Into the rabbit hole

Over the past few weeks you have seen a brief introduction to all of the interns, what we do, exciting visitors, and wonderful tours. Now, I think, it is time to jump into the rabbit hole, and see what the collection holds.

First, I should provide some background information about most of the fossils we work with. The Mapes collection holds primarily fossil cephalopods (ammonoids and nautiloids – the externally shelled ancestors of squids and octopi). These fossils can come in any size from microscopic (you will see this later) to extremely large (some can have external shell diameters of 8+ feet). Modern Nautilus, shown below, are thought to be the closest model for all of these extinct shelled organisms. 

Nautilus pompilius (left) and Allonautilus scrobiculatus (right) – modern representatives of an externally shelled cephalopod (image courtesy of University of Washington).

Nautiloids and ammonoids are revered for their shells and the patterns you can find on them. These patterns – called sutures – represent the contact point of dividing walls (septal walls – provide structural support for the shell, does have some other minor functions) inside the shell with the exterior shell body. These patterns cannot be seen on modern nautilus until the outer layers of the shell have been worn away. One of the coolest things about working with the Mapes collection is you can see the evolution of complex sutures through time.

 

Sutures started out in the “nautiloid” form which is the simplest pattern one can find on a shelled squid. Modern nautilus and its ancestor nautiloids have retained this simple pattern throughout time. Ammonoids, on the other hand, have not. They have developed an increasingly complex suture pattern through time right until they went extinct in the Cretaceous. From the “nautiloid” pattern, sutures developed first into a “goniatitic” form (looks like waves or subsequent chevron folds) during the mid-paleozoic. Then, the “ceratitic” forms developed in the later Paleozoic. Both the goniatitic and ceratitic forms coexisted in the later Paleozoic. Once you reach the Mesozoic, the suture patterns become their most extreme in the “ammonitic” form during the cretaceous. Below you can see a generalized schematic of each type with a corresponding picture taken from specimens in the Mapes collection. Keep in mind, these types are more of a continuum than a “four types fits all” scheme. Not every ammonoid will fall into one of these categories, and will sometimes fall somewhere in between.  

Generalized schematic of suture types with corresponding images of real specimens within the Mapes Collection.

 

The Mapes Collection can tell amazing stories, like the sutures above. You can also see the diversity in ammonoid shapes that have arisen through time.

 

One of the most uniquely shaped groups in the world of ammonites are the heteromorphs. These ammonites are not your typical spiral shape. Some have long extending hooks detached from the main shell (if you want an example of hooks on ammonite shells click here). Some don’t even resemble an ammonite at all. For example, one of the interns had this Cretaceous aged torticone (a turreted spiral shape) ammonite in one of their cabinets.

As you can see, the Mapes Collection holds a wide array of unique stories that aren’t just limited to cephalopods. The collection houses more than we thought possible. In the past week we have found cephalopods (by the ton in ammonoids, nautiloids, and some coleoids (modern squids with internalized shells), vertebrates, bivalves (clams), brachiopods (they are similar in appearance to clams but not even closely related), even some of the more mysterious groups like conularids (there is no way to describe them, no one knows where they belong, click here for more on conularids), and scaphopods (tusk-shells).

Our task, as described in an earlier post, is to “rehouse, conserve, and catalog” the Mapes Collection. This is easier said than done. As you have seen, the collection houses just about every type of organism imaginable from a vast array of locations. Over the past few weeks we have sorted by locality, changed trays, assigned catalog numbers, and digitally linked any associated information for more than 2,000 catalog numbers (keep in mind 1 catalog number can hold anywhere from 1 specimen to upwards of 500 depending on the tray). We are aimed to pass the half way mark this week to meet our goal of 5,000 lot numbers (I think this totals about 27 cabinets).

You have seen some of the wonders this collection can hold. However, for each wonder there are a host of surprises and problems that can arise in our line of work. This week we were introduced to new methods of cataloging as we encountered unexpected microscope slides hosting ammonitella (embryonic stage ammonoids – more commonly known among the interns as tiny baby ammonites).

Microscope slide hosting numerous ammonitella.

There have also been severe cases of pyrite disease. Pyrite disease is where the mineral pyrite (FeS2), or potentially similar minerals, form within the bone, shell, or other material of the fossil. If incorporated, pyrite can oxidize (FeSO4 – Iron sulfate). Iron sulfate is much larger in volume than the original material and during crystal growth can cause the specimen to fracture. This is especially common in more humid conditions. The end result is what appears to be a large pile of cigarette ash with no specimen to be found. Shown below is a picture of a pyrite diseased specimen found in one of our cabinets.

 

However, pyrite does have its redeeming qualities. All of the problems and unexpected surprises within the collections become worth the effort when you find a true gem like the one below. This is a pyritized ammonoid. Pyritization is not the same as pyrite disease. Pyrite has replaced the original shell material and does not oxidize. This specimen also depicts some beautiful goniatitic sutures.   

Unusual localities have been a reoccurring theme this week. For example, one of the interns ran across a lagerstätte. For those of you who don’t know, a lagerstätte (lagerstätten – plural) is a sedimentary deposit that exhibits fossils with truly extraordinary preservation. This preservation can include soft tissues and other fragile pieces of anatomy. Below are some pictures of preserved original orthoconic nautiloid shell material from the Buckhorn Asphalt Quarry deposit. This material is impregnated with hydrocarbons (oil) preventing the destruction of the original aragonitic shell material. For some context, finding a lagerstätte is equivalent to finding a diamond in the rough. They are very rare, and those that do exist provide us with a fortune in scientific insights into what some of these organisms actually looked like with all preserved soft parts (not typically found in your everyday fossil bed), behaved, and where they lived.

 

Orthoconic (straight) nautiloid with original shell material from the Buckhorn Asphalt Quarry.

Granted, all this work isn’t without the typical mid-week break. This week we went on a tour of the herpetology departmental collections. Let me tell you, some weird things are housed there. I am going to let the pictures speak for themselves here rather than provide narration. Well…maybe some so you know what you are looking at.  

Talk about an unusual find…an approximately 4,000-year-old gecko. This gecko was found during an archaeology dig in Egypt. It was thought to be an accident as animals were not usually buried within the mummy wrappings. Though animals were typically buried with the mummies within the tombs. 

Your typical crocodile hide with skull.

Your typical crocodile hide with skull.

Did I forget to mention they have Komodo Dragons?

Don’t forget the live animals too J. These tortoises seemed content basking in the light of their heat lamp.

Sorry, I forgot what kind of snake this was…

Oh, and have you ever seen a rattlesnake penis?

Now you have.

As I have no real sign off ideas, I will leave you with one last image that I believe summarizes our goal for this collection. Be forewarned, it may not be what you expect.