Abstract The molluskan order Neogastropoda encompasses over 15,000 almost exclusively marine species playing important roles in benthic communities and in the economies of coastal countries. Neogastropoda underwent intensive cladogenesis in the early stages of diversification, generating a “bush” at the base of their evolutionary tree, which has been hard to resolve even with high throughput molecular data. In the present study to resolve the bush, we use a variety of phylogenetic inference methods and a comprehensive exon capture dataset of 1817 loci (79.6% data occupancy) comprising 112 taxa of 48 out of 60 Neogastropoda families. Our results show consistent topologies and high support in all analyses at (super)family level, supporting monophyly of Muricoidea, Mitroidea, Conoidea, and, with some reservations, Olivoidea and Buccinoidea. Volutoidea and Turbinelloidea as currently circumscribed are clearly paraphyletic. Despite our analyses consistently resolving most backbone nodes, 3 prove problematic: First, the uncertain placement of Cancellariidae, as the sister group to either a Ficoidea-Tonnoidea clade or to the rest of Neogastropoda, leaves monophyly of Neogastropoda unresolved. Second, relationships are contradictory at the base of the major “core Neogastropoda” grouping. Third, coalescence-based analyses reject monophyly of the Buccinoidea in relation to Vasidae. We analyzed phylogenetic signal of targeted loci in relation to potential biases, and we propose the most probable resolutions in the latter 2 recalcitrant nodes. The uncertain placement of Cancellariidae may be explained by orthology violations due to differential paralog loss shortly after the whole genome duplication, which should be resolved with a curated set of longer loci.

ATIMO VATAE, AURORA 2007, BIOMAGLO, BIOPAPUA, CORSICABENTHOS 1, DongSha 2014, EXBODI, ILES DU SALUT, INHACA 2011, KANACONO, KANADEEP, KARUBENTHOS 2, KAVIENG 2014, KOUMAC 2.1, KOUMAC 2.3, MADEEP, MADIBENTHOS, MAINBAZA, NanHai 2014, PAPUA NIUGINI, TAIWAN 2013, Tuhaa Pae 2013, ZhongSha 2015

KANACONO

The exon capture approach allows for sequencing a large number of loci to reconstruct phylogenetic relationships at varying taxonomic levels. In order to efficiently recover the targeted loci, the probes designed to capture the exons need to be genetically sufficiently similar to bind to the DNA, with a proposed limit of 10% of divergence. However, this threshold has never been tested with a specific protocol. We have designed a set of probes to capture 1125 exons in the Neogastropoda (Mollusca, Gastropoda), processed with the same protocol from the field to the DNA sequencing to control for potential bias in DNA quantity and quality. We sequenced 30 different species, including 14 species of Neogastropoda and 16 species of Caenogastropoda non-­Neogastropoda. Each species includes five specimens, for a total of 150 specimens, and for four specimens among the 150, DNA extracts were aliquoted in four samples, sequenced separately, to estimate the intraspecific and intraspecimen variability in capture success. Our results confirm the impact of genetic distance on the success of exon capture with a negative linear correlation between the genetic distance and the number of exons captured for each sample. Consequently, designing new capture probes would allow for capturing exons in genetically more distant groups without the need to redesign a new set of exons.

CORSICABENTHOS 3