Premium
Molecular operational taxonomic units reveal restricted geographic ranges and regional endemism in the Indo‐Pacific octocoral family Xeniidae
Author(s) -
McFadden Catherine S.,
Gonzalez Asaul,
Imada Rei,
Shi Sara S.,
Hong Prudence,
Ekins Merrick,
Benayahu Yehuda
Publication year - 2019
Publication title -
journal of biogeography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.7
H-Index - 158
eISSN - 1365-2699
pISSN - 0305-0270
DOI - 10.1111/jbi.13543
Subject(s) - taxon , geographical distance , biology , species richness , beta diversity , ecology , biogeography , octocorallia , phylogenetic tree , phylogenetic diversity , distance matrices in phylogeny , multidimensional scaling , distance decay , indo pacific , endemism , mantel test , geography , population , coral , cnidaria , coelenterata , genetic variation , paleontology , biochemistry , statistics , demography , mathematics , sociology , gene
Aim To quantify taxon diversity, biogeographic distributions and patterns of community assembly in xeniid octocorals using molecular operational taxonomic units ( MOTU s). Location Red Sea, Indian and western Pacific Oceans. Taxon Xeniidae, a family of reef‐dwelling octocorals (Anthozoa, Octocorallia). Methods Xeniids collected at 13 locations were sequenced at three barcode loci, and assigned to MOTU s defined by minimum genetic distance thresholds. Taxon richness (number of MOTU s) and endemicity (per cent of MOTU s found at a single location) were quantified. Patterns of β‐diversity (species turnover) and phylogenetic β‐diversity (lineage turnover) among geographical regions were visualized using hierarchical clustering, non‐metric multidimensional scaling ( NMDS ) plots and distance‐decay relationships. Community assembly was investigated by comparing the mean pairwise distance ( MPD ) and mean nearest taxon distance ( MNTD ) separating species in each assemblage to values generated for null communities. Results A genetic distance threshold of 0.3% discriminated 67 MOTU s, with taxon richness ranging from 2–18 MOTU s per site. Out of the 67 MOTU s, 48 (72%) were found at only a single location, and only two spanned both the western Indian and Pacific Oceans. Species turnover among sites was high, but phylogenetic β‐diversity was lower than β‐diversity and differed significantly from null models of community assembly at only two sites. β‐diversity and phylogenetic β‐diversity both increased significantly with geographic distance, and sites clustered into three distinct biogeographic regions (Red Sea and western Indian Ocean; Western Australia; western Pacific Ocean and Great Barrier Reef, Australia). All five major clades of xeniids were represented in each region. Main conclusions A genetic approach to biodiversity estimation suggests that most xeniid taxa are regional endemics whose geographic distribution is likely governed by dispersal limitation. This conclusion contrasts with published records of certain morphospecies occurrences, which imply that they have broad geographic ranges. So far, the distribution of xeniid biodiversity mirrors that of scleractinian corals, with species richness highest in the Coral Triangle, but endemicity peaking in peripheral areas.