Reconstructing a Gomphothere (Mastodont relative)

Photo by Ariel Guggino

This past week I was assign to reconstruct a gomphothere’s tusk and rib bone. I am actually the fourth person that has worked on this project, and most likely the last before it goes in the museum’s collections.

For some of you that are still wondering what is a gomphothere, this is a relative of the mastodon and mammoth. This extinct proboscidean lived during the Miocene and Pliocene, which is about 12 – 1.6 million years ago. These mammals were globally distributed, its remains have been found in North America, East Africa, Europe, Japan and China.

Fossil Friday 5/29/15: An oreodont humerus

The humerus of a merycoidodontid oreodont. The distal end is toward the left and the proximal end is toward the right. The humeral head has been damaged, however the distal end, which forms a joint like our elbow, remains intact. (Photo © Rachel Narducci)

This Fossil Friday I’m presenting an oreodont humerus that was prepared by PCP PIRE preparator Rachel Narducci.

SPNHC 2015!

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.

Fossil Friday 5/22/15: A cownose ray

The dental plate of a cownose ray, Rhinoptera sp. (Photo © VP FLMNH)

This Fossil Friday we have the dental plate of a cownose ray (genus Rhinoptera).

All the Small Things

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.

Intro to Morphometrics and R

PCP-PIRE intern Justy Alicea measuring turtle skulls for his morphometric analysis

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.

Fossil Friday 5/15/15: A kogiid whale

UF280000, a dorsal view of the skull of Nanokogia isthmia. (Photo excerpted from Velez-Juarbe et al. 2015)

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.

A photo of a modern Kogia breviceps, the pygmy sperm whale. (Photo courtesy of the National Oceanic and Atmospheric Administration)

Reference:

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 Fall 2015 Museum Internship Application Now Available!

Spring-Summer museum intern Ariel Guggino examines leaf fossils in the paleobotany collections at FLMNH.

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.

Spring-Summer museum intern Justy Alicea 3D scanning a fossil turtle skull.

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.

Fossil Friday 5/8/15: Barnacles!

The shell of the modern muricid gastropod Murex globusus (left) and UF 250804, a fossil barnacle with an incomplete drill hole from the Armuelles Formation of Panama. (M. globusus photo courtesy of Kevmin, barnacle photo excerpted from Klompmaker et al. 2015)

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.

Reference:

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

Milly the Millipede

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.