Tag Archives: extinction

Fossil Monochrome

orthoceras

 

straight horned fusillade,

storm of black and white bullets

shot through ancient seas

racing head and foot into

eternity’s sediments

 

Orthoceras are ancient mollusks. They first emerged nearly 500 million years ago and went extinct nearly 200 million years ago. (They existed from the Ordovician through the Triassic. They had a 200 million year overlap with their younger cephalopod cousins, the ammonites.)

 

Imagining orthoceras alive.

 

Their name is descriptive, it means straight horn. They were soft bodied creatures that lived in the newest segment of the shell. Periodically they would grow a separating wall called a septa and close off the too small part of the shell. The different composition of septa and the external shell allowed them to fossilize differently, so we can still see their shapes today. (The curved lines running perpendicular to the outline of the fossil.)

 

The long channel you can see running along the center of the fossil-two parallel thin dark lines-was a hole that housed a strand of tissue called the siphuncle. It was (and is in nautiluses today) a way for them to filter water in and out of closed chambers, controlling buoyancy.

 

They probably worked in a similar fashion to those of creatures living today. It’s a pretty interesting method of control. It isn’t a muscular thing like you’d imagine. Instead it works by osmosis. Basically the change was controlled by blood salinity. Water would move from areas of lower salinity to higher in an attempt to achieve an equilibrium. Gases dissolved in the blood would slowly fill the chambers as the water moved elsewhere.

 

Despite the likelihood of this passive method of control, some propose that this might also have aided in propulsion.

 

Since all of orthoceras relatives were/are predators, it is fair to guess that they were as well.

 

Their fossils are often found in assemblages-like sheets of them mostly parallel-the only species present. It looks like an Edward Gorey inspired repeating wallpaper pattern! You see beautiful displays of them in museums or at fossil shows. (I’ve also seen really cool things made out of them, including the best bathroom sink ever!) Interestingly these groupings are found mostly amongst the older of the fossils.

 

Scientists aren’t sure why this is. Some believe it is evidence of post mating mass deaths, others that they simply traveled in schools. It’s been suggested that they are aligned so nicely because they shifted after death due to currents over the ocean floor.

 Minimalist Monochrome Orthoceras Pendant

I’m fascinated by the elegant simplicity of orthoceras fossils. They’re often black and gray and the smooth bullet like shape is a lot of fun to work with. It suits a lot of different styles. In my most recent turn with them I used three different colors of wire to try to mimic the tones and striped effect of the chambers in a simple woven frame.

Advertisements

Leave a comment

Filed under Crafts, Natural Science, Poetry

Extinction and Engraving

We saw a northern white rhino (well, the rear of one) at the San Diego Zoo Safari Park. The guide told us that they’re extinct in the wild, that the last ones left in zoos are too few (and too old) to breed. Conservationists tried to quasi-release some under guard in the wild again some years ago, hoping maybe that would encourage some last minute breeding…

It wasn’t even subtle human messing about with environment or land encroaching so much as poaching. One more species humans hunted out of existence.

 

For horns.

 

How do you react to that? I mean, really?

 

The guide was saying that they’re as happy as animals can be, they’ve food, a lot of land to wander in, and they’re safe. They don’t know that they’re the last of their kind.

 

My first thought was how surreal it is, to see something alive and *know* it’s extinct. That it’s past the point of no return and will be gone in my lifetime. Fossils are one thing, they’re long gone. I admit that I don’t get pangs working with ammonite fossils. I feel rather more disgusted with our species looking at the bones of megafauna that humans killed off in prehistoric times, though with that at least you can plead ignorance.

 

It was hot and sticky out and I still had that wet blanket feeling dropped on me feeling. Sometimes it’s really embarrassing to be human. Like you need to apologize to every other species on the planet. (Okay, except perhaps for rats, pigeons and mosquitoes, they’ve done well off of us!)

 

That was thought one on seeing the rhinos.

Thought two? Durer!

 

Size.

            Strength.

                        Shock.

                                    Awe.

                                                Sketch.

Powerful first impressions,

whispers down the lane…

exotic gift from afar-

mythical beast lost at sea.

