Reticulofenestra
Classification: ntax_cenozoic -> Isochrysidales -> Noelaerhabdaceae -> Reticulofenestra
Sister taxa: Emiliania, Gephyrocapsa, Pseudoemiliania, Reticulofenestra, Noelaerhabdus, Bekelithella, Pyrocyclus
Taxonomy:
Citation: Reticulofenestra Hay, Mohler & Wade, 1966Rank: GenusType species: Reticulojenestra caucasica Hay Mohler & Wade, 1966Synonyms:
- Crenalithus - the genus Crenalithus has often been used as a synonym of small Reticulofenestra in modern and Quaternary studies. However, the holotype of the type species, Coccolithus doronicoides Black & Barnes 1961 is a proximal view of Gephyrocapsa oceanica (see Young 1998, Jordan & Young 1990).
- Apertapetra Hay, Mohler & Wade, 1966
- Stradnerius Haq, 1968 (type species D. dictyodus)
- Ericsoniella Krhovsky, 1979 - synonym of Cribrocentrum and so Reticulofenestra
- Praenoelaerhabdus Mihajlovic 1993
- Nannoserratolithus Martini & Schiller 1998 - etched Reticulofenestra [my interpretation - JRY 2021]
Variants:
- Dictyococcites Black, 1967 - like Reticulofenestra but with closed central-area. [NB Objectively Dictyococcites is a junior synyom of Reticulofenestra since the type secies D. danicus does not have a closed central area, so a new generic name should be proposed if this morphotype is distinguished]
- Cribrocentrum Perch-Nielsen 1971 - like Reticulofenestra but with robust grill in central area
Taxonomic discussion: Coccoliths are assigned to Reticulofenestra on the basis of absence of distinguishing features, consequently the genus is certainly highly paraphyletic and possibly polyphyletic.
Subdivision of the genus is notoriously problematic, numerous species names have been proposed and species concepts vary widely between authors. Some distinctive groups can be recognised but many taxa are separated on arbitrary criteria such as size. In consequence it is good practice for authors to clearly define their adopted species concepts in all publications.
Here we distinguish seven groups of species. The C. floridanus, R. bisecta, R. lockeri and R. reticulata groups are distinctive sets of species which are rather readily distinguished on straightforward criteria - and indeed have been regarded as separate genera by some authors. The remaining species are all elliptical reticulofenestrids with central openings. These morphotypes occur from the Eocene to the present day often at very high abundances. They vary greatly in size, central opening size and grill details (when visible and preserved) and almost certainly numeros different species are included. Subdivision is, however, very problematic. They are much less common in the Late Oligocene and Early Miocene and in consequence different species names are usually used before and after this interval, so we have separated the R. umbilicus and R. pseudoumbilicus groups.
Distinguishing features: No bridge, no slits
Farinacci & Howe catalog pages: Reticulofenestra + + + * , Dictyococcites + + * , Crenalithus + * , Apertapetra * , Cribrocentrum * , Ericsoniella * , Stradnerius * , Nannoserratolithus [no catalog entry yet]
Morphology: Coccoliths circular to elliptical, central-area open or closed; central area grill delicate, but quite often preserved.
Most likely ancestor: Toweius - at confidence level 3 (out of 5). Data source: e.g. Romein 1979, Perch-Nielsen 1985, Gallagher 1989, Young et al. 1991 .
Likely descendants: Bekelithella; Gephyrocapsa; Noelaerhabdus; Pseudoemiliania;
Search data:
| Tags | LITHS: placolith, circular, CA: ca_conjunct, grill, vacant,
CSPH: equant, monomorphic, CROSS-POLARS: rim-unicyclic, R-prominent, |
| Metrics | Lith size: 1->20µm; |
The morphological data given here can be used on the advanced search page. See also these notes
Geological Range:
Last occurrence (top): Extant Data source: Total of range of species in this database
First occurrence (base): in upper part of Thanetian Stage (62% up, 57.2Ma, in Thanetian 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: Noelaerhabdaceae
References:
Black, M. & Barnes, B. (1961). Coccoliths and discoasters from the floor of the South Atlantic Ocean. Journal of the Royal Microscopical Society. 80: 137-147. gs
Black, M. (1967). New names for some coccolith taxa. Proceedings of the Geological Society of London. 1640: 139-145. gs
Hay, W. W., Mohler, H. P. & Wade, M. E. (1966). Calcareous nannofossils from Nal'chik (northwest Caucasus). Eclogae Geologicae Helvetiae. 59: 379-399. gs V O
Jordan, R. W. & Young, J. R. (1990). Proposed changes to the classification system of living Coccolithophorids. INA Newsletter. 12(1): 15-18. gs V O
Krhovsky, J. (1979). Calcareous nannoplankotn from the Eocene/Oligocene boundary of some localities of the Pozdrany and Zdanice units (the West Carpathians, Czechoslovakia). In, V. , P. (ed.) Palaeontological Conference 1977, University Karlova Praha. University Karlova Praha, Prague 775-791. gs
Martini, E. & Schiller, W. (1998). Calcareous nannoplankton from Sieblos/Rhoen and the Nieuwied Basin (Lower Oligocene). Geologisches Abhandlungen Hessen. 100: 165-172. gs
Young, J. R. (1998). Neogene. In, Bown, P. R. (ed.) Calcareous Nannofossil Biostratigraphy. British Micropalaeontological Society Publication Series. 225-265. gs V O
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