Home › nanno-taxonomy › Nannoliths › Discoasteraceae › Discoaster › D. pentaradiatus group

Revision of D. pentaradiatus group from Mon, 14/01/2008 - 12:33

Mon, 14/01/2008 - 12:37 — Jeremy Young
Citation: 
Discoaster pentaradiatus group

This is an informal grouping for symmetric 5-rayed discoasters. These species probably do not form a clade but are a characteristic component of Late Miocene and Pliocene assemblages, including several important marker species.

Taxa included

quinqueramus.jpg

D. bergenii - D. berggrenii - D. quinqueramus lineage (NN11)

- non-bifurcate rays, concavo-convex, large proximal boss

pentaradiatus.jpg

D. pentaradiatus (NN10B-NN17)

- bifurcate rays, concavo-convex, each ray behaves as separate crystal

prepentaradiatus.jpg

D. prepentaradiatus (NN9-10A)

- bifircate ray tips, complanate, whole disc behaves optically as single crystal

hamatus.jpg

D. hamatus (NN9)

- asymetric & downward deflected ray tips

bellus.jpg

D. bellus (NN8-11)

- simple ray tips, more or les planar

 

 

 

Post new comment

The content of this field is kept private and will not be shown publicly.
  • Web page addresses and e-mail addresses turn into links automatically.
  • Lines and paragraphs break automatically.
  • Use <bib>...</bib> to insert automatically numbered references.
  • You may quote other posts using [quote] tags.
  • Glossary terms will be automatically marked with links to their descriptions. If there are certain phrases or sections of text that should be excluded from glossary marking and linking, use the special markup, [no-glossary] ... [/no-glossary]. Additionally, these HTML elements will not be scanned: a, abbr, acronym, code, pre.
  • Insert Google Map macro.

More information about formatting options

Scratchpads developed and conceived by: Vince Smith, Simon Rycroft & Dave Roberts