Smithsonian National Museum of Natural History

Research begins with detailed discussions between the artist and scientist. The scientist provides the artist with: information concerning the age and locality of the fossil material; a list of the organisms needing to be included in the scene; his or her vision of the particular landscape to be reconstructed; reference materials such as specimens, photographs, scientific descriptions, relevant publications, and other background material; and information regarding the extinct organisms' closest living relatives. Discussions and critiques continue throughout the entire reconstruction process.

Study area for this reconstruction
The scene described in this site is based on fossil material from the Calhoun coal, found in Berryville, Illinois. The fossil material is Late Carboniferous, and is approximately 310 million years old.

Specimen list
The scientist begins each reconstruction by providing the artist with a list of the organisms that need to be included in the reconstruction. Below is the list Tom Phillips provided for this project, which he organized by mode of life.

Trees
Medullosa (seed fern), Psaronius (tree fern), Pecopteris (tree fern foliage), Sigillaria (giant lycopod), Calamites (giant horestail), Cordaites (tree form)

Shrubs
Cordaites (shrub form)

Ground cover
Zygopteris (fern), Botryopteris (fern), Callistophyton (fern), Tubercaulis (fern), Sphenophyllum

Marshland edge or shallow water (lycopods)
Selaginella, Chaloneria

Epiphytes and vines
Ankyropteris (fern), Heterangium (pteridosperm)

Specimen illustration
Each species to be included must be carefully reconstructed individually (such as the Ankyropteris fern below) and approved by the appropriate specialist.

The scientist provides the fossil material for the artist to use to reconstruct the individual organisms to be reconstructed. This process can be extremely time consuming, particularly if the organism has never before been reconstructed, or the scientist is reinterpreting previously reconstructed organisms. Most fossil remains are fragmentary, and usually a great deal of research must be done before a whole organism is understood well enough to be added to the scene.

Scientists must also determine the geomorphology, sedimentological structure, and other geological and environmental aspects of the environment that are represented in the illustration.

The research phase of the illustration usually accounts for at least 70% of the total time spent on a well done reconstruction.

Fossil coal ball specimen with coal ball acetate peels from University of Illinois

Coal balls are concretions made largely of calcium carbonate which precipitated in ancient Carboniferous peat beds, thus preserving much anatomical structure of the original plants in the coal swamps. Coal balls are usually found intermittently in coal seams, to the dismay of coal miners and the delight of paleobotanists. Occasionally, as with the material pertaining to this reconstruction, they are found in outcrops of streambeds. Though difficult for a layperson to decipher, the data represented in this reconstruction was obtained primarily from the scientists’ studies of the delicate structures preserved in coal ball peels. Coal ball peels are prepared by slicing a coal ball with a lapidary saw, etching the cut and smoothed surface with hydrochloric acid, and applying a sheet of cellulose acetate to the etched surface with acetone which embeds the fossil cell walls to the cellulose acetate. When dry, the cellulose acetate is pulled from the coal ball and the peel is ready for study.

Fossil specimens of Seed ferns from University of Illinois with sketch of seed fern thicket by Mary Parrish

Selected bibliography used for the reconstruction of the Carboniferous peat swamp

DiMichele, W. A. and Phillips, T. L. 2002. The ecology of Paleozoic ferns, Review of Paleobotany and Palynology, 119:143-159

Eggert, D. A. 1959. Studies of Paleozoic Ferns, the morphology, anatomy and taxonomy of Ankyropteris glabra, American Journal of Botany, 46:510-520

Eggert, D. A. 1963. Studies of Paleozoic Ferns: The frond of Ankyropteris glabra, American Journal of Botany 50:379-387

Eggert, D. A., and Taylor, T. N. 1966. Studies in Paleozoic Ferns: On the genus Tedelea gen. nov. Palaeontographica 118B:52-73

Galtier, J., and Scott, A. C. 1979. Studies of Paleozoic Ferns: On the genus Corynepteris, a redescription of the type and some other European species, Palaeontographica B 170, 81-125

Delevoryas, T., and Morgan, J. 1954. Observations on petiolar branching and foliage of an American Botryopteris. American Midland Naturalist 52:374-387

Phillips, T. L., Avcin, M. J., and Berggren, D. 1976. Fossil Peat of the Illinois Basin: A guide to the study of coal balls of Pennsylvanian Age, Illinois State Geological Survey

Phillips, T. L., and Galtier, J. 2005. Evolutionary and ecological perspectives of Late Paleozoic ferns Part I. Zygopteridales, Review of Palaeobotany and Palynology 135:165-203

Phillips, T. L., and Andres, H. N. 1968. Biscalitheca (Coenopteridales) from the Upper Pennsylvanian of Illinois. Palaeontology 11, 103-115

Stewart, W. N. and Rothwell, G.W. 1993. Paleobotany and the Evolution of Plants. Cambridge University Press

Stidd, B. M. 1974. Evolutionary trends in the Marattiales, Annals of the Missouri Botanical Gardens, 61(2):388-407

Stidd, B. M. 1971. Morphology and anatomy of the frond of Psaronius, Palaeontographica 134 B: 87-123