Friday, March 16, 2012

Herp Club Alumni Describe Smallest Known Vertebrate

Early this year, several online journals including National Geographic and the BBC reported on the latest vertebrate described as the world's smallest at an average body size of only 7.7 mm, a tiny frog species from Papua New Guinea (Paedophryne amauensis).  The news especially excited us in the Cornell Herpetological Society because three out of five authors of the paper that described it are among our recent club alumni and former presidents: Eric Rittmeyer (class of ’08), Derrick Thompson (class of ’09) and Mike Gr√ľndler (class of ’10). You can find their article on PLoS One.

Paedophryne amauensis on a dime
Eric, Derrick, and Mike started the journey that would ultimately lead to New Guinea while they were still undergrads at Cornell. The idea came from a vertebrates class guest lecture by Ed Scholes, who studies birds of Paradise in New Guinea. In the fall of 2007, they went to Dr. Kraig Adler (the herp club’s advisor) and presented their idea. Dr. Howie Evans of the vet school also helped them out, giving them valuable information drawn from his own experience in New Guinea. They decided to do a transect starting on the coast of New Guinea and heading up a mountain into the interior of the country in an attempt to examine the turnover in herp species composition across an elevation gradient.
Once their plan began to form, they needed to raise money for the venture, which they estimated would require roughly $25,000. Dr. Adler had friends affiliated with the Bishop Museum who were starting a field station in New Guinea, and Allen Allison of the museum agreed to help the three undergrads after Dr. Adler sent Mike’s proposal.  More help came in the form of $2,000 from a herp club grant provided by an anonymous donor. By the time Eric, Derrick, and Mike went to New Guinea, they had managed to raise $13,000. The Bishop Museum covered their other expenditures in the the country.

The trio worked hard to prepare for the trip. For the fall field trip, the herp club visited Harvard’s Museumof Comparative Zoology, which has a very large collection of New Guinea herps. Dr. Adler tipped off the museum’s director Jim Hanken, who made a point to show the club many of the New Guinea specimens. He also allowed the future explorers to come back to Harvard during spring break to familiarize themselves with the animals and take photos in preparation for their project. Their preparation also included a trip to get a feel for working outside of the temperate zone: in January 2008 they went to Costa Rica with several other herp club members to practice working in a tropical environment.

Finally the summer arrived and our heroes made the long trip to New Guinea. When they got there, it turned out that the coastal village where they were staying had been in recent conflicts with a neighboring village farther inland, and carrying out their original transect up the mountain would put them in danger from the conflict. They could not safely go more than 1000 meters above sea level, so they ultimately did general surveys and collected specimens at several low elevation sites.

Mike and Derrick


The transects provided baseline data for long-term frog population monitoring and also produced species unreported from the area, including several previously undescribed species: Paedophryne amauensis, now the world’s tiniest known vertebrate, Paedophryne swiftorum, a close relative, and a species of Choerophryne, another microhylid frog with a distinct elongate snout. The latter species was known from a single specimen, and during one night they managed to collect a female and five male specimens as well as record the calls of three different males.

Paedophryne swiftorum

Paedophryne amauensis

Eric Rittmeyer graduated from Cornell in 2008 and went to Louisiana State University to pursue his PhD in the lab of Dr. Christopher Austin. He returned to New Guinea in 2009 and collected specimens and tissues of Carlia eothen, a species in a group of skinks that he is focusing on for his dissertation. Eric will be giving a talk about his research to the herp club on April 23.

Derrick Thompson graduated in 2009. He moved to Thailand, where he now teaches.

Mike Gr√ľndler  graduated in 2010 and spent time in Trinidad studying guppies, then at Archbold Field Station in Florida studying sand skinks and beetles. Now he is a Luce Foundation fellow in Mongolia translating Futuyma’s evolution textbook from English into Mongolian.

Photos courtesy of Eric Rittmeyer

Post by Jessica Tingle

Saturday, March 10, 2012

Salamander Migration

The weather is getting warmer and rainy, and that means it's about time for salamanders to start migrating from the woods to breeding ponds.

The salamanders you will see in vernal ponds around Ithaca are in the family Ambystomatidae. The two likeliest species are spotted salamanders (Ambystoma maculatum) and Jefferson's salamanders (Ambystoma jeffersonianum), though just north of Ithaca is a hybrid zone between Jefferson's salamander and it's northerly relative the blue-spotted salamander (Ambystoma laterale). They are relatively large salamanders measuring 5-7 cm and sporting heavier bodies than many of our other local salamanders.

Spotted salamander, Ambystoma maculatum

They spend most of the year under debris or underground, but like most amphibians their life cycle is tied to the water. Unlike reptile eggs, amphibian eggs don't have a shell to protect them from desiccation, so females lay their eggs in small ponds or other moist locations. Spotted and Jefferson's salamander courtship and fertilization also take place in the water. 

In the early spring, warm rain signals to these salamanders that it is time to breed. Males and females migrate to their breeding ponds, where the males court the females using pheromones released from their cloacal glands. They may use their their tails to fan the pheromones towards the females underwater. When a female becomes interested, the male walks and she follows him. He deposits a gelatinous packet of sperm called a spermatophore onto the bottom of the pond, then she walks over it and picks it up with her cloaca. Fertilization is internal, as it is with all other salamanders except for Cryptobranchids such as hellbenders.

Ambystoma maculatum in shallow pond

Jefferson's salamanders generally come out earlier in the spring than spotted salamanders do, and have even been known to crawl over snow on their way to the pond.

Ambystoma jeffersonianum braving the snow to breed

Many years, tens or possibly even hundreds of salamanders will come to a pond during a single night in a phenomenon often called explosive breeding. It is a fantastic thing to see and it attracts many people. While going out to see the salamanders provides an exciting night and a good learning experience, we must take care that we do not negatively impact the salamanders and their habitat.

-If you drive to a pond, make sure to park your car far enough away that you do not run over any salamanders that may be crossing the road.

-Each person in your group should have a bright light to see the ground around them. Keep your eyes on the ground and walk slowly, taking care not to step on any animals.

-Salamanders, like all amphibians, have very delicate skin. They easily absorb anything in environment, so touching one when you have lotion, bug spray, or anything else on your hands can harm them very badly. In addition, their skin must stay moist at all times. It is best not to pick them up, but if you do, first get your hands wet with damp leaves or water from the pond (not tap water from a water bottle-it has chlorine that can hurt them).

Notice how he got his hands damp before holding the salamander.

While you are out at the pond, you may hear or see other breeding amphibians. Some that we have locally are spring peepers, pickerel frogs, and wood frogs.

Happy spring and please enjoy the amphibians responsibly!

Photos: Brian Sherman

 Post by Jessica Tingle