Nannotax3 - ntax_non_cocco

Distinguishing features:
Parent taxon (Inorganic):
This taxon: Inorganic crystals

Synonyms: Possible examples of inorganic crystals described as nannofossils.

Bucculinus Noël 1956
Bucculinus algeriensis Noël 1956
Bucculinus hirsutus Noël 1956
Fibrillinus Noël 1956
Fusellinus Noël 1956
Fusellinus insolitus Noël 1956
Hexalithus lecali Gardet 1955 - unidentifiable from the sketch but probably inorganic
Nannoturba Müller (1979)
Nannoturba robusta Müller (1979)
Nannoturba spinosa Müller (1979)
Neoangulolithina Guptha (1979)
Neoangulolithina qasimii Guptha (1979)
Palamygdalithus Deflandre (1970)
Palamygdalithus noelae Deflandre (1970)
Pyrobolella Black (1971)
Pyrobolella bradfieldii Black (1971)
Tetralithus Gardet (1955)
Tetralithus pyramidus Gardet (1955) - unidentifiable and possibly inorganic
Tetralithus isoplexiros Zanin in Zanin et al (2012) - probably diagentic crystals [my interpretation - JRY 2021]
Tetralithus? cassianus Jafar (1983) - diagenetic crystals cf. Bralower et al. (1991)
Tetralithus pseudotrifidus Jafar (1983) - diagenetic crystals cf. Bralower et al. (1991)
Pyxolithus Deflandre in Deflandre & Fert (1954)
Pyxolithus problematicus Deflandre in Deflandre & Fert (1954)

Taxonomic discussion: Inorganic crystals resembling nannofossils can occur in nannofossil (and coccolithophore) preps as a result of other inclusion of diagenetic crystals in samples or precipitation of minerals during preparation. They can sometimes be mistaken for nannofossils and have occasionally been described as new species.

Distinguishing features:
Parent taxon (Inorganic):
This taxon: Inorganic crystals

Determining whether simple nannolith-like forms are biogenic fossils or abiogenic crystals is a long-standing problem for nannofossil palaeontology. Indeed Ehrenberg initially thought discoasters and simple coccoliths were inorganic and described them as "Crystalldrusen" and calcareous "morpholithe" (Siesser 1984). Likewise fossil Florisphaera profunda liths were only recognised as fossils after study of the living organism. A few criteria which can be applied include:

Consistent asymettry - spherical, lozenge-shaped and radiate structures can easily be produced abiogenically, but consistent asymettry such as the concavo-convex shape of many coccoliths is much more likely to be biogenic.
Consistent complexity - e.g. development of separate central area and rim structures
Consistent chirality - most nannofossils show chirality and when they do, the sense of chirality is consistent. Inorganic forms will normally randomly produce left and right-handed forms.
Consistent stratigraphic range - fossils should occur only within a discrete stratigraphic interval. Ths can be dificult to determine initially but it is an important long-term test.
Consistent size - this is a weaker test but generally speakng fosil should show a consistent size range whilst inorganic crystals can occur over a wide size range, even many orders of magnitude (e.g. rhombic calcite crystals can range in size form <1µm to >1m).

For example the kite-shaped nannofossil Minylitha convallis is not obviously biogenic but well-preserved speciemens show additional morphological complexity - with a distinct rim, they have a conistent size and only occur within a short interval in the Late Miocene.

Geological Range:
Last occurrence (top): at top of (100% up, 0Ma, in "Holocene" stage). Data source: Total of ranges of the species in this database
First occurrence (base): within (-Ma, base in "Holocene" stage). Data source: Total of ranges of species in this database

References:

Black, M. (1971b). Problematical Microfossils from the Gault Clay. Geological Magazine. 108(4): 325-327. gs

Deflandre, G. & Fert, C. (1954). Observations sur les coccolithophoridés actuels et fossiles en microscopie ordinaire et électronique. Annales de Paléontologie. 40: 115-176. gs

Deflandre, G. (1970). Présence de nannofossiles calcaires (coccolithes et incertae sedis) dans le Siluro-dévonien d'Afrique du Nord. Comptes rendus hebdomaire de l'Académie des sciences, Paris. 270: 2916-2921. gs

Gardet, M. (1955). Contribution à l'étude des coccolithes des terrains néogènes de l'Algérie. Publications du Service de la Carte Géologique de l'Algérie. 5: 477-550. gs O

Guptha, M. V. S. (1979). New genus and new species of coccoliths in a deep sea sediment core from South Eastern Arabian Sea. In, unknown (ed.) 4th International Palynological Conference, Lucknow. 115-116. gs

Jafar, A. S. (1983). Significance of Late Triassic calcareous nannoplankton from Austria and Southern Germany. Neues Jahrbuch für Geologie und Paläontologie, Abhandlungen. 166: 218-259. gs

Mai, H. (2001). New coccolithophorid taxa fom the Guelhemmerberg airshaft. Lower Paleocene, The Netherlands. Micropaleontology. 47: 144-154. gs

Mai, H., von Salis, K., Willems, H. & Romein, A. J. T. (1997). Fossil coccospheres from the K/T boundary section from Geulhemmerberg, The Netherlands. Micropaleontology. 43: 281-303. gs

Müller, C. (1979). Calcareous nannofssils from the North Atlantic (Leg 48). Initial Reports of the Deep Sea Drilling Project. 48: 589-639. gs

Noël, D. (1957). Coccolithes des terrains Jurassiques de l'Algérie. Publications du Service de la Carte Géologique de l'Algérie Bulletin. 8: 303-385. gs

Perch-Nielsen, K. (1971c). Elektronenmikroskopische untersuchungen an Coccolithen und verwandten Formen aus dem Eozan von Danemark. Biologiske Skrifter, Kongelige Danske Videnskabernes Selskab. 18(3): 1-76. gs O

Siesser, W. G. (1994). Historical background of coccolithophore studies. In, Winter, A. & Siesser, W. G. (eds) Coccolithophores. Cambridge University Press, Cambridge 1-11. gs

Wise, S. W. & Wind, F. H. (1977). Mesozoic and Cenozoic calcareous nannofossils recovered by DSDP Leg 36 drilling on the Falkland Plateau, south-west Atlantic sector of the Southern Ocean. Initial Reports of the Deep Sea Drilling Project. 36(269-491): -. gs O

Zanin, Y. N., Zamirailova, A. G. & Eder, V. G (2012). Some Calcareous Nannofossils from the Upper Jurassic-Lower Cretaceous Bazhenov Formation of the West Siberian Marine Basin, Russia. The Open Geology Journal. 6: 25-31. gs