To re-evaluate the relationships of the major bivalve lineages, we amassed detailed morpho-anatomical, ultrastructural and molecular sequence data for a targeted selection of exemplar bivalves spanning the phylogenetic diversity of the class. We included molecular data for 103 bivalve species (up to five markers) and also analysed a subset of taxa with four additional nuclear protein-encoding genes. Novel as well as historically employed morphological characters were explored, and we systematically disassembled widely used descriptors such as gill and stomach ‘types’. Phylogenetic analyses, conducted using parsimony direct optimisation and probabilistic methods on static alignments (maximum likelihood and Bayesian inference) of the molecular data, both alone and in combination with morphological characters, offer a robust test of bivalve relationships. A calibrated phylogeny also provided insights into the tempo of bivalve evolution. Finally, an analysis of the informativeness of morphological characters showed that sperm ultrastructure characters are among the best morphological features to diagnose bivalve clades, followed by characters of the shell, including its microstructure. Our study found support for monophyly of most broadly recognised higher bivalve taxa, although support was not uniform for Protobranchia. However, monophyly of the bivalves with protobranchiate gills was the best-supported hypothesis with incremental morphological and/or molecular sequence data. Autobranchia, Pteriomorphia, Heteroconchia, Palaeoheterodonta, Archiheterodonta, Euheterodonta, Anomalodesmata and Imparidentia new clade ( = Euheterodonta excluding Anomalodesmata) were recovered across analyses, irrespective of data treatment or analytical framework. Another clade supported by our analyses but not formally recognised in the literature includes Palaeoheterodonta and Archiheterodonta, which emerged under multiple analytical conditions. The origin and diversification of each of these major clades is Cambrian or Ordovician, except for Archiheterodonta, which diverged from Palaeoheterodonta during the Cambrian, but diversified during the Mesozoic. Although the radiation of some lineages was shifted towards the Palaeozoic (Pteriomorphia, Anomalodesmata), or presented a gap between origin and diversification (Archiheterodonta, Unionida), Imparidentia showed steady diversification through the Palaeozoic and Mesozoic. Finally, a classification system with six major monophyletic lineages is proposed to comprise modern Bivalvia: Protobranchia, Pteriomorphia, Palaeoheterodonta, Archiheterodonta, Anomalodesmata and Imparidentia.

MAINBAZA

The tropical deep-water Cominellinae commonly assigned to the genera Manaria E. A. Smith, 1906 and Eosipho Thiele, 1929 are revised. While the taxonomic details at the generic level were discussed by Kantor et al. (2013), the species level is discussed here. Twentyone new species are described: Manaria astrolabis n. sp. (French Polynesia), M. borbonica n. sp. (Réunion), M. circumsonaxa n. sp. (Papua New Guinea and the Solomons), M. corindoni n. sp. (Indonesia), M. corporosis n. sp. (the Solomons, Vanuatu, Coral Sea and New Caledonia), M. explicibilis n. sp. (Papua New Guinea and the Solomons), M. excalibur n. sp. (Indonesia and Western Australia), M. fluentisona n. sp. (the Solomons, Fiji, Wallis and Tonga), M. hadorni n. sp. (Papua New Guinea and New Caledonia), M. indomaris n. sp. (India), M. loculosa n. sp. (Fiji), M. lozoueti n. sp. (North Fiji Basin), M. terryni n. sp. (Mozambique Channel), M. tongaensis n. sp. (Tonga), M. tyrotarichoides n. sp. (Mozambique Channel), Calagrassor bacciballus n. sp. (Philippines), C. delicatus n. sp. (New Zealand), C. hespericus n. sp. (Mozambique), C. pidginoides n. sp. (Philippines, Papua New Guinea, the Solomons and Vanuatu), Enigmaticolus marshalli n. sp. (Kermadec Ridge, Monowai Caldera), and E. voluptarius n. sp. (New Caledonia). Considerable range extensions are recorded: Manaria kuroharai Azuma, 1960 is recorded from the Solomons, New Caledonia, Vanuatu and Tonga; M. brevicaudata (Schepman, 1911) is recorded from Taiwan, the Philippines, the Solomons and Fiji; and Calagrassor poppei (Fraussen, 2001) is recorded from Indonesia and the Solomons. Lathyrus jonkeri Koperberg, 1931, a fossil described from Indonesia, is recorded from the Recent fauna of Indonesia, Philippines and Fiji and is redescribed and placed in Manaria. Sipho jonkeri Koperberg, 1931, another fossil described from Indonesia in the same work, is a secondary homonym of Manaria jonkeri (Koperberg, 1931) and is renamed Manaria koperbergae nom. nov.

