Photo by John Hayes

Seminar Summary: Evolutionary diversification of the Chortis Herpetofauna

Authors: Jenna Cole, Carrie De Jesus

Dr. Joe Townsend is a University of Florida/Wildlife Ecology and Conservation alumni who focused his PhD dissertation on the amphibians and reptiles in the Chortis Block region of Central America. Dr. Townsend is now an Associate Professor at Indiana University of Pennsylvania (IUP) where he has continued his work in the Chortis Block. His current research is focused on systematics, evolution, and conservation of neotropical amphibian and reptiles. Dr. Townsend is also involved in biodiversity conservation and sustainable energy development within the region, as well as primary, secondary, and postsecondary education and outreach in Honduras.

The Chortis Block includes the countries of Nicaragua, Honduras, El Salvador and Guatemala. It's habitats range from montane cloud forests with dry valleys in-between. This part of Mesoamerica has had an active geological history experiencing three periods of volcanism. One of these volcanic events was the second largest volcanic event in history, which has implications on the evolutionary history of species in the Chortis Block. The volcanic activity led to the elimination of virtually all species in the area, allowing for recolonization by construction of entirely new ecosystems.

Species diversity of amphibians and reptiles in the Chortis Block is very high. There are 406 species of reptiles and amphibians, 38% are endemic to the region, and 96% of the endemic species are on the International Union for Conservation of Nature (IUNC) Red List. The remaining for 4% are not placed on the list due to lack of knowledge on the species. To help remedy this lack of knowledge, Dr. Townsend created a phylogenetic inventory of reptile and amphibians for the Chortis Region as part of his PhD, and has continued to expand upon it. He sequenced 1,994 samples for two mtDNA barcoding loci (COI, 16S). For amphibians 52 named species were identified with another 36 unnamed species. For reptiles 21 taxa were identified with another 7 unnamed candidate lineages.

Another group of amphibians that is a focus of research are the Chortis salamanders. There are 45 document species of the lungless salamanders, of which 39 endemic species exist, and 3 are in the process of being described. The whole group has widespread cryptic diversity and homoplasy (convergent evolution). This means that the salamanders all appear to be the same species, but are much more genetically diverse. The Townsend lab can find 3-6 species of salamanders per mountaintop, and are currently focusing on Moss Salamanders. Moss salamanders are small cryptozoic salamanders (cryptic natural history), and can be found in moss mats or in orchids and other bromeliads. This makes them challenging to study, along with their highly conserved morphology. There are two radiations of moss salamanders. One in the north in the Chortis Block, and a second in the Costa Rican highlands. The Townsend lab has worked hard to described 5 new species over the years of 2010-2016, and the proposed phylogenetic tree that has resulted from their studies.

Anoles are another cryptic organism that causes confusion and chaos when it comes to identifying individuals. In this region there are 37 species, 19 of them are endemic, and there are 2 introduced species as well. Most are described based on male specimen only (hemipenal and/or dewlap morphology), which makes females challenging to ID. The Townsend lab began a barcoding library to ID females. This effort has showed there are 32 native species, and 45 lineages were recovered across all analysis. They also discovered that potentially 30% of anole species in the Chortis Block are undescribed.

Currently the lab is shifting to focus research on the Rana, or true frogs, found in the Chortis Block. These are some of the best studied model organisms, but they are severely lacking in natural history. Six recognized species exist in the Chortic block. These species are ubiquitous, and are represented in virtually every habitat in the region. There are no taxonomic resolutions for species found east or south of Mexico which remain largely unstudied, and lots of unresolved taxonomic issues exist within the phylogenetic history of this group. There are at least 12 lineages with no name. The population of leopard frogs in SW Honduras were described as 'hybrids' between two lowland species, however apparent differences exist including a difference in adult size. The Townsend lab have applied DNA, bioacoustics, morphology, and distribution modeling to these frogs, and are going to shift focus to clearing up Rana issues.

The ultimate goal of Dr. Townsend and his lab is conservation. He displayed the following quote during his seminar:

"The one process now going on that will take millions of years to correct is the loss of genetic and species diversity by the destruction of natural habitats. This is the folly our descendants are least likely to forgive us." E. Wilson

In Honduras compliance for energy development projects is needed. Dr. Townsend acts as a consultant for various projects including micro-hydro electric projects adjacent to cloud forests, biomass energy plants, and conversion of abandoned commercial agricultural lands to biofuel production. His goal working with these projects is to help mitigate the impacts they are having on the ecosystems. Success of his ability to mitigate impacts has show in a biomass energy plant project where it was found that the Kings Grass being grown acted as a wildlife corridor for Jaguars.

To extend education to others Dr. Townsend has fostered a partnership to develop a joint Master's program with Universidad Nacional Autonoma de Honduras en el Valle de Sula (UNAH-VS) and his current institution IUP. In Nicaragua and many of the other Mesoamerican countries graduate programs in biology are not available. Students in this region that are interested in these degrees have to travel to Mexico, Costa Rica, the United States or Europe. With the joint MS in Biology Program in place students would be able to take some courses at IUP, and complete remaining coursework at UNAH-VS. The program will be launching Fall 2018.