Specimens which cannot be assigned to established species
| Daughter taxa (time control age-window is: 0-800Ma) | ||||
| | | Hendersonites carinatus | |
| Hendersonites sp. Specimens which cannot be assigned to established species | ||||
Taxonomy
Original description: Diagnosis.– Heterohelicidae with test wall flexure on the lateral sides of the test, resulting in carinate appearance.
Description.– Test is biserial throughout. Chambers are globular to subrectangular in lateral view, increasing gradually and moderately in size as added. Sutures are distinct and depressed, straight to slightly oblique to the test axis of growth. Periphery is subacute due to the development of a test wall flexure, which results in the duplication of the test wall in the periphery region. Aperture is arch-shaped, situated at the base of the last formed chamber. Two small and symmetrical periapertural flanges, rimmed or not, border the aperture on the lateral sides. Apical part can be smooth. Pustulose periapertural area is present above the aperture. Chamber surface ornamented with costae, which can be parallel to the periphery, longitudi- nal or oblique to the test axis of growth. Ornamentation thickenings can be present on the earlier chambers in the proximity of the central ‘zigzag’ suture. Test wall calcareous, hyaline perforate; pores can be simple, or situated in the center of a crater-like structure in the evolved species.
Entries in the Catalog of original descriptions: Hendersonia, Hendersonites
Distinguishing features:
Parent taxon (Heterohelicidae): Aperture symmetrical, ranging from a low slit to a high arch at the base of the final chamber, becoming terminal in uniserial taxa.
This taxon: Biserial throughout, test compressed with a carinate peripheral margin
Geological Range:
Last occurrence (top): in upper part of Campanian Stage (68% up, 75.8Ma, in Campanian stage). Data source: Total of range of species in this database
First occurrence (base): near top of Coniacian Stage (87% up, 86.7Ma, in Coniacian stage). Data source: Total of range of species in this database
Plot of range and occurrence data:
References:
 |
Hendersonites compiled by the pforams@mikrotax project team viewed: 29-3-2023
Short stables page link: https://mikrotax.org/pforams/index.php?id=110279 Go to Archive.is to create a permanent copy of this page - citation notes |
Comments
(1)
Hendersonites carinatus; genus is masculine
ref.: Georgescu, M. D.; Abramovich, S. (2008). Taxonomic revision and phylogenetic classification of the Late Cretaceous (Upper Santonian-Maastrichtian) serial planktonic foraminifera (Family Heterohelicidae Cushman, 1927) with peripheral test wall flexure. Revista Española de Micropaleontología. 40: 97-114.
Sounds fair, I'll ask Brian to take a look at this - Jeremy