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Genetic divergence between branched and unbranched forms of the thecate hydroid Aglaophenia pluma

Published online by Cambridge University Press:  11 May 2009

J. P. Thorpe
Affiliation:
Department of Environmental and Evolutionary Biology, University of Liverpool, Port Erin Marine Laboratory, Port Erin, Isle of Man.
J. S. Ryland
Affiliation:
Marine, Environmental and Evolutionary Research Group, School of Biological Sciences, University of Wales, Swansea, Singleton Park, Swansea, SA2 8PP.
P. F. S. Cornelius
Affiliation:
Department of Zoology, Natural History Museum, Cromwell Road, London, SW7 5BD
J. A. Beardmore
Affiliation:
Marine, Environmental and Evolutionary Research Group, School of Biological Sciences, University of Wales, Swansea, Singleton Park, Swansea, SA2 8PP.

Extract

Samples of branched and unbranched forms of the marine thecate hydroid Aglaophenia pluma (L.) (Hydrozoa, Plumulariidae) were collected from the western and eastern sides respectively of Carmarthen Bay (South Wales). Tissue from various colonies of each type was cleaned of epifauna and homogenized for horizontal starch gel electrophoresis. Useful results were obtained for 14 enzyme loci coding for a total of 11 different enzymes. Eleven of the 14 loci showed no common allele between the branched and unbranched forms. Nei's genetic identity was estimated as 0·18 and genetic distance as 1·7. Such a high level of genetic differentiation between morphotypes provides strong evidence that the populations are reproductively isolated and should be regarded as distinct species. It is suggested that the branched form may be Aglaophenia parvula Bale, a species until recently better known from the southern hemisphere. Morphological distinctions between the two species are discussed.

Type
Research Article
Copyright
Copyright © Marine Biological Association of the United Kingdom 1992

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