This week the FLMNH hosted the annual Society for the Preservation of Natural History Collections’ conference. I was lucky enough to be able to both volunteer at and attend the event. Through attending the conference, I was able to see many interesting talks regarding museum collections. I was especially interested in seeing talks regarding outreach and advocacy. I watched talks that described how museum specimens can be used to teach all types of people, from small children to people with disabilities. These presentations have inspired me to think about how we can use museum collections as more than sources of data for researchers, but as tools to instill an appreciation of science into the public. Overall the SPNHC meeting was a great experience and I got to meet many interesting people from all sorts of natural history museum related careers.
This Fossil Friday we have the dental plate of a cownose ray (genus Rhinoptera). This fossil is from the Gatún Formation and is late Miocene in age. Today, modern members of this genus (see photo below) can be found swimming in the shallows of the Pacific Ocean. A ray that possessed this dental plate would have used it to prey on invertebrates by sucking them into its mouth and crushing them. Skates and rays are known as batoids and, like sharks, are cartilaginous fish (chondricthyans).
To learn more about this specimen, check out the Fossils of Panama page on it here.
Over the past couple of weeks I’ve been working on several smaller projects around the lab that have included identifying specimens from the Gatun formation, washing samples of Pacific Muck in the screen washing room, and unpacking specimen from several storage boxes in the lab.
Working with the specimen from Gatun was a fun, though some times tedious, experience. Getting a chance to sit down with multiple specimen and try my hand at identifying them wasn’t something I had done before. Studying the shells and figuring out the, often, minute differences between different species was an enjoying break from reading papers on millipedes and editing my own work.
Though I’ve done screen washing before, having spent last summer at PRI screen washing, it was great to see a different system, with several different screens as opposed to a single screen. It was also nice to work with sediment that was dry and sandy instead of a moist, muddy, clay. Being able to see the different contents of the samples was exciting as well. The Pacific muck contained quite a diverse faunal selection while the samples at PRI where mainly oysters (having been sampled from a fossil oyster reef).
Unpacking the stored fossils was also a good experience, being able to see what had been previously collected and shipped up from Panama. Many of the specimen were in great shape and seeing the diversity of the fauna was great.
This week the new field interns came to Gainesville to get a training before heading down to Panama at the end of May. On Tuesday I got to work with them throughout the day and show them some of the things I do during the day. I was able to save some of the work I had from the past week to show them and teach them a little about it.
In order to tell whether the turtle skull I am studying is different than the skulls of modern relatives, I needed to run a morphometric analysis. This means I needed to take measurements of many different features on many different specimens and then analyze the relationships among those measurements. There are a few ways to do this. Traditionally, measurements of lengths, angles, masses, etc are taken and compared between a set of specimens. These measurements are essential and are the first step in studying variation in a species. We can use this data to understand development, as in a growth series, or population differentiation across space. The main challenge for interpreting these relationships is that most of these measurements are correlated, for example, forearm length will vary with the length of the humerus. In order to make these comparisons informative, we have to remove the effects of size. We do this by standardizing the data.
As one may imagine, it is difficult to make comparisons as the data sets get larger and larger in terms of number of specimens and number of measurements. There are programs that can be used to help visually represent this variation. R is a statistical analysis program that allows you to write computer code to take the data and manipulate it in all kinds of ways. The manipulated data can be visually represented by any number of graphs and charts. As in all code writing, there is a lot of going back and forth, fixing code errors that can be as small as a misplaced comma. I started by looking at box plots of my measurements to see where the greatest variation was and then looked over bivariate plots to see which pairs of measurements have most interesting or unexpected relationships.
I am still working my way through a great R tutorial created by DataCamp (www.datacamp.com) and hosted by the swirl project (www.swirlstats.com). It’s not easy but it’s not unlike learning how to use a suped-up scientific calculator. I still have a lot to learn but I can see the power of adding a program like R to my Paleo toolkit.
For this Fossil Friday we have a whale of a discovery to share, specifically the skull of a kogiid whale. Nanokogia isthmia is the first fossil kogiid whale found in the Central America and Caribbean region. It was collected from the Piña Facies of the Chagres Formation and is about 7.5 million years old (late Miocene). Kogiids are a family of odontocete (toothed) whales and are represented by only two species in the modern day, Kogia breviceps and Kogia sima. Although kogiids can be found in waters worldwide, they are quite rare both today and in the fossil record. This discovery of a kogiid whale in Panama helps show that these whales were a part of Neotropical marine communities since at least the late Miocene.
The description of this discovery was written by former PCP PIRE postdocs Jorge Velez-Juarbe (first author), Aaron Wood, and Austin Hendy and former STRI fellow Carlos De Gracia. Be sure to check out their publication on this fascinating find here.
