Microgastropods associated with the natural bank of Arca zebra (Swainson, 1833; Mollusca: Bivalvia) located in Chacopata, Sucre State, Venezuela (original) (raw)
Related papers
Geological Journal, 2007
This paper provides an updated taxonomic inventory of the bivalve fauna collected in the Pilmatué Member of the Agrio Formation of the Neuquén Basin, west-central Argentina, places the fauna in its palaeobiogeographic setting, and addresses its palaeoecological significance. Thirty-one Late Valanginian to Early Hauterivian bivalve species within 24 genera were identified. A large part (32%) of the identified bivalve species occur over a wide geographical area: from the Pacific coast of South America to Europe, North Africa, Central Asia and East and South Africa; some are also recorded in Japan. A relatively high degree of endemism (26%) is shown, suggesting that some of the bivalve species had barriers to their dispersal; larval strategy and length of larval development were probably important. A significant number (42%) of the bivalve taxa are left in open nomenclature as they are probably new species. Bivalve guilds are described to interpret palaeoecology, in particular the ecospace utilization. Guilds are based on tiering, life habit, and feeding category. Eight guilds are recognized: free-lying epifaunal, cemented epifaunal, epibyssate, boring, endobyssate, shallow burrowing, deep burrowing and deep burrowing with symbiotic bacteria. The fauna is composed only of suspension-feeders indicating that food resources were dominantly in suspension, in agreement with the predominantly shallow-water aspect of the study deposits. The ecospace utilization in the shoreface is broader than in the offshore shelf, suggesting more favourable living conditions and/or a wider range of different habitat types represented.
Beds of the Atlantic pearl oyster (Pinctada imbricata) and the turkey wing (Arca zebra) of contrasting population densities were evaluated to determine the occurrence of associated decapod crustaceans. In these beds at Cubagua Island, Venezuela, we recorded 40 decapod species belonging to 18 families. Mithraculus forceps (Majidae), Pilumnus caribaeus (Pilumnidae), Cuapetes americanus (Palaemonidae) and Petrolisthes galathinus (Porcellanidae) were the most common species found in these assemblages. The medium-and high-density bivalve beds exhibited more species and a greater abundance of associated decapods than the low-density bivalve beds, and more taxonomic distinctness. Multivariate analysis detected different groups of decapods in the low-density beds and the medium-to high-density beds. Additionally, similarities were found in the communities of crustaceans in the beds of Atlantic pearl oysters and turkey wing, demonstrating that bed density is important for the composition of associated fauna. RESUMEN: Composición de ensambles de crustáceos decápodos en bancos de Pinctada imbricata y arca zebra (Mollusca: Bivalvia) en la Isla de Cubagua, Venezuela: Efecto de la densidad del banco. -Bancos de la ostra perla del Atlántico (P. imbricata) y de la pepitona (A. zebra) de densidades poblacionales contrastantes fueron evaluados para determinar la ocurrencia de crustáceos decápodos asociados. En estos bancos en la isla de Cubagua, Venezuela, fueron colectadas 40 especies de decápodos, pertenecientes a 18 familias. Mithraculus forceps (Majidae), Pilumnus caribaeus (Pilumnidae), Cuapetes americanus (Palaemonidae) y Petrolisthes galathinus (Porcellanidae) fueron las especies más comunes en estos ensambles. Los bancos de densidad media y alta mostraron mayor riqueza de especies y abundancia que los de baja densidad de bivalvos, así como mayor distinción taxonómica. Análisis multivariados detectaron diferentes grupos de decápodos en los bancos de baja densidad en relación a los de densidad media y alta. Adicionalmente, la fauna encontrada en bancos de ostra perla y pepitona no mostró diferencias, demostrando que la densidad es importante para la composición de la fauna asociada.
