Marine Iguanas (Past)

Marine iguanas (Amblyrhynchus cristatus) are some of the most of remarkable Galápagos organisms. They are the only lizards in the world that have adapted to the marine environment, as they  exclusively feed on algae in the tidal and subtidal zone. Being active swimmers and divers, these large and mobile animals have colonized all major and minor islands of the archipelago. All the populations are included in the genus, Amblyrhynchus, which  in the same clade with three species of Galápagos land iguanas (genus Conolophus). Only a single species of marine iguanas is formally recognized although high levels of genetic and morphological distinctiveness characterize most of its populations. We have been working on the evolutionary and ecological genetics of these unique animals to understand the history of their colonization and the interplay between hybridization and speciation in shaping the observed patterns of genetic variation. We are also interested in understanding the impact of cyclical natural environmental  events, such El Nino, or human determined ones, such as oil spills,  in modulating the amounts and patterns of genetic variation in this species.  In parallel to the development and use of neutral DNA markers were developed non-neutral markers associated with the Major Histocompatability Loci (MHC). These genes are traditionally associated with the capacity of organisms to respond to environmental changes or stress.  In addition to the genetic focus work we are involved in ongoing collaborations to look at the evolutionary, environmental and ecological determinants of the striking difference in body size and shape observed across different populations from different islands.

Collaborations: Sebastian SteinfartzScott Glaberman (University of South Alabama) Ylenia Chiari, Deborah Lanterbecq (University of Mons-Hainaut, Belgium).

Publications: MacLeod, A., Rodríguez, A., Vences, M., Orozco-terWengel, P., García, C., Trillmich, F., … & Steinfartz, S. (2015). Hybridization masks speciation in the evolutionary history of the Galápagos marine iguana. Proceedings of the Royal Society B: Biological Sciences, 282(1809), 20150425.

Steinfartz, S., Glaberman, S., Lanterbecq, D., Russello, M. A., Rosa, S., Hanley, T. C., … & Dell’Olmo, G. (2009). Progressive colonization and restricted gene flow shape island-dependent population structure in Galápagos marine iguanas (Amblyrhynchus cristatus). BMC Evolutionary Biology, 9(1), 297.

Glaberman, S., Moreno, M. A., & Caccone, A. (2009). Characterization and evolution of MHC class II B genes in Galápagos marine iguanas (Amblyrhynchus cristatus). Developmental & Comparative Immunology, 33(8), 939-947.

Glaberman, S., Du Pasquier, L., & Caccone, A. (2008). Characterization of a nonclassical class I MHC gene in a reptile, the Galápagos marine iguana (Amblyrhynchus cristatus). PloS one, 3(8), e2859.

Steinfartz, S., Glaberman, S., Lanterbecq, D., Marquez, C., Rassmann, K., & Caccone, A. (2007). Genetic impact of a severe El Niño event on Galápagos marine iguanas (Amblyrhynchus cristatus). PLoS One, 2(12), e1285.

Hanley, T. C., & Caccone, A. (2005). Development of primers to characterize the mitochondrial control region of Galápagos land and marine iguanas (Conolophus and Amblyrhynchus). Molecular Ecology Notes, 5(3), 599-601.