AURORA 2007, BATHUS 1, BATHUS 2, BATHUS 3, BATHUS 4, BENTHAUS, BERYX 11, BIOCAL, BIOGEOCAL, Restreint, BIOPAPUA, BOA0, BOA1, BORDAU 1, BORDAU 2, CHALCAL 1, CONCALIS, CORAIL 2, CORINDON 2, Restreint, Restreint, Restreint, EBISCO, HALIPRO 1, KARUBAR, MAINBAZA, MIRIKY, MUSORSTOM 10, MUSORSTOM 2, MUSORSTOM 3, MUSORSTOM 4, MUSORSTOM 5, MUSORSTOM 6, MUSORSTOM 7, MUSORSTOM 8, PANGLAO 2005, SALOMON 1, SALOMON 2, SALOMONBOA 3, SANTO 2006, SMIB 4, SMIB 5, SMIB 6, SMIB 8, TAIWAN 2000, TAIWAN 2001, TAIWAN 2002, TAIWAN 2004, TARASOC, TERRASSES, VOLSMAR

Extracting DNA from gastropods presents particular difficulties due to the capacity of the living animal to retract into the shell, resulting in poor penetration of the ethanol into the tissues. Because the shell is essential to establish the link between sequences and traditional taxonomic identity, cracking the shell to facilitate fixation is not ideal. Several methods are currently in routine use to overcome this difficulty, including chemical relaxation, drilling the shell and boiling. Most of these methods are time-consuming, may be safety hazards and constitute a bottleneck in the preparation of large numbers of specimens in the field. We have experimented with a method traditionally used to clean shells that involves placing the living gastropods in a microwave (MW) oven; the electromagnetic radiation very quickly heats both the animal and the water trapped inside the shell, resulting in separation of the muscles that anchor the animal to the shell. Done properly, the body can be removed intact from the shell and the shell voucher is preserved undamaged. To test the method, the bodies of live-collected specimens from two gastropod species were separated from their shell by microwaving and by anesthetizing/drilling. After identical extraction and PCR procedures, the gels showed no difference in DNA quantity or quality, and the resulting sequences are identical within species. The method was then implemented on a large scale during expeditions, resulting in higher percentage of DNA extraction success. The MWs are also effective for quickly and easily removing other molluscs from their shells, that is, bivalves and scaphopods. Workflows implementing the MW technique show a three- to fivefold increase in productivity compared with other methods.

ATIMO VATAE, AURORA 2007, KARUBENTHOS 2012, PANGLAO 2004, PANGLAO 2005, PAPUA NIUGINI, SANTO 2006, Restreint

AURORA 2007, Restreint, KARUBAR, MUSORSTOM 2, MUSORSTOM 3, PANGLAO 2004, PANGLAO 2005, Restreint

Reconstructing historical biogeography of the marine realm is complicated by indistinct barriers and, over deeper time scales, a dynamic landscape shaped by plate tectonics. Here we present the most extensive examination of model-based historical biogeography among marine invertebrates to date. We conducted the largest phylogenetic and molecular clock analyses to date for the bivalve family Cardiidae (cockles and giant clams) with three unlinked loci for 110 species representing 37 of the 50 genera. Ancestral ranges were reconstructed using the dispersal–extinction–cladogenesis (DEC) method with a time-stratified paleogeographic model wherein dispersal rates varied with shifting tectonics. Results were compared to previous classifications and the extensive paleontological record. Six of the eight prior subfamily groupings were found to be para- or polyphyletic. Cardiidae originated and subsequently diversified in the tropical Indo-Pacific starting in the Late Triassic. Eastern Atlantic species were mainly derived from the tropical Indo-Mediterranean region via the Tethys Sea. In contrast, the western Atlantic fauna was derived from Indo-Pacific clades. Our phylogenetic results demonstrated greater concordance with geography than did previous phylogenies based on morphology. Time-stratifying the DEC reconstruction improved the fit and was highly consistent with paleo-ocean currents and paleogeography. Lastly, combining molecular phylogenetics with a rich and well-documented fossil record allowed us to test the accuracy and precision of biogeographic range reconstructions.

