title: Molecular phylogenetic analysis supports a Gondwanan origin of the Hyriidae (Mollusca: Bivalvia: Unionida) and the paraphyly of Australasian taxa.
abstract: The freshwater mussel family Hyriidae (Mollusca: Bivalvia: Unionida) has a disjunct trans-Pacific distribution in Australasia and South America. Previous phylogenetic analyses have estimated the evolutionary relationships of the family and the major infra-familial taxa (Velesunioninae and Hyriinae: Hyridellini in Australia; Hyriinae: Hyriini, Castaliini, and Rhipidodontini in South America), but taxon and character sampling have been too incomplete to support a predictive classification or allow testing of biogeographical hypotheses. We sampled 30 freshwater mussel individuals representing the aforementioned hyriid taxa, as well as outgroup species representing the five other freshwater mussel families and their marine sister group (order Trigoniida). Our ingroup included representatives of all Australian genera. Phylogenetic relationships were estimated from three gene fragments (nuclear 28S, COI and 16S mtDNA) using maximum parsimony, maximum likelihood, and Bayesian inference, and we applied a Bayesian relaxed clock model calibrated with fossil dates to estimate node ages. Our analyses found good support for monophyly of the Hyriidae and the subfamilies and tribes, as well as the paraphyly of the Australasian taxa (Velesunioninae, (Hyridellini, (Rhipidodontini, (Castaliini, Hyriini)))). The Hyriidae was recovered as sister to a clade comprised of all other Recent freshwater mussel families. Our molecular date estimation supported Cretaceous origins of the major hyriid clades, pre-dating the Tertiary isolation of South America from Antarctica/Australia. We hypothesize that early diversification of the Hyriidae was driven by terrestrial barriers on Gondwana rather than marine barriers following disintegration of the super-continent.
authors: Biology Department, University of Wisconsin-Stevens Point, Stevens Point, WI 54481, USA. Electronic address: dgraf@uwsp.edu.
authors: Daniel L
authors: DL
authors: Graf
authors: Department of Anatomy & Histology, University of Sydney, Sydney, NSW 2006, Australia.
authors: Hugh
authors: H
authors: Jones
authors: Department of Biology, University of Rochester, NY 14627, USA.
authors: Anthony J
authors: AJ
authors: Geneva
authors: Department of Biological Sciences, University of Alabama, Tuscaloosa, AL 35487, USA.
authors: John M
authors: JM
authors: Pfeiffer
authors: School of Veterinary & Life Sciences, Murdoch University, Perth, WA 6230, Australia.
authors: Michael W
authors: MW
authors: Klunzinger
mesh_terms: D000818:Animals; D001315:Australia; D001499:Bayes Theorem; D005075:Biological Evolution; D049872:Bivalvia / Q000145:classification* / Q000235:genetics; D017931:DNA Primers; D004272:DNA, Mitochondrial / Q000235:genetics; D005580:Fossils; D016013:Likelihood Functions; D008957:Models, Genetic; D010802:Phylogeny; D017422:Sequence Analysis, DNA; D013020:South America
chemical_list: D017931:DNA Primers; D004272:DNA, Mitochondrial
keywords: Australasia; Freshwater mussel; Gondwana; Hyriidae; Phylogeny