The Formation and Preservation of the Solnhofen Fossils


June 3, 2010
649 Views

Our new Archaeopteryx exhibition has stunning complete fossils of fish, turtles, crocodiles, shrimp, sharks and much more, all from Solnhofen, Germany. In this blog, Dr. Bakker explains why Solnhofen produced and preserved so many spectacular, intact specimens.

The Mystery of Tropical Germany

From the first diggings in the late 1700’s,  Solnhofen presented a profound puzzle: Why was  Germany tropical in the Jurassic?

The fossil evidence was perplexing:

Fish
Amiopsis Lepidota

Big, long-lived reefs grow only in the tropics – how could northern Europe have supported the Solnhofen reef?

Large crocodiles thrive only in the warmest climate – how could giant sea-crocodiles flourish at Solnhofen?

Huge tree ferns today are emphatically warmth-loving plants – how could tropical ferns grow luxuriously at Solnhofen?

The mystery was world-wide. In the Jurassic, big crocodilians, tree ferns and reefs had spread all over Europe, Asia and North America. The tropical belt must have extended into Alaska and far south into Argentina.

Solnhofen was part of the proof that the Jurassic was one of the warmest periods in the history of life. Since the end of the Jurassic, on average Europe and North America suffered a gradual decrease in winter warmth.

Solnhofen – A Real Jurassic Park

Big-Budget movies have made the Jurassic Period  the most famous sector of geological time in our modern world. But in fact, the Jurassic was already world-renowned by the 1830’s. The first carnivorous dinosaurs known from good skeletons came from the Jurassic of Oxford. The first dinosaur tracks discovered in abundance were from the Jurassic of Massachusetts. The first complete skeletons of giant sea-reptiles were excavated from the Jurassic of southern England.

But no locale has gave finer fossils from the Jurassic than Solnhofen, Germany. Beginning in the mid 1700’s, Solnhofen has provided a never-ending stream of petrified animals and plants.

Fish
Liodesmus Sprattiformis

The exquisite skeletons lie in lithographic limestone, a rock that records not only bones but  impressions of skin and other soft tissue. Vertebrate bodies are preserved in exceptional detail. The pterodactyls at Solnhofen often have fossilized wing membranes. Crustaceans and mollusks are often fossilized as complete bodies. Even the most delicate  parts of squid – tentacles, eyes, and ink sacs – are recorded as high-resolution impressions.

Solnhofen lithographic stone has captured a more complete picture of Jurassic life than any other kind of sediment. Fossils are not common – hundreds of rocks slabs must be split to expose a single animal. Fortunately, the discovery of fossils is encouraged by commercial interests. Beginning in 1798, the lithographic stone has been quarried to make stone plates used to print high-resolution images of paintings, etchings and, later, photographs.

Many scientific publications about Solnhofen fossils have been illustrated by drawings of specimens reproduced via lithographic limestone plates.

Why are Solnhofen fossils so magnificent? The environment  around a tropical reef  was perfect for preservation. Reef-building organisms – sponges, microbes, corals – built up an arc of hard calcium carbonate that shielded a quiet lagoon. All manner of salt-water fish and invertebrates hunted for food in the upper warm waters. Land-living animals came to the beach to search for washed-up carcasses. In the air flew ‘dactyls and, on occasion, a  bird.

When an animal died and sank to the bottom of the lagoon, the water chemistry offered protection from  the forces of decay and dismemberment. The hot tropical climate concentrated the salts in the quietest part of the lagoon, so that most decomposers – organisms that would destroy the carcass – were kept away. Salt-loving microbes spread a thin film over the bottom, and this film functioned like a death-shroud, further protecting the body of dead animals. Perfect fossils were formed when the microbial mat excluded every crab, snail and  bottom-living shark that would otherwise destroy the body.

Extinct Sea Turtle
Eurysternum Wagleri

Solnhofen brings to us a picture of half-way evolution. The rich fish fauna was being modernized by natural selection. Old-fashioned armored fish were going extinct. New styles of jaws and fins were being developed among what would become the dominant fish families in the modern world. Many Solnhofen fish were living-fossils in their own day, representing evolutionary designs that had first appeared two hundred million years earlier. Other Solnhofen fish were the first successful members of clans that dominate today.

Pterodactyls and sea-reptiles too were about half-way in their Darwinian trajectory. Sea-turtles had not yet evolved their specialized flipper. Sea-crocodiles were about to suffer extinction and replacement by the new ocean-going species of the Cretaceous Period. Crustaceans were starting the wave of evolution that would continue as modern crabs and shrimp and lobsters.

There collection displayed here in our exhibit is one of the finest samplings of the entire Solnhofen biota. The Archaeopteryx at the center of the exhibit is the only Archaeopteryx in the New World.

Bob
Authored By Bob Bakker

The Museum’s Curator of Paleontology, world-renowned Dr. Robert T. Bakker (or, as some call him, Bob) is the leader of the handful of iconoclastic paleontologists who rewrote the book on dinosaurs three decades ago. Along with other noted paleontologists, Bakker has changed the image of dinosaurs from slow-moving, slow-witted, cold-blooded creatures to — at least in some cases — warm-blooded giants well-equipped to dominate the Earth for 200 million years. Dr. Bakker can be found all over the globe, notably leading the Museum’s paleontology field program.

3 responses to “The Formation and Preservation of the Solnhofen Fossils”

  1. Christina says:

    I’ve been to see this exhibit twice and we’ll be back at least one more time, so a geologist friend from Austin can see it, too. It’s INCREDIBLE.

  2. Raptor Lewis says:

    Holy Cretaceous…..or is it….Jurassic? lol! 😉 I must convince my parents to take me to the HMNS one more time just to see this exhibit! 🙂

  3. Paul says:

    I’m curious. The image for Liodesmus sprattiformis (correct way to write it), is the only one anywhere with this body shape. All other images I can find, and there are many, show an entirely different body shape; more streamlined.
    Why is this the only one with this shape?

Leave a Reply

Your email address will not be published. Required fields are marked *

Become An HMNS Member

With a membership level for everyone; Don't just read about it, see it.

View All Membership Levels

Editor's Picks May Educator How-To: Make a Roman Mosaic What’s The Splatter? The Science Behind Bug Guts on your Windshield. 5 Of The Rarest Objects On Display At HMNS Questions From A Perceptive Third Grader New Special Exhibition at HMNS – Vanishing Arts: Highlights from the Beasley-Hwang Collection Your Spring Break Guide for a Fossil-filled Visit to HMNS
Follow And Subscribe

Equally Interesting Posts




HMNS at Hermann Park

5555 Hermann Park Dr.
Houston,Texas 77030
(713) 639-4629


Get Directions Offering varies by location
HMNS at Sugar Land

13016 University Blvd.
Sugar Land, Texas 77479
(281) 313-2277


Get Directions Offering varies by location
George Observatory

21901 FM 762 Rd.
Needville, Texas 77461
(281) 242-3055

Hours
Tuesday - Saturday By Reservation
Saturdays 3:00PM - 10:00PM
Saturdays (DST) 3:00PM - 11:00PM
DST = Daylight Savings Time.
Please call for holiday hours. Entry to Brazos Bend State Park ends at 9:30 p.m. daily
Get Directions Offering varies by location

Stay in the know. Join our mailing list.