Ulva and Enteromorpha (Ulvales, Ulvophyceae, Chlorophyta) in eastern Australia: Comparison of morphological features and analyses of nuclear rDNA sequence data

Abstract

Specimens of Ulva Linnaeus and Enteromorpha Link (Ulvales, Ulvophyceae, Chlorophyta) were collected from 12 sites in eastern Australia and identified to species level on the basis of morphological characters described in the major Australian study of Womersley (1984). The species recognised were Ulva australis Areschoug, U. lactuca Linnaeus, U. fasciata Delile, Enteromorpha compressa (Linnaeus) Greville, E. flexuosa (Wulfen ex Roth) J.Agardh and E. intestinalis (Linnaeus) Link. Species placement within the genera Ulva and Enteromorpha is problematic and features of DNA were examined in order to assess their potential use as characters in species determinations. Analyses were conducted on sequence data derived from the internal transcribed spacer region ITS2, and the 5.8S gene. Groupings of the 12 isolates based on DNA analyses do not correlate with the species identified using morphology nor with the two genera. Further work is required before authoritative conclusions can be reached regarding the significance of morphological plasticity in determination of differences within and between Ulva and Enteromorpha species; nevertheless, DNA studies may provide a backbone of characters upon which to base such a study.