John Diederich Haseman (September 14, 1882 – May 1969) was an American zoologist, geologist, and explorer for the Carnegie Museum.
As an undergraduate he went on two trips to explore caves in Cuba and spent three summers at the IU Biological Station in Winona Lake.
[3][4] Haseman’s big break came in 1906 when John Casper Branner invited Eigenmann to accompany him on an expedition to Brazil.
Haseman learned as much as he could in the few days he had with Branner before starting his own exploration of eastern Brazil, Uruguay, Argentina, and Paraguay.
He made ten individual trips into the South American interior and did not return home until February 1910.
This collection was used by Marion Durbin Ellis in 1911 to identify and describe three new genera of fishes, including Hasemania, and their species.
[7] It was also used by Arnold Edward Ortmann for his study of South American naiads which was published in 1921 and described thirteen new taxa.
[6] He also made notes on the Pawumwa Indians and their language[8] as well as collected information for a book he authored: Some Factors of Geographical Distribution in South America.
In Appendix A of the book, Roosevelt praises Haseman’s accuracy and theories but is critical of his writing style.