Mark has been a curator in the Division of Invertebrates at AMNH since 1999. His interest in leeches developed during his graduate school days at the University of Toronto while studying blood parasites of frogs, turtles and marine fishes. In each case the malaria-like parasites were transmitted by the bite of a leech, usually a particular species. These observations led to Mark's wondering whether or not leeches and blood parasites have coevolved; a question which was thwarted at the time by the lack of an evolutionary tree for leeches. Together, Mark and Gene developed the first phylogenetic analysis of leeches and so sparked a 12-year collaboration that continues with this expedition. Mark brought Liz into his lab first as a his scientific assistant, which was quickly followed by her starting a PhD project on the terrestrial leeches of the world. Together with Juli the four comprise the Leech-PEET team funded by the National Science Foundation to expand our knowledge of leech taxonomy, systematics and phylogeny while also expanding the base of expertise in young investigators.