Age Determination in the Sand Dollar Mellita tenuis
نویسندگان
چکیده
منابع مشابه
Phylogeography of the sand dollar genus Mellita: cryptic speciation along the coasts of the Americas.
Sand dollars of the genus Mellita are members of the sandy shallow-water fauna. The genus ranges in tropical and subtropical regions on the two coasts of the Americas. To reconstruct the phylogeography of the genus we sequenced parts of the mitochondrial cytochrome oxidase I and of 16S rRNA as well as part of the nuclear 28S rRNA gene from a total of 185 specimens of all ten described morphospe...
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The feeding mechanism of Mellita quinquiesperforata (Leske) has been examined in detail. This sand dollar is a deposit feeder, ingesting particles mostly in the range of 100-250 µm. The particles are picked out of the substrate individually by specialized long barrel-tipped podia, which form a narrow palisade surrounding the geniculate spine fields on the oral surface. Selected food items are p...
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It is now clear that the mitotic figure of dividing echinoderm eggs plays a causal role in the determination of the furrow. Since Hiramoto ('56) showed that removal of the mitotic apparatus before appearance of the furrow did not prevent division , it is convenient to consider the apparatus the source of a stimulus which is the immediate trigger for cytokinesis. Neither the area of the cell whi...
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Swimming behaviors of marine invertebrate larvae play key roles in larval dispersal and survival and, hence, have important consequences for adult population dynamics. However, to date, insufficient quantitative information exists on larval swimming to understand and predict swimming movements in most marine invertebrate species. Previous work suggests that larvae swim more slowly at lower temp...
متن کاملObservations on the Uptake of Tritiated Thymidine in the Pronuclei of Fertilized Sand Dollar Embryos
Following fertilization of the egg of the sand dollar Echinarachnius parma, tritiated thymidine (H(3)TDR) was taken up independently by the male and female pronuclei beginning within about 15 to 20 minutes, and the labeled pronuclei fused at about 30 to 40 minutes. At cleavage 90 minutes later the labeled nuclear material was distributed to both daughter cells. Unfertilized eggs and sperm expos...
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ژورنال
عنوان ژورنال: Gulf of Mexico Science
سال: 2001
ISSN: 1087-688X
DOI: 10.18785/goms.1901.04