Tm. Ridgway et al., Limited population differentiation in the bearded limpet Patella barbara (Gastropoda : Patellidae) along the coast of South Africa, J MARINE BI, 79(4), 1999, pp. 639-651
Citations number
44
Categorie Soggetti
Aquatic Sciences
Journal title
JOURNAL OF THE MARINE BIOLOGICAL ASSOCIATION OF THE UNITED KINGDOM
Patterns of genetic and morphological variation among eight populations of
Patella barbara along the coast of South Africa were examined to see whethe
r reported differences in shell morphology and behaviour between the west a
nd east coasts were mirrored by other morphological and/or genetic differen
ces. Morphological analyses of radular structure, gut-loop coiling and sper
m microstructure revealed no differences between the populations. Discrimin
ant functions analysis based on shell morphometrics showed major overlap be
tween populations and failed to separate them. Electrophoretic analysis of
17 enzyme loci have an overall genetic identity (Nei) value of 0.995, a val
ue which lies within the generally accepted range for conspecific populatio
ns. In two of the populations, at Dwesa and Arniston, individuals were foun
d to be 'gardening' algal resources. At Clovelly, a 'normal' form of P. bar
bara was found on the rocks, whereas a reduced and tall-shelled form occurr
ed on the ascidian Pyura stolonifera, demonstrating phenotypic morphologica
l plasticity. It was concluded that different populations of Patella barbar
a are both morphologically indistinguishable and genetically homogenous alo
ng the coast of South Africa, thus providing good evidence for widespread g
ene flow.