Diatoms & Silicoflagellates


  1. Siliceous microfossils: diatoms, radiolarians, and a silicoflagellate from the Middle Eocene of the southwest Pacific (Deep-Sea Drilling Project site 206C). Height of the field is 285 microns. Light micrograph. Photo by J. A. Barron, U. S. G. S.

 

  1. Marine diatoms: Large discoid diatom is Coscinodiscus morenoensis (diameter = 122 microns). The stick-like diatom is Gladius speciosus. These planktonic diatoms are typical of the Late Cretaceous. The triangular species is Trinacria spp. Moreno Formation, Upper Cretaceous, California. Light micrograph.

 

  1. Diatom: Paralia sulcata, a nearshore semi-planktonic diatom. Although this specimen (diameter = 27 microns) is from the Late Cretaceous Moreno Formation of California, the species is still living today. Light micrograph. Photo by J. A. Barron, U. S. G. S.

 

  1. Benthic marine diatoms from the middle Miocene of Castel, Hungary. Two pennate diatoms (genus Diploneis) are shown on either side of the disc-like Aulacodiscus. Diploneis possesses a median groove (raphe) and is capable of movement along a substrate. Aulacodiscus is an attached form. Light micrograph by J. A. Barron, U. S. G. S.

 

  1. Benthic diatom: Entogonia pulcherimma. Eocene. Indian Ocean. Length of base is 128 microns. Light micrograph by J. A. Barron, U. S. G. S.

 

  1. Planktonic diatom: An oblique view of Craspedodiscus rydei from the Lower Miocene of the equatorial Pacific Ocean (Deep-Sea Drilling Project site 77B). Scanning electron micrograph. Courtesy of J. A. Barron, U. S. G. S.

 

  1. Silicoflagellate: Distephanus speculum, showing hollow skeleton. Upper Miocene near San Felipe, Baja California. Upper specimen is about 60 microns from spine tip to tip. Scanning electron micrograph. From Y. T. Mandra and H. Mandra, Occasional Papers of the California Academy of Sciences, no. 99. Used with the permission of Y. T. Mandra, San Francisco State University.

 

  1. Silicoflagellate: Distephanus speculum with a double skeleton. Late Miocene. Lompoc, California. Length is 45 microns. Courtesy of J. A. Barron, U. S. G. S.

 

  1. Silicoflagellate: Hannaites quadria. Eocene. R/V Vema core 107, southwestern Atlantic Ocean. Scanning electron micrographs of four specimens. Courtesy of Y. T. Mandra, San Francisco State University. Copyright Cushman Foundation for Foraminiferal Research, Inc., 1987.