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	Department of Geology, University at Buffalo
		Radiolarians are a group of siliceous microfossils with a high biostratigraphic potential, as they show a fast rate of evolution through time.
		The discovery of well-preserved radiolarian faunas in limestone is a rare opportunity to investigate details not found in most faunas and to gain insight into the actual diversity of the faunas, as well as information for a better phylogenetic understanding of this group of skeleton-bearing marine protists.
		In the Llandovery, the radiolarian faunas are dominated by the Secuicollactidae, represented by small spherical radiolarians with a variable number of primary units or spicules.
	www.geology.buffalo.edu /contrib/research/malradio.htm (782 words)

	Oceanlink \| Ocean Info
		Radiolarians are tiny protozoans that live exclusively in the ocean.
		Radiolarians have such a good fossil record because their silicon skeletons preserve so well.
		The quarries used for the Egyptian pyramids are mostly radiolarian and foraminiferan (another shelled protozoan) shells.
	oceanlink.island.net /oinfo/radiolarians/radiolarian.html (282 words)

	Radiolarian - Wikipedia, the free encyclopedia
		Radiolarians (also radiolaria) are amoeboid protozoa that produce intricate mineral skeletons, typically with a central capsule dividing the cell into inner and outer portions, called endoplasm and ectoplasm.
		Radiolarians have many needle-like pseudopodia supported by bundles of microtubules, called axopods, which aid in flotation.
		The main class of radiolarians are the Polycystinea, which produce siliceous skeletons.
	en.wikipedia.org /wiki/Radiolarian (428 words)

	Olympus Microscopy Resource Center: Specialized Microscopy Techniques - Phase Contrast Photomicrography Gallery - ...
		Radiolarians are single-celled protistan marine organisms that distinguish themselves with their unique and intricately detailed glass-like exoskeletons.
		The radiolarian tests are produced in a wide variety of patterns, but most contain many spines and holes that regulate a network of pseudopods useful in gathering food.
		Radiolarians reproduce asexually, usually by division of the cell (including the exoskeleton), with the remaining daughter cells each regenerating a complete organism.
	www.olympusmicro.com /primer/techniques/phasegallery/radiolarians.html (177 words)

	Radiolaria.org
		Radiolarians have existed since the beginning of the Paleozoic era, producing an astonishing diversity of intricate shapes during their 600 million year history.
		Individual radiolarians are normally in the size range of hundredths to tenths of millimeters, but some reach dimensions of a millimeter or more, large enough to be seen with the naked eye.
		Nutrition of radiolarians involves a large variety of materials, including many zooplankton groups such as copepods, crustacean larvae, ciliates, and flagellates, and such phytoplankton groups as diatoms, coccolithophores, and dinoflagellates.
	www.radiolaria.org /what_are_radiolarians.htm (865 words)

	The Rad Page
		Radiolarians Polycystines are unicellular planktonic marine organisms belonging to the class Actinopoda which absorb silica from the marine environment and construct tiny skeletons (0.1-0.2 mm in diameter) according to well defined geometric patterns.
		Radiolarian fossils are known from the early Phanerozoic to the present (550 million years) and, because an immense diversity of taxons evolved rapidly, they have a significant stratigraphic interest.
		Radiolarian biostratigraphy provide a mean of controlling the age of these sediments, and therefore the age of oceanic crust itself.
	radpage.univ-lyon1.fr /rad_en.html (359 words)

	Radiolarian extraction
		Radiolarians are no bigger than 0.1 - 0.2 mm in average and are not easily detectable in the field.
		By applying micropaleontological observation techniques, the rate of recovery is improved (radiolarian ribbon chert, limestone, siliceous shale, mudstone, and siltstone).
		Polycystines radiolarian shells are made of silica (post-mortem recrystallization Opal A - Opal CT - Quartz).
	radpage.univ-lyon1.fr /method.html (293 words)

	Radiolarian Skeletons
		Radiolarian skeletons tend to have arm-like extensions that increase surface area for buoyancy and assist in the capture of small prey.
		Radiolarians occur in large populations to comprise a significant part of the ocean's plankton.
		Radiolarian fossils are known from the Cambrian period (540 million years ago).
	www.astrographics.com /GalleryPrintsIndex/GP2005.html (238 words)

	Radiolarian (Site not responding. Last check: 2007-10-14)
		This beautiful vase-like structure is the skeleton of a single-celled organism called a radiolarian.
		Radiolarians live in large quantities as part of the ocean's plankton.
		After millions of years of radiolarian shells "raining down" on the sea floor, they accumulate in great quantities.
	www.mos.org /sln/sem/radio.html (83 words)

	december 2003
		This study is devoted to the radiolarian biostratigraphy of Middle-Upper Jurassic pelagic siliceous successions in the Southern Alps and in Western Sicily (Italy).
		The close occurrence of ammonites and well preserved radiolarians is generally quite rare: the investigated sections allow the radiolarian zones to be well calibrated by ammonites zones.
		The abundance of radiolarians in the selected successions enable us to study them for a twofold purpose: to date directly most of the sections (whose age was generally based on the ages of the bracketing formations), and to improve the calibration of radiolarian zones thanks to the occurrence of ammonites.
	www.zrc-sazu.si /ssg/december2003.htm (511 words)

	Art Forms From The Ocean: The Radiolarian Atlas Of 1862 by Prestel Publishing
		Radiolarians are a total blank to the majority of people, yet these remarkable builders of glass houses (microscopic to be sure) abound in the world's oceans.
		Ernst Haeckel, the Nineteenth Century German biologist and supporter of Darwin, wrote the most comprehensive monograph on the group in his Radiolarian Atlas of 1862, which is still in use today.
		In many ways I wish that the text would have included descriptions of the radiolarians illustrated and their distributions, but that probably would have been of little interest to the general public.
	www.floridakeysdiving.net /stuff-3791333275.html (333 words)

	Reticulated Geodesic Constructions
		For the radiolarian image, x=t=6, the hexagonal tessellation option was chosen, and vertices were randomly perturbed up to 0.25 times the edge distance.
		As the radiolarian prongs are not multiply divided in my final design, the L-system approach turned out not to be necessary, but the initial design allowed for the possibility of a higher level of division.
		In a final step, as a touch of the artist's hand, a dozen prongs were manually deleted from the file, giving a small "bald spot" to the right of center in the image, allowing a clearer side-on view of the prongs beyond it.
	www.georgehart.com /radiolaria/radiolaria.html (1649 words)

	Glass model of radiolarian- Virtual Wonders at The Natural History Museum
		Radiolarians are small, one-celled drifting (nektonic) plankton with silica-based "skeletons" called tests.
		The true size of the model is 15 x 17 cm but radiolarians are really microscopic, about 0.035 µm by 0.06 µm.
		There is mention of this model in the 'Catalogue of Glass Models of Invertebrate Animals' (1888) by Henry Ward, Rochester, N.Y. This is one of eighteen protozoan models registered within the Zoology Department of the Museum in 1889.
	www.nhm.ac.uk /nature-online/virtual-wonders/vrblaschka1.html (150 words)

	GEOGRAPHIC AND VERTICAL DISTRIBUTION: CLASSIFICATION AND DISTRIBUTION OF SOUTH ATLANTIC RECENT POLYCYSTINE RADIOLARIA
		On their way to the sea-floor and after settling, radiolarian remains are grazed upon by various consumers thus breaking their skeletons into unidentifiable fragments.
		In the southern part of the ocean high densities are probably associated with the subantarctic belt and its northern extensions, the Malvinas (=Falkland) and the Benguela Currents.
		Worldwide depth zonations, however, cannot be defined in terms of fixed depths because the distribution of radiolarian species is related to water masses which move vertically as well as horizontally.
	palaeo-electronica.org /1998_2/boltovskoy/geograph.htm (1994 words)

	Life History and Ecology of the Radiolaria
		Radiolarian species are non-motile; they drift along water currents while those currents compartmentalize the ocean into finer ecological domains.
		Besides water temperature and salinity, there is evidence that maximum concentrations of radiolarian below the surface are associated with maximum concentrations of chlorophyll.
		Radiolaria provide ammonium and carbon dioxide for the dinoflagellate symbionts, and in return the dinoflagellates provide their radiolarian host with a jelly-like layer that serves as both for protection and capturing prey.
	www.ucmp.berkeley.edu /protista/radiolaria/radlh.html (499 words)

	Geosciences : Faculty & Research : Emile Pessagno
		A colleague and myself were able to establish via physical stratigraphy and radiolarian paleobiogeography that the Caribbean Plate originated in the Pacific during the Late Jurassic.
		Dissertation: Radiolarian biostratigraphy of the Upper Jurassic strata of the San Pedro del Gallo Terrane, north-central Mexico, and the Lower Cretaceous strata of the Nooksack Group, Nooksack Terrane, Northwestern Washington.
		Invited to be plenary speaker at Interrad XI Conference: Radiolarians in stratigraphy and paleoceanography: 11th Meeting of International Association of radiolarian paleontologists and Circum-Pacific Triassic Stratigraphy and Correlation, a symposium hosted by IGCP 467 and STS.
	www.utdallas.edu /nsm/geosciences/faculty/pessagno.html (1206 words)

	What we do. Earth History : GNS Science Limited
		Current research on radiolarians at GNS is focussed on fossil assemblages from marine sedimentary strata of Late Cretaceous and early Cenozoic age (80 - 40 million years ago).
		A spumellarian radiolarian in a thin section of the basal Tutuiri Greensand siliceous unit.
		Since the discovery in the early 1970s of the hydrofluoric acid method of extraction of radiolarians from hard rocks such as cherts and siliceous mudstones and the development of the scanning electron microscope for detailed identifications based on external magnification, radiolarians have become a major tool for age determinations in New Zealand's basement rocks.
	www.gns.cri.nz /what/earthhist/fossils/radiolarians/radiolarians.html (377 words)

	Ben Barnes (Site not responding. Last check: 2007-10-14)
		Although radiolarians are closely related to the amoebas, radiolarians are distinguished by their intricate exoskeletons, or tests, which are formed by secretions.
		However, radiolarian skeletons are extremely diverse, and they are the key feature on the basis of which this subclass is classified into smaller units (classes, superorders, orders, families, genera and species).
		When radiolarians die, their shells sink, forming the so-called radiolarian ooze of deep ocean floors that has formed many formations of sedimentary rock over the course of geological time.
	hoopermuseum.earthsci.carleton.ca /2001_radiolarians_bb/intro.html (409 words)

	CHANGXINGIAN (UPPER PERMIAN) RADIOLARIAN FAUNA FROM MEISHAN D SECTION, CHANGXING, ZHEJIANG, CHINA, AND ITS POSSIBLE ...
		This radiolarian fauna is characterized by low abundance and low diversity, and apparently occurred in a water depth of 150-200 m.
		However, because of the morphological differences between modern radiolarians and ancient ones, it is difficult to reconstruct precisely the ecology of ancient radiolarians.
		In order to advance the study of radiolarian paleoecology, this paper summarizes the characteristics of radiolarian fauna from the Changxing Formation of the Meishan D section and infers some characteristics of marine water in which the radiolarian fauna from this paper occurs, based on previous lithology and paleobiology research (Yang et al., 1991; Zhang, 1995).
	www.findarticles.com /p/articles/mi_qa3790/is_200503/ai_n11827020 (785 words)

	Geometry and Pattern in Nature 3: The holes in radiolarian and diatom tests. (Site not responding. Last check: 2007-10-14)
		In theory, the skeletons of diatoms and radiolarians are also designed to offer protection against predators; however, dinoflagellates have evolved their own methods of circumventing this problem by
		It is interesting that, unlike the holes in similarly sized triangular diatoms, the perforations appear to be arranged in rows, rather than radiating from the centre; the fact that the diatom is three-sided does much to reinforce this illusion, and ensures that the “rows” will “read” correctly whichever side they are viewed from.
		Where extreme close-packing or large vesicles have obviously not been present, the holes tend to be much reduced in size, and either be randomly scattered throughout the frustule, radiate from the centre, or lie in accordance with the lines of patterned ridging or protuberances present on the top surface of the frustule.
	www.microscopy-uk.net /mag/artfeb05/cbdiatoms.html (1575 words)

	Franciscan Radiolarian Cherts, TSAW Project (Site not responding. Last check: 2007-10-14)
		A example of a modern environment in which the majority of Marin's cherts were formed is seen in this seismic profile collected during the voyage of the USNS Kane in 1968.
		Microscopic radiolarian skeletons, are today, forming extensive sediments in the Equatorial regions - they seem to like warm water and thrive in the nutrient rich Equatorial upwelling region.
		Radiolarians are protozoans which form skeletons of glass (SiO2).
	www.marin.cc.ca.us /~jim/ring/rchert.html (361 words)

	Radiolaria.org
		Radiolaria.org is an online database containing information about radiolarians - fossil and recent, with images, descriptions, references, synonyms and links to other online resources.
		As with many planktonic organisms, their abundance in a geographical region is related to quality of the water mass, including such variables as temperature, salinity, productivity, and available nutrients.
		Radiolarians have been an inspiration for many artists.
	www.radiolaria.org (84 words)

	Radiolaria.org
		Radiolarian pictures taken by Chris Hollis (a GNS scientist) featuring in an art exhibition which will tour New Zealand for the next two years.
		The database deals with radiolarian type specimens which were described from Japan and by Japanese researchers.
		The Micropalaeontological Society is a multidisciplinary group with researchers in the fields of silicofossils (radiolarians, diatoms, sponge spicules, and silicoflagellates), foraminifera, nannofossils etc...
	www.radiolaria.org /links.htm (1044 words)

	A Smooth Fossil Transition: Radiolarian (Site not responding. Last check: 2007-10-14)
		In sample seven, there are no longer intermediates, and the original species has now split into two species.
		Radiolarians are small, one-celled drifting (nektonic) plankton with silica-based "skeletons" (tests).
		The fossils in the diagram were found in deep-sea drill cores from the northern Pacific.
	www.don-lindsay-archive.org /creation/radiolarian.html (363 words)

	Introduction to the Radiolaria (Site not responding. Last check: 2007-10-14)
		With their glassy skeletons of often perfect geometric form and symmetry, radiolarians are among the most beautiful of all protists.
		Their skeletons tend to have arm-like extensions that resemble spikes, which are used both to increase surface area for buoyancy and to capture prey.
		Until comparatively recently, radiolarians were primarily studied by micropaleontologists, and only at the end of the 20th century have scientists from other fields begun to study these fascinating protists as well.
	www.ucmp.berkeley.edu /protista/radiolaria/rads.html (272 words)

	paleolab13microfossils
		Radiolarians show strong vertical stratification in ocean waters to depths of 1,000 m, and are also highly abundant: enough so to produce what is known as "radiolarian ooze" sediments on the ocean floor!
		Radiolarians are important microfossils in paleoclimate analysis, and have been used to reconstruct oxygen isotope records of the past conditions of the oceans, just as has been done with forams.
		Examine the radiolarians in the teaching collection and draw a radiolarian shown on the Radiolarian strewn slides.
	www.personal.kent.edu /~alisonjs/paleo/paleolab13microfossils.htm (906 words)

	hypotheses for bedded cherts
		The fourth hypothesis may be supported by sediment accumulation rates for the Franciscan chert/shale pairs suggesting that the Milankovitch climatic cycle (~100,000 years cycles of warm and cold periods) could explain the pairings.
		In this hypothesis, during the warm periods, the radiolarians thrived and their skeletons rained onto the ocean floor.
		In colder periods, the radiolarians were scarce and clays transported by ocean currents or winds were deposited.
	www.marin.cc.ca.us /~jim/ring/beddedcherts.html (140 words)

	Radiolarian biostratigraphy from the Russian Platform (Site not responding. Last check: 2007-10-14)
		The aim of the present biostratigraphic investigation is to construct a discrete radiolarian biochronological scale for the Paleogene of the Voronesh Anticline, processing data with the BIOGRAPH program (Savary and Guex 1991).
		This new approach allows to resolve the contradictions in correlation that have existed in numerous previous publications and resulted in the creation of three different radiolarian biostratigraphic schemes for the same region of the Russian Platform.
		The base material for our study are radiolarian assemblages collected from four Paleogene sections located in Russia and Ukraine.
	www.mnhn.fr /publication/geodiv/g02n1a1.html (510 words)

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