The use of a multidisciplinary approach for the characterization of a diploid parthenogenetic Artemia population from Torre Colimena (Apulia, Italy)

A parthenogenetic Artemia population from Torre Colimena, southern Italy, originally reported in 1998, is characterized by a multidisciplinary approach including cyst and naupliar biometry, morphometry of adults, scanning electron microscopy (SEM) of brood pouch, cytogenetics and 16S rRNA PCR-RFLP analysis. We confirmed parthenogenetic status, inferred ploidy level and determined phenotypic and molecular relationships of this population through comparisons with other asexual Artemia strains as well as bisexual species found (A. salina) or introduced (A. franciscana) in the Mediterranean basin. Cyst and naupliar sizes for Torre Colimena are among the smallest recorded for asexual Artemia while the opposite is true for chorion thickness. Discriminant analysis of adult body measurements shows increased differentiation (89.5% for the first four out of the taselve functions produced) from tetraploid parthenogenetic strains and bisexual species (A. salina and A. franciscana). Scanning electron micrographs of brood pouch reveal the characteristic morphology of asexual strains, while chromosome observations of instar-I nauplii unequivocally establish diploid>. Restriction patterns give evidence that the Torre Colimena population shares an identical set of mitochondrial DNA (mtDNA) polymorphisms with a diploid Spanish parthenogenetic strain and it is well differentiated from other tetraploid as well as bisexual auto- and allochthonous strains (A. salina and A. franciscana) from the Mediterranean. The present study may serve as a reference methodological framework for multidisciplinary characterization and biodizjersiy assessments in the genus Artemia.