The small polychaete Platynereis dumerilii revealed as a large species complex with fourteen MOTUs in European marine habitats

• DOI: 10.3897/aca.4.e64937
• Publication Date: 2021-03-04T14:00:35Z
• Authors: Marcos A. L. Teix...; Arne Nygren; Ascensão Ravara; Pedro E. Vieira; José Carlos Herná...; Filipe O. Costa
• Keywords: Marine invertebrates; Marine larval ecology; Annelid; Species complex

Recent studies reporting complexes of cryptic or pseudo-cryptic species with narrow geographic distributions have been challenging the cosmopolitan status a fair number marine benthic invertebrates. Morphologically similar are often overlooked but molecular techniques extremely effective in signalling potential hidden diversity which, complemented further detailed examination, might reveal unique morphological and ecological features. Evidence stasis, where no clear stable differences apparent, can be exemplified by annelids Platynereis dumerilii (Audouin & Milne Edwards, 1833) massiliensis (Moquin-Tandon, 1869). These sibling species, usually found among algae intertidal subtidal habitats, only distinguished their different reproductive strategies life histories. The former is gonochoric, single event (semelparous) transforming into pelagic epitokous form called heteronereis, has free spawning synchronized lunar periodicity larval stage planktotrophic development; while latter shows transformation protandrous hermaphrodite, characterized egg brooding lecithotrophic stages semi-direct development. In order to verify possible existence additional within P. morphotype, we used multi-locus approach investigate 26 populations along Europe from NE Atlantic Macaronesia islands (Azores, Madeira Canaries) Western Eastern Mediterranean Sea. We concatenated mtDNA COI-5P, rDNA 16S 28S-D2 sequences performed phylogenetic analysis through Bayesian inference (BI). To depict Molecular Operational Taxonomic Units (MOTUs), applied three delimitation methods (ABGD, bPTP GYMC) alignment, except for COI also Barcode Index Number (BIN), implemented BOLD, which exclusive this locus. Consensus MOTUs were defined based on majority rule and, case draw, most conservative chosen. detected at least 14 23.1% mean K2P distance (6.6 - 32.6%). BI tree split major clades (Clade A: 1-3, Clade B: 4-9 C: 10-14), MOTU 3 appearing represent sensu stricto 9 . This assumption data Type locality previous study Wage et al. (2017), combined phylogeographic (COI barcode region), biology life-history observations some selected thriving vent areas Italian Ischia Vulcano. Major Cade C seems as visible specimens, example, size tentacular cirri lack dorsal pigmentation, contrast Clades A B, pigmentation types so far. Spanish archipelago Canary Islands whole Sea seem hotspot. Five five sympatric present Gran Canaria La Palma alone. Additionally, lineages exclusively four spotted southeast Spain (Calpe) Greek island Crete. Three out shared one part continent. Failure recognise biodiversity may compromise accuracy interpretation biomonitoring other relevant studies. Integrative taxonomy thus essential solve these uncertainties allow naming involved undescribed species. Otherwise, providing enough support hypothesis will continue unused, large fractions persist unnoticed.