Zoosystema, 2012
The deep-water molluscs collected during the expedition MD55 off SE Brazil have been gradually studied in some previous papers. The present one is focused on samples belonging to caenogastropod taxa Xenophoridae Troschel, 1852, Cypraeoidea Rafinesque, 1815, mitriforms and Terebridae Mörch, 1852. Regarding the Xenophoridae, Onustus aquitanus n. sp. is a new species, collected off the littoral of Espírito Santo and Rio de Janeiro, Brazil, 430-637 m depth (continental slope). The main characters of the species include the small size (c. 20 mm), the proportionally wide shell, the white colour, the short peripheral flange, the oblique riblets weakly developed and a brown multispiral protoconch. This appears to be the smallest living species of the family, resembling in this aspect fossil species. In respect to the Cypraeoidea, the following results were obtained: family Cypraeidae Rafinesque, 1815: Erosaria acicularis (Gmelin, 1791) and Luria cinerea (Gmelin, 1791) had the deepest record, respectively 607-620 m and 295-940 m, although the samples were all dead, eroded shells. Family Lamellariidae d'Orbigny, 1841: a total of three lots were collected, provisionally identified as Lamellaria spp. as the samples consist of only vestigial shells; possibly each lot represents a different species. Family Pediculariidae Gray, 1853: a sample of Pedicularia tibia Simone, 2005 was found, expanding the range c. 1000 km southwards, from Ceará to Espírito Santo. Family Ovulidae Fleming, 1822: Pseudosimnia lacrima n. sp., collected off Espírito Santo, 607-620 m depth, is described here and is mainly characterised by its strong biconic outline, small size (c. 7 mm), and a thick peripheral callus. Family Triviidae Troschel, 1863: Cleotrivia antillarum (Schilder, 1922) is recorded for the first time as deep as 620 m, and its distribution expanded from Rio Grande do Norte to Espírito Santo; Dolichupis akangus n. sp. with rounded outline and c. 15 transverse ribs; D. pingius n. sp. with the outer lip expanded posteriorly and c. 10 ribs. In respect to the mitriform neogastropods, the following species are emphasised: family Costellariidae MacDonald, 1860:
Journal of Molluscan Studies, 2015
The Spheniopsidae are today represented by five living species of Spheniopsis and nine of Grippina, distributed in the Pacific and Atlantic Oceans. Little is known of their anatomy and the phylogenetic position of the family within the Bivalvia is debated. In order to investigate these questions, the functional morphology of Grippina coronata obtained from the continental shelf off Rio de Janeiro and Espı´rito Santo States, Brazil, has been examined. Less than 2 mm in shell length, the siphonal apparatus of G. coronata is complex, with seven sensory papillae, and the ctenidia are reduced to transverse septa pierced by four pairs of ciliated pores. There are no labial palps and the stomach is of Type II with epibenthic harpacticoid and ostracod prey identified inside it. Although there is an intestine producing faeces, the stomach also possesses a unique waste storage pouch for exoskeletal remains of digested prey. Collectively, these features suggest that the Spheniopsidae comprise carnivorous taxa belonging to the Cuspidarioidea within the Anomalodesmata. Grippina coronata is a self-fertilizing simultaneous hermaphrodite that, uniquely, broods fertilized oocytes within the ovarian follicles and, thereby, provides the first example of intrafollicular fertilization and brooding in the Bivalvia. Release of the encapsulated oocytes must be by parental death, which coincidentally releases the exoskeletal remains from the storage pouch. Such post mortem semelparity creates a life-history trait hitherto unrecognized in the Bivalvia. desmatan clades stand out, for mention, however. The first includes the adventitious tube-dwelling representatives of the Clavagelloidea (Morton, 2007). The second comprises the remarkable deeperwater predatory bivalves often collectively referred to as the septibranchs. The classification schemes erected for these latter bivalves have undergone many changes over the last 50 years and these were reviewed by Morton (1982: Table II). The septibranchs are today thought to be represented by the fossil Orthonotoidea (Bieler, Carter & Coan, 2010) and three extant superfamilies: the Verticordioidea (Verticordiidae, Euciroidae and Lyonsiellidae), Poromyoidea (Poromyidae) and the Cuspidarioidea (Keen, 1969; Bernard, 1979; Bieler et al., 2010). Hitherto, this last superfamily has been considered to comprise but one extant family-the Cuspidariidae-although, as will be described and discussed, the most recent classification by Carter et al. (2011) considered