Multilocus phylogeny reveals Gibsmithia hawaiiensis (Dumontiaceae, Rhodophyta) to be a species complex from the Indo-Pacific, with the proposal of G. eilatensis sp. nov.

Abstract

Gibsmithia hawaiiensis is a peculiar red alga characterized by furry gelatinous lobes arising from a cartilaginous stalk. The species has been recorded from tropical reef systems throughout the Indo-Pacific. A multilocus phylogeny (UPA, rbcL, COI-5P) of 36 specimens collected throughout the species distribution range, showed high genetic diversity at species level. Two major groups were identified, each consisting of multiple lineages. Genetic variability was low in the Hawaiian Islands and the northern Red Sea and high in the Western Indian Ocean and the Coral Triangle, where lineages overlap in distribution. Genetic distances suggest that G. hawaiiensis represents a complex of five cryptic species, with no difference observed in the external morphology corresponding to separate lineages. Anatomical and reproductive differences were observed at the microscopic level for the lineage from the Red Sea, which is here described as G. eilatensis sp. nov. The geographic range of the species complex is here expanded to include Madagascar, the Red Sea and the Indo-Malay region, and the generitype seems endemic to the Hawaiian Islands. Algal diversity on coral reef systems is discussed from a conservation perspective using G. hawaiiensis as an example.

Taxonomic reassessment of the Indo-Pacific Scytosiphonaceae (Phaeophyceae): Hydroclathrus rapanuii sp. nov. and Chnoospora minima from Easter Island, with proposal of Dactylosiphon gen. nov. and Pseudochnoospora gen. nov.

“…Our current understanding of global algal biodiversity and the phylogenetic relationships of macroalgae has been reshaped by the advent of DNA phylogenies. Using molecular phylogenetic tools, reports of high levels of cryptic and/or pseudo-cryptic diversity are common, especially among widespread species, such as Acinetospora crinita (Carmichael) Sauvageau (Yaegashi et al 2015), Centroceras clavatum C. Agardh (Schneider et al 2015), Gibsmithia hawaiiensis Doty (Gabriel et al 2016), Lobophora variegata (J.V. Lamouroux) Womersley ex E.C.…”

Beneath the hairy look: the hidden reproductive diversity of the Gibsmithia hawaiiensis complex (Dumontiaceae, Rhodophyta)

“…The identification of Gibsmithia species was primarily based on the studies from Kraft () and Gabriel et al. (). The total collection consisted of 64 new samples from various locations in the Indo‐Pacific (Table in the Supporting Information; Fig.…”

“…), and cox59F, cox176F and cox606R (Gabriel et al. ); rbc L, amplified in two fragments, used the pair of primers F15‐R916 and F645‐R1389 (Gabriel et al. , Lin et al.…”

“…Among tropical members of the family, Gabriel et al. () recently investigated the Gibsmithia hawaiiensis complex, a peculiar taxon characterized by ephemeral clusters of “hairy” gelatinous lobes arising from perennial, cartilaginous stalks (Fig. ).…”

“…Based on three genetic markers (mitochondrial COI‐5P, and plastid rbc L and UPA), Gabriel et al. () suggested that G. hawaiiensis represents a species complex comprising five distinct lineages: the generitype from the Hawaiian archipelago (Fig. A), the newly described Gibsmithia eilatensis from the Red Sea (Fig.…”