M. , Kavanagh, K. 2009. The senses and environmental cues used by larvae of marine fish and crustacean decapods to find tropical ecosystems. Chapter 3.6. In: Ecological interactions between tropical coastal ecosystems. Springer.
3. A review of the fossil record of the Pomacentridae (Teleostei: Labroidei) with a description of a new genus and species from the Eocene of Monte Bolca, Italy;Zoological Journal of the Linnean Society,1996
4. Monophyletic origin of brood care in damselfishes;Molecular Phylogenetics and Evolution,2011
5. Bernardi, G. , Longo, G. C. , & Quiros, T. A. L. (2017). Altrichthys alelia, a new brooding damselfish (Teleostei, perciformes, pomacentridae) from Busuanga Island, Philippines. ZooKeys, (675), 45.