Sympatry and allopatry in the deeply divergent mitochondrial DNA clades of the estuarine pulmonate gastropod genus Phallomedusa (Mollusca, Gastropoda)
DNA sequences of the mitochondrial cytochrome c oxidase subunit I (COI) gene were collected from estuarine snails in the genus Phallomedusa to examine the effects of estuarine isolation on population structure and gene flow. Three clades were recovered, one corresponding to Phallomedusa austrina and two others with the morphology of Phallomedusa solida. The haplotype diversity in all three clades indicated recent population expansion. Phallomedusa austrina was restricted to the west of a previous land bridge in the Bass Strait between mainland Australia and Tasmania, and P. solida to its east and to northern Tasmania. Phylogeographic analysis of P. austrina and P. solida shows strong geographic separation of species, but no local genetic structure indicative of regional or estuarine isolation. The clades of P. solida exhibit substantial genetic divergence and were sympatric across their entire distribution in eastern Tasmania and mainland Australia. Such a situation, which has not previously been observed in phylogeographic studies of southeast Australia, suggests that P. solida has had a complex refugial history during periods of environmental challenge.
KeywordsInternal Transcribe Spacer Mangrove Forest Haplotype Network Larval Shell Posterior Probability Support
Funding for this project was provided by the Australian Museum and the James N. Kirby Foundation. REG was supported by a Chadwick Biodiversity Fellowship from the Australian Museum. Assistance from the Australian Museum DNA laboratory and malacology collections staff is gratefully acknowledged. Two anonymous reviewers are thanked for their comments.
- Folmer O, Black M, Hoeh W, Lutz R, Vrijenhoek R (1994) DNA primers for amplification of mitochondrial cytochrome c oxidase subunit I from diverse metazoan invertebrates. Molec Mar Biol Biotech 3:294–299Google Scholar
- Golding RE, Ponder WF, Byrne M (2007) Taxonomy and anatomy of Amphiboloidea (Gastropoda: Heterobranchia: Archaeopulmonata). Zootaxa 1476:1–50Google Scholar
- Hall TA (1999) BioEdit: a user-friendly biological sequence alignment editor and analysis program for Windows 95/98/NT. Nucl Acids Symp Ser 41:95–98Google Scholar
- Kuroda T (1928) Two families new to Japan. Venus 1:11Google Scholar
- Maddison WP, Maddison DR (2009) Mesquite: a modular system for evolutionary analysis. Version 2.72 http://mesquiteproject.org
- Martens E, von in Schacko G (1878) Die Zungenbewaffnung der Gattung Amphibola. Jahrbüch. d. Deutsch. Malak Ges 5:1–9Google Scholar
- Martyn T (1786) Universal conchologist. LondonGoogle Scholar
- Nylander JAA (2004) MrModeltest v2. Program distributed by the author. Evolutionary Biology Centre, Uppsala UniversityGoogle Scholar
- Pilkington MC, Pilkington JB (1982) The planktonic veliger of Ammphibola crenata (Gmelin). J Moll Stud 48:24–29Google Scholar
- Rogers AR, Harpending HC (1992) Population growth makes waves in the distribution of pairwise genetic differences. Mol Biol Evol 9:552–569Google Scholar