FIVE CRYPTIC SPECIES OF PORPHYRA FROM THE NORTHWEST ATLANTIC

Abstract

As one part of a multi‐institutional project on the biology of Porphyra, we collected extensive population samples of native Porphyra species from Long Island Sound to Nova Scotia. Samples were initially identified to species based on morphological features using taxonomic keys in Bird & McLaughlin (1992). Collections were analyzed using starch gel electrophoresis to look for intra‐specific variation useful in assessing population genetics. Isozyme variation in samples that had been originally identified as Porphyra leucosticta was far greater than expected. Samples from some collections differed by as much as 7 out of 7 loci. Other investigators have used starch gel electrophoresis to reveal cryptic differences in Porphyra that led to the descriptions of new species. In light of our isozyme results, we began a thorough examination of what had been identified as P. leucosticta in the northwestern Atlantic. The study included new collections as well as herbarium specimens. We examined morphology, habitat, seasonality, reproductive patterns, cell size & shape. We also extracted DNA and sequenced 1484bp of the rbcL gene. Based on this evidence, we feel we can circumscribe at least five distinct taxa of Porphyra not previously described from the northwestern Atlantic. Whether these represent new species, or previously described taxa from other geographic regions, we are not yet certain. We present here in detail, descriptions of each species along with summarized results of isozyme and DNA analyses.