Taxonomic determination of the cryptogenic red alga, Chondria tumulosa sp. nov., (Rhodomelaceae, Rhodophyta) from Papahānaumokuākea Marine National Monument, Hawai‘i, USA: A new species displaying invasive characteristics

Researchers have identified and described a new species of red alga, Chondria tumulosa, found in the Papahānaumokuākea Marine National Monument, Hawai‘i. This discovery stems from NOAA survey cruises in 2016 and 2019 that uncovered an undetermined seaweed rapidly covering benthic areas at Pearl and Hermes Atoll. Through light microscopy and molecular analysis—including mitochondrial COI barcode marker, plastidial rbcL gene, and nuclear SSU gene—the study confirmed the alga's unique genus-level placement within Rhodomelaceae. Chondria tumulosa is distinguished by its large, robust thalli, mat-forming tendency, and distinct morphological traits. While not meeting the criteria for an invasive species, its sudden appearance and rapid proliferation in this pristine, uninhabited island chain raise concerns about potential ecological impacts.

Sherwood, A. R., Huisman, J. M., Paiano, M. O., Williams, T. M., Kosaki, R. K., Smith, C. M., Giuseffi, L., & Spalding, H. L. (2020). Taxonomic determination of the cryptogenic red alga, Chondria tumulosa sp. nov., (Rhodomelaceae, Rhodophyta) from Papahānaumokuākea Marine National Monument, Hawai‘i, USA: A new species displaying invasive characteristics. Plos One, 15(7), e0234358. https://doi.org/10.1371/journal.pone.0234358