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Comparative Anatomy of Selected Marine Bivalves from the Florida Keys, with Notes on Brazilian Congeners (Mollusca: Bivalvia)
Abstract and Figures
To broaden the anatomical knowledge of marine bivalves, detailed gross anatomical studies of 20 species from the Florida Keys are presented, representing 19 families: (Cardiidae) and Scissula similis (J. Sowerby, 1806) (Tellinidae). These taxa represent various clades of the class Bivalvia and interface with broader regional and phylogenetic studies (e.g., the Bivalve Tree of Life, http://www.bivatol.org, and Bivalves-in-Time-and-Space, http://www.bivatol.org/bits), in which many serve as exemplar species in different contexts. These descriptions provide the most complete anatomical descriptions yet presented for all species, most especially for Solemya occidentalis, Limopsis aff. cristata, Hyotissa mcgintyi, H. hyotis, Carditamera flori-dana, Entodesma beana, Chama macerophylla and Polymesoda floridana, for which no or only minimal anatomical information has been previously published. This work presents the first anatomical description of any species of Scissula, based on S. similis. Two controversial characters – the promyal passages (in Hyotissa spp., in Anomia simplex noted here for the first time, and in Crassostrea reported in the literature) and the various kinds of posterior apertures and siphons present in the species examined and across the Bivalvia – emphasize the need for further comparative study to confirm homologies. Conspecificity of Brazilian material with that from the North American coast is clarified for all species, resulting in nine species being removed from Brazilian checklists (S. occidentalis, B. exustus, I. alatus, P. carnea, C. floridana, C. macerophylla, L. hians, L. serratum, and S. similis). Pertinent anatomical characters are summarized in a data matrix, and an analysis is provided to demonstrate the utility and resolving power of such characters (but from this limited taxon sampling is not intended to provide a revised phylogenetic hypothesis of bivalve relationships); data for three additional species from Florida, published earlier, are included in the analysis and discussion.
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... Moreover, the muscle structures located around the digestive system proved to be very complex, with bundles of transverse musculature between two groups of intestine loops, between the stomach caeca, below the dorsal appendix, and concentrated along the style sac wall. This pattern is aforementioned by Simone and Wilkinson (2008) and Simone et al. (2015). Simone and Wilkinson (2008) also recognized the presence of transverse intestinal muscles and a specific pattern of intestine loops as putative synapomorphies, which are dismissed here as we verified their presence in all tellinoid families. ...
... Navajo rugs representing the summary of clades resulting across type of analysis (weighted or unweighted) and matrix (just with discrete characters or coupled with Procrustes or landmark morphometric characters) is provided in lower left. Black cells represent clades appearing in all analyses; grey cells represent clades appearing in the majority (> 50%) of analysis; white cells represent none clade results (Yonge, 1967), Spondylidae (Simone et al., 2015), Ostreidae (Amaral & Simone, 2014), and more expressively in Anomiidae (Morton, 1976;Simone et al., 2015). The Pteriomorphia present recognized asymmetry in mantle structures (Haszprunar, 1983;Temkin, 2006;Simone et al., 2015;Harper & Checa, 2020) and digestive and nervous systems (Marques et al., 2014). ...
... Navajo rugs representing the summary of clades resulting across type of analysis (weighted or unweighted) and matrix (just with discrete characters or coupled with Procrustes or landmark morphometric characters) is provided in lower left. Black cells represent clades appearing in all analyses; grey cells represent clades appearing in the majority (> 50%) of analysis; white cells represent none clade results (Yonge, 1967), Spondylidae (Simone et al., 2015), Ostreidae (Amaral & Simone, 2014), and more expressively in Anomiidae (Morton, 1976;Simone et al., 2015). The Pteriomorphia present recognized asymmetry in mantle structures (Haszprunar, 1983;Temkin, 2006;Simone et al., 2015;Harper & Checa, 2020) and digestive and nervous systems (Marques et al., 2014). ...
One of the main questions of phylogenetic systematics has recently focused on the reliability and robustness of taxonomic
data. Many recent studies are devoted almost exclusively to the molecular-morphological couplet. However, in many metazoan
taxa, the presence of skeletal parts or poorly preserved soft parts is dominant in collections, making it difficult to extract
genetic material. This is the case with many invertebrates and unfortunately a very common situation in mollusk collections.
