Alvarado et al. 2022

scientific article | Algae

Unveiling mesophotic diversity in Hawai‘i: two new species in the genera Halopeltis and Leptofauchea (Rhodymeniales, Rhodophyta)

Alvarado EA, Cabrera FP, Paiano MO, Fumo JT, Spalding HL, Smith CM, Leonard JC, Lopes Jr KH, Kosaki RK, Sherwood AR


Two genera of the Rhodymeniales, Halopeltis and Leptofauchea, are here reported for the first time from the Hawaiian Islands and represent the deepest records for both genera. Molecular phylogenetic analyses of cytochrome oxidase subunit I (COI), rbcL, and large subunit ribosomal DNA (LSU) sequences for Hawaiian specimens of Leptofauchea revealed one well-supported clade of Hawaiian specimens and three additional lineages. One of these clades is described here as Leptofauchea huawelau sp. nov., and is thus far known only from mesophotic depths at Penguin Bank in the Main Hawaiian Islands. L. huawelau sp. nov. is up to 21 cm, and is the largest known species. An additional lineage identified in the LSU and rbcL analyses corresponds to the recently described L. lucida from Western Australia, and is a new record for Hawai‘i. Hawaiian Halopeltis formed a well-supported clade along with H. adnata from Korea, the recently described H. tanakae from mesophotic depths in Japan, and H. willisii from North Carolina, and is here described as Halopeltis nuahilihilia sp. nov. H. nuahilihilia sp. nov. has a distinctive morphology of narrow vegetative axes that harbor constrictions along their length. The current distribution of H. nuahilihilia includes mesophotic depths around W. Maui, W. Moloka‘i, and the island of Hawai‘i in the Main Hawaiian Islands. Few reproductive characters were observed because of the small number of specimens available; however, both species are distinct based on phylogeny and morphology. These descriptions further emphasize the Hawaiian mesophotic zone as a location harboring many undescribed species of marine macroalgae.

Depth range
76- 104 m

Mesophotic “mentions”
36 x (total of 6730 words)

* Presents original data
* Reports new species
* Focused on 'mesophotic' depth range
* Focused on 'mesophotic coral ecosystem'

Molecular ecology

Algae (Macro, Turf and Crustose Coralline)

USA - Hawaii

Manned Submersible
SCUBA (open-circuit or unspecified)

Author profiles