Comparative phylogeography of two coastal polychaete tubeworms in the Northeast Atlantic supports shared history and vicariant events

Abstract

The historic processes which have led to the present-day patterns of genetic structure in the marine coastal fauna of the Northeast Atlantic are still poorly understood. While tectonic uplifts and changes in sea level may have caused large-scale vicariance, warmer conditions during glacial maxima may have allowed pockets of diversity to persist to a much wider extent than in the Northwestern Atlantic. The large-scale geographic distribution of deeply divergent lineages of the coastal polychaete tubeworms Pectinaria koreni (two clades) and Owenia fusiformis (three clades) were compared using a fragment of the mitochondrial cytochrome oxidase I gene (mtCOI). All lineages were present along the biogeographic transition zone on the north coast of Brittany (France) and we found evidence pointing towards congruence in the timing of cladogenic events between Pectinaria sp. (P. auricoma/P. belgica and P. koreni) and Owenia sp., suggesting a shared history of vicariant events. More conserved 16SrRNA sequences obtained from four species of Pectinariidae together with mtCOI sequences of P. koreni seem consistent with an initial establishment of pectinariids in the north, and a southward colonization of the Northeast Atlantic. Phylogeographic patterns in O. fusiformis were also consistent with a north/south pattern of lineage splitting and congruent levels of divergence were detected between lineages of both species. We observed signatures of both persistence in small northern glacial refugia, and of northwards range expansion from regions situated closer to the Mediterranean. However, whether the recolonization of the Northeast Atlantic by both species actually reflects separate interglacial periods is unclear with regards to the lack of molecular clock calibration in coastal polychaete species.

Large-scale genetic patchiness among NE Atlantic populations of the brittle star Ophiothrix fragilis

“…Since the Isle of Man sample we collected was taken just a few kilometres from the sampling by Baric & Sturmbauer (1999), our northern Atlantic/Channel populations correspond to Lineage I (while nothing could be said regarding Lineage II). This cryptic divergence within species reinforces the vicariance hypothesis proposed by Jolly et al (2006) for coastal species of the NE Atlantic. However, unlike the coastal polychaetes Pectinaria spp.…”

“…and Owenia spp. (Jolly et al 2006), the distributions of the cryptic lineages of O. fragilis do not seem to overlap at the entrance of the English Channel, rather they are separated along the coasts of Galicia, in a way similar to what was observed for the crab Carcinus maenas (Roman & Palumbi 2004) and the mysid Mesopodopsis slabberi (Remerie et al 2006).…”

Biodiversity and phylogeography of Arctic marine fauna: insights from molecular tools

“…3 Map depicting proposed secondary contact zones and locations of Arctic glacial and periglacial marine refugia for various taxa: a clam Macoma balthica (Luttikhuizen et al 2003;Väinölä 2003;Nikula et al 2007); b jellyfish Obelia geniculata (Govindarajan et al 2005); c scale worm Harmothoe imbricata (this study); d red macroalga Phycodrys rubens (van Oppen et al 1995); e ice cream cone worm Pectinaria koreni (Jolly et al 2006); f barnacle Pollicipes pollicipes (Campo et al 2010); g clam Arctica islandica (Dahlgren et al 2000;Maggs et al 2008; but see Ingólfsson 2009); h brown macroalga Fucus serratus (Hoarau et al 2007); i capelin Mallotus villosus (Dodson et al 2007); j rainbow smelt Osmerus mordax (Bernatchez 1997); k sea stars Asterias spp. ; l hermit crab Pagurus longicarpus (Young et al 2002); m Arctic charr Salvelinus alpines (Brunner et al 2001); n whitefish Coregonus sp.…”

Evaluating Signatures of Glacial Refugia for North Atlantic Benthic Marine Taxa

“…This result must however be distinguished carefully from that of secondary contact due to nonrefugial events like anthropogenic admixture, or longdiverged cryptic species coming into sympatry, such as the narrow parapatric boundary at the tip of Brittany seen for two clades of the polychaete worm Pectinaria koreni (Jolly et al 2005(Jolly et al , 2006 Fig. 9; see also Plate 1).…”