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Abstract

Recent collections from a shipwreck in ~30 m depth off the Florida Keys recovered an exceptionally large gryphaeid oyster that was identified on morphological grounds as Hyotissa hyotis (Linnaeus, 1758), a common constituent of Indian and Pacific Ocean near-shore faunas. This identification was confirmed by molecular characterisation: the Florida specimen had an almost identical large mitochondrial ribosomal subunit (16S) genotype to that obtained from a western Pacific (Guam) conspecific, differing in only two nucleotide positions that were heteroplasmic in the Guam specimen. Although this species has been variously cited to occur in the western Atlantic, careful examination of these records revealed them to be misidentifications of Hyotissa mcgintyi (Harry, 1985), originally described from south-eastern Florida. Because H. hyotis is much larger than any other regional oyster, it is unlikely to have been overlooked in earlier biotic surveys. It is therefore likely that this specimen, and another recently discovered off West Palm Beach, Florida, stem from a recent undocumented introduction to the western Atlantic.

Non-native molluscan colonizers on deliberately placed shipwrecks in the Florida Keys, with description of a new species of potentially invasive worm-snail (Gastropoda: Vermetidae)

“…This large-shelled Indo-Pacific species had frequently been confused with the presumably native foam oyster Hyotissa mcgintyi (Harry, 1985) [see discussion below and Fig. 2C], and Bieler et al (2004) established that prior western Atlantic records of H. hyotis were in fact based on H. mcgintyi specimens. Hyotissa mcgintyi is widely distributed in the natural reef throughout the Florida Keys (e.g., in the Coffins Patch Sanctuary Preservation area in the middle Keys [FMNH 317472/FK-625], at Looe Key Reef in the middle Keys [FMNH 333460/FK-987], and off the Dry Tortugas [FMNH 317475/FK-606].…”

“…The giant foam oyster, Hyotissa hyotis (Linnaeus, 1758)—also known as the giant honeycomb or giant coxcomb oyster, was the first report of a non-native molluscan species in the Florida Keys from shipwrecks, as discussed by Bieler et al (2004) and Mikkelsen & Bieler (2007); Fig. 2B.…”

Molecular characterization and phylogenetic position of the giant deep-sea oyster Neopycnodonte zibrowii Gofas, Salas & Taviani, 2009

“…The taxonomic assessment of oysters based on morphology can be challenging due to a high shell variability and a low number of diagnostic characters (Lam and Morton 2006;Raith et al 2015;Salvi et al 2021). Molecular data have a key role in species delimitation and taxonomic identification of oyster species (Lam and Morton 2003;Bieler et al 2004;Kirkendale et al 2004;Al-Kandari et al 2021;Salvi et al 2022) and would provide compelling evidence that the giant deep-sea oyster N. zibrowii is a distinct species rather than a deep-water ecophenotype of N. cochlear (Wisshak et al 2009b).…”