Meeting Abstract

94.5  Thursday, Jan. 7  Baikalian sponges as a model for the study of endemic speciation LAVROV, D.V.*; BURLAKOVA, O.O.; ITSKOVICH, V.B.; WEINBERG, E.V.; BELIKOV, S.I.; Iowa State Unviersity; Limnological Institute, Irkutsk, Russia; Limnological Institute, Irkutsk, Russia; Limnological Institute, Irkutsk, Russia dlavrov@iastate.edu

Speciation – the emergence of discrete entities (species) in the course of continuous biological evolution – is a fundamental process underlying most of the Earth’s perceivable biodiversity. This process can be particularly striking in lakes and on islands, where large endemic biotas often evolve in relatively short periods of time. Although much progress has been made on understanding speciation from genetic, paleontological, microevolutionary, and ecological perspectives, the number of systems where it has been studied remains surprisingly small, and studies that approach a single system from multiple perspectives are rare. Here we introduce Lake Baikal sponges as a convenient system to study the process of speciation using phylogenetic, microevolutionary and paleontological approaches. Situated in Southeast Siberia, Lake Baikal is the oldest, deepest, and most voluminous lake in the world that contains 20% of the world’s total unfrozen fresh water. Baikal’s age, size, and isolation has produced one of the world’s richest and most unusual freshwater faunas (2500 described species; more than half of them endemic), and has earned the lake the name of the ‘Galapagos of Russia’. Baikal sponges (family Lubomirskiidae) dominate the benthic community of the lake, play an essential role in its ecology, and represent the most spectacular example of endemic radiation in freshwater sponges in the world. We show that both molecular markers and fossil record can be informative for understanding the process of speciation in this group.