CONCALIS, Restreint, EBISCO, MAINBAZA, MIRIKY, PANGLAO 2004, PANGLAO 2005, SALOMON 2, SANTO 2006, TERRASSES

The hyperdiverse group of venomous Conoidea has eluded attempts to construct a robust and stable classification owing to the absence of a robust and stable phylogenetic framework. New molecular data have greatly enhanced our understanding of conoidean evolution, allowing the construction of a new family-level classification. This expanding framework has also allowed the discovery of several independent lineages that merit recognition at familial rank. One of these, based on seven specimens collected over more than 20 years from deep waters off New Caledonia, represents a unique, monotypic lineage closely related to Mitromorphidae, which we here name as the new family Bouchetispiridae. This new lineage bears a unique combination of teleoconch, protoconch and anatomical characters previously unknown within the Conoidea, including a translucent, fusiform shell with sculpture of strong axial ribs crossed by spiral cords, a multispiral protoconch of only 2.5 whorls with punctate sculpture, hypodermic marginal teeth and a multilayered venom bulb with two layers of muscle separated by connective tissue. This lineage may represent the sole survivor of a previously more diverse clade, or is simply one of many unique taxa that have arisen among the isolated sea mounts off New Caledonia.

AURORA 2007, BIOCAL, EBISCO, NORFOLK 2, PANGLAO 2004, PANGLAO 2005, SALOMON 2, SANTO 2006, TERRASSES

AURORA 2007, BIOPAPUA, BOA1, CONCALIS, SALOMON 1, SALOMON 2, SALOMONBOA 3, SANTO 2006, TAIWAN 2000

BATHUS 1, BATHUS 2, BATHUS 3, BATHUS 4, BERYX 11, BIOCAL, BIOGEOCAL, CALSUB, CHALCAL 1, CHALCAL 2, CONCALIS, EBISCO, HALIPRO 2, LAGON, LIFOU 2000, LITHIST, Restreint, MUSORSTOM 4, MUSORSTOM 5, MUSORSTOM 6, NORFOLK 1, NORFOLK 2, PALEO-SURPRISE, SMIB 2, SMIB 3, SMIB 4, SMIB 8, TERRASSES, VAUBAN 1978-1979, VOLSMAR

MAINBAZA

Identifying life stages of species with complex life histories is problematic as species are often only known and/or described from a single stage. DNA barcoding has been touted as an important tool for linking life-history stages of the same species. To test the current efficacy of DNA barcodes for identifying unknown mollusk life stages, 24 marine gastropod egg capsules were collected off the Philippines in deep water and sequenced for partial fragments of the COI, 16S and 12S mitochondrial genes. Two egg capsules of known shallow-water Mediterranean species were used to calibrate the method. These sequences were compared to those available in GenBank and the Barcode of Life Database ( BOLD). Using COI sequences alone, only a single Mediterranean egg capsule was identified to species, and a single Philippine egg capsule was identified tentatively to genus; all other COI sequences recovered matches between 76% and 90% with sequences from BOLD and GenBank. Similarity-based identification using all three markers confirmed the Mediterranean specimens' identifications. A phylogenetic approach was also implemented to confirm similarity-based identifications and provide a higher-taxonomic identification when species-level identifications were not possible. Comparison of available GenBank sequences to the diversity curve of a well-sampled coral reef habitat in New Caledonia highlights the poor taxonomic coverage achieved at present in existing genetic databases, emphasizing the need to develop DNA barcoding projects for megadiverse and often taxonomically challenging groups such as mollusks, to fully realize its potential as an identification and discovery tool.

AURORA 2007

AURORA 2007, BATHUS 1, BATHUS 2, BATHUS 4, BIOCAL, BOA0, BOA1, HALIPRO 1, MUSORSTOM 10, PANGLAO 2005, SALOMON 1, SALOMON 2, SALOMONBOA 3, SMIB 8

