Rüdiger Bieler

Based on morphological examination of rock-, shell-, and coral-boring bivalves in the marine genus Botula, Wilson and Tait (1984) concluded that this genus comprised a single Recent species, Botula fusca (Gmelin, 1791), with a pan-tropical distribution spanning the western Atlantic, Pacific, and Indian Oceans. Variation in shell colour, habitat, depth, and anatomy were determined to reflect variation within this one species. In a subsequent review of Recent and fossil Botula, Kleemann (2007) expressed doubts about a monotypic Botula given "striking morphological differences" between several described species, advocating for the study of soft tissues and application of molecular tools to help resolve species identities. Here, for the first time, we have undertaken a molecular phylogenetic approach to explore species-level relationships within the genus Botula. Our taxon sampling included freshly collected specimens from the Florida Keys National Marine Sanctuary in the context of ongoing research into bioeroding bivalves at reef restoration sites, in addition to previous collections from the western Atlantic, Pacific, and Indian Oceans available at the Florida Museum of Natural History and the Santa Barbara Museum of Natural History. Based on analyses of mitochondrial (COI and 16S rRNA) and nuclear (H3 and 28S rRNA) genes, the genus Botula appears to be monophyletic, with the contentious species currently classified as Leiosolenus kleemanni (Valentich-Scott, 2008) falling within Botula rather than Leiosolenus. High levels of sequence differentiation among samples in this study, including ones previously identified as "Botula silicula", Botula cinnamomea, "Leiosolenus" kleemanni, and Botula fusca, supported them as distinct species. Our phylogenetic analyses also identified a potential cryptic species within western Atlantic Botula fusca. Increased knowledge of diversity within the genus Botula should lead to a more accurate understanding of the role of these bioeroding species in reef ecosystems.

Vermetid worm-snails are sessile and irregularly coiled marine mollusks common in warmer nearshore and coral reef environments that are subject to high predation pressures by fish. Often cryptic, some have evolved sturdy shells or long columellar muscles allowing quick withdrawal into better protected parts of the shell tube, and most have variously developed opercula that protect and seal the shell aperture trapdoor-like. Members of Thylacodes (previously: Serpulorbis) lack such opercular protection. Its species often show polychromatic head-foot coloration, and some have aposematic coloration likely directed at fish predators. A new polychromatic species, Thylacodes bermudensis n. sp., is described from Bermuda and compared morphologically and by DNA barcode markers to the likewise polychromatic western Atlantic species T. decussatus (Gmelin, 1791). Operculum loss, previously assumed to be an autapomorphy of Thylacodes, is shown to have occurred convergently in a second clade of the family, for which a new genus Cayo n. gen. and four new western Atlantic species are introduced: C. margarita n. sp. (type species; with type locality in the Florida Keys), C. galbinus n. sp., C. refulgens n. sp., and C. brunneimaculatus n. sp. (the last three with type locality in the Belizean reef) (all new taxa authored by Bieler, Collins, Golding & Rawlings). Cayo n. gen. differs from Thylacodes in morphology (e.g., a protoconch that is wider than tall), behavior (including deep shell entrenchment into the substratum), reproductive biology (fewer egg capsules and eggs per female; an obliquely attached egg capsule stalk), and in some species, a luminous, “neon-like”, head-foot coloration. Comparative investigation of the eusperm and parasperm ultrastructure also revealed differences, with a laterally flattened eusperm acrosome observed in two species of Cayo n. gen. and a spiral keel on the eusperm nucleus in one, the latter feature currently unique within the family. A molecular phylogenetic analysis based on mitochondrial and nuclear rRNA gene sequences (12SrRNA, trnV, 16SrRNA, 28SrRNA) strongly supports the independent evolution of the two non-operculate lineages of vermetids. Thylacodes forms a sister grouping to a clade comprising Petaloconchus, Eualetes, and Cupolaconcha, whereas Cayo n. gen is strongly allied with the small-operculate species Vermetus triquetrus and V. bieleri. COI barcode markers provide support for the species-level status of the new taxa. Aspects of predator avoidance/deterrence are discussed for these non-operculate vermetids, which appear to involve warning coloration, aggressive behavior when approached by fish, and deployment of mucous feeding nets that have been shown, for one vermetid in a prior study, to contain bioactive metabolites avoided by fish. As such, non-operculate vermetids show characteristics similar to nudibranch slugs for which the evolution of warning coloration and chemical defenses has been explored previously.