Herein we carry out a phylogenetic analysis of the transisthmian American tellinid bivalve genus Eurytellina based
on anatomical and morphometric characters, using different ways to analyze the morphometric data under parsimony-based
methods. Species in this genus are recognized as deep infaunal burrowers and present a strong filter-feeding apparatus. We
included 144 taxonomically important morphoanatomical and morphometric characters and 19 landmark characters. The
main results are a) Tellinota (formerly a synonym of Eurytellina) is confirmed as a taxon restricted to Africa; b) Eurytellina
lineata is confirmed as sister group to all the other members of the genus; c) there is strong evidence for three robust clades,
here named as groups trinitatis, nitens and punicea; d) some transisthmian sister species hypotheses are confirmed—although
the pattern of speciation and radiation may be related to a complex long-term elevation of the Panama Isthmus and previous
events (probably since the early Cenozoic). Furthermore, several new anatomical characters are described within the Order
Tellinoidea, which should be considered in future studies.
... The putative phylogenetic relationships of dimyids can be found elsewhere (Waller, 2012: 837), and suggest a close relationship to Prospondyloidina (Waller & Stanley, 2005: 47), a taxon that also includes Prospondylidae, Plicatulidae and anomiidae. the anatomical data surveyed in this paper is inserted in a wider dataset on bivalve phylogeny (Simone, 2009(Simone, , 2011Simone et al., 2015), in order to provide an alternative hypothesis of relationships, and to motivate further study of dimyid relationships from a morpho-anatomical perspective. ...
... japonica was preserved in 70% ethanol (specimen data follows the description in the Systematics section). It was dissected under a stereomicroscope while immersed in preservative; the dissection methods are traditional (Simone et al., 2015). Digital photographs of most dissection steps were produced for reference, with some of these included here. ...
... The data obtained here were integrated into the phylogenetic scenario of Simone et al. (2015), which also incorporated data found in other papers (Simone, 2009(Simone, , 2011, complementing species and characters, in order to better understand the relationship of the studied dimyid within a wider analysis, and using the same level of phenotypic details. The methodology of phylogenetic analysis is the same explained in Simone (2011Simone ( , 2020 Lemche, 1957. the internal branch "Barbatia spp." is based on the ground plan by Simone & Chichvarkhin (2004), which is the set of apomorphies and plesiomorphies that support the node of that genus and is used as a single terminal. ...
Phenotypic characters of the uncommon Dimya cf. japonica, based on a specimen from Niue Is. in the South Pacific, are reported to represent the enigmatic Dimyidae in a wide-ranging Bivalvia phylogenetic scenario. The main conclusion is that dimyids are placed between ostreoideans and pectinoideans. This is supported by five synapomorphies. Dimyids are closer to pectinoideans, in that they share four synapomorphies.
... The character matrix derived from analysis of the shell and internal tissue morphology of the taxa relates to representatives of all 22 families of the Anomalodesmata including the recently described Bentholyonsiidae . The data matrix obtained includes 65 ingroup taxa plus three outgroup taxa, with shell features and anatomical data available from the literature (Morton 1987a;Paine and Allen 1991;Simone et al. 2015), including representatives of F. M. Machado and F. D. Passos Invertebrate Systematics Table 1. List of the extant families of Anomalodesmata with the 65 ingroup taxa included in this phylogenetic analysis and the main references. ...
The Anomalodesmata Dall, 1899 includes some of the rarest and most specialised species of marine bivalves. This rarity has consequently constituted the greatest obstacle for understanding the internal relationships due to the low representativeness of species present in any phylogenetic reconstructions. Therefore, with the primary purpose of creating a more comprehensive morphological analysis, data including all the anomalodesmatan families were gathered into a cladistic analysis. Our data set includes, for the first-time, information about members of the families Clistoconchidae, Cetoconchidae, Protocuspidariidae, Spheniopsidae and the recently described Bentholyonsiidae. Information on shell morphology, anatomy and behaviour of anomalodesmatans was compiled through a review of the literature (from 1895 to 2022) and a re-analysis of shells and internal anatomy of some freshly collected and archived specimens in museum collections around the world. Our analysis suggests a deep division of the Anomalodesmata into two distinct clades: the first generally composed of shallow water species from 12 families and a second clade of a carnivorous lineage mainly comprising deep water species from 10 families. Consequently, a new topology for Anomalodesmata is suggested bringing new insights into the interfamilial relationships of this sometimes bizarre clade of bivalves.
