Tag Archives: Peabody Museum of Natural History

Florissant fossils

One of the many pleasures of my visit to Yale last month was a visit to the collections of the Yale Peabody Museum. Among its treasures, the museum holds many of the fossils that were collected in the early 1900s from Florissant, Colorado.

The Florissant site is famous for its beautifully preserved plant and insect fossils, remains of the flora and fauna of the late Eocene, about 34 million years ago. In those good ol’ days, the climate was warmer and wetter, so a rich temperate forest grew in what is now a mix of dry, open grassland and ponderosa pine (replete with modern mammals, as I learned during my visit to the site last summer).

Most of the fossils are preserved in the finely laminate shale. Some of these laminae represent one year’s deposition: a layer of diatoms from the summer, overlain with ashy clay in the winter. These are interspersed with coarser material from rivers and landslides.

Division of Paleobotany, YPM 30074. Copyright 2014, Peabody Museum of Natural History, Yale University, New Haven, CT. All rights reserved.

Division of Paleobotany, YPM 30074. Copyright 2014, Peabody Museum of Natural History, Yale University, New Haven, CT. All rights reserved. The whole section depicted here is about 5 mm deep.

Many of the animals from the Florissant fossil beds look familiar to us, an indication of the continuity of taxa and their ecological roles across tens of millions of years.

Tethneus twenhofeli (orb-weaving spider). Collected by W. H. Twenhofel, date unknown. Described by A. Petrunkevitch, 1922. (Division of Invertebrate Paleontology, YPM 25588. Copyright 2014, Peabody Museum of Natural History, Yale University, New Haven, CT. All rights reserved.)

Tethneus twenhofeli (orb-weaving spider). Collected by W. H. Twenhofel, date unknown. Described by A. Petrunkevitch, 1922. (Division of Invertebrate Paleontology, YPM 25588. Copyright 2014, Peabody Museum of Natural History, Yale University, New Haven, CT. All rights reserved.)

Cranefly. Collected by J. T. Gregory, 1953. (Division of Invertebrate Paleontology, YPM 50208. Copyright 2014, Peabody Museum of Natural History, Yale University, New Haven, CT. All rights reserved.)

Cranefly. Collected by J. T. Gregory, 1953. (Division of Invertebrate Paleontology, YPM 50208. Copyright 2014, Peabody Museum of Natural History, Yale University, New Haven, CT. All rights reserved.)

The flora likewise contains many familiar taxa — redwoods, poplars, pines, hickories — but it also contains some enigmatic extinct species. One such puzzle is Fagopsis longifolia, a tree that may belong to the Fagaceae. If this interpretation is correct, Fagopsis is  kin to the modern oaks and beeches.

The following remarkable fossil shows Fagopsis with attached leaves and a fluffy ball of staminate inflorescences (i.e, the “male flowers,” bearing the stamens that produce pollen).

Fagopsis longifolia. Division of Paleobotany, YPM 30249. Copyright 2014, Peabody Museum of Natural History, Yale University, New Haven, CT. All rights reserved.

Fagopsis longifolia. Division of Paleobotany, YPM 30249. Copyright 2014, Peabody Museum of Natural History, Yale University, New Haven, CT. All rights reserved.

The separate pistillate inflorescence (the “female flower”) is also beautifully preserved.

Fagopsis longifolia. Division of Paleobotany, YPM 30121. Copyright 2014, Peabody Museum of Natural History, Yale University, New Haven, CT. All rights reserved.

Fagopsis longifolia. Division of Paleobotany, YPM 30121. Copyright 2014, Peabody Museum of Natural History, Yale University, New Haven, CT. All rights reserved.

Here is a close-up of the same specimen, showing the details of the long styles.

Fagopsis longifolia. Division of Paleobotany, YPM 30121. Copyright 2014, Peabody Museum of Natural History, Yale University, New Haven, CT. All rights reserved.

Fagopsis longifolia. Division of Paleobotany, YPM 30121. Copyright 2014, Peabody Museum of Natural History, Yale University, New Haven, CT. All rights reserved.

The most comprehensive treatment of the Fagopsis is Manchester and Crane‘s analysis of the leaves, flowers, fruits, and pollen of the species. It was therefore a privilege to examine the fossils with Peter Crane and to learn that the species still presents something of a puzzle, not fitting neatly into any modern group.

My thanks to Peter Crane, Shusheng Hu, Susan Butts, Derek Briggs, and Rick Prum for their welcome and assistance at the Museum. If you’re in New Haven, I strongly recommend a visit to the museum.