Abstract
Resting egg surface morphological variations usually occur among different Artemia species; however, in Artemia franciscana Kellogg, 1906 from Chile, which is a typical dweller of brackish and hypersaline inland lakes and coastal lagoons in America, the extent and the origin of these morphological variations are largely unknown. This study analyses the effects of two microalgal diets, Dunaliella tertiolecta Butcher, 1959, and Tetraselmis suecica (Kylin) Butcher, 1959, on the resting egg surface morphology of nine A. franciscana populations from northern and central Chile, including two reference populations. The scanning electron microscopy (SEM) was used to document the effect of microalgal dietary change on the resting egg surface morphology. Nine resting egg surface morphotypes across populations were observed, with the smooth (48.3%), rough (13.7%), and humped (9.3%) surfaces being the most common. The principal component (PCs) analysis revealed that the smooth (PC1) and rough (PC2) morphotypes explain a large proportion of surface morphotype variance (59.78%). The microalgal dietary change significantly modified the frequency of resting egg surface morphotypes in all populations (p < 0.00001). These results support a great variation in the resting egg surface morphotypes in A. franciscana populations from Chile, variability that may be affected by changes in the microalgal diet.