... Solemyids are burrowers, often building a U-to Y-shaped burrow extending as deep as 30 cm below the sediment-water interface (Owen 1961;Stanley 1970;Reid 1980;Stewart and Cavanaugh 2006;Seike et al. 2012), and can be occasionally trapped and killed in their burrows by rapidly deposited sediment cover (Hryniewicz et al. 2020). The species of Solemya living in settings with high organic matter content are often gutless (e.g., Reid 1980;Coan et al. 2000), while others have retained their gut and are capable of suspension feeding (e.g., Krueger et al. 1992;Taylor et al. 2008;Simone et al. 2015). Relatively little is known about the biology of Acharax, but the available data suggest that at least some species are gutless (Métivier and Cosel 1993). ...
Bivalves are an important part of the methane seep fauna ever since seeps appeared in the geologic record. The chronostratigraphic ranges of seep-inhabiting chemosymbiotic bivalves show an overall increase in diversity at seeps since the Paleozoic. The most common group at Paleozoic and early Mesozoic seeps are modiomorphids, with a few additional records of solemyids and anomalodesmatans. The most common infaunal chemosymbiotic bivalve taxa at modern seeps, lucinids and thyasirids, appeared at seeps in the Late Jurassic and earliest Cretaceous. They diversified during the Cretaceous synchronous with the peak of the “Mesozoic Marine Revolution” and first occurrences of gastropod predatory drill holes in the shells of seep-inhabiting bivalves, soon after the appearance of these gastropods in the mid-Cretaceous. The two dominant bivalve clades of the modern vent and seep fauna, bathymodiolins and vesicomyids, appeared in the Eocene. Their origin has been linked to a deep-water extinction event at the Paleocene-Eocene Thermal Maximum. However, the fossil record of chemosymbiotic bivalves at seeps during this time interval does not display any extinction. Rather, the mid-Eocene appearance of semi-infaunal and epifaunal bivalves such as bathymodiolins and vesicomyids might be linked to a dramatic rise in seawater sulfate concentrations at this time.KeywordsBivalvesChemosymbiosisEvolutionSulfate concentrationMesozoic marine revolutionSolemyidaeNucinellidaeBathymodiolinaeModiomorphidaeKalenteridaeLucinidaeThyasiridaeVesicomyidaeAnomalodesmatas
... They were mainly deposited in the MZSP collection, with paratypes selected for other indicated institutions. The dissection procedures and terminology are standard (Simone et al. 2015), with the specimens dissected under dissecting stereomicroscope, immersed in the fixative. Digital photos of the dissecting steps were obtained by connected digital camera. ...
Eupera troglobia sp. nov. is the first fully described troglobitic bivalve discovered in the Americas, and possibly the second in the world. The troglobitic designation is based on the lack of pigmentation, reduction in size and shell thickness, and large and few offspring. Unlike its relatives that live in the roots of the water hyacinth , this new species is attached to the walls of the caves with a byssus. The anatomical study shows some peculiarities in comparison with the congeners, especially the simplicity of the foot, the siphons and the gut. This discovery is a new contribution to the efforts for the conservation of subterranean habitats in Brazil. http://zoobank.org/9301CE77-42B5-4F66-A62B-1E99949D6467
... This species can be considered rare, as only the type material was collected and is mostly comprised of empty shells and valves. The single specimen collected alive was dissected using standard techniques (Simone et al. 2015) under a stereomicroscope with the specimen immersed in fixative. An adult paratype is preserved with soft parts (MZSP 108256), but both shell and soft parts were inexplicably crushed. ...
Semele trindadis is a new species so far endemic to Trindade Island, a remote island in the northwestern South Atlantic Ocean. The study is based on 17 specimens, including 2 with soft parts. The main character of this species is strong concentric sculpture. The anatomy of a young specimen is described, and it shows typical semelid features, but the retractor siphonal muscles, the palps, and the foot are small, the intestine has a single loop, and there is a distinctive arrangement of muscles in the siphonal chamber. This species is easily distinguishable as the only semelid, and even tellinoidean, from Trindade Island.
... Entodesma navicula is hermaphroditic (Yonge, 1952). Similar anatomical results have also been described for Entodesma beana (d'Orbigny, 1853) by Simone et al. (2015). The organs of the mantle cavity of Mytilimeria nuttalli, as seen from the right lateral aspect, are illustrated in Fig. 12. ...
The fossil record shows that the two clavagelloid or watering pot families evolved at different times, the Clavagellidae first in the late Mesozoic (100–66 mya), the Penicillidae later in the Cenozoic (33–23 mya)—the former originally with, thus, a near-global Tethyan distribution, the latter restricted to the Indo-West Pacific. Representatives of the two clavagelloid families, moreover, have wholly different adventitious tube/crypt structures and, thus, methods of formation suggesting that evolutionary experiments have been undertaken to achieve such radical architectural novelties. This has resulted in one of the most surprising examples of convergent evolution in the Bivalvia.