 

When I saw the Greater One-Horned Rhinoceros at the San Diego Zoo I decided that for never having seen one and being really inaccurate, Durer did an excellent job capturing the general power and texture and feel of a rhinoceros. You can’t entirely fault him for adding rivets and plates to the cobblestone hide.

They’re not attractive (okay, so maybe they’re a little cute in an odd way when nibbling at leaves) but boy are they impressive. The ground was dry enough that they were making little dust storms on every exhale.

 

Albrecht Durer (1471-1528) was a German artist with a workshop in Nuremburg. (Though he work was greatly influenced by his travels through Italy.) He worked in a broad range of media-drawing, painting and printing. (Two of my favorite pieces are his young hare and owl, both of which are watercolors.) The delicacy of his lines across styles always astounds me.

 

Durer’s Rhinoceros is actually a woodcut, not an engraving. It recorded the first arrival of a rhinoceros in Europe in 1000 years. That particular rhinoceros was a gift from an Indian ruler to governor of Portuguese India who then gave it to the King of Portugal. It arrived in Lisbon in May 1515. The king then sent it as a gift to the Pope, but it died in a shipwreck. (Poor thing, talk about regifting!)

 

A description of it reached Durer in Nuremburg, probably with some sketches.

Leave a comment

Filed under Art, Natural Science

Fossil Echoes

nature, she echoes

variation on a theme

of fractal design

changed over millennia

past fossils like growing leaves

 

Brachiopods (literally arm-foot) appeared at the beginning of the Cambrian and peaked during the Ordovician (490-445 mya).

What’s fascinating is that while most of them have gone extinct, some species of brachiopod are still around, so it’s a story of survival. Even though I’m working with fossils of creatures that died hundreds of millions of years ago, a number of their descendants and cousins are still on sea floors the world over. (Around 100 different genera still exist, over 5000 are known to have existed.)

Brachiopods are bottom feeding marine creatures with two shells. (You can see the lip of their joint nicely in the fossils I picked up.) They’re symmetrical when viewed from above, unlike bivalves.

Mine are members of the spiriferidia. I think they’re of the Mucrospirifer genus. Some of the rock hounds on deviantart are thinking along the same lines, but I don’t have a location of origin to narrow matters down.

The one I bought more recently was from southwest Ontario and identified as a Mucrospirifer thedfordensis from the mid Devonian. (That’s about 385 million years ago.) My previous stash were probably from the same general area. (I’ve been told New York State is another possible origin.) This genus reached its highest levels of number and diversity during this period, so it’s a probably a safe guess that all the ones I’ve worked with are all (loosely!) around the same age.

I’m not sure all of my original stash were of the same species to begin with; since some were chubbier like the thedfordensis and others were much slimmer, though they all share the same basic shape and nice curve. I don’t know how much variation existed between individuals of a species.

Mucrospirifer thedfordensis

(I’m not very good at identifying fossils beyond the general. Anyone know of a good, *simple* guide for fossils? I like playing with ammonites too but can never divide them into species either.)

They would have lived in soft mud on the sea floor and attached to the bottom with a fleshy stalk. They were found all over the world. Brachiopods took a hit at the end of the Devonian period, but a diverse number survived into the next hundred million years. A lot of brachiopod species went extinct during the Permian Mass Extinction ( about 251 mya), along with a lot of the other ‘classic’ species we’re familiar with–like the trilobites. The corals of the era were so badly destroyed it took over 10 million years for them to recover, and 150 million for biodiversity to bounce back to pre-extinction levels. (Some of the Mucrospirifers survived the Permian Mass Extinction and held on into the Jurassic period.)

Walking past the brachiopods on a dealer’s table en masse they reminded me of fallen ginkgo leaves. I decided that I had to play with that resemblance by wrapping them with ‘stems.’ Now I want more to experiment with, and to learn how to properly identify the little suckers. I’d really like to take the term butterfly shells literally and do a butterfly shaped wrap somehow.

(Yes, I wrote a tanka over a fossil, I wrote a few about different types actually…)

5 Comments

Filed under Crafts, Natural Science