We can dig it: Celebrate National Fossil Day and learn what to do with what you find

There’s a day for just about everything these days, but National Fossil Day is one we can really dig.

Organized by the National Park Service, National Fossil Day isn’t just about appreciating past millennia frozen in time by the likes of these little guys:

A teensy TrilobiteA stunning pair of Trilobites, currently residing in the Morian Hall of Paleontology.

It’s also about public awareness and promoting stewardship of fossils. Says the National Park Service:

Fossils discovered on the nation’s public lands preserve ancient life from all major eras of Earth’s history, and from every major group of animal or plant. In the national parks, for example, fossils range from primitive algae found high in the mountains of Glacier National Park, Montana, to the remains of ice-age animals found in caves at Grand Canyon National Park, Arizona. Public lands provide visitors with opportunities to interpret a fossil’s ecological context by observing fossils in the same place those animals and plants lived millions of years ago.

Do you know the rules when it comes to fossils found on public lands? If not, educate yoself! Happy finding!

On Happy Puppies, “Bugs” and Honorary Dinos: A statement by Dr. Robert T. Bakker

When I was a lowly freshman hanging around the Yale Peabody Museum, one mind-opening surprise was the unrestrained joy of paleontological language. I’d been a dino-geek since the fourth grade. I knew a dozen duck-billed dinosaurs by name — their technical names.  I’d met Corythosaurus casuararius and Saurolophus osborni face-to-face in the exhibit halls of the New York museum.

But real-life paleontologists in the Yale lab addressed their favorite fossils as if they were family pets. The great Tyrannosaurus rex had been known as “that big bug” since 1909. The Montana canyon where the finest rex had been dug was “Bug Creek.”  And the whole slice of geological time recorded by the rocks there had become the “Bug Creekian Age.”

buggy blogOur esteemed Curator of Paleontology, Dr. Robert T. Bakker

The term “bug” was a term of paleontological endearment. Tiny, microscopic fossils were “bugs.” The paleo folks squinting down their microscopes searching for single-celled fossils said they were searching for “my beloved Early Paleocene bugs.” Field expeditions looking for tiny Jurassic mammals spoke of “furry bug jaws,” a.k.a. the dentigerous rami from Paurodon, Docodon, and Ctenacodon.

Gigantic species, too, were encompassed by the affectionate buggy label.

Trilobite specialists — and I have met many — always smiled when they showed us students an especially ornate Devonian phacopidan: ”Check out this elegant bug,” they’d say. Trilobites with smooth, streamlined shells — adaptations for burrowing through the sediment — invariably were “mud-bugs.”

buggy blogA trilobite or “dino-bug,” as they are affectionately called in the paleontological community.

“Puppy” was popular for Mammalia of gargantuan sizes. The immense, multi-ton Eobasileus cornutus, an herbivore with six horns and giant saber-teeth, was “that bumpy-headed puppy.”  Even cold-blooded Amphibia could enter that category.  When we moved a cast replica of the Triassic Mastodonsaurus, with its yard-long skull, we were cautioned to be especially careful with that “monstrous puppy.”

The term “Dinosaur” was an honorific as well as a narrowly defined taxonomic category. Any fossil that evoked the mystery of the Deep Past could be an “honorary dinosaur.” Mastodons and mammoths, saber-toothed cats and fin-backed Dimetrodons were all included in the “dinosaur exhibit.” Trilobites, because they were so captivating, were honorary “dinosaur-bugs.”

The labels in our new HMNS fossil hall follow the paleontological tradition of using both technical and affectionate terms. The free app, which be available soon, will give even more scientific data, plus stories from the scientists. Our superb skeleton of an Early Permian lake amphibian is labeled as an Early Permian archegosaurid. But it also goes by the nickname bestowed by the collection-management crew when the crate was opened — “Happy Puppy.”

The breathtaking sea reptile with seven unborn embryos is described in the signage as “Stenopterygius from the Toarcian Age of the Early Jurassic.”  And also as “Jurassic Mom.”

Our HMNS trilobite display is among the very best in the world. All our many trilobites are identified by genus and species, family and geological age. There’s a compact but precise scientific family tree of all trilobites, showing their Darwinian booms and the puzzling busts of extinction. But, since we are very fond of every single trilobite specimen, we are are quite happy to call them “bugs,” too.

The only way to experience the joy of paleo-nomenclature in all its multi-levels is to visit our hall, stroll past the petrified bugs, puppies and mini-monsters, and thereby absorb the wonder of the Deep Past.

She has a gift: 7-year-old Hannah Aaronson lends a rare Anomalocaris to HMNS’ new Hall of Paleontology

Anomalocaris. This shrimp-like creature, which measured about 6 and a half feet long, was the biggest predator of the Cambrian Explosion — around 530 million years ago.

