Townsend Lab researchers and associates are involved in a range of projects dealing with the phylogenetic and morphological systematics of amphibians and reptiles in Mexico and Central America.
Endemism in Tropical Montane Cloud Forests
The Chortís Highlands have been shown to have a distinctive component of endemic biodiversity, particularly in amphibians and reptiles; however, molecular characterization of evolutionary diversification patterns in this region has been limited to a few studies of a restricted taxonomic breadth and broader geographic focus. This region has a challengingly complex geological history, and is located to the south and east of the tectonic boundary between the Chortís and Mayan Blocks and north of the Nicaraguan Depression, and are also referred to as Eastern Nuclear Central America.
The majority of the geographical extent of the Chortís Highlands is found within the political boundaries of Honduras, the country that is home to at least 103 endemic species with the highest degree of herpetofaunal endemism of any Central American nation. The majority of endemic species are restricted to one or a few isolated cloud forest localities, with many cloud forests supporting their own unique endemic communities of amphibians and reptiles.
While undertaking remote fieldwork in Mesoamerican cloud forests, it is not uncommon to stumble across previously unknown or overlooked taxa. These can include cryptozoic species, like Typhlops tycherus and Tantilla olympia, as well as somewhat more conspicuous taxa, like Anolis morazani.
Salamanders of the Chortis Highlands
Neotropical salamanders can be characterized by their high degree of diversification and widespread morphological conservatism and homoplasy. Diverse radiations of plethodontids are well documented in western Nuclear Central America (southern México and Guatemala) and southern Central America (Costa Rica and western Panama); however, much of this cryptic diversity has been revealed only recently by molecular studies. Like the better characterized areas of western Nuclear and southern Central America, the Chortís Highlands are a site of remarkable plethodontid diversity. The salamander fauna of the Chortis Highlands represent one of the richest (36 species) and most endangered (70+% threatened with extinction) components of the montane biota.
The Bolitoglossa (Magnadigita) dunni species group is a Chortís Highlands endemic radiation of 12 named species, and has the highest estimated rate of diversification of any major clade of Mesoamerican salamanders. Cryptic diversity and paraphyly in some named species, such as B. porrasorum, is currently being investigated in the Townsend Lab.
Moss salamanders of the genus Nototriton also represent an important component of the cloud forest fauna of the Chortís Highlands, with five endemic species inhabiting highland forests in eastern Guatemala and northern and central Honduras: N. barbouri, N. brodiei, N. lignicola, N. limnospectator, N. mime, N. picucha, N. stuarti, and N. tomamorum. Three of these species were discovered in the past few years by Dr. Townsend and associates, and at two additional new species are currently being described.
Worm salamanders (genus Oedipina) represent another challenging group of salamanders, due to their secretive fossorial habits and poor representation in collections. Recent work in Nicaragua has revealed a new species of the Chortís Highland endemic subgenus Oeditriton, O. nica, as well as a cryptic species, O. koehleri, previously referred to as O. pseudouniformis.