Velez-Juarbe, J., Wood, A. R., De Gracia, C., Hendy, A. J. W. (2015) Evolutionary Patterns among Living and Fossil Kogiid Sperm Whales: Evidence from the Neogene of Central America. PLoS ONE 10(4): e0123909. doi:10.1371/journal.pone.0123909
PCP PIRE’s museum internship application for Fall 2015 is now available! Fall 2015 museum interns will be able to explore questions dealing with the paleobiology of the Neotropics at the Florida Museum of Natural History. Applicants interested in all aspects of paleontology including paleobotany, invertebrate paleontology, and vertebrate paleontology are encouraged to apply.
This internship for undergraduates/post-baccalaureate students coincides with the University of Florida Fall Semester (August 24 – December 18). A monthly stipend is provided, as is assistance with locating housing in Gainesville, FL. Applications are due July 1, 2015. Click here for application instructions.
This Fossil Friday we have a barnacle from the Pleistocene Armuelles Formation. Barnacles are crustacean arthropods (Phylum Arthropoda, Subphylum Crustacea), so they are somewhat related to crabs and lobsters. Something special about this particular barnacle is the incomplete hole in one of its plates. This barnacle was preyed upon by a drilling predator just like many other shelled marine invertebrates, such as clams, snails and crabs, to name a few. Possible culprits behind these drill holes, which are still around and continue to drill today, are muricid snails (see photo) and octopods.
To read more about this specimen and barnacles as victims of drilling predators, check out the publication here.
Klompmaker, A.A., R.W. Portell, S.E. Lad, and M. Kowalewski. 2015. The fossil record of drilling predation on barnacles. Palaeogeography, Palaeoclimatology, Palaeoecology 426: 95–111. doi:10.1016/j.palaeo.2015.02.035
For the last few weeks Roger and I have been prepping out the millipede that was found by Aaron Wood in Panama. It went from about fifty percent covered in matrix and 100 percent covered in butvar to fully uncovered and exposed! It took about a week and a half of scraping with a pin vice and dental picks to remove all the unwanted material. In the middle of it I was also pulled away from work by a family emergency which slowed down the preparation immensely. Together with the millipede from Florida the Panamanian specimen will the be foundation to my paper.
While working on the preparation we found that along most of the dorsal side of the millipede many of the leg attachments were still there, though most of the legs had been broken off. Along the end where we think the head might be many of the leg segments were still attached, though they easily broke off when the matrix was removed from around them. We are hoping that by using the air abrasive unit we will be able to more delicately remove the matrix from around the legs and preserve the segments in place.
This past Tuesday Roger and I went to the state Museum of Entomology in Gainesville to meet with Dr. G. B. Edwards in hopes that he could help narrow down the possible identifications for us. As can be seen in the photograph above neither specimen has very many, if any, diagnostic details preserved. Dr. Edwards was able to point us in the direction of a few families of millipedes but because his area of interest lies with jumping spiders (which are extremely interesting and colorful I might add), he was not able to help us identify the specimens more then that, though he did provide a name of a specialist who would likely be able to help us.
Hopefully within the next few weeks we will be able to take some more high quality images of the fully prepared millipedes and send them off to at least a few specialist who can help us get a better sense of what we might have.
Lately Ariel and myself have been working on identifying specimens that were recovered from the Nebraska All Hands trip last year. We have been identifying the taxon, the nature of the element, the side, and the tooth position of various different specimens. We are working with taxa ranging from Brontotheres to rodents. Working with the Panama collection was an integral reason as to why we are able to do this because we learned so much about various taxa from doing so. I have been working with Aldo Rincon on measuring camel teeth, and he has taught me a great deal about artiodactyls. This makes it much easier to identify the artiodactyls in the Nebraska collection, and I have been surprising myself with how much I am able to identify. For specimens that we cannot identify readily, we have been using comparative specimens also from Nebraska. All in all this has kept us very busy, as there are hundreds of specimens awaiting identification.
This week’s Fossil Friday is the subject of a paper recently published by former PCP PIRE Post Doc Aaron Wood and Spring 2013 field intern Nicole Ridgwell. The specimen is a right first or second lower molar of a chalicothere (Family Chalicotheriidae), which are an extinct group of clawed perissodactyls. The molar, collected by one of the authors of the paper, Nicole Ridgwell, was found in the Las Cascadas Formation in the Lirio Norte area of the Panama Canal. It is early Miocene in age and is the first record of a chalicothere from Central America.
To access the paper detailing this chalicothere molar, click here.
Reference: Wood, A. R., Ridgwell, N. M. 2015. The first Central American chalicothere (Mammalia, Perissodactyla) and the paleobiogeographic implications for small-bodied schizotheriines, Journal of Vertebrate Paleontology. DOI: 10.1080/02724634.2014.923893