I am the Curator of Paleontology at the Alabama Museum of Natural History. I have set up this blog to share my research experiences as a vertebrate paleontologist working primarily on fossil sharks and turtles.

Thursday, July 15, 2010

On the ground...

Made it to Lima on Tuesday night. First flight was delayed, I had 5 minutes to run to the second flight before they closed the doors..Close call! The flight to Peru was one of the bumpiest I've been on... Add an old German man in front of me screaming at the stewardess for bumping his arm during drink service and you can imagine how happy I was to be on the ground... Renting a room from a friend of the paleontologists at the Museo de Historia Natural, Javier Prado and so far so good. Walked the 30+ blocks to the museum this morning... However, I opted for a taxi on the way back, since it was dark and I had my laptop with me... The first two days at the museum have been interesting as usual. Besides the sharks, which I will get to, I was fortunate enough to see the type specimen of Leviathan melvillei, the recently described, very large sperm whale. Along with a small, but VERY well preserved dermochelyid still in its jacket, a new archaeocete whale skull, and a host of other treasures...

The reason for my journey down here, though, is sharks, or tiburones if you wish.... I am particularly interested in the lamniforms as discussed in my previous blog. The Museo de Historia Natural, Javier Prado just so happens to have an extraordinarily complete skeleton of Cosmopolitodus (or Carcharodon if you will humor me) hastalis on display. I actually put up a picture last time, so I won't repeat. This specimen contains both upper and lower jaws full of teeth and portions of the neurocranium. Although, the specimen is ventral side up, and the dorsal side has not been prepared... In the next week and a half I will be measuring, photographing, poking, and maybe a little bit of prodding (haha) the specimen, so stay tuned. In the meantime, a paleontologist here at the museum collected one of the most complete carcharhinid (requiem sharks) skeletons I have ever seen. A nice spinal column of vertebral centra, a partial neurocranium, and both palatoquadrates (upper jaws) and Meckel's cartilages (lower jaws). Surprisingly, even after having two people work on it with air scribes all day, still no teeth! I say surprisingly, because typical shark fossils are just isolated teeth... So to have all the cartilage preserved, and not see any teeth is not a normal occurrence. However, I suspect the teeth are still in the jaw cartilages, and once the specimen is turned over, and the other side is prepared, we should be in for a treat....

I am off to Ica in the morning to spend the weekend in the desert collecting. So, look forward to updates and new pictures sometime next week!

Sunday, July 11, 2010

Testing, Testing, Is this thing on?

So, I've taken my failed running blog and reinvented it following other blogs I've seen by paleontologists. I will use this as a forum to show images of my travels, discuss my research and thoughts, and whatever else comes along. So, first things first, who am I?

My name is Dana Ehret and I am a Ph. D. student at the Florida Museum of Natural History working on the evolution, paleobiology, and paleoecology of lamniform sharks. What is a lamniform shark you ask? The Order Lamniformes are also known as the mackerel sharks and are defined by a number of key features including: 2 dorsal fins, an anal fin, five gill slits, eyes without nictating membranes, and a mouth extending behind the eyes. Living lamniforms include the white (Carcharodon), mako (Isurus), salmon and porbeagle (Lamna), thresher (Alopias), sand tiger (Carcharias) or 'ragged toothed' (Odontaspis), basking (Cetorhinus), megamouth (Megachasma), goblin (Mitsukurina), and crocodile (Pseudocarcharias) sharks. Extinct lamniforms can be found in the fossil record stretching back to the Jurassic, and include: the megatoothed (Otodus and Carcharocles), crow (Squalicorax) and sand tiger (Jaekelotodus) among a large variety of other species. Sharks pose an interesting dilemma in paleontology because their soft, cartilaginous skeleton rarely preserves in the fossil record. The result is a large fossil recored, almost entirely comprised of isolated teeth.

My research has focused mainly on the evolution of the white shark and the evolution of body size in the megatoothed sharks, which includes Carcharocles megalodon, the largest shark that ever lived. My studies have taken me all over the world, including Peru, South Africa, and Poland to name a few more exotic locales. Much of my research focuses on transitional white shark fossils from the southwestern coast of Peru and includes the most complete white shark fossil known. My research has been featured on the Discovery Channel, NPR, and the New York Times, among other news outlets.

I am leaving for Lima, Peru this coming week to study fossil shark skeletons in the National Museum. These skeletons belong to a species known as Cosmopolitodus (or Carcharodon as far as I'm concerned) hastalis, a taxon that most likely gave rise to the modern white sharks we love today. I'll try to post pictures and details of my journey. Enjoy!