Animals 2011, 1, 205-241; doi:10.3390/ani1020205 animalsOPEN ACCESS ISSN 2076-2615 www.mdpi.com/journal/animals Article Aquatic Biodiversity in the Amazon: Habitat Specialization and Geographic Isolation Promote Species Richness James S. Albert 1,*, Tiago P. Carvalho 1, Paulo Petry 2, Meghan A. Holder 1, Emmanuel L. Maxime 1, Jessica Espino 3, Isabel Corahua 3, Roberto Quispe 3, Blanca Rengifo 3, Hernan Ortega 3 and Roberto E. Reis 4 1 Department of Biology, University of Louisiana at Lafayette, Lafayette, LA 70504, USA; E-Mails:
[email protected] (T.P.C.);
[email protected] (M.A.H.);
[email protected] (E.L.M.) 2 The Nature Conservancy and Museum of Comparative Zoology, Harvard University, MA 02138, USA; E-Mail:
[email protected] 3 Museo de Historia Natural, Universidad Nacional de San Marcos, Lima, Peru; E-Mails:
[email protected] (J.E.);
[email protected] (I.C.);
[email protected] (R.Q.);
[email protected] (B.R.);
[email protected] (H.O.) 4 Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, RS, Brazil; E-Mail:
[email protected] * Author to whom correspondence should be addressed; E-Mail:
[email protected]. Received: 22 February 2011; in revised form: 21 April 2011 / Accepted: 22 April 2011 / Published: 29 April 2011 Simple Summary: The immense rainforest ecosystems of tropical America represent some of the greatest concentrations of biodiversity on the planet. Prominent among these are evolutionary radiations of freshwater fishes, including electric eels, piranhas, stingrays, and a myriad of small-bodied and colorful tetras, cichlids, and armored catfishes.