Current Research

Experimental taphonomy of small vertebrates

Leonard Brand, Ph.D., Prof of Biology and Paleontology, Loma Linda University

Laboratory research on the decay and disarticulation of small amphibians, reptiles, birds, and mammals, in controlled conditions and under normal external environmental conditions in dry Southern California, with rain only in the winter. The experimental design allowed direct comparison of taphonomic processes in four classes of small vertebrates, in different size classes and in different simulated environments. The data from these experiments provides an analogue that can be helpful in interpreting fossil vertebrate assemblages.

Conditions used were:

  1. 1) Freshwater and 2) seawater, in indoor, room temperature aquaria
  2. 3) A repeat of the above, with temperature the same as outdoors
  3. 4) Terrestrial, in cages on the ground outside of the research building
  4. 5) Terrestrial, then after about a month, transferred to freshwater aquaria (simulating death on land, then transport into a fluvial or lacustrine environment)
  5. 6) Terrestrial, then transfer to a wet terrestrial cage, simulating a higher rainfall environment

 

This research was conducted by Leonard Brand, with:

John Taylor, M.S. in biology

Michael Hussey, M. S. in geology

Brand, L. R., M. Hussey, and J. Taylor. 2003. Decay and disarticulation of small vertebrates in controlled experiments. Journal of Taphonomy, 1 (2): 69-95.

Brand, L. R., M. Hussey, and J. Taylor. 2003. Experimental taphonomy of turtles. Journal of Taphonomy, 1 (4) 2003 (2004):233-245.

 

Figures below show typical data from these experiments:

 

Black bars show percent of bones disarticulating from skeleton during each two week period. Gray polygons show cumulative percent of bones disarticulated until the entire skeleton was disarticulated. Aquatic condition graphs show percent of specimens floating on the water each week.

 

Each horizontal symbol indicates when each bone disarticulated from the skeleton, showing median time, range, and time at which 25 percent and 75 percent of bones of that type were disarticulated. Skulls show average number and type of teeth missing from skulls at end of the three year experiment. Shaded parts of skulls indicate which bones were disarticulated from skull at end of experiment, and what percent of these bones were disarticulated at that time.

 

Above: Disarticulation times for turtles. Description of the first graph, above, applies to this graph except for the following: Green polygon is cumulative disarticulation of the entire turtle. Black and red polygon in middle of each section is cumulative disarticulation of shell only. The black portion indicates 25 to 75 percent disarticulation of shell. The two black portions in the uppermost graph are two turtles that disarticulated on quite different schedules.