Distinguishing features:
Parent taxon (Biscutaceae): Regular placoliths; rim broad, central area relatively narrow, with variable central structures.
The distal shield is formed from V-units and the proximal shield and tube cycle are formed from R-units.
This taxon: Circular with proximal shield wider than distal; spine with helical structure
Daughter taxa (time control age-window is: 0-800Ma)![]() | ||||
Helicorhabdus asymetricus Helicorhabdus species with well-developed spine topped by an asymmetric plate-like calyx | ||||
Helicorhabdus sp. Specimens not identified to species level |
Taxonomy:
Farinacci & Howe catalog pages: Helicorhabdus *
Distinguishing features:
Parent taxon (Biscutaceae): Regular placoliths; rim broad, central area relatively narrow, with variable central structures.
The distal shield is formed from V-units and the proximal shield and tube cycle are formed from R-units.
This taxon: Circular with proximal shield wider than distal; spine with helical structure
Morphology:
Size:
Ecology & Biogeography
Biology & life-cycles
Phylogenetic relations
LITHS: placolith, circular, CA: process, closed, CROSS-POLARS: rim-unicyclic, V-prominent, |
Lith size: 1.5->2.5µm; Data source notes: size range of included species |
Geological Range:
Last occurrence (top): at top of Albian Stage (100% up, 100.5Ma, in Albian stage). Data source: Total of range of species in this database
First occurrence (base): in lower part of Albian Stage (43% up, 107.6Ma, in Albian stage). Data source: Total of range of species in this database
Plot of occurrence data:
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Helicorhabdus compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 29-1-2023
Short stable page link: https://mikrotax.org/Nannotax3/index.php?id=10513 Go to Archive.is to create a permanent copy of this page - citation notes |
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