Tessler, Michael main content.

Michael Tessler

Photo of Michael Tessler

PhD Student, Richard Gilder Graduate School


  • Fall 2013–present Ph.D. in Comparative Biology, Richard Gilder Graduate School, American Museum of Natural History, anticipated graduation in August 2017.
  • M.S. in Biology (Ecology track), Fordham University, August 2013.
  • B.A. in Natural History, Sterling College, December 2009.

Research Interests

My research explores the evolution and ecology of overlooked organisms. I spent much of my childhood chasing snakes, tadpoles, and fish, or wandering about forests and botanical gardens. This love continues to channel into an ever more focused journey into animals and plants. Microscope journeys brought my concentration to moss, with their perfect little leaves that hide just outside of the perception of most people. For my M.Sc., I explored the ecology of mosses in streams and the environmental variables related to their distributions. After completing this degree, my interests took a turn for the creepy crawly, intermingling my love of horror films with science – leeches are the core of my dissertation work. Under the tutelage of Dr. Mark Siddall, I am investigating the relationships and classification of land leeches (yes, they exist; go to southeast Asia in the rainy season) and the evolution of anticoagulants that make leeches so famous (leech bites make you bleed a lot). My initial research on leeches was the first to explore the internal anatomy of leeches using micro-CT scanning. The study allowed for the species description of a minute terrestrial leech, which was too small for classic dissections. This project also presented a molecularly based tree of life (phylogeny) for the family of leeches in which this species was found, resulting in a reclassification of the group as molecular evidence strongly conflicted with prior classifications. I have continued this phylogenetic research for terrestrial leeches, combining my own collections from China and Cambodia with AMNH’s legacy collections to produce a phylogenetic revision of all terrestrial leech groups. These specimens will also have the blood they fed on sequenced to determine what mammals these leeches parasitize, expanding our knowledge of the ranges of difficult to survey mammals. Of equal interest in my dissertation is the evolution of leech anticoagulants. My research on anticoagulants surveys these proteins across all major groups of leeches, focusing on how leeches process difficult to digest blood such as urea-packed shark blood, and what has happened to anticoagulants in leech lineages that no longer drink blood and instead eat invertebrates.


In prep.

  • Tessler, M. and T. A. Clark. The impact of bouldering on rock-associated vegetation. In prep.
  • Tessler M., M. R. Brugler, R. DeSalle, R. Hersch, L. F. M. Velho, F. A. Lansac-Toh, and M. J. Lemke. A Global Comparison of Freshwater Bacterioplankton Assemblages, with a Focus on the Large-River Floodplain Lakes of Brazil. In prep.


  • Tessler, M., A. Barrio, E. Borda, R. Rood-Goldman, M. Hill, and M. E. Siddall. Description of an extant species with microcomputed tomography and phylogenetic revision of duognathous terrestrial leeches (Hirudinida: Arhynchobdellida: Haemadipsidae: Chtonobdella). Accepted pending minor revision, Zoologica Scripta.
  • Rosenfeld, J. A., D. Reeves, M. R. Brugler, A. Narechania, S. Simon, S. Kolokotronis, R. Durret, J. Foox, K. Shianna, M. C. Schatz, J. Gandara, E. Afshinnekoo, E. T. Lam, A. R. Hastie, S. Chan, H. Cao, M. Saghbini, A. Kentsis, P. J. Planet, V. Kholodovych, M. Tessler, Richard Baker, R. DeSalle, L. Sorkin, M. Siddall, G. Amato, and C. E. Mason. Genome assembly, annotation, and geospatial urban phylogenomics of the bedbug (Cimex lectularius). Accepted, Nature Communications.


  • Hekkala, E. R., S. G. Platt, J. B. Thorbjarnarson, T. R. Rainwater, M. Tessler, S. W. Cunningham, C. Twomey, and G. Amato. Integrating molecular, phenotypic, and environmental data to elucidate patterns of crocodile hybridization in Belize. Royal Society Open Science 2: 150409 (DOI: 10.1098/rsos.150409).


  • Tessler, M., K. T. Truhn, and J. D. Wehr. 2014. Diversity and distributions of stream bryophytes: does pH matter? Freshwater Science 33(3): 778-787 (DOI: 10.1086/676996).


Teaching Experience

  • Adjunct Faculty in Ecology, Sterling College, 2013-present. Created curriculum and taught Field Botany of Cryptogams.
  • Graduate Teaching Assistant for Phylogenomics course, Columbia University, 2015. Created and conducted labs for Phylogenomics course.
  • Invited Guest Lecturer, Columbia University’s Summer Program for High School Students, Summer 2015. Created and taught a lecture on leeches in conservation for a Conservation Biology course.
  • Guest Presentation, Science and Nature Program, American Museum of Natural History, Spring 2015. Created and taught hands on presentation, including live and preserved specimens.
  • Guest Instructor, Murry Bergtraum High School, Winter 2015. Created and taught hands-on class to high school students with a focus on leeches.
  • Guest Instructor, YouthCaN program at AMNH, Fall 2014. Created and taught hands on classroom and field classes to high school students with a focus on biodiversity.
  • Assistant Presenter, World Science Festival’s Cool Jobs, Spring 2014. Presented leeches on stage and assisted with preparing for the presentation Wildlife Conservation Corps Volunteer, NJ Fish and Wildlife.
  • Invited Guest Lecturer, St. Francis College, Fall 2013. Created and taught a lecture on bryophytes for a Botany course.
  • Created and Led Public Event on Bryophytes, Mohonk Preserve, Summer 2013
  • Research Associate, Mohonk Preserve, 2011–present.
  • Graduate Assistant, Fordham University, Fall 2010-Spring 2013. TA for Ecology, Fall 2011–Spring 2013; TA for Biology I and II, Fall 2010–Spring 2011.