title: Body size evolution of a shell-brooding cichlid fish from Lake Tanganyika.
abstract: The substrate-brooding cichlid fish Telmatochromis temporalis in Lake Tanganyika demonstrates a simple example of ecological speciation between normal and dwarf morphs through divergent natural selection on body size. The dwarf morph most likely evolved from the ancestral normal morph; therefore, elucidating the evolution of its small body size is a key to understanding this ecological speciation event. Previous studies suggest that the small body size of the dwarf morph is an adaptation to the use of empty snail shells as shelters (males) and spawning sites (females), but this idea has not been fully evaluated. Combining original and previously published information, this study compared likelihood values to determine the primary factor that would be responsible for regulating the body size of the dwarf morph. Male body size is most likely regulated by the ability to turn within shells, which may influence the predation avoidance of adult fish. Females are smaller than males, and their body size is most likely regulated by the ability to lay eggs in the small spaces within shells close to the shell apices where predation risk on eggs is lower. This study provides new evidence supporting the hypothesis that different natural selection factors affected body size of the different sexes of the dwarf morph, which has not been reported in other animal species.
authors: Institute of Natural and Environmental Sciences, University of Hyogo, Sanda, Hyogo, Japan.|Division of Nature and Environmental Management, Museum of Nature and Human Activities, Sanda, Hyogo, Japan.
authors: T
authors: T
authors: Takahashi
authors: Laboratory of Animal Sociology, Graduate School of Science, Osaka City University, Osaka, Japan.
authors: K
authors: K
authors: Ota
mesh_terms: D000818:Animals; D005075:Biological Evolution; D049628:Body Size; D023681:Cichlids / Q000033:anatomy & histology*; D005260:Female; D060106:Lakes; D008297:Male; D012641:Selection, Genetic; D013636:Tanzania
keywords: 
  Telmatochromis temporalis
  ; likelihood; magic trait; natural selection; shell brooder