Good day, I would like to ask, how long did T. rex probably exist as a species? What is the earliest record of its presence in the late Maastrichtian strata? It went extinct 66.0 mya, which is quite well known, but when did it first appear? Was it 68.5, 68.0 or rather 67.5 mya? Thank you very much, in advance!
Thomas R. Holtz, Jr.
Email:Âtholtz@umd.eduÂÂÂÂÂÂÂÂ Phone: 301-405-4084
Principal Lecturer, Vertebrate Paleontology
Office: Geology 4106, 8000 Regents Dr., College Park MD 20742
Dept. of Geology, University of Maryland
Fax: 301-314-9661ÂÂÂÂÂÂ ÂÂÂÂÂÂÂ
Faculty Director, Science & Global Change Program, College Park Scholars
Office: Centreville 1216, 4243 Valley Dr., College Park MD 20742
Mailing Address:ÂÂÂÂÂÂÂ Thomas R. Holtz, Jr.
ÂÂÂÂÂÂÂ ÂÂÂÂÂÂÂ ÂÂÂÂÂÂÂ Department of Geology
ÂÂÂÂÂÂÂ ÂÂÂÂÂÂÂ ÂÂÂÂÂÂÂ Building 237, Room 1117
ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ 8000 Regents Drive
ÂÂÂÂÂÂÂ ÂÂÂÂÂÂÂ ÂÂÂÂÂÂÂ University of Maryland
ÂÂÂÂÂÂÂ ÂÂÂÂÂÂÂ ÂÂÂÂÂÂÂ College Park, MD 20742-4211 USA