the Cuspidarioidea to also include the (unstudied) Halonymphidae, Protocuspidariidae and the Spheniopsidae (similarly unstudied). A fourth family of deep-water predatory bivalves, the Parilimyidae, is believed to be affiliated with the Pholadomyoidea (Morton, 1982). The predatory anomalodesmatan bivalves have received some attention, focusing largely on anatomy. Prior to a greater appreciation of their familial diversity, such bivalves were judged to belong, collectively, to the Septibranchia, characterized by the presence of a horizontal muscular septum in place of the typical bivalve ctenidium. This generalization, however, is not true-Halicardia nipponensis Okutani, 1957 (Verticordiidae), for example, possesses a
Zoologia Caboverdiana, 2010
Based on newly collected samples and data from the literature, an updated list of the marine bivalves of the Cape Verde Islands is presented. From 2004 to 2006, collections were made at 22 sampling points in the islands of Santiago, São Vicente, Santa Luzia, São Nicolau, Boavista and Maio. Using qualitative and direct sampling methods, 39 species of bivalves, belonging to 20 families, were identified. Families most represented were Veneridae (6 species), Cardiidae (5 species), Arcidae (4 species) and Mytilidae (4 species). Islands with the largest diversity of species were São Vicente (30 species) and Santiago (23 species), probably due to the larger number of sample points (64% of total). Six species not previously reported from the archipelago were collected, i.e. Irus irus, Venus declivis, Timoclea ovata, Diplodonta rotundata, Plagiocardium papillosum and Tagelus adansoni. Corbicula fluminea, supposedly a man assisted introduction, was also collected.
An important ark clam (Arca zebra) artisanal fishery takes place in the east region of Venezuela. Besides the target species, trawling extracts a significant bycatch of several mollusk species including the gastropod Voluta musica, a threatened species according to the Venezuelan Red List of Endangered Species. In this paper we evaluate: 1) the composition of mollusk species in the bycatch, 2) the number of individuals of V. musica caught as bycatch and, 3) the abundance and size structure of the exploited population. Each fishing night, about 27,830 m 2 are trawled by each boat extracting on the average 607 kg of A. zebra meat and 19 kg of V. musica (whole shelled animal). This fishery activity potentially captures ~30,000 kg of ark clam meat and 922 kg of V. musica in one week (~95 snails/fishing night/boat). The size structure of the V. musica population at the ark clam bed is significantly smaller than in other nearby sites not impacted by trawling fishing activities. Non-target...
Journal of Fish Biology, 2007
The original description of Mugil gaimardianus has created various taxonomic problems in the past since the description is ambiguous and the type specimen is apparently lost. The name M. gaimardianus could not be reliably applied to any known species and was suppressed by the International Commission on Zoological Nomenclature (ICZN) (Bulletin of Zoological Nomenclature, 51: 286–287, 1994). Nevertheless, karyological evidence has shown that there is a species of mullet in Venezuelan coastal waters that does not conform to the description of any other mullet from the Western Central Atlantic and has the feature of a red eye that was often used by earlier authors to define nominal M. gaimardianus. The purpose of this study was to make a morphological description of these unusual specimens, provide a morphological diagnosis from other species of Mugil present in the Caribbean and Western Central Atlantic and establish a valid name for the species.
2020
The phytal environment is a complex system that involves the association between marine organisms and macroalgae. In this paper, we investigate the diversity of bivalves associated with macroalgae on the continental shelf between the states of Alagoas and Bahia, including Sergipe, in northeastern Brazil. Macroalgae and associated fauna were collected during two sampling campaigns under the MARSEAL project (February and July 2011 [dry and rainy seasons, respectively]), covering 24 stations and three isobaths (10, 25 and 50 m). The following ecological descriptors were calculated: abundance (N), richness (S), diversity (H') and evenness (J). A total of 1384 individuals from 20 families, 28 genera and 44 species were obtained. Arcidae was the most abundant group, followed by the families Pteriidae and Mytilidae. The most abundant species were Arca zebra, Anadara sp. 1 and Pinctada imbricata, representing 71% of the total abundance. The families Arcidae, Corbulidae and Mytilidae wer...
