November 15, 2006
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Photo K. Blackburn
Dave Blackburn working in the Herpetology Collections
of Harvard's Museum of Comparative Zoology. |
When scientists return from the field, their research and work is only just beginning. Once we were back at the museum, we began to catalogue the specimens by entering them into the collections of the herpetology department of Harvard’s Museum of Comparative Zoology (MCZ). These specimens are then used in both our own research as well as that of researchers at other universities and museums. In the lab, we also began processing the many tissue samples that we collected in the field. These tissue samples serve as our source for obtaining DNA sequences of the frogs we collected during the trip. This type of information is useful for describing new species, understanding how different species are related to each other, and learning how populations of the same species that live in different areas are related to one another. As of mid-October, most of the material that we collected this summer had already been accessioned (or officially catalogued) in the herpetology collections of the MCZ. The data will soon be posted on the museum’s online database
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Joe Martinez is a curatorial assistant in the Herpetology Department of Harvard’s Museum of Comparative Zoology. When specimens collected during fieldwork arrive at the museum, Joe takes on the huge task of formally getting the specimens into the collections. This includes entering all of the data about the specimen into the computerized collection database and tying a tag to the specimen that lists its new museum number (this is in addition to the tag with a field number that is already tied to the specimen). Joe then sorts the specimens by species and puts them in jars filled with 70% ethanol for storage in the collection. The specimens are stored in the collection with thousands of other jars filled with reptile and amphibian specimens collected from around the world. |
Now that I’m back at Harvard, I am working on several exciting projects. All of these projects utilize the many specimens we collected during our fieldwork this past summer. First, I am using both anatomy of the skeleton and DNA data to determine how the many species of the African frog family Arthroleptidae are related to one another. This family is made up of three genera, Arthroleptis, Cardioglossa, and Schoutedenella, all of which we collected in Cameroon this summer. Once we figure out how these species are related, we can ask questions about patterns in the diversity of this family. I will investigate patterns in the geographic distribution of species (“biogeography”) and try to understand how features such as the strange, long fingers of male arthroleptid frogs have evolved.
In collaboration with two other scientists, I am currently working on the description of the new species of Cardioglossa that we collected in the forests at the very top of Mount Manengouba . In the lab, we are also busy doing laboratory work on the toads and many tadpoles that we collected during the fieldwork. Over the past year, a Harvard undergraduate, Annelise Sterne, has been working with me to determine the relationships of the strange toads (Nectophryne, Werneria, and Wolterstorffina) that are endemic to Cameroon and neighboring countries. This year, Annelise’s main research project is to use molecular data (that is, DNA) to help identify the many tadpoles that the team collected. Since relatively little is known about the tadpole stage of most Cameroonian frogs, we are likely to contribute a lot of new knowledge through this research. Because many of these tadpoles have unusual biology, it will be interesting to match the tadpoles with adult frogs. This is especially important since so many frog species in Cameroon are threatened with extinction. We will do this by getting DNA sequences from the tadpoles and then using several methods to try to match these with the sequences from adult frogs collected at the same places.
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Annelise Sterne is an undergraduate working with Dave Blackburn in the laboratory of Jim Hanken at Harvard University. Annelise is working on two projects using specimens that Dave collected in Cameroon in 2004 and 2006. In the first project, DNA sequence data is being used to determine the relationships between the strange toads of the genera Nectophryne, Werneria, and Wolterstorffina found in Cameroon and adjacent countries. In the other project, which has just begun, DNA sequence data is being used to match the many unidentified tadpoles the team collected to adult specimens from the same places. |
In the end, we hope to not only get a better idea of frog diversity and evolution within Cameroon, but also of Africa as a whole. Because Cameroon is one of the ‘hotspots’ of amphibian diversity in Africa, it plays a key role in our understanding of the amphibians of Africa. We hope that our information will be useful to other researchers asking questions about the diversity and distribution of animals in sub-Saharan Africa. As most of Africa is still poorly explored and documented, our work is very exciting in that we are in the position to discover many exciting new things about these frogs and document new patterns and processes in the organisms that we study.
For more information on Dave Blackburn's work, visit his web site:
http://www.oeb.harvard.edu/hanken/public_html/Blackburn.htm
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