Species delimitation in poorly known and diverse taxa is usually performed based on monolocus, DNA-­barcoding-­like approaches, while multilocus data are often used to test alternative species hypotheses in well-­studied groups. We combined both approaches to delimit species in the Xenuroturris/Iotyrris complex, a group of venomous marine gastropods from the Indo-P­ acific. First, COI sequences were analysed using three methods of species delimitation to propose primary species hypotheses. Second, RAD sequencing data were also obtained and a maximum-l­ikelihood phylogenetic tree produced. We tested the impact of the level of missing data on the robustness of the phylogenetic tree obtained with the RAD-­seq data. Alternative species partitions revealed with the COI data set were also tested using the RAD-­seq data and the Bayes factor species delimitation method. The congruence between the species hypotheses proposed with the mitochondrial nuclear data sets, together with the morphological variability of the shell and the radula and the distribution pattern, was used to turn the primary species hypotheses into secondary species hypotheses. Allopatric primary species hypotheses defined with the COI gene were interpreted to correspond to intraspecific structure. Most of the species are found sympatrically in the Philippines, and only one is confidently identified as a new species and described as Iotyrris conotaxis n. sp. The results obtained demonstrate the efficiency of the combined monolocus/multilocus approach to delimit species.

ATIMO VATAE, INHACA 2011, MAINBAZA, Restricted, PAPUA NIUGINI, SANTO 2006, TERRASSES

In shelled molluscs, assigning valid species names to independent evolutionary lineages can be a difficult task. Most original descriptions are based on empty shells and the high levels of variation in shape, color and pattern in some groups can make the shell a poor proxy for species-level identification. The deep-sea gastropod turbinid genus Bolma is one such example, where species-level identification based on shell characters alone is challenging. Here, we show that in Bolma both traditional and molecular taxonomic treatments are associated with a number of pitfalls that can lead to biased inferences about species diversity. Challenges derive from the few phylogenetically informative characters of shells, insufficient information provided in original descriptions and sampling artefacts, which at the molecular level in spatially fragmented organisms can blur distinctions between genetically divergent populations and separate species. Based on a comprehensive dataset combining molecular, morphological and distributional data, this study identified several cases of shell-morphological plasticity and convergence. Results also suggest that what was thought to be a set of distinct, range-restricted species corresponds instead to a smaller number of more widespread species. Overall, using an appropriate sampling design, including type localities, allowed us to assign available names to evolutionarily significant units.

ATIMO VATAE, AURORA 2007, BIOPAPUA, BORDAU 1, CONCALIS, EBISCO, EXBODI, MAINBAZA, MIRIKY, NORFOLK 2, PANGLAO 2004, PANGLAO 2005, SALOMON 2, SALOMONBOA 3, TAIWAN 2004, TERRASSES

Marginelliform gastropods are a heterogeneous and diverse group of molluscs encompassing over 1,600 living species, among which are the smallest known neogastropods. The relationships of marginelliform gastropods within the order Neogastropoda are controversial, and the monophyly of the two marginelliform families the Marginellidae J. Fleming, 1828 and the Cystiscidae Stimpson, 1865, remains unconfirmed. DNA sequence data have never been used to assess the relationships of the marginelliform gastropods, making this group the only major branch missing in our current understanding of the neogastropod tree of life. Here we report results of the first multilocus phylogenetic analysis of marginelliform gastropods, which is based on a dataset comprising 63 species (20 genera) of Marginellidae and Cystiscidae, and a wide range of neogastropod lineages. The Marginellidae and Cystiscidae form a moderately supported clade that is sister to the family Volutidae. Marginellona gigas appears to be sister to all other marginelliforms. The subfamily Marginellinae was recovered as a well-supported clade, and good resolution of this part of the tree makes it possible to propose amendments to the family-level classification of the group. The relationship between Granulina and other marginelliforms could not be resolved and requires further study. Due to poor resolution of basal relationships within the Marginellidae–Cystiscidae clade, the monophyly of the Cystiscidae was neither confirmed nor convincingly rejected. The shell morphology of most marginellid and cystiscid genera is taxonomically not very informative but, nevertheless, of the traditionally recognized genera only Gibberula and Dentimargo were shown to be polyphyletic. Although a comprehensive systematic revision of the group requires more extensive taxonomic sampling (e.g. with better representation of the type species of nominal genus-group names), our results support the superfamily Volutoidea, comprising four families (Volutidae, Cystiscidae, Marginellidae and Marginellonidae), with the placement of the Granulinidae uncertain for the time being.

ATIMO VATAE, Restricted, DongSha 2014, EXBODI, GUYANE 2014, ILES DU SALUT, INHACA 2011, KANACONO, KARUBENTHOS 2, KAVIENG 2014, MADEEP, MADIBENTHOS, MAINBAZA, PAPUA NIUGINI, Restricted

The family Pinnidae Leach, 1819, includes approximately 50 species of large subtidal and coastal marine bivalves. These commercially important species occur in tropical and temperate waters around the world and are most frequently found in seagrass meadows. The taxonomy of the family has been revised a number of times since the early 20th Century, the most recent revision recognizing 55 species distributed in three genera: Pinna, Atrina and Streptopinna, the latter being monotypic. However, to date no phylogenetic analysis of the family has been conducted using morphological or molecular data. The present study analyzed 306 pinnid specimens from around the world, comprising the three described genera and ca. 25 morphospecies. We sequenced the mitochondrial genes 16S rRNA and cytochrome c oxidase subunit I, and the nuclear ribosomal genes 18S rRNA and 28S rRNA. Phylogenetic analysis of the data revealed monophyly of the genus Atrina but also that the genus Streptopinna is nested within Pinna. Based on the strong support for this relationship we propose a new status for Streptopinna Martens, 1880 and treat it as a subgenus (status nov.) of Pinna Linnaeus, 1758. The phylogeny and the species delimitation analyses suggest the presence of cryptic species in many morphospecies displaying a wide Indo-Pacific distribution, including Pinna muricata, Atrina assimilis, A. exusta and P. (Streptopinna) saccata but also in the Atlantic species A. rigida. Altogether our results highlight the challenges associated with morphological identifications in Pinnidae due to the presence of both phenotypic plasticity and morphological stasis and reveal that many pinnid species are not as widely distributed as previously thought.

BIOPAPUA, EXBODI, INHACA 2011, KARUBENTHOS 2012, Restricted

Bathymodiolinae mussels have been used as a biological model to better understand the evolutionary origin of faunas associated with deep-sea hydrothermal vents and cold seeps. Most studies to date, however, have sampled with a strong bias towards vent and seep species, mainly because of a lack of knowledge of closely related species from organic falls. Here we reassess the species diversity of deep-sea mussels using two genes and a large taxon sample from the South-Western Pacific. This new taxonomic framework serves as a basis for a phylogenetic investigation of their evolutionary history. We first highlight an unexpected allopatric pattern and suggest that mussels usually reported from organic falls are in fact poorly specialized with regard to their environment. This challenges the adaptive scenarios proposed to explain the diversification of the group. Second, we confirm that deep-sea mussels arose from organic falls and then colonized hydrothermal vents and cold seeps in multiple events. Overall, this study constitutes a new basis for further phylogenetic investigations and a global systematic revision of deep-sea mussels. (C) 2010 Elsevier Inc. All rights reserved.

AURORA 2007, BOA1, BORDAU 1, EBISCO, PANGLAO 2005, SALOMON 2, SANTO 2006