Body imprints of Carboniferous amphibians discovered in the USA

This video is called: Evolution, fish with fingers. Transitional fossils.

From ScienceDaily:

Fossilized Body Imprints Of Amphibians Found In 330 Million-year-old Rocks

(Oct. 29, 2007) — Unprecedented fossilized body imprints of amphibians have been discovered in 330 million-year-old rocks from Pennsylvania. The imprints show the unmistakably webbed feet and bodies of three previously unknown, foot-long salamander-like critters that lived 100 million years before the first dinosaurs.

“Body impressions like this are wholly unheard of,” said paleontologist Spencer Lucas, a curator at the New Mexico Museum of Natural History and Science. Lucas will present the discovery on October 30, 2007, at the annual meeting of the Geological Society of America in Denver.

The fossil imprints, while lacking any bones of the animals, actually contain rare information that bones cannot, said Lucas. Without the imprints of the webbed four-toed feet, for instance, it would be virtually impossible to say they were truly amphibians. The imprints also provide body proportions and important clues to the kind of outer skin the little beasts had. The skin is smooth, not armor plated as many would have expected, Lucas said.

The imprints were found in reddish brown, fine-grained sandstone rocks of the Mauch Chunk Formation in eastern Pennsylvania that correspond to what’s known as the Visean Age, an early part of the Mississippian Epoch. That, in turn, is part of the [Carboniferous period of the] Paleozoic Era that stretched from 542 million years ago to 251 million years ago, when the age of reptiles started. The Mauch Chunk is older and therefore located beneath the heavily mined coal beds of Pennsylvania.

Also found in rocks from the same formation and of the same age are footprints of other relatively large animals and fossils of insects and plants, Lucas explained. There is even a saucer-sized footprint of an unknown vertebrate that suggests larger four-footed beasts lived far earlier than ever before suspected.

“It’s bigger than anything discovered in the bone record,” said Lucas.

Interestingly, the rock specimen with the triple imprints was collected decades ago near Pottsville, Schuylkill County, eastern Pennsylvania, but had been sitting, unexamined, in the Reading Public Museum Collection, said Lucas. As part of his senior thesis, Kutztown State University student David Fillmore uncovered the imprint fossil while studying the large collection of Mauch Chunk Formation footprints in the Reading Public Museum Collection.

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8 thoughts on “Body imprints of Carboniferous amphibians discovered in the USA

  1. Oct 30, 6:26 PM EDT

    Experts discover rare amphibian imprints

    Associated Press Writer

    DENVER (AP) — A rock that sat untouched in a Pennsylvania museum’s fossil collection for years has rare full-body imprints of not just one, but three, ancient amphibians.

    Researchers found the imprints in sandstone rocks collected in eastern Pennsylvania decades ago and stored in the museum in Reading, Pa. The body impressions of the salamander-like creatures are estimated to be 330 million years old, or about 100 million years before the first dinosaurs appeared.

    Many ancient footprints have been found, but a full-body animal impression is unusual. The three impressions show the foot-long temnospondyls had webbed feet and smooth skin similar to modern-day amphibians, rather than armored bodies.

    “The most remarkable thing about these is they exist at all. This is a very rare preservation,” said John Bolt, curator of fossil amphibians and reptiles at The Field Museum in Chicago.

    Details were being presented Tuesday in Denver at the annual meeting of the Geological Society of America.

    “They’re really some of the oldest body imprints of land-living amphibians,” said Spencer G. Lucas of the New Mexico Museum of Natural History and Science, who was making the presentation.

    “They show you what the shape of the body was, they show you what the texture of the skin was like,” Lucas said. “These are things we don’t know from bones. They’re giving us new information about the anatomy of these long-extinct amphibians.”

    The fossil could indicate social behavior or even courtship, Lucas speculated, or the impressions also could have been made at different times.

    “The real question is why do you have three close together on a rock,” he said.

    David Fillmore, who was doing postgraduate work with Kutztown University geology professor Edward Simpson, found the impressions two years ago when the two were studying Mauch Chunk Formation footprints in a fossil collection at Pennsylvania’s Reading Public Museum.

    “We looked at each other and were speechless. It’s way beyond anything we could imagine finding,” Fillmore said.

    © 2007 The Associated Press.


  2. Arthropod remains in the oral cavities of fossil reptiles support inference of early insectivory

    1. Sean P. Modesto1,*,
    2. Diane M. Scott2 and
    3. Robert R. Reisz2

    + Author Affiliations

    Department of Biology
    , Cape Breton University,
    Sydney, Nova Scotia B1P 6L2
    , Canada
    Department of Biology
    , University of Toronto in Mississauga,
    Mississauga, Ontario L5L 1C6
    , Canada

    1. *Author for correspondence (


    Inference of feeding preferences in fossil terrestrial vertebrates (tetrapods) has been drawn predominantly from craniodental morphology, and less so from fossil specimens preserving conclusive evidence of diet in the form of oral and/or gut contents. Recently, the pivotal role of insectivory in tetrapod evolution was emphasized by the identification of putative insectivores as the closest relatives of the oldest known herbivorous amniotes. We provide the first compelling evidence for insectivory among early tetrapods on the basis of two 280-million-year-old (late Palaeozoic) fossil specimens of a new species of acleistorhinid parareptile with preserved arthropod cuticle on their toothed palates. Their dental morphology, consisting of homodont marginal dentition with cutting edges and slightly recurved tips, is consistent with an insectivorous diet. The intimate association of arthropod cuticle with the oral region of two small reptiles, from a rich fossil locality that has otherwise not produced invertebrate remains, strongly supports the inference of insectivory in the reptiles. These fossils lend additional support to the hypothesis that the origins and earliest stages of higher vertebrate evolution are associated with relatively small terrestrial insectivores.


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