Indo-Pacific Phylogeography of the Lemon Sponge Leucetta chagosensis

Abstract

The sponge Leucetta chagosensis Dendy (1913) has a wide distribution throughout the Indo-Pacific (IP) region, with previous studies focussing primarily on the western Pacific Ocean. To increase our knowledge of the spatial variation of genetic diversity throughout the IP, we constructed a phylogeny for L. chagosensis for the IP to assess the evolutionary patterns for this species. We generated 188 sequences of L. chagosensis and constructed maximum likelihood and Bayesian inference trees, using concatenated mitochondrial cytochrome oxidase subunit 3 gene (cox3) and nuclear ribosomal RNA gene (28S) markers for the first time. The spatial variation of genetic diversity of L. chagosensis was assessed using a phylogeographic approach. Leucetta chagosensis is composed of five cryptic lineages confined to different biogeographic regions with the specimens found in the Indian Ocean differing significantly from those found in the rest of the IP region. Genetic divergence was particularly high for the cox3 marker, with a low nucleotide diversity but high haplotype diversity for most lineages. This study highlights the need for a sustained effort in studying sponge diversity, boosted by the ongoing discovery of hidden biodiversity among this ecologically important taxon.

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

“…The intraspecific p-distance among them was 0.0-2.3% for the C-LSU and 1.5% for the ITS. This relatively high p-distance and wide-spread scenario suggest that L. chagosensis may be a complex of cryptic species, as already proposed by Wörheide et al (2002Wörheide et al ( , 2008, Klautau et al (2020) and Pasnin et al (2020). Our results indicate that L. villosa is part of this complex (see the 'Taxonomic remarks' of L. chagosensis).…”

“…Of course, it is possible that L. chagosensis is a species complex. A recent work using more variable markers (Pasnin et al, 2020) found five lineages restricted to different biogeographic regions. The authors said they did not find morphological differences, but no morphological analyses were presented and they did not propose to split L. chagosensis.…”

“…Ecoregion -Salomon, Chagos Archipelago (Dendy, 1913); Houtman Ecoregion -Houtman Abrolhos (Dendy & Frederick, 1924); Maldives Ecoregion -Maldives (Wörheide et al, 2008;Van Soest & De Voogd, 2018;Pasnin et al, 2020); Arabian (Persian) Gulf Ecoregion -Red Sea (Wörheide et al, 2008;Voigt et al, 2012;Van Soest & De Voogd, 2018;Pasnin et al, 2020); India (Van Soest & De Voogd, 2018;George et al, 2020) & De Voogd, 2018;Pasnin et al, 2020); La Réunion (Trentin & Massé, 2018;Pasnin et al, 2020). PACIFIC OCEAN: Banda Sea Ecoregion -Indonesia; Sulawesi Sea Ecoregion -Sulawesi; Lesser Sunda Ecoregion -Bali (Wörheide et al, 2002(Wörheide et al, , 2008Pasnin et al, 2020); Eastern Philippines Ecoregion -Philippines (Wörheide et al, 2008;Voigt et al, 2012;Van Soest & De Voogd, 2015Pasnin et al, 2020); Great Barrier Reef, Australia; Tweed Moreton Ecoregion -Queensland, Australia (Wörheide & Hooper, 1999;Wörheide et al, 2002Wörheide et al, , 2004Wörheide et al, , 2005Wörheide et al, , 2008Voigt et al, 2012;Pasnin et al, 2020); Mariana Islands Ecoregion -Guam, South Kuroshio Ecoregion -Taiwan; Central Kuroshio Current Ecoregion -Japan (Wörheide et al, 2002(Wörheide et al, , 2008Pasnin et al, 2020); Bismarck Sea Ecoregion and Solomon Sea Ecoregion -Papua New Guinea, West Caroline Islands Ecoregion -Palau Islands (Wörheide et al, 2002(Wörheide et...…”

“…Taxonomic remarks: Leucetta chagosensis is a widespread species in the Indo-Pacific Ocean, which likely represents a species complex (Wörheide et al, 2002(Wörheide et al, , 2005(Wörheide et al, , 2008Voigt et al, 2012;Pasnin et al, 2020). Descriptions of this species show variable morphologies, including variation in the external shape (globular to pyriform to massive lobate), colour after fixation (white or brown) and, perhaps, the spicules' size (Table 8; e.g.…”

Addition to Sweden’s freshwater sponge fauna and a phylogeographic study of Spongilla lacustris (Spongillida, Porifera) in southern Sweden

“…In addition to environmental parameters to explain the distribution of a species (Økland & Økland 1996;Evans & Montagnes 2019) there is also the historical component, which Avise and co-workers (Avise et al 1987) designated intraspecific phylogeography. There have not been many studies of phylogeography in marine sponges (Wörheide et al 2002;Duran et al 2004;Nichols & Barnes 2005;Becking et al 2013;Pasnin et al 2020) and but a few for freshwater sponges (Schröder et al 2003;Lucentini et al 2013). Although assessing phylogeography in the marine environment is an aim, the external factors affecting dispersal are rarely explicitly clear, making it difficult to erect prior hypotheses of expected patterns.…”