Christopher E. Carlton
Carlton hassles a bullsnake in New Mexico, July, 2012 (photo, S. Hisamatsu).
I am interested in evolutionary and biogeographic patterns, and view systematic specialization as a means of examining such patterns on a manageable and personally satisfying scale. Most of my systematic research concentrates on the diversity and phylogenetic relationships of the staphylinid beetle subfamily Pselaphinae. Pselaphines possess an amazing array of species-level morphologies, including bizarre secondary sexual characters and sensory structures. They also exhibit highly derived evolutionary innovations associated with small size and a predatory lifestyle in interstitial spaces. As small organisms with extremely limited dispersal capabilities, many are indicators of relict faunal associations that reflect ancient biogeographic relationships. My other systematic interests extend in diverse directions, including some of the cucujoid families, especially Nitidulidae and Endomychidae. I particularly like the diversity of larval forms and developmental life histories within those groups.
In the field of conservation biology I am working towards a better understanding of the diversity and relationships of forest litter arthropod communities of natural ecosystems in the circum-Caribbean region. Current long-term projects include diversity studies in beech-magnolia forests on the Gulf Coastal Plain, and tropical forests in Central America and the Caribbean. Beech-magnolia forests in Louisiana occupy only a fraction of the area it covered prior to European settlement. This habitat is significant across the Gulf Coast because such forests harbor relict species of taxa that were displaced south during climatic changes that accompanied the advance of glaciers across much of eastern North America as recently as 15,000 years ago. The distributions of these species and their phylogenetic relationships provide important information for reconstructing historical events that had major impacts on the biota of the southern United States. Counterparts to these northern outliers include many species having affinities with neotropical taxa in Mesoamerica, particularly the Caribbean faunas of peninsular Florida, the West Indies, eastern Mexico, and the northern Central American countries of Belize, and Honduras. When sea levels dropped during Pleistocene glaciation, the land connections between these areas were much closer due to an extensive area of exposed continental shelf in the Gulf. Thus, it is important to consider these neighboring regions to develop a full understanding of the faunal associations of the Gulf Coast of the United States.
Beetle biodiversity in Great Smoky Mountains National Park along the Tennessee and North Carolina border continues to be an important focus of research in my lab. This is the most biologically diverse area in eastern United States thanks to its equable climate, its geographic location south of the limits of Pleistocene glaciation, and its mountainous terrain. The Park is the target of one of the most ambitious and long-standing All Taxa Biodiversity inventories in the world, initiated during the late nineties and is still going strong (see the Discover Life in America website). I'm in charge of coordinating Coleoptera studies for the project and pursue various specialized taxonomic projects within the context of the overall goals of the Coleoptera component of the ATBI. Our lab has been involved in the project 2001 and made tremendous progress in documenting the beetle fauna of the region thanks to a major NSF Biotic Surveys and Inventory grant. More recently, I have focused attention on the pselaphine staphylinid fauna of the New Zealand region in collaboration with colleagues in North America and New Zealand. The taxon is diverse at the species level in New Zealand, but has suffered from a near complete lack of systematic attention since the original descriptions during the late 19th and early 20th century. As a result, they have not been available to help address important questions about the origin and biogeography of the New Zealand endemic biota.
In addition to pursuing my own research program, I serve the agricultural community and the general public through identification and diagnosis of arthropods and related problems in Louisiana. As Director of the Lousiana State Arthropod Museum, I am responsible for fulfilling the objectives and managing the growth of the largest arthropod collection and research voucher repository in Louisiana. My teaching responsibilities include Insect Taxonomy and General Entomology (beginning 2006) courses.