But, what were the ancestors of the Clavagelloidea? The shell and internal morphology of representatives of the three recognized genera of the Lyonsiidae, that is, Lyonsia, Entodesma and Mytilimeria, are described. Species of the latter two genera are highly specialized epibenthic, byssate, nestlers and embedded symbionts of ascidian colonies and sponges, respectively. Species of Lyonsia, however, are mostly shallow endobenthic burrowers. On the basis of these studies, it is concluded that species of Lyonsia can be regarded as representative of the ancestral watering pot (Clavagelloidea) condition. Evidence for this conclusion include the mineralogy, characteristics and ligament structure of the shell and features of the anatomy, importantly the modification of the vestigial pedal retractor muscles to form simple (Clavagellidae) and more complex (Penicillidae) proprioreceptors. Such an anatomy-based conclusion is supported to some extent by DNA analyses of representatives of the Lyonsiidae and the two constituent families of the Clavagelloidea. To some extent because all clavagelloids are exceedingly rare hindering such analyses. Such rarity, however, also argues for the strict conservation of all the species of the Clavagelloidea.
Increasing habitat modification and species loss demand consistent efforts to describe and understand biodiversity patterns. The BIOTA/FAPESP Program was created in this context and it has been a successful initiative to promote studies on biodiversity and conservation in Brazil. The BIOTA/Araçá is an interdisciplinary project that provided a detailed evaluation of the biodiversity of Araçá Bay, a coastal seascape located on the North coast of the state of São Paulo, Southeast Brazil. The bay encompasses multiple habitats, such as beaches, mangroves, rocky shores, and a tidal flat, and provides important ecosystem services. Unfortunately, the bay is the subject of complex social-environmental conflicts that oppose economic, social, and environmental demands (i.e., the expansion of neighboring harbor activities vs. small-scale artisanal fisheries and protection of biodiversity). The present study presents a survey of the benthic species occurring in the different habitats of Araçá Bay, including data obtained during the BIOTA/Araçá project and previous assessments of the area. The benthic species play an important role in marine environments and studying the diversity of these organisms that live associated with the bottom is indispensable for comprehending the environment’s functioning. The macrofauna, meiofauna, and microorganisms associated with soft and hard bottom were listed, and additional information, such as the habitat and geographical distribution, were provided for each species. The checklist includes 826 species, almost 70% recorded during the BIOTA/Araçá project. The most speciose taxa were the annelids (225 spp.), mollusks (194 spp.), and crustaceans (177 spp.). Seven benthic species are endemic to Araçá Bay, 14 are considered threatened, and seven are economically exploited. Furthermore, the bay is the type locality of many taxa, and 11 new benthic species were described based on specimens sampled during the project. This project shows the importance of Araçá Bay as a unique biologically rich environment and highlights the need for conservation efforts in light of the current threats.
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.
This datasheet on Chama macerophylla covers Identity, Overview, Distribution, Dispersal, Diagnosis, Biology & Ecology, Impacts, Uses, Prevention/Control, Further Information.
The Mollusca are a large, diverse, and economically important group that ranges from slugs and snails through clams and oysters to octopus, squid, and cuttlefish. They are evolutionarily ancient and better known than most invertebrate groups because of their calcareous skeletons, which has led to their excellent preservation as fossils. This is a state-of-the-art summary of research into Molluscs and their evolution, including recent developments in phylogenetic analysis and molecular techniques. Since the last book on this topic was published in 1985, the vast amount of updated information found here should be on the bookshelf of every zoologist, evolutionary biologist, and taxonomist.
A anatomia funcional de B. solisianus, foi estudada com especial atenção ao funcionamento dos sifões, palpos, ctenídios e estômago. Procurou-se dar ênfase às adaptações daquelas estruturas ao meio em que o animal vive. Foram analisados com detalhe a motilidade e sensibilidade dos sifões, a estrutura muscular, o pé e o bisso, a movimentação e ciliação dos palpos, a forma e ciliação dos ctenídios, a estrutura e funcionamento do estômago e os õrgãos excretores. Em B. solisianus, os sifões são do tipo A (II) (Yonge, 1948), os ctenídios do tipo B (I) (Atkins, 1937a); a relação entre os palpos e ctenídios pertence a categoria I (Stasek, 1963), as estruturas labiais são do tipo simples (Bernard,1972). 0 estômago é do tipo III (Purchon, 1957), ou da Secção I de Dinamani (1967), apresentando mecanismos de triagem dos tipos A e B de Reid (1965).