DNA sequencing and anatomy demonstrate that Pacific Codium simulans is a genetically variable species found in the floras of Bermuda and Florida

Abstract

SUMMARY When DNA sequences from Bermuda plants described as Codium isthmocladum ssp. clavatum and a recent collection from Florida originally thought to be C. decorticatum were analyzed, they were found to be a genetic match to the Pacific Mexican species C. simulans. Historical voucher collections assigned to C. isthmocladum ssp. clavatum show that this Pacific lineage has been present in Bermuda (Atlantic) waters for over a century, thus precluding a very recent introduction from the Pacific. We hypothesize that C. simulans may have hitched a ride on the ballast rocks of early commercial ships plying their trade between the Pacific and Atlantic Oceans.

The Marine Benthic Algal Flora of Puerto Rico, II. Chlorophyta and Prasinodermatophyta

“…clavatum) is reported from 67-73 m depths (Norris and Olsen 1991), and in Brazil it is reported at 75 m depths (Joly and Yoneshigue Braga 1966). Schneider et al (2020) demonstrated that Bermudan species historically treated as Codium isthmocladum subsp. clavatum molecularly conformed to Codium simulans from Pacific Mexico.…”

“…clavatum molecularly conformed to Codium simulans from Pacific Mexico. Codium simulans is now considered to be both a morphologically (Pedroche et al 2002) and genetically (Schneider et al 2020) variable species. [Illustrations: as Codium isthmocladum subsp.…”