Cerithium koperbergi is a rare gastropod of the family Cerithiidae from the tropical Indo-West Pacific. The species has a small, unusual shell and often inhabits deeper water, fore-reef habitats that are atypical for the genus. Anatomical investigations reveal that it possesses a combination of features heretofore considered diagnostic of two main cerithiid subfamilies: Cerithiinae and Bittiinae. While the shell is bittiine, the animal lacks mesopodial pedal glands and possesses a seminal receptacle (vs. a spermatophore bursa) in the lateral lamina of the oviduct, which are considered to be cerithiine features. Re-evaluation of the anatomy of Bittium reticulatum, the type species of Bittium, indicates the defining anatomical difference in oviduct anatomy between the two subfamilies does not stand up to closer scrutiny. Partial mitochondrial cytochrome c oxidase I (COI) sequences support the interpretation that C. koperbergi is a species complex around the western Pacific rim comprising three divergent mitochondrial lineages. Bayesian analysis of partial mitochondrial COI and 16S rRNA sequences confirm the placement of the C. koperbergi complex within a monophyletic Bittiinae, despite the apparent absence of a unifying anatomical feature. Species in the C. koperbergi complex are here united in Pictorium nov. gen. and two species are described as new. It is hypothesized that features of the midgut may be diagnostic of the Bittiinae, but more comparative data are needed.

ATIMO VATAE, LIFOU 2000, PANGLAO 2004, PANGLAO 2005, SALOMON 1, SANTO 2006

The genus Clea from SE Asia is from one of only two unrelated families among the megadiverse predatory marine Neogastropoda to have successfully conquered continental waters. While little is known about their anatomy, life history and ecology, interest has grown exponentially in recent years owing to their increasing popularity as aquarium pets. However, the systematic affinities of the genus and the validity of the included species have not been robustly explored. Differences in shell, operculum and radula characters support separation of Clea as presently defined into two distinct genera: Clea, for the type species Clea nigricans and its allies, and Anentome for Clea helena and allies. A five-gene mitochondrial (COI, 16S, 12S) and nuclear (H3, 28S) gene dataset confirms the placement of Anentome as a somewhat isolated offshoot of the family Nassariidae and sister to the estuarine Nassodonta. Anatomical data corroborate this grouping and, in conjunction with their phylogenetic placement, support their recognition as a new subfamily, the Anentominae. The assassin snail Anentome helena, a popular import through the aquarium trade so named for their voracious appetite for other snails, is found to comprise a complex of at least four species. None of these likely represents true Anentome helena described from Java, including a specimen purchased through the aquarium trade under this name in the US and one that was recently found introduced in Singapore, both of which were supported as conspecific with a species from Thailand. The introduction of Anentome “helena” through the aquarium trade constitutes a significant threat to native aquatic snail faunas which are often already highly imperiled. Comprehensive systematic revision of this previously unrecognized species complex is urgently needed to facilitate communication and manage this emerging threat.

ATIMO VATAE, BIOPAPUA, EXBODI, INHACA 2011, KARUBENTHOS 2012, MAINBAZA, PANGLAO 2004, Restreint, SANTO 2006

A new genus, Limatium gen. n., and two new species, L. pagodula sp. n. and L. aureum sp. n. are described, found on outer slopes of barrier reefs and fringing reefs in the South Pacific. They are rare for cerithiids, which typically occur in large populations. The two new species are represented by 108 specimens sampled over a period of 30 years, only 16 of which were collected alive. Three subadults from the Philippines and Vanuatu likely represent a third species. In addition to their rarity, Limatium species are atypical for cerithiids in their smooth, polished, honey to golden brown shells with distinctive white fascioles extending suture to suture. The radula presents a unique morphology that does not readily suggest an affinity to any of the cerithiid subfamilies. Two live-collected specimens, one of each species and designated as holotypes, were preserved in 95% ethanol and sequenced. Bayesian analysis of partial COI and 16S rDNA sequences demonstrates a placement in the Bittiinae, further extending our morphological concept of the subfamily.

ATIMO VATAE, BATHUS 1, BENTHAUS, BORDAU 2, CORAIL 2, EBISCO, INHACA 2011, LAGON, LIFOU 2000, MONTROUZIER, MUSORSTOM 3, PANGLAO 2004, RAPA 2002, SANTO 2006, Tuhaa Pae 2013

The Tonnoidea is a moderately diverse group of large, predatory gastropods with ∼360 valid species. Known for their ability to secrete sulfuric acid, they use it to prey on a diversity of invertebrates, primarily echinoderms. Tonnoideans currently are classified in seven accepted families: the comparatively well known, shallow water Bursidae, Cassidae, Personidae, Ranellidae, and Tonnidae, and the lesser-known, deep water Laubierinidae and Pisanianuridae. We assembled a mitochondrial and nuclear gene (COI, 16S, 12S, 28S) dataset for ∼80 species and 38 genera currently recognized as valid. Bayesian analysis of the concatenated dataset recovered a monophyletic Tonnoidea, with Ficus as its sister group. Unexpectedly, Thalassocyon, currently classified in the Ficidae, was nested within the ingroup as the sister group to Distorsionella. Among currently recognized families, Tonnidae, Cassidae, Bursidae and Personidae were supported as monophyletic but the Ranellidae and Ranellinae were not, with Cymatiinae, Ranella and Charonia supported as three unrelated clades. The Laubierinidae and Pisanianuridae together form a monophyletic group. Although not all currently accepted genera have been included in the analysis, the new phylogeny is sufficiently robust and stable to the inclusion/exclusion of nonconserved regions to establish a revised family-level classification with nine families: Bursidae, Cassidae, Charoniidae, Cymatiidae, Laubierinidae, Personidae, Ranellidae, Thalassocyonidae and Tonnidae. The results reveal that many genera as presently circumscribed are para- or polyphyletic and, in some cases support the rescue of several genus-group names from synonymy (Austrosassia, Austrotriton, Laminilabrum, Lampadopsis, Personella, Proxicharonia, Tritonoranella) or conversely, support their synonymization (Biplex with Gyrineum). Several species complexes are also revealed that merit further investigation (e.g., Personidae: Distorsio decipiens, D. reticularis; Bursidae: Bursa tuberosissima; Cassidae: Echinophoria wyvillei, Galeodea bituminata, and Semicassis bisulcata). Consequently, despite their teleplanic larvae, the apparently circumglobal distribution of some tonnoidean species is the result of excessive synonymy. The superfamily is estimated to have diverged during the early Jurassic (∼186 Ma), with most families originating during a narrow ∼20 My window in Albian-Aptian times as part of the Mesozoic Marine Revolution.

ATIMO VATAE, AURORA 2007, CONCALIS, EBISCO, GUYANE 2014, INHACA 2011, KARUBENTHOS 2012, KARUBENTHOS 2015, MAINBAZA, MIRIKY, NORFOLK 2, Restreint, PANGLAO 2004, PANGLAO 2005, SALOMON 2, SANTO 2006, TAIWAN 2004, TERRASSES, Restreint, ZhongSha 2015

Carnivory is unusual among bivalve molluscs and is limited to a few families in the distantly related orders Pectinida, Mytilida and Anomalodesmata. Despite the significance of dietary shifts in the evolution of the bivalves, the anatomy of the alimentary system, and of the gastric chamber in particular, has been described in detail for only a few carnivorous species. Here we describe the anatomy of the gastric chamber in a pectinid, Propeamussium jeffreysii, and an anomalodesmatan, Bathyneaera demistriata, expanding the known morphological disparity of the alimentary system in both groups. We found the stomachs of both to be modified to varying degrees for a carnivorous habit, with thickened, muscular walls, extensive cuticular linings, and reduced sorting areas and gastric chamber compartments (i.e. the dorsal hood, the left pouch and the food-sorting caecum). Despite some superficial similarity, each retains distinct hallmarks of their ancestry among filter-feeding relatives, allowing precise homology assessment of individual characters to differentiate between them. In addition, we found that the gastric chamber of P. jeffreysii represents an intermediate morphology between previously described P. lucidum and filter-feeding pectinids. Consequently, variation in the anatomy of the gastric chamber in Pectinida parallels a previously identified trend towards greater specialization for carnivory in the Anomalodesmata. Our results indicate that the current classification scheme of stomach types does not reflect phylogenetic affinity across the Bivalvia and highlight the need for accurate homology assessment of individual characters of the gastric chamber for inferring evolutionary relationships.

MAINBAZA

Elaphriella n. gen. is a new genus of small to fairly large (up to 18 mm) solariellids superficially resembling the genus Archiminolia Iredale, 1929. The latter differs, among others, by a much thicker columella, spiral cords or grooves that often continue on the body whorl and spiral cords inside the umbilicus. The two genera form distinct clades in a molecular phylogeny of the family Solariellidae. Seven new species are described, all from deep water (300-900 meters) in the South and West Pacific: Elaphriella cantharos n. sp., E. eukhonikhe n. sp., E. paulinae n. sp., E. wareni n. sp., E. dikhonikhe n. sp., E. helios n. sp. and E. leia n. sp.

BATHUS 4, BENTHAUS, BIOPAPUA, BOA1, EBISCO, KARUBAR, MUSORSTOM 10, MUSORSTOM 7, PANGLAO 2005, SALOMON 1, SALOMON 2, SALOMONBOA 3, TARASOC, TERRASSES