It was a funky-looking thing, with two funny feeding appendages at its front and undulating lobes down its sides. It was a swift swimmer, and feasted on trilobites much the same way we eat crawfish today — breaking them open and sucking out their insides.

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Our top-of-the-line Anomalocaris replica, courtesy of a generous young donor.

To suss out the teensy trilobites, Anomalocaris used its super sharp vision. It had 30,000 lenses in each eye — compare that to the dragonfly’s 28,000!

When something is hundreds of millions of years old, it’s easy to understand why a complete specimen might be hard to come by. Although the Museum does have an original arm segment of a 500 million-year-old Anomalocaris, we wanted a high-end replica so patrons could get an idea of what this creature was really like.

Japan-based Griffon Enterprises had just such a model. The problem? It wouldn’t be on sale for many months after our new Hall of Paleontology opened to the public.

Enter miss Hannah Aaronson. Hannah won one of the company’s original prototypes in an auction, and decided to lend her spiffy prehistoric model to the Museum.

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Hannah and her mom at the installation of her Anomalocaris at HMNS’ new Hall of Paleontology.

Hannah’s generous gift — on loan for one year — helps to complete the evolutionary story of the trilobite. Anomalocaris had been a mysterious creature to scientists for some time, and many now speculate that it may have contributed to trilobites evolving the ability to roll up for protection.

Once the model becomes available for purchase, the museum will get its own Anomalocaris and return our current model to its rightful owner, who promises to visit it while it’s on loan to HMNS.

Of course, you should visit, too! The new Hall of Paleontology opens Friday to members and June 2 to the general public.

Your questions, answered: Do we know when chimaeras shifted to deep-water habitats?

Earlier this month we received a question on one of our past posts, The Ghost Sharks of the Jurassic, asking:

“Do we know when these chimaeras shifted to deep-water habitats? If predation and, in particular, the evolution and diversification of predatory species prompted their geographic transition, at what point would a sort of critical level have been reached to drive them into the deep? How many predators are too many?”

Why do “living fossils of the deep sea” so often represent lingering survivors of groups that long ago flourished in shallow water?

 
Rabbitfish

Examples: Rabbitfish (aka chimaeras), Coelacanths, Goblin Sharks, Giant Squid.

Excellent question – one that keeps evolutionary biologists awake at 2 a.m.

First thing: we never know when a clan of species invades deep water. This is why:

Sediments deposited on top of oceanic crust in deep-water – thousands of feet deep – rarely come to the surface where the layers can be seen by fossil-hunting paleontologists. Mud does form at the bottom of deep seas and fossils do form here. But such deep specimens have a low chance of being found by us.

Deep sea bottom mud is raised above sea level when continents collide and abyssal sediment is squeezed up and thrust across slabs of continental crust. There are narrow zones of such squeezed sediments – for example, in the Taconic Mountains of New York State. Here are slices of deep crust and sediment with deep-water trilobites. However, very few vertebrate and squid fossils are known from squeezed deposits.

Medium-deep sediment, up to 200 meters deep,  do form in the bottom of “epi-continental seas” like the famous  “Cretaceous Ocean of Kansas” that covered much of the central areas of North America. Such epi-continental seas  do drain away, and the bottom sediment becomes lifted hundreds or thousands of feet, so wind and water can erode valleys into the rock layers, exposing fossils. Epi-continental sea bottoms have given us 90% of our marine vertebrate and cephalopod fossils.

Coelacanth fossils are common in shallow-water and medium-deep sediments beginning in the Early Devonian, over 400 million years ago. From then on, coelacanths remain widespread and often common. Were they in deep water too? We don’t know – we don’t have enough deep sediment exposed for study.

Abruptly, coelacanths disappear from epi-continental sea deposits in the Late Cretaceous. Naturally, we thought they were extinct. But then the fish show up alive and well, hanging around at 130 meters to 700 meters.

Ditto for the Goblin Shark: common as a fossil along New Jersey in shallow sediment but now restricted to much deeper waters. Ditto for the giant squid, who left their shells in the Cretaceous epi-continental sea sediment but now prefer deeper water.

Goblin Shark

Is there a common explanation for all the survivors in deep waters?

The most popular theory is: 1) Most new types of fish and cephalopods first evolve in shallow water. 2) It takes time for evolution to modify a fish or cephalopod so the beast can survive at 200m + depths. So the early coelacanths couldn’t colonize the great depths for tens of millions of years. As more and more clans of fish evolved in shallow water, some began their adaptive descent too – but the coelacanth had a head start. Being fully adapted to great depth already may have protected the fish from predators and competitors who are behind in the degree of their transition.

There are holes in the theory. Coelacanths do have predators – they show up in shark stomachs. They must have competitors too – teleost fish with more complex jaws.

Deep Sea Refuges continue to irritate our neat little hypotheses.

WAnt more? See the past post on ghost sharks and full comment.