Morphometric and Phylogenetic analysis of morphotypes in Artemia franciscana Kellogg, 1906 (Crustacea: Anostraca)

We document morphology and genetic relatedness of morphotypes within the Artemia franciscana that has colonized Covelong saltern in Kelambakkam (South India). They exhibits high phenotypic plasticity and intra-population variation in a supposedly panmictic population. Morphometric analysis was carried out on 18 traits in males and 15 in females and subjected to multivariate analysis. Three types each in males (M1, M3 and M4) and females (F1, F2 and F3) were singled out. The axes in the plot explain 77.9% in males and 73.9% in females of the variation through discriminant function analysis. The sequence divergence of the population was evaluated through mtDNA (16S rRNA) and nDNA (p26 gene) markers. The substantial sequence divergence was observed between the morphotypes through nDNA and appearing sequence divergence was recognized by mtDNA. Likewise, phylogenetic analyses of maximum likelihood and Bayesian analysis through nDNA revealed a maximum similarities between M1, M4 with F1 & F2 and M3 with F3. Further, haplotype distribution of nDNA revealed unique haplotype between M1 and M4 with F1 and F2 morphotypes. This study thus confirms the occurrence of morphotypes with specific characteristics inside a seemingly homogeneous population.