Elaphrobates euzeti One of approximately 130 blood flukes that have been identified in bony fish this worm infects the heart and gills of red snapper E euzeti is one of over 100 parasite species attracted to red snapper but it s the only one known to specialize on this fish s blood Griphobilharzia amoeng Crocodiles are more closely related to humans than they are to turtles But when we look at their parasites the opposite is true that is croc and turtle blood flukes are most similar This is an example of host switching in which two distantly related organisms e g crocs and turtles share a closely related parasite likely because of overlapping environments e g freshwater Hapalotrema mehrai Current research suggests that humans and green sea turtles are actually more genetically different than their blood flukes are H mehrgi looks and acts much more like the fluke that inhabits humans than the one that affects freshwater turtles Schistosoma mansoni This worm parasitizes 83 million people and can damage the spleen bladder lungs and liver S mansoni s eggs exit the body through urine and feces and then seek out aquatic snails where they multiply and grow To complete their life cycle the parasites return to the water in search of human skin to penetrate once more Spirochis haematobius As some fish were evolving into the early tetrapods that later gave rise to organisms like turtles their parasites adapted as well and began to split off into different families S haematobius parasitizes the freshwater snapping turtle and is part of a family of blood flukes that infect turtles and crocodiles BUILD A TREE MISSION 5 S mansoni H mehrai G amoena S haematobius T position 8 C position 7 T position 2 If blood flukes were to exhibit strict cophyly over millions of years you would predict that blood flukes would Evolve in a way that s completely different from their current host Evolve in a manner that parallels the evolution of their host Spread to a species that s not closely related Take a bow In cophyly parasites evolve in parallel with their hosts 1 E euzeti G amoena H mehrai S mansoni S haematobius A T T T T GC T CT CT T TC T position 4 NEXT XXX