Moss Fossils

Another national area with cool mosses is the Florissant Fossil Beds National Monument. It is located near Colorado Springs, Colorado and has some of the most diverse fossil beds in the world. Around 1700 different species have been described from this monument alone. Considering that fossilization is a chance event that requires very specific conditions, it is pretty amazing that this many species were preserved within a 6,000 acre area. Most of the fossilized plants and animals are from the Eocene epoch (one of the fancy names for dividing up the past into smaller chunks), which was approximately 55 to 34 million years ago (mya).

They have an online museum where they list some of the fossilized species along with their photos that have been found at the monument. Their fossil list would not be complete without mentioning the fossilized mosses. One of the species that they found is Plagiopodopsis cockerelliae (Cockerell's moss) and they have a very detailed photograph of the fossil posted online. This moss is really tiny. I think that the scale bar that they show is a centimeter long with the tick marks indicating millimeters. This fossil appears well preserved. Individual leaves and the sporophytes topped by calyptrae can be seen in the fossil. (A calyptra is a organ that grows from the leafy green maternal gametophyte. It covers the sporophyte during its development.) I think calyptrae are really neat organs. Studying their interaction with the developing sporophyte is the main focus of my PhD.

This fossil of Plagiopodopsis cockerelliae is a more recent fossil than many of those found at the Florissant Fossil Beds National Monument. It is from the Miocene epoch (23 to 5 mya). I guess recent is all relative. It is recent considering that mosses evolved around 400 mya. The age of this fossil is not mentioned on the website. I did some research and found this publication on fossil mosses that discusses Plagiopodopsis cockerelliae in more detail.

Steere, W. C. 1946. Cenozoic and Mesozoic Bryophytes of North America. American Midland Naturalist 36(2):298-324.


Some fun facts about Plagiopodopsis cockerelliae from the paper are below the fold.

1) This was the first fossil moss found with sporophytes in North America.

2) It was collected from the Florissant lake deposits by Professor and Mrs. T. D. A. Cockerell in 1906. Hence the common name (Cockerell's moss) and specific epithet (cockerelliae).

3)In 1915 E. G. Britton described the fossil genus Plagiopodopsis. She thought that it resembled the living moss Plagiopus, hence the similarities in the names. However in Steere's (1946) paper he mentions that the specimens of Plagiopodopsis that he has seen do not look like Plagiopus. Thus he is of the opinion that this fossil and living taxa are not closely related and the scientific names are misleading.

{This post is dedicated to my friends who are in love with Colorado Springs.}