Nannotax3 - ntax_cenozoic - Reticulofenestra

Reticulofenestra


Classification: ntax_cenozoic -> Isochrysidales -> Noelaerhabdaceae -> Reticulofenestra
Sister taxa: Emiliania, Gephyrocapsa, Pseudoemiliania, Reticulofenestra, Noelaerhabdus, Bekelithella, Pyrocyclus

Daughter taxa (time control age-window is: 0-800Ma)Granddaughter taxa
Neogene and extant species
R. pseudoumbilicus group
Neogene elliptical reticulofenestrids with an open central area (spanned by delicate proximal net, not visible in lm)
Reticulofenestra calicis
Reticulofenestra pseudoumbilicus
Reticulofenestra haqii
Reticulofenestra minuta
Reticulofenestra minutula
Reticulofenestra asanoi
Reticulofenestra kahniae
Reticulofenestra rotaria
Reticulofenestra pospichalii

Reticulofenestra sessilis
Closed central area. Rather heavily calcified giving irregular form, strongly crenulate margin.

Eocene to Early Miocene species
C. floridanus group
Subcircular to broadly-elliptical reticulofenestrids with a narrow central area (spanned by delicate proximal net, not visible in lm)
Cyclicargolithus abisectus
Cyclicargolithus bukryi
Cyclicargolithus floridanus
Cyclicargolithus luminis
Cyclicargolithus parvus
Cyclicargolithus sp.

R. bisecta group
Elliptical reticulofenestrids, central area closed by very robust, conspicuous distal ‘plug’ (birefringent).
Reticulofenestra bisecta
Reticulofenestra filewiczii
Reticulofenestra stavensis
Reticulofenestra magniscutum
Reticulofenestra perplexa
Reticulofenestra producta
Dictyococcites sp.

R. lockeri group
Elliptical reticulofenestrids with relatively open central area spanned on the proximal surface by a robust grill (clearly visible in lm as a birefringent plate with variable number of perforations).
Dictyococcites chriskingii
Reticulofenestra daviesii
Reticulofenestra gartneri
Reticulofenestra lockeri
Reticulofenestra onusta
Reticulofenestra macmillanii
Reticulofenestra martinii
Hornibrookina nicolasii

R. reticulata group
Typically circular reticulofenestrids with relatively narrow circular central area with robust grill (clearly visible in lm).
Reticulofenestra reticulata
Reticulofenestra isabellae
Reticulofenestra erbae
Reticulofenestra nanggulanensis
Reticulofenestra westerholdii
Cyclicargolithus artuziae
Reticulofenestra sp. cf. reticulata

R. umbilicus group
Paleogene elliptical reticulofenestrids with open central area (spanned by delicate proximal net, not visible in lm)

Reticulofenestra sp.
Specimens which cannot be assigned to established species - AND SPECIES OF UNCERTAIN VALUE

Taxonomy:

Citation: Reticulofenestra Hay, Mohler & Wade, 1966
Rank: Genus
Type species: Reticulofenestra caucasica Hay Mohler & Wade, 1966
Synonyms:
Variants:
Taxonomic discussion: Within the Noelaerhabdaceae, species 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 six 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 numerous different species are included. Subdivision is, however, very problematic. At low to mid-latitudes they are usually much less common in the Late Oligocene and Early Miocene and in consequence different species names are usually used before and after this interval, i.e in the Eocene to Early Oligocene and in the Middle Miocene to Pliocene. So, we have separated the species from these two periods, as the R. umbilicus and R. pseudoumbilicus groups.

Extant species the species R. parvula has now been transferred to Gephyrocapsa since it is very closely related to G. ericsonii and so only indirectly related to the fossil Reticulofenestra. This leaves R. sessilis as the only extant species and this is a rather rare and very unusual taxon with a symbiotic relationship with a diatom. 

Distinguishing features:
Parent taxon (Noelaerhabdaceae): Heterococcoliths with Reticulofenestra-type structure, V-units vestigal, R-units forming grill, both shields, and two-layered tube
This taxon: 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.

Size:

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; plot with descendants

Search data:
LITHS: placolith, circular, CA: ca_conjunct, grill, vacant,
CSPH: equant, monomorphic, CROSS-POLARS: rim-unicyclic, R-prominent,
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:

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 V O

Hay, W. W., Mohler, H. P. & Wade, M. E. (1966). Calcareous nannofossils from Nal'chik (northwest Caucasus). Eclogae Geologicae Helvetiae. 59: 379-399. gs 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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Reticulofenestra compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 25-9-2022

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Short stable page link: https://mikrotax.org/Nannotax3/index.php?id=1152 Go to Archive.is to create a permanent copy of this page - citation notes



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