Here I am on the shores of Lake Nicaragua with
Volcan Concepcion in the background.
As part of my research program investigating the
systematics of freshwater mussels, I have started exploring the
understudied unionoid fauna in Central America.
The first stop, on what I intend to be a long-term collaborative
investigation is Lake
Nicaragua, also known as Cocibolca, or "the sweet sea" by locals.
Lake Nicargua is one of the largest freshwater lakes in the Western
Hemisphere. The lake is approximately 3 million years old and was
formed by volcanic and tectonic activity. The lake is home to a
relatively diverse fish community which includes members of several
families including Cichlidae, Characidae, Megalopidae, Pimelodidae,
Lepisosteidae, Poeciliidae, as well as Carcharhinidae, and
Pristidae. The freshwater bivalve fauna is also fairly diverse
and inlcudes members of two families: Unionidae and Mycetopodidae.
The first of (hopefully) many trips to Nicaragua was recently
During the trip I accomplished several goals including collection live
freshwater mussels representing the three families found in
Nicaragua. These specimens will be examined and represent an
important part of a planned monograph of the freshwater mussels of Lake
Nicaragua. Tissue samples were also preserved for DNA extraction
Thanks to the assistance of Stephen Robinson (undergraduate, Iowa State
University), the Nicaraguan project is moving forward. Stephen is
making headway sequencing two mitochondrial genes for specimens
collected in Nicaragua, and is using his artistic talents to prepare
illustrations for the upcomming monograph on the unionids of Lake
Nicaragua. A preliminary phylogeny of North American unionids inluding
some of our Nicaraguan specimens was presented at the 2006 meeting of
the American Malacological Society in Seattle, and can be seen
below. These results imply that Central American unionids are
dispersed throughout the phylogeny of their northern cousins and has
implications for the evolution of characters and life-history traits in
The phylogenetic hypothesis above traces the
number of demibranchs (all 4, or outer or inner 2) that are used to
brood larvae. Nicaraguan taxa are highlighted by the blue and red boxes.