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Marine Ecology Progress Series

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MEPS 165:225-233 (1998)  -  doi:10.3354/meps165225

Genetic relationships between ecologically divergent species of talitrid amphipod (Crustacea)

M. B. Conceição*, J. D. D. Bishop**, J. P. Thorpe***

The University of Liverpool, Port Erin Marine Laboratory, Port Erin, Isle of Man, IM9 6JA, United Kingdom
*Present address: Lab. Bioquímica Marinha, Depto. Química, Fundação Universidade do Rio Grande, CP 474, Rio Grande, RS-96201-900, Brazil
**Present address: Marine Biological Association of the UK, The Laboratory, Citadel Hill, Plymouth PL1 2PB, UK

Allozyme electrophoresis was used to investigate the genetic relationships between several species of the amphipod family Talitridae representative of different ecomorphological groups. The analysis of 21 putative gene loci revealed that in general the species studied have relatively low levels of genetic variability when compared with published data for other crustaceans, including other amphipod species. The genetic identities between the species studied were in general accord with existing taxonomy and in good agreement with the broad relationship expected between taxonomic divergence and genetic identity. Dendrograms produced by UPGMA and Wagner clustering procedures differed in the position of 1 species. However, both dendrograms suggested that species of the genera Orchestia (beachfleas) and Talorchestia (sandhoppers) are more closely related to each other than to Talitrus saltator (also a sandhopper), and hence the results did not show a clear genetic divergence between the different ecological groups of talitrids. The analyses supported the taxonomic decision of previous authors to remove the genus Hyale from the family Talitridae. However, the levels of genetic divergence found within the family are too low to reconcile readily with the proposed radiation of the group during the Cretaceous period and indicate that the talitrids probably evolved considerably more recently.

Talitrids · Genetics · Allozymes · Amphipods

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