Ameghiniana, 2008
The Upper Cretaceous-lower Paleogene rocks from northern Patagonia yield a rich fauna of marine mollusks that may be useful in elucidating paleobiogeographic and paleoenvironmental changes taking place across the K/P boundary in the region. Most of the mollusk faunas remain poorly understood, as the preservation is generally deficient. This paper describes three new species of mytilids (Septifer mayai n. sp., Mytilaster ? edseli n. sp. and Gregariella amara n. sp.), and records four species of pinnids, one of which is new (Plesiopinna pampeana n. sp.). All the material comes from the Maastrichtian Jagüel Formation, and the Maastrichtian/Danian Roca Formation, exposed in the provinces of Río Negro, Mendoza and La Pampa (Argentina). A survey of the stratigraphic distribution of the material described shows that the only Maastrichtian species that survived into the Danian was Gregariella amara. Resumen. MYTÍLIDOS Y PÍNNIDOS (MOLLUSCA: BIVALVIA) DEL MAASTRICHTIANO TARDÍO-DANIANO DEL NORTE DE PATAGONIA, ARGENTINA. Las rocas del Cretácico Superior-Paleógeno inferior expuestas en el norte de Patagonia contienen una rica fauna de moluscos cuyo estudio es importante para comprender los cambios paleobiogeográficos y paleoambientales producidos en la región durante el límite K/P. Sin embargo, una porción considerable de esta fauna permanece poco estudiada, probablemente a causa de su pobre preservación. En este trabajo se describen tres especies nuevas de mytílidos (Septifer mayai n. sp., Mytilaster ? edseli n. sp. y Gregariella amara n. sp.) y cuatro especies de pínnidos de las cuales una es nueva (Plesiopinna pampeana n. sp.). Todos los ejemplares provienen de las formaciones Jagüel (Maastrichtiano) y Roca (Maastrichtiano/Daniano) expuestas en las provincias
The temperate zone of the southwestern Atlantic Ocean (23–42°S), which includes the Patagonian Shelf Large Marine Ecosystem and the Subtropical Convergence Zone, is one of the most productive areas of the Southern Hemisphere. Key features of this region are a wide continental shelf, the convergence of cold and warm currents, and continental freshwater input of the La Plata River. The Uruguayan marine and estuarine waters are at the core of this zone. The marine and estuarine bivalve fauna of Uruguay has received good attention since the publication of the Voyage of Alcide d'Orbigny (1834–1846). Here we provide an overview of taxonomic, faunistic and b iogeographic issues, identifying knowledge gaps and highlighting priorities for future research. The main threats for that fauna are discussed, with emphasis on species of current or potential socioeconomic interest. Of the 231 species reported from the area, only four species are strictly estuarine: Erodona mactroides Bosc, 1801, Tagelus plebeius (Lightfoot, 1786), Brachidontes darwinianus (d'Orbigny, 1842) and Mytella charruana (d'Orbigny, 1842). All of these have large biomasses, as is also the case for the marine eurihaline Mactra isabelleana d'Orbigny, 1846. A total of 112 deep-sea species (i.e., living deeper than 200 m) are recorded for the region, including almost every known group occurring elsewhere in deep-sea basins, with the exception of sunken wood associated species. Of these, 38 have been recorded only from the Argentine Basin. Some new records are preliminarily reported and discussed, including Acharax Dall, 1908 (Solemyidae), Lucinoma Dall, 1901, Graecina Cosel, 2006 (Lucinidae), and Callogonia Dall, 1889 (Vesicomyidae), all from the continental slope. A total of 19 warm and warm/temperate bivalve species have their southern distribution boundary in Uruguayan waters associated to warm waters of/or derived from the Brazil Current, including species distributed from the U.S.A. to Uruguay or from southeast Brazil to Uruguay. On the other hand, at least eight exclusively cold-water bivalves exhibit their northernmost distribution boundary off La Plata River; their occurrence there is associated with offshore sub-Antarctic waters. Uruguayan waters represent a critical biogeographical and ecological crossroads because of the complex interaction of currents and water masses. This region is thus particularly well suited as a system for the study of processes underlying biodiversity patterns. Pending challenges in taxonomic and biogeographic research will be successfully addressed only if multinational collaborative initiatives are undertaken in a framework of integrative taxonomy.