Search results for "Spatangoida"
showing 4 items of 4 documents
Characterization of eight microsatellite loci for the sea urchin Meoma ventricosa (Spatangoida, Brissidae) through Next Generation Sequencing.
2015
Eight microsatellite loci were characterized for Meoma ventricosa (Lamarck, 1816), a burrowing sea urchin that can be afflicted by a bacterial disease causing localized mass mortality. For the analyzed population (29 individuals from St. Croix, US Virgin Islands), we observed 8.125 mean number of alleles, 0.640 mean observed heterozygosity (Ho) and 0.747 mean expected heterozygosity (He). Two loci showed significant deviations from Hardy-Weinberg equilibrium. Overall, the described loci were characterized by a moderately highlevel of polymorphism suggesting that these markers are useful for a population genetic studyin the Caribbean Sea.
Tuberculation in spatangoid fascioles: Delineating plausible homologies
1998
The existing definition of spatangoid fascioles as a narrow band of minute tubercles (miliaries) is inadequate. One reason is that many intermediates between the presence of indisputable fascioles and their total absence are known. Although fascioles are widely used in the classification of spatangoids, diversity of fasciole tuberculation has largely been ignored. We examine fascioles in about 100 spatangoid species, focusing on the earliest manifestations of fascioles (both developmentally and phylogenetically) and on their variable tuberculation. Qualitative observations are complemented by quantitative analyses (ANOVA and PCA) of 21 species. Three types of fascioles are defined according…
Notes on selected Cretaceous echinoids from south-central Sakhalin, Far East Russia
2013
AbstractFrom Albian, Santonian and Campanian strata in south-central Sakhalin, four echinoid taxa are described, illustrated and discussed. In Far East Russia, echinoids are rare constituents amongst mid- and Late Cretaceous macrofaunal assemblages in which inoceramid and non-inoceramid bivalves, plus heteromorph and non-heteromorph ammonites predominate. The sole regular species in the present lot is represented by an incomplete external mould of a primary spine of a rhabdocidarid,Polycidaris(?) sp., from the lower Campanian. Irregular taxa include a fragmentary, specifically indeterminate ‘pygurid’,Echinopygus(?) sp., of late Albian age, as well as two spatangoids. One of these, a toxaste…
Biodiversity dynamics and their driving factors during the Cretaceous diversification of Spatangoida (Echinoidea, Echinodermata)
2004
Abstract Variations in recorded diversity over time present a scrambled signal that is modulated by a large number of variables: the potential of particular life forms to generate evolutionary innovations, external constraints induced by the environment in its broad sense, the heterogeneity of the fossil record and the analytical artefacts due to sampling bias. A key question is how to characterise and quantify the separate input of any given factor in the overall diversity signal. This paper explores the structure of diversity data for spatangoid heart urchins and the sensitivity of recorded diversity to different factors of analytical bias (length of geological periods, proportion of pala…