Maryland: Astrodon johnstoni (state dinosaur)

Maryland has a diverse fossil record, and is one of two states which have designated both a state fossil and a state dinosaur. Whereas the state fossil, a Miocene snail, is abundant and well known, the state dinosaur, the sauropod Astrodon johnstoni, is rare and fragmentary.

Astrodon was a large-bodied, long-necked dinosaur which lived during the Early Cretaceous, 130 - 95 million years ago. It is found in an area of coastal Maryland thought to have been swampy, but may not have actually lived in the swamp -- perhaps its bones washed into the swamp via a river after the dinosaur died somewhere inland.

Astrodon was first reported in 1859 based on the discovery of two isolated teeth. It was scientifically described and named by Joseph Leidy in 1865, becoming the first sauropod dinosaur described from North America and Maryland. In fact, the name means "star tooth," a reference to the appearance of the tooth's dentine in cross section.

Few remains have been discovered in the century and a half since that time, leaving this dinosaur poorly known. A large femur was found near Washington, D.C. in 1942, and another fragmentary femur (upper leg bone) was discovered near Muirkirk in 1991, but these represent most of the known Astrodon material.

Nevertheless, because of its historical importance to the state, the Maryland General Assembly passed House Bill 1170 and Senate Bill 520 by wide margins, and the governor signed them into law on October 1, 1998, giving Maryland its own state dinosaur.

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Maryland symbols

Maryland State Dinosaur