文獻來源: Rutjes HA, de Zeeuw MP, Van den Thillart GEEJM, Whitte F. 2009. Changes in ventral head width, a discriminating shape factor among African cichlids, can be induced by chronic hypoxia. Biological Journal of the Linnean Society 98(3): 608-619.Abstract
A massive enlargement of the gill surface proved to be an important factor in the hypoxia survival of young cichlids. Because the heads of cichlids are densely packed with structures related to both feeding and breathing, we hypothesized that the extra space needed for gill enlargement requires such large structural reorganizations that outer head shape is affected. We used a three-dimensional model to describe changes in the outer head shape of cichlids. Broods of cichlids of different phylogenetic lineages, habitats, and trophic specialization were split and raised at either 10% or 80–90% air saturation. Despite the above-mentioned differences between the species that were used, all hypoxia raised groups showed similar volume enlargements. Volume increases were most prominent in the ventral suspensorial and ventral opercular subcompartments. A relation with the enlarged gills of hypoxia raised fish is likely because the gills are mainly located in these compartments. The differences in ventral width correspond to those found in other studies comprising a wide variety of genotypic and phenotypic variations. The present study shows that such variation in the ventral width is conceivable by phenotypic plasticity alone.
圖片連結: http://www.gcca.net/fom/fom_pix/haplochromis_ishmael.jpg
