Integrative taxonomy of calcareous sponges (Porifera: Calcarea) from Réunion Island, Indian Ocean

Abstract

The Western Indian Ocean Province is reckoned for its rich marine diversity; however, sponges of the Mascarene Islands ecoregion are still poorly known. In La Réunion, only three species of class Calcarea have been registered. Hence, calcareous sponges were searched in seven sites representing various habitats of the Western coast of La Réunion, but found in only three of them. A total of 23 sponge samples was identified using morphological and molecular taxonomy. This sampling represents 11 species, all new records for the region, and seven of them are new to science: Ascandra mascarenica sp. nov., A. oceanusvitae sp. nov., Janusya indica gen. et sp. nov., Leucascus tenuispinae sp. nov., Lelapiella tertia sp. nov., Soleneiscus intermedius sp. nov. and Leucandra ornata sp. nov.; and a new genus, Janusya gen. nov.. Based on results from this and from previous studies, we propose the synonymization of the order Murrayonida with Clathrinida. A very low sampling effort has thus increased the number of calcareous sponge species from the Mascarenes Islands ecoregion by 69 % and from La Réunion by 367%.

A checklist of the southwestern Madagascar sponge fauna with taxonomic updates based on the current systematics

“…Although these two sponge classes also include the lower numbers of sponge species worldwide, it is believed by these authors that their diversities may be largely underestimated in the Toliara region. Indeed, a better exploration of cryptic habitats, such as underwater caves and reef tunnels, may reveal a greater number of new species, as found in other regions (Pérez et al, 2017;Klautau et al, 2021). In Reunion Island for example, very few explorations of underwater caves resulted in 11 new records of Calcarea, seven of which being new to science (Klautau et al, 2021).…”

“…Indeed, a better exploration of cryptic habitats, such as underwater caves and reef tunnels, may reveal a greater number of new species, as found in other regions (Pérez et al, 2017;Klautau et al, 2021). In Reunion Island for example, very few explorations of underwater caves resulted in 11 new records of Calcarea, seven of which being new to science (Klautau et al, 2021).…”

“…The WIO region is home to a potentially rich sponge fauna that has mostly gone unstudied, owing to a lack of local taxonomic competence and of regional research programmes (Barnes and Bell, 2002;Van Soest et al, 2012). Nonetheless, this sponge fauna of the WIO has been subjected to local inventories (e.g., Rützler, 2004;de Voogd et al, 2023), resulting to the description of new taxa (e.g., Samaai et al, 2020;Klautau et al, 2021).…”