Three new Master Cylinders sequences of Mitochondrial cytochrome c-oxidase subunit 2 (mtDNA cox-2) from C.pelagicum parasite of Spheniscus magellanicus, the Magelanicus penguin, were determined from Brazilian waters.The sequences presented 99 and 98% of similarity with C.
pelagicum sequences from Argentina, deposited on GenBank for the same genetic region and with a strong statistical support inferred from the phylogenetic tree.The greygasms morphological and ultrastructural studies that were carried out confirmed the genetic analysis.