The purpose of this application, under Article 55.3.1 of the Code, is to remove the homonymy of Margaritidae Blainville, 1824 (type genus Margarita Leach, 1814) (Mollusca: Bivalvia) with Margaritidae Thiele, 1924 (type genus Margarites Gray, 1847) (Mollusca: Gastropoda) by emending the latter to Margaritesidae. These two homonymous family-group names are based on similar but not identical type-genus names and both are in current use.

A cladistic analysis for 12 genus-group taxa of the Architectonicidae (Architecton­ ica, Philippia, Psilaxis, Basisulcata, Discotectonica, Granosolarium, Solatisonax, Pseu­ dotorinia, Pseudomalaxis, Spirolaxis, Heliacus, and an unnamed new taxon), including most of the Recent and fossil species, was conducted using the computer program packages PAUP and PHYSYS. The family Architectonicidae is well-defined by a suite of synapomorphies (e.g., a crescent-shaped osphradium, the lack of lateral radular teeth, a projection on the inner side of the operculum). Possible outgroups in the 'Heterogastropoda' and Allogastropoda are discussed, and the data available for a species currently grouped in the Mathildidae, Gegania valkyrie, were used for outgroup comparison. Architectonicidae and Mathildidae, forming the superfamily Architectonicoidea, share synapomorphies in anatomy (e.g., two juxtaposed ciliary tracts on the left side of the mantle cavity; fused salivary glands; a longitudin...

Research Infrastructures (RIs) are facilities, resources and services used by the scientific community to conduct research and foster innovation. LifeWatch ERIC has developed various virtual research environments, which include many virtual laboratories (vLabs) offering high computational capacity and comprehensive collaborative platforms that supporting the needs of digital biodiversity science. Over its 250 years of history, the taxonomic research community has developed a system for describing, classifying and naming taxa across multiple levels. For the marine biota, taxonomic information is organized and made publicly available through the World Register of Marine Species (WoRMS) that records more than 250,000 described valid species. Although scientists tend to assign an equal status (in terms of contribution to overall diversity) to each taxon used in taxonomy, biogeography, ecology and biodiversity, the question “are all taxa equal?” has never been tested at a global scale. W...

'Miniaturization' is a widespread phenomenon among the Metazoa. In the molluscan class Bivalvia, records of miniaturization are numerous. Among the Archiheterodonta, Warrana besnardi (Klappenbach, 1963) has attracted attention for its tiny size, which does not exceed 1.5 mm in shell length, and because it belongs to a group with limited anatomical information and often-debated status, the "Condylocardiidae" (which recent molecular studies place deeply nested within the family Carditidae). All species of Warrana Laseron, 1953 are small-bodied, and so miniaturization presumably occurred from a large-bodied ancestor within the Carditidae sensu lato. South American W. besnardi is here studied in detail. Its small size and the enlargement of the anterodorsal region during growth, reflects (and likely led) to infaunal habit, living as a burrowing bivalve that passively feeds on deposit particles entering the pallial cavity anteriorly. Mantle glands, previously reported as a common feature of other archiheterodonts, are missing in W. besnardi, but spongiform tissue in the antero-ventral portion of the mantle lobes presumably represents a blood sinus that might compensate for the great reduction of the ctenidia. Lecithotrophy is reported, with yolky oocytes bearing a thick non-cellular capsule layer; brooding was not observed, and it is here hypothesized that the extreme miniaturization, with the great reduction of ctenidia, is responsible for a shift in the reproductive mode of condylocardiids, contrasting with the commonly reported ovoviviparity of the carditids.

The American conchologist Isaac Lea had a long and productive career during which he introduced more than 1,800 names of molluscan species between 1827 and 1874, the majority North American land and freshwater species. His idiosyncratic way of publishing, by describing
new taxa multiple times in duplicated and variously modified journal papers as well as in retitled collections of extracts, has led to considerable difficulties in determining accurate dates of his original descriptions. He considered the reading and presentation of a manuscript before a "learned society" as the date of its original publication and therefore his own recorded dates must be approached with caution. The problem of interpreting Lea’s names was compounded
by the fact that Lea frequently modified his own new taxonomic names in his subsequent publications, and often without providing justification for the change. The various name versions were inconsistently applied by subsequent authors. The current paper analyses Lea’s substitutions and other modifications of his own names of molluscan species and discusses 131 of his publications in this context, for which attempts at precise dating were made. The status of these "replacements" of Lea’s taxonomic names were evaluated under the current ICZN Code (1999). A few additional cases of changes of Lea’s names by other authors are included; these are instances in which Lea had missed a primary homonym or a secondary homonym was discovered later. While some of the names here discussed are currently resting in synonymy, others are of greater current relevance as they are in use as valid names for taxa
of conservation/management concern, including IUCN and U.S.-federally listed species.
The following 98 discussions of often-complex name changes involve 348 species-group names and their subsequent spellings, 231 of which were introduced by Lea. Based on their current taxonomic status, the names belong to 4 bivalve and 11 gastropod families, with the vast majority concentrated in Unionidae and Pleuroceridae. Under the current ICZN Code, the investigated changes fall into many different categories, which impacts their nomenclatural availability: 35 names changed by Lea (plus 6 by other authors) are interpreted as substitute names for junior primary homonyms, 7 of which were unnecessary; 1 name (plus 6 by others) as substitute names for junior secondary homonyms, 1 of which was unnecessary; 13 names as justified emendations; 10 names (plus 1 by another) as unjustified emendations that have not entered prevailing usage; 1 name determined by his first reviser action; 37 names (plus many by others) as incorrect subsequent spellings that are not in prevailing usage; and 1 incorrect subsequent spelling that is shown to be in prevailing usage and thus considered a correct original spelling. The concept of “prevailing usage,” ill-defined under the current (1999) ICZN Code, is addressed in this context. The following names in current use
are corrected as follows: Helix balasteriana I. Lea, 1840 (taxon inquirendum, ?Dyakiidae), Lioplax cyclostomatiformis (I. Lea, 1844), Diplodon demararaensis (I. Lea, 1859), Iheringella isocardiodes I. Lea, 1856, Dilatata brongniartiana (I. Lea, 1843), Elliptio nasutidus (I. Lea,
1863), Elliptio pullata (I. Lea, 1857), Pleurocera picta (I. Lea, 1841) [instead of P. curta (Haldeman, 1841), which is preoccupied] and Beringiana youconensis (I. Lea, 1847); many others are confirmed in their recently applied spellings. This work serves as an example that the
basic endeavor of summarizing available and valid names from the published literature is not always a straightforward task.

CABI Invasive Species Compendium: Chama macerophylla is a common epifaunal chamid bivalve native to the western Atlantic (the Caribbean, the Gulf of Mexico, and the southern east coast of the United States). This species and several others of the same genus readily settle on artificial substrata including ship hulls and have high invasive potential. C. macerophylla has been reported from attached specimens in Pacific island localities (Hawaii and Guam), from floating debris that had drifted across the Atlantic Ocean to the coasts of Ireland and the United Kingdom, and from barcoded larval samples in various Indo-Pacific locales. However, there are few reports of its becoming established outside its native range. Ecological impacts remain unstudied. The species is listed in the US NEMESIS database (Fofonoff et al., 2019) and has been placed on several watch lists in the Pacific Ocean (e.g. the Galapagos -- Keith et al., 2015) and the Atlantic Ocean (e.g. the genus is so listed in Wales -- Welsh Government, 2017).

The anthropogenic transfer of non-indigenous marine species (NIMS) into new areas of the oceans is a key issue. Despite increasing research effort in recent years many fundamental questions remain to be answered before we can effectively manage the issue. One question is whether the greater number of NIMS thus far documented in temperate waters is real or an artefact of fewer surveys being undertaken in tropical environments. Another one is whether poor taxonomic knowledge of the biodiverse tropics hides NIMS that actually occur there. Extensive taxonomic work in three Pacific localities (Guam, northern Western Australia and Singapore) has been collated in previous papers showing that there are relatively few NIMS in these biodiverse environments. The present paper replicates investigations for a low latitude environment in southern Florida in the Atlantic Ocean. The focus area includes the extensive Florida Keys coral reef environment, the southern margin of the Everglades on Florida Bay and the major PortMiami. Only 48 NIMS were identified in a literature-based compilation of 4,615 species; 15 species were represented by isolated records and have not established populations, leaving only 33 NIMS that are established or whose status is unknown. Records for Mollusca, the group with the most species (1,153) in the compilation, were individually researched and taxonomically verified. It is argued that the relative paucity of NIMS is not a straightforward temperature-driven tropical/temperate issue, but instead there are biological factor(s) restricting the ability of NIMS to colonise biodiverse environments compared to less diverse areas.

Background: Photosymbiotic associations between metazoan hosts and photosynthetic dinoflagellates are crucial to the trophic and structural integrity of many marine ecosystems, including coral reefs. Although extensive efforts have been devoted to study the short-term ecological interactions between coral hosts and their symbionts, long-term evolutionary dynamics of photosymbiosis in many marine animals are not well understood. Within Bivalvia, the second largest class of mollusks, obligate photosymbiosis is found in two marine lineages: the giant clams (subfamily Tridacninae) and the heart cockles (subfamily Fraginae), both in the family Cardiidae. Morphologically, giant clams show relatively conservative shell forms whereas photosymbiotic fragines exhibit a diverse suite of anatomical adaptations including flattened shells, leafy mantle extensions, and lens-like microstructural structures. To date, the phylogenetic relationships between these two subfamilies remain poorly resolved, and it is unclear whether photosymbiosis in cardiids originated once or twice.
Results: In this study, we establish a backbone phylogeny for Cardiidae utilizing RNASeq-based transcriptomic data from Tridacninae, Fraginae and other cardiids. A variety of phylogenomic approaches were used to infer the relationship between the two groups. Our analyses found conflicting gene signals and potential rapid divergence among the lineages. Overall, results support a sister group relationship between Tridacninae and Fraginae, which diverged during the Cretaceous. Although a sister group relationship is recovered, ancestral state reconstruction using maximum likelihood-based methods reveals two independent origins of photosymbiosis, one at the base of Tridacninae and the other within a symbiotic Fraginae clade.
Conclusions: The newly revealed common ancestry between Tridacninae and Fraginae brings a possibility that certain genetic, metabolic, and/or anatomical exaptations existed in their last common ancestor, which promoted both lineages to independently establish photosymbiosis, possibly in response to the modern expansion of reef habitats.

Members of the small bivalve family Cyrenoididae inhabit brackish waters of the eastern and western Atlantic Ocean. Cyrenoida floridana (Dall, 1896) from the western Atlantic is poorly known aside from shell descriptions. A detailed shell and anatomical study of C. floridana is here presented and compared with available data for Cyrenidae and Glauconomidae, two families of closest relationship according to recent phylogenetic studies. The species is characterized by valves externally covered by thin light brown periostracum; muscle scars and pallial line (without sinus) weakly impressed on the internal shell surface; a unique hinge pattern composed of cardinal and lateral teeth joining each other, right hinge with two laterals and two cardinals forming two inverted-V-shaped teeth and left hinge with two cardinals and one lateral forming a horizontal reversed F-shaped tooth; and microtubules inside the shell walls. Anatomically, the species presents unequal adductor muscles; demibranchs fused to each other along their posterior ends; a pair of totally fused, pigmented siphons; two pairs of siphonal retractor muscles; and a stomach with conjoined style sac and intestine, a single typhlosole, and three sorting areas. Evidence of shell parasitism is described.

Our world is in the midst of unprecedented change-climate shifts and sustained, widespread habitat degradation have led to dramatic declines in biodiversity rivaling historical extinction events. At the same time, new approaches to publishing and integrating previously disconnected data resources promise to help provide the evidence needed for more efficient and effective conservation and management. Stakeholders have invested considerable resources to contribute to online databases of species occurrences. However, estimates suggest that only 10% of biocollections are available in digital form. The biocollec-tions community must therefore continue to promote digitization efforts, which in part requires demonstrating compelling applications of the data. Our overarching goal is therefore to determine trends in use of mobilized species occurrence data since 2010, as online systems have grown and now provide over one billion records. To do this, we characterized 501 papers that use openly accessible biodiversity databases. Our standardized tagging protocol was based on key topics of interest, including: database(s) used, taxa addressed, general uses of data, other data types linked to species occurrence data, and data quality issues addressed. We found that the most common uses of online biodiversity databases have been to estimate species distribution and richness, to outline data compilation and publication, and to assist in developing species checklists or describing new species. Only 69% of papers in our dataset addressed one or more aspects of data quality, which is low considering common errors and biases known to exist in opportunistic datasets. Globally, we find that biodiversity databases are still in the initial stages of data compilation. Novel and integrative applications are restricted to certain taxonomic groups and regions with higher numbers of quality records. Continued data digitization, publication, enhancement, and quality control efforts are necessary to make biodiversity science more efficient and relevant in our fast-changing environment. PLOS ONE | https://doi.org/10.1371/journal.pone.

The drivers of latitudinal differences in the phylogenetic and ecological composition of communities are increasingly studied and understood, but still little is known about the factors underlying morphological differences. High-resolution, three-dimensional morphological data collected using computerized micro-tomography (micro-CT) allows comprehensive comparisons of morphological diversity across latitude. Using marine bivalves as a model system, this study combines 3D shape analysis (based on a new semi-automated procedure for placing landmarks and semilandmarks on shell surfaces) with non-shape traits: centroid size, proportion of shell to soft-tissue volume, and magnitude of shell ornamentation. Analyses conducted on the morphology of 95% of all marine bivalve species from two faunas along the Atlantic coast of North America, the tropical Florida Keys and the boreal Gulf of Maine, show that morphological shifts between these two faunas, and in phyloge-netic and ecological subgroups shared between them, occur as changes in total variance with a bounded minimum rather than directional shifts. The dispersion of species in shell-shape morphospace is greater in the Gulf of Maine, which also shows a lower variance in ornamentation and size than the Florida Keys, but the faunas do not differ significantly in the ratio of shell to internal volume. Thus, regional differences conform to hypothesized effects of resource seasonality and predation intensity, but not to carbonate saturation or calcifica-tion costs. The overall morphological differences between the regional faunas is largely driven by the loss of ecological functional groups and family-level clades at high latitudes, rather than directional shifts in morphology within the shared groups with latitude. Latitudinal differences in morphology thus represent a complex integration of phylogenetic and ecological factors that are best captured in multivariate analyses across several hierarchical levels.

Shell aperture modifications are well known in terrestrial and aquatic gastropods, with apertural lip thickening and tooth development common in species with terminal (determinate) shell growth. In contrast, secondary shell openings are rare in snails and are largely limited to slit shells, keyhole limpets, and abalone of the Vetigastropoda. When such features occur in other groups, they are noteworthy and raise interesting questions concerning the functional/adaptive significance of these shell  modifications. Here we report on one such modification in a newly described species of vermetid snail. Members of the worm-snail family Vermetidae are sessile, suspension-feeding caenogastropods found in warm temperate to tropical marine environments worldwide. As juveniles, vermetids permanently cement their shells to hard substrata and subsequently produce irregularly coiled polychaete-like shell tubes with indeterminate growth and typically a simple circular shell aperture. In one previously studied group (genus Cupolaconcha), the aperture can be covered by a shell dome with a central slit that retains its widest opening in the center of the aperture. Vermetid specimens collected in the barrier reefs of Belize and the Florida Keys show an extreme aperture modification previously unknown in Gastropoda, in which the shell opening is covered by an apertural dome that leaves two equal-sized circular holes, each corresponding to the inflow and outflow water exchange currents of the animal’s mantle cavity. The function of this perforated apertural dome is unknown, and it is in some ways antithetical to the suspension feeding habit of these snails. Further field and laboratorybased studies will be needed to clarify the functional significance and trade-offs of this unique morphology. The new taxon, which is not closely related to the previously described dome-building clade Cupolaconcha, is described and named as Vermetus biperforatus Bieler, Collins, Golding & Rawlings n. sp.

Bivalvia has been the subject of extensive recent phylogenetic work to attempt resolving either the backbone of the bivalve tree using transcriptomic data, or the tips using morpho-anatomical data and up to five genetic markers. Yet the first approach lacked decisive taxon sampling and the second failed to resolve many interfamilial relationships, especially within the diverse clade Imparidentia. Here we combine dense taxon sampling with 108 deep-sequenced Illumina-based transcriptomes to provide resolution in nodes that required additional study. We designed specific data matrices to address the poorly resolved relationships within Imparidentia. Our results support the overall backbone of the bivalve tree, the monophyly of Bivalvia and all its main nodes, although the monophyly of Protobranchia remains less clear. Likewise, the inter-relationships of the six main bivalve clades were fully supported. Within Imparidentia, resolution increases when analysing Imparidentiaspecific matrices. Lucinidae, Thyasiridae and Gastrochaenida represent three early branches. Gastrochaenida is sister group to all remaining imparidentians,
which divide into six orders. Neoheterodontei is always fully supported, and consists of Sphaeriida, Myida and Venerida, with the latter now also containing Mactroidea, Ungulinoidea and Chamidae, a family particularly difficult to place in earlier work. Overall, our study, by using densely sampled transcriptomes, provides the best-resolved bivalve phylogeny to date.

The 2017 annual meeting of the American Malacological Society (AMS) was preceded by an iDigBio/National Science Foundation supported workshop on digitizing mollusk specimen data in non-federal Natural History Collections in the USA and Canada. The AMS President’s Symposium invited mollusk researchers, curators and collection managers, who are creating and employing digital specimen data
in research to highlight the many new avenues that are opening up due to the growing landscape of digital data available. Here we describe the symposium, the workshop, and the workshop outcomes. Among the priorities identified were imaging of primary types, expanding taxonomic authority files and initiating collaborative georeferencing.

Robert Robertson (1934−2018) was systematic malacologist, natural historian, and reproductive biologist, focusing on marine gastropods and based at the Academy of Natural Sciences in Philadelphia (ANSP) for most of his career. An account of his professional life is presented, based in part on a brief autobiography here included. Lists of his 142 publications (published and unpublished, formal and informal) and 13 taxa, as well as taxa named for him and publications written about him, are provided

A new species of vermetid gastropod belonging to the genus Novastoa Finlay, 1926, N. rapaitiensis sp. nov., is described from French Polynesia and the Great Barrier Reef, based on morpho-anatomical and molecular data, increasing the recognized extant diversity of this genus from five to six species. The new species is characterized by the largest operculum in the genus to date, with a conspicuous spindle-shaped mammilla that readily distinguishes this species from its congeners. Based on available data, members of the studied populations of N. rapaitiensis sp. nov. are interpreted as a single species, although slight morphological and color differences exist between localities separated by up to 7000 km. The larval development of N. rapaitiensis sp. nov. is inferred to be direct, raising new questions about genetic connectivity and dispersal trajectories across a vast geographic range. Additional molecular data may prove helpful in refining our current knowledge on the morphological variability within this species and verifying the degree of cryptic diversity in this genus.

Artificial reefs created by deliberately sinking ships off the coast of the Florida Keys island chain are providing new habitat for marine invertebrates. This newly developing fouling community includes the previously reported invasive orange tube coral Tubastraea coccinea and the non-native giant foam oyster Hyotissa hyotis. New SCUBA-based surveys involving five shipwrecks spanning the upper, middle, and lower Florida Keys, show T. coccinea now also established in the lower Keys and H. hyotis likewise extending to new sites. Two additional mollusks found on the artificial reefs, the amathinid gastropod Cyclothyca pacei and gryphaeid oyster Hyotissa mcgintyi, the latter also common in the natural reef areas, are discussed as potentially non-native. A new species of sessile, suspension-feeding, worm-snail, Thylacodes vandyensis Bieler, Rawlings & Collins n. sp. (Vermetidae), is described from the wreck of the USNS Vandenberg off Key West and discussed as potentially invasive. This new species is compared morphologically and by DNA barcode markers to other known members of the genus, and may be a recent arrival from the Pacific Ocean. Thylacodes vandyensis is polychromatic, with individuals varying in both overall head-foot coloration and mantle margin color pattern. Females brood stalked egg capsules attached to their shell within the confines of their mantle cavity, and give rise to crawl-away juveniles. Such direct-developing species have the demonstrated capacity for colonizing habitats isolated far from their native ranges and establishing rapidly growing founder populations. Vermetid gastropods are common components of the marine fouling community in warm temperate and tropical waters and, as such, have been tagged as potentially invasive or with a high potential to be invasive in the Pacific Ocean. As vermetids can influence coral growth/composition in the Pacific and have been reported serving as intermediate hosts for blood flukes of loggerhead turtles, such new arrivals in the Florida Keys National Marine Sanctuary are of concern. Growing evidence indicates that artificial reefs can act as permanent way-stations for arriving non-natives, providing nurseries within which populations may grow in an environment with reduced competition compared to native habitats. How to cite this article Bieler et al. (2017), Non-native molluscan colonizers on deliberately placed shipwrecks in the Florida Keys, with description of a new species of potentially invasive worm-snail (Gastropoda: Vermetidae). PeerJ 5:e3158; DOI 10.7717/peerj.3158

Mussels (Mytilida) are a group of bivalves with ancient origins and some of the most important commercial shellfish worldwide. Mytilida consists of approximately 400 species found in various littoral and deep-sea environments, and are part of the higher clade Pteriomorphia, but their exact position within the group has been unstable. The multiple adaptive radiations that occurred within Pteriomorphia have rendered phylogenetic classifications difficult and uncertainty remains regarding the relationships among most families. To address this phylogenetic uncertainty, novel transcriptomic data were generated to include all five orders of Pteriomorphia. Our results, derived from complex analyses of large datasets from 41 transcriptomes and evaluating possible pitfalls affecting phylogenetic reconstruction (matrix occupancy, heterogeneity, evolutionary rates, evolutionary models), consistently recover a well-supported phylogeny of Pteriomorphia, with the only exception of the most complete but smallest data matrix (Matrix 3: 51 genes, 90% gene occupancy). Maximum-likelihood and Bayesian mixture model analyses retrieve strong support for: (i) the monophyly of Pteriomorphia, (ii) Mytilida as a sister group to Ostreida, and (iii) Arcida as sister group to all other pteriomorphians. The basal position of Arcida is congruent with its shell microstructure (solely composed of aragonitic crystals), whereas Mytilida and Ostreida display a combination of a calcitic outer layer with an aragonitic inner layer composed of nacre tablets, the latter being secondarily lost in Ostreoidea.

ABSTRACT Sperm ultrastructural features of the honeycomb (foam) oysters Hyotissa hyotis, H. sinensis, and H. mcgintyi (Gryphaeidae) are described and compared with other Ostreoidea and more generally with other pteriomorphian Bivalvia. Spermatozoa of H. sinensis and H. mcgintyi (the type species of Parahyotissa Harry 1985) exhibit (1) a broad, low-conical acrosomal vesicle; (2) subacrosomal material (very electron-dense granular material and an almost electron-lucent axial rod); (3) a spheroidal nucleus with a wide anterior invagination (filled with subacrosomal components); (4) a midpiece composed of four spherical mitochondria surrounding a pair of centrioles (rootlet associated with proximal centriole); and (5) a flagellum. Sperm of Hyotissa hyotis (type species of Hyotissa Stenzel 1971) differ markedly from those of H. sinensis and H. mcgintyi, in having (1) a conical acrosomal vesicle showing coarse granular texture anteriorly; (2) a very electron-dense axial rod; (3) a barrel-shaped nucleus with a long, narrow anterior invagination (filled with both subacrosomal components) and a basal invagination partly housing the proximal centriole; and (4) five midpiece mitochondria and no proximal centriolar rootlet. Results indicate that H. sinensis should be relocated to another genus, possibly a revised genus Parahyotissa, and also show that the sperm of H. sinensis and H. mcgintyi show many similarities to those of the Ostreidae, with the exception that the ‘axial rod’ component of the subacrosomal material is less electron-dense than the surrounding substance (more dense in Ostreidae, as in H. hyotis). No family defining sperm features of the Gryphaeidae can be identified.

... In addition, I would strongly recommend this book to all malacologists and shell collectors. It just might entice them to take the plunge into the exciting, if not tumultuous, world of bivalvetaxonomy."--Paul Valentich-Scott, The Festivus. Endorsements: ...

MolluscaBase, which will be a Global Species Database covering all marine, freshwater and terrestrial molluscs, recent and fossil, was launched on February 6-7, 2014 at the Flanders Marine Institute (VLIZ) at Ostende, host institute of the World Register of Marine Species (WoRMS). Currently, the WoRMS database contains more than 44,000 valid, verified species names of Recent marine Mollusca, which are estimated to represent approximately 95% of all valid species. Beyond catching up with the missing 5%, and keeping up with the yearly established new species, the molluscan component of WoRMS shall be expanded to contain freshwater and terrestrial Mollusca, estimated on ca 28,000 valid species. Adding the aspect of time to the current database, and acknowledging the fossil record as the source of extant diversity, it has been agreed that the list should be extended to include all fossil mollusc taxa. A solid estimate of the number of fossil mollusc species is not available yet. Mollusc...