A new species of Gibsmithia (Dumontiaceae, Rhodophyta) from mesophotic depths of the Papahānaumokuākea Marine National Monument, Hawai‘i, USA

Researchers have identified a new species of red algae, Gibsmithia punonomaewa, from the mesophotic depths (79–104 m) of the Papahānaumokuākea Marine National Monument in Hawaiʻi. This discovery increases the number of Gibsmithia species recorded from Hawaiʻi to three and highlights the unique characteristics of this species, including moderate thallus size, smooth and terete gelatinous lobes, presence of a stipe (often branched), globose carposporangia, and non-isodiametric shaped cells subtending tetrasporangia. Phylogenetic analyses revealed that G. punonomaewa is most closely related to species found in tropical and subtropical surface waters, contrasting with its dark mesophotic habitat. The study used molecular phylogenetic techniques to clarify the diversity of Dumontiaceae, including a tentative record of Dudresnaya babbittiana, pending type material sequencing.

Sherwood, A. R., Cabrera, F. C., Kalaiwaa, G., Fumo, J. T., Spalding, H. L., Kosaki, R. K., Wagner, D., & Paiano, M. O. (2022). A new species of Gibsmithia (Dumontiaceae, Rhodophyta) from mesophotic depths of the Papahānaumokuākea Marine National Monument, Hawai‘i, USA. Phycologia, 61(5), 558–569. https://doi.org/10.1080/00318884.2022.2093540