Thomas worked at the Natural History Museum on mammals, describing about 2,000 new species and sub-species for the first time. He was appointed to the Museum Secretary's office in 1876, transferring to the Zoological Department in 1878. In 1891 Thomas married an heiress to a small fortune, which gave him the finances to hire mammal collectors and present their specimens to the museum. In 1896 when William Henry Flower took control of the Department he hired Richard Lydekker to rearrange the exhibitions, allowing Thomas to concentrate these new specimens.
Reference
The Natural History Museum at South Kensington, William T. Stearn ISBN 0434736007
Roger Thomas announced his plans to retire effective the end of summer, 2002, and Dr. Ileana Arias officially resigned her faculty position on December 31, 2001, to take a permanent position at the Centers for Disease Control in Atlanta.
Thomas has been recommended for Emeritus Professor status, and Dr. Arias was given an adjunct appointment in the department.
Kecia Thomas serves as Chair of the Committee for Ethnic Minority Affairs for the Society for Industrial and Organizational Psychology (SIOP) and was elected as a member of the Executive Committee for the Gender and Diversity in Organizations Division of the Academy of Management.