Ascidian spicules

Classification: non_cocco -> Ascidian spicules
Sister taxa: Haptophytes, Parmales, Silicoflagellates, scales and miscellaneous, Dinophytes, Diatoms, Zooplankton groups, Ascidian spicules, Crystals and crud, Palaeozoic nannofossils, hidden,

Distinguishing features: Typically spherically-radiate calcite bodies, formed of largish tapering, radiate elements with radial c-axes. Larger and less regularly-shaped than typical nannofossils.

Daughter taxa: (blue => in age window 0-800Ma) Granddaughter taxa
V or horseshoe shaped nannolith showing high birefringence and c-axis parallel to length of nannolith


Citation: Ascidian spicules
Rank: Order
Synonyms: Fossil taxa which are probably based on ascidian spicules include the following [all based on my interpretation unless otherwise noted JRY]
Discoaster athanasiui Filipescu & Hanganu 1960
Discoaster irregularis Filipescu & Hanganu 1960
Discoaster mrazeci Filipescu & Hanganu 1960
Discoaster multinucleatus Filipescu & Hanganu 1960
Discoaster olteniae Filipescu & Hanganu 1960
Discoaster pentaradiatus communis Filipescu & Hanganu 1960
Discoaster pentaradiatus flosculoides Filipescu & Hanganu 1960
Discoaster sabbae Filipescu & Hanganu 1960
Discoaster slatiorensis Filipescu & Hanganu 1960
Gongylis Hoffman 1970 [type species is clearly an Ascidian spicule the other two species might be something else]
Gongylis salzwedelensia Hoffman 1970
Heliodiscoaster cayeuxi Filipescu & Hanganu 1960
Heliodiscoaster cernaensis Filipescu & Hanganu 1960
Heliodiscoaster concentricus Filipescu & Hanganu 1960
Heliodiscoaster deflandrei Filipescu & Hanganu 1960
Heliodiscoaster irregularis Filipescu & Hanganu 1960
Heliodiscoaster rumanus Filipescu & Hanganu 1960
Hemidiscoaster triradiatus aquitanicus Filipescu & Hanganu 1960
Micrascidites Deflandre & Deflandre-Rigaud 1956  
Micrascidites vulgaris Deflandre & Deflandre-Rigaud 1956  
Perforocalcinella Bóna 1964
Perforocalcinella fusiformis Bóna 1964
Perforocalcinella petali Bóna & Kernerné Sümegi (1966)
Tansinius Filipescu & Hanganu 1960
Tansinius angularis Filipescu & Hanganu 1960
Tansinius irregularis Filipescu & Hanganu 1960
Tansinius olteniae Filipescu & Hanganu 1960
Tansinius rectangularis Filipescu & Hanganu 1960
Tansinius stefanescui Filipescu & Hanganu 1960
Notes & discussion: Ascidians (common name sea squirts) are benthic tunicates, so nothing really to do with nannoplankton. However, the spicules they produce commonly occur in nannoplankton preparations, especially from shallow marine environments. So, nannoplankton workers need to be able to recognise them. Varol & Houghton (1996) provide a useful overview for nannofossil specilaists and also propose Linnean names for varous different morphotypes. Varol (2006) developed this approach further, proposing names for many different Mesozoic morphotypes. Lukowiak et al. (2016) record fossil speciemns from the Miocene and give modern references.
Discoaster athanasiui * Discoaster irregularis * Discoaster mrazeci * Discoaster multinucleatus * Discoaster olteniae * Discoaster pentaradiatus communis * Discoaster pentaradiatus flosculoides * Discoaster sabbae * Discoaster slatiorensis * Gongylis * Gongylis salzwedelensia * Heliodiscoaster cayeuxi * Heliodiscoaster cernaensis * Heliodiscoaster concentricus * