Cephalopod Awareness Days: Back to the Basement
Greetings Blogophiles! How is your search for cephalopods going? Today in my quest to become aware of all the cephalopods we have at the Museum, my meanderings have led me back to the basement and into the Paleontology Collections. Admittedly I am cheating by searching for cephalopods here. Technically I am the Collections Manager for Geology/ Paleontology at the Museum so, if I can’t find cephalopods in this collection there’s a good chance no one can. Welcome to my job! But before we get to what’s actually in the Paleontology Collection, I thought I’d stop by the Paleontology Lab on A-level to visit one of our volunteers who has been meticulously preparing a fossil squid.
Everyone meet John. It may not look like much in the photo, but John is working on excavating the gladius or pen of a large Cretaceous squid (Tusoteuthis). Dan Lawver and I collected this specimen a couple of years ago during one of our big squid hunts. John has been working on this specimen once a week for almost two years now. He is very carefully scraping the sediment away from the gladius using a pin vise. Because the specimen is very fragile, and there is a lot of sediment that needs to be removed, this process is very, very slow. John doesn’t usually wear a squid hat when he volunteers, but as this work can be tedious, sometimes I try to inspire him by making him wear silly hats. Perhaps he’d make more progress if I left him alone… off to the collections.
Welcome to the cephalopods in the Paleontology Collection. Though the specimens in this collection may not all be as showy as some of the specimens on exhibit or as weird-looking as the ones in the Aquatic Invertebrate Collection, I still find them fascinating and hopefully you will too. As you might expect the Paleontology Collection has its fair share of nautiloids and ammonites, some of which were found in North Carolina. But what you probably aren’t aware of are some of the more obscure cephalopods we have. All of which are great examples of some of the unique problems associated with working on extinct organisms.
Belemnites! Okay, admittedly belemnites aren’t all that obscure. In fact they’re fairly common fossils from the Mesozoic. But they do tend to confuse people. Belemnites are an extinct squid-like cephalopod with an internal shell. It is the internal shell or rostrum that people find as fossils. For some reason, people occasionally confuse belemnites with fossilized remains of orthocone cephalopods (cone shaped external shells of nautiloid-like creatures from the Paleozoic) or bacculites (cone-shaped external shells of ammonites from the Mesozoic). When it comes to conical shells, the whole internal versus external shell can be tough to wrap one’s brain around. Basically, in life, belemnites were chewy on the outside and crunchy on the inside, whereas orthocone cephalopods and bacculites were crunchy on the outside and chewy on the inside. As fossils they are all crunchy all the way through.
Another cephalopod curiosity in Paleontology Collection is ammonite aptychi. Aptychi… there’s a word for you to impress your friends with. But what are they? Very good question, I’m glad you asked. Over the years there has been a lot of debate on the subject. Aptchyi are often found in pairs and sort of look like clam shells. In fact that’s what they were originally classified as. We now know, because they are occasionally found in association, aptychi are a preserved part of ammonites, exactly what part is still in question. Some scientists argue aptchyi are jaw apparatuses, while others argue that aptchyi are opercula (similar to the head shield of a nautilus) used to close the ammonite shell. Which do you think they are?
Not to be outdone, nautiloids also have “jaw” parts one can find as fossils. These calcified cores of their beaks are called rhyncholites (upper beaks) and conchorhynchs (lower beaks). Rhyncholites are much more common in the fossil record than conchorhynchs. Why? Good question. The thinking is the lower “beak” was less calcified. Okay but why give them different names? Here again is another case of cephalopods being prime examples of problems that plague paleontologists. Oftentimes fossils are incomplete. Word problem time…one paleontologist finds a fossil nautiloid shell a gives it a name, another paleontologist finds an upper beak and gives it a name, a third finds a lower beak and names that, then a fourth paleontologist finds a shell and both beaks in association. All already have their own names. What should the fourth paleontologist do? I’ll let you ponder the problem while we move on.
Great! Now Trish is giving us word problems… let’s see if these extinct cuttlefish-like critters can help. In the photo shown above are some internal shells of Anomalosaepia (an extinct cuttlefish-like critter), basically these are fossil cuttlebones. In the photo below are some molds or steinkerns of the phragomocone (chambered portion) of an extinct cuttlefish-like organism. Should we call them Anamalosaepia? They’re from the same locality and though they were not found together, they do seem to be from a similar organism. Wait…on closer inspection the second from the left seems to have less highly angled “lines” than the others… can I even call them the same name as the others in the same photo? Dang and Blast! That’s a lot to be aware of. Obviously extinct cuttlefish-like critters are no help at all. Yep, but it’s these types of questions that make working with extinct organisms and fossil cephalopods so interesting. The beauty of paleontology is we don’t know all the answers so we have to keep looking. Call it job security.
On that note, I wish you all Happy Cephalopod Awareness Days! I sincerely hope you’ve enjoyed this series of blogs. Whether you’re visiting a museum, trawling the Internet, listening to music, reading a book, eating, or whatever it is you spend your time doing, be aware of cephalopods. You never know where they’ll turn up next.