Calyculus
Classification: ntax_mesozoic -> Podorhabdales -> Calyculaceae -> Calyculus
Sister taxa: Calyculus, Carinolithus
Distinguishing features: High, broad, flaring distal-shield composed of radial, non-imbricating elements, and a proximal-shield which is often reduced to a simple, narrow cycle of elements; central-area structures are highly variable, including numerous bars, concentric structures, nets and grills.
Daughter taxa (time control age-window is: 0-800Ma) |
| Central area with lozenge & cross-bars (Calyculus) |
 |  |  |  | Calyculus cribrum
Elliptical Calyculus ; rim moderately elevated; central area with axial cross,concentric lozenge.
|
 |  | | | Calyculus depressus
Small elliptical Calyculus; rim low & narrow; central area with axial cross and concentric lozenge.
|
| Central area with radial bars (Vikosphaera) |
 |  |  |  | Calyculus noeliae
Calyculus with central area with around 14-20 lateral bars. Rim elevation very variable, even on a single coccosphere
|
| Central area with lozenge, cross-bars & radial bars (Catillus) |
 | | | | Calyculus hommerili
Elliptical Calyculus ; rim low; central area with axial cross; concentric lozenge and short radial bars
|
 | | | | Calyculus serrai
Elliptical Calyculus; rim moderately elevated; central area with axial cross, small lozenge and long radial bars.
|
| Central area with grill (Incerniculum) |
 |  | | | Calyculus absolutus
Elliptical Calyculus; rim moderately elevated, narrow; central area with finely perforate net and spine-base
|
| | | | Calyculus derivatus
Elliptical Calyculus ;rim moderately elevated; central area with axial cross finely perforate net and large spine-base
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| | | | Calyculus magnus
Large (ca 6-8 µm across), broadly elliptical Calyculus; rim elevated, broad; central area with grill
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 |  |  |  | Calyculus sp.
Specimens not identified to species level
|
Taxonomy:
Citation: Calyculus Noël, 1973Rank: GenusType species: Calyculus cribrum Noël, 1973.Synonyms: Proculithus Medd, 1979; Incerniculum Goy, 1979; Vikosphaera Goy, 1979; Catillus Goy, 1979.
NB The genera Incerniculum, Vikosphaera and Catillus were proposed based on variations in central area structure, Bown (1987) and Crux (1987) both argued that this was impractical and such characters were better used at specific level. Nonetheless, it is useful to sort the species out into the categories proposed by Goy in order to understand the taxonomy - this is what I have done in the table [JRY]
Farinacci & Howe catalog pages: Calyculus + * , Proculithus * , Incerniculum * , Vikosphaera * , Catillus *
Distinguishing features: High, broad, flaring distal-shield composed of radial, non-imbricating elements, and a proximal-shield which is often reduced to a simple, narrow cycle of elements; central-area structures are highly variable, including numerous bars, concentric structures, nets and grills.
Morphology: Species are often difficult to differentiate in LM because the distinctive central area structures may be imperceptible or missing.
Search data:
| Tags | LITHS: placolith, elliptical, hollow, CA: concentric-ring(s), cross-axial, ca_disjunct, grill, CROSS-POLARS: rim-unicyclic, V-prominent, |
| Metrics | Lith size: 3->8µm;
Data source notes: size range of included species |
The morphological data given here can be used on the advanced search page. See also these notes
Geological Range:
Last occurrence (top): in lower part of Bajocian Stage (30% up, 169.7Ma, in Bajocian stage). Data source: Total of range of species in this database
First occurrence (base): in lower part of Pliensbachian Stage (40% up, 187.6Ma, in Pliensbachian stage). Data source: Total of range of species in this database
Plot of occurrence data:
- Range-bar - range as quoted above, pink interval top occurs in, green interval base occurs in.
- Triangles indicate an event for which a precise placement has been suggested
- Neptune data: This is a higher taxon page so Neptune data is not plotted. See also: customisable plot Parent: Calyculaceae
References:
Bown, P. R. & Cooper, M. K. E. (1998). Jurassic. In, Bown, P. R. (ed.) Calcareous Nannofossil Biostratigraphy. British Micropalaeontological Society Publication Series. 34-85. gs
Bown, P. R. (1987a). Taxonomy, evolution, and biostratigraphy of Late Triassic-Early Jurassic calcareous nannofossils. Special Papers in Palaeontology. 38: 1-118. gs
Crux, J. A. (1987a). Concerning dimorphism in Early Jurassic coccoliths and the origin of the genus Discorhabdus Noël 1965. Abhandlungen der Geologischen Bundesanstalt. 39: 51-55. gs V O
Goy, G., Noël, D. & Busson, G. (1979). Les conditions de sédimentation des schistes-carton (Toarcien inf.) du bassin de Paris déduites de l'étude des nannofossiles calcaires et des diagraphies. Documents des laboratories de géologie Lyon. 75: 33-57. gs
Medd, A. W. (1979). The Upper Jurassic coccoliths from the Haddenham and Gamlingay boreholes (Cambridgeshire, England). Eclogae Geologicae Helvetiae. 72: 19-109. gs V O
Noël, D. (1973). Nannofossiles calcaires de sédiments jurassiques finement laminés. Bulletin du Muséum National d'Histoire Naturelle. 75: 95-156. gs
