The first step to figuring out if the physical appearance of these lizards do indeed change according to their ecological context was to visit natural history museums, looking for patterns in preserved specimens. After a bit of searching, I found that Yale, Harvard and the American Museum of Natural History in NYC all had preserved samples of Podarcis erhardii. The next step was visiting the museums to take a look at their lizards.
Here’s an example of my set up, with eight erhardii specimens in the Yale collection (1). You can see already from the picture that they reflect an interesting assortment of sizes and colors. To rigorously quantify this seeming diversity of morphology, that is, physical appearance, I took a slew of measurements on each individual. All of the traits I measured (for example, body length, sex, head width, leg length and length of the longest toe) have been shown in other lizard species to affect those lizards’ interactions with their surroundings. For example, head width determines the prey that lizard can eat, and leg length, in Anolis for example, is strongly related to the environment that lizard is crawling around in. Characteristics that affect the performance or reproductive success of a species are called “functional traits.” You’ll be hearing me talk a lot about them in the future.
It’s an amazing thing working behind the scenes in a natural history museum. While the dioramas and exhibits are wonderful and important, locked away behind closed doors of each museum is an astounding library cataloguing the diversity of life on Earth. For me, the biggest thrill of the project was working in the American Museum of Natural History in NY. When I arrived I was greeted at the door by one of the herpetology collection curators who led me through a winding maze of exhibits to an unremarkable door labeled “authorized personnel only.” In we walked to a much quieter world replacing crowded exhibit halls with corridors filled with filing cabinets spilling papers and shelves of books and collections from all over the world. I was told to be sure to close doors behind me because the department had a tortoise that sometimes wandered the halls. It’s insanely nerdy but I got so excited to see my name on the calendar of visiting researchers I decided to take a picture:
I followed my host through a maze of corridors and up and down several half flights of stairs until I’d completely lost my sense of direction. Eventually we made it to a tidy lab bench with bright fiberoptic lights, a microscope, an odd assortment of measuring tools and a jar full of lizards just waiting for me. The museum only had six specimens, all collected some 70 years ago, but it was well worth the visit just to see the collection and talk with some really interesting researchers. I could have spent ages wandering through the various offices filled with souvenirs from all over the world. To cap off the trip, the museum put the pictures I took of their specimens up on their digital catalog so anyone looking for erhardii in the future will be able to pull up my photos! Check them out here
(to see the photos, click on the link, click “herpetology” and then select, and type in Podarcis and erhardii in genus and species)
Next post I’ll give you a quick summary of what all I found from all that measuring.
1) Credit to Division of Vertebrate Zoology, YPM #15175, 15176, 15172, 15173,15174,15169,15170 (Left to right). Copyright 2013 Peabody Museum of Natural History, Yale University, New Haven, Connecticut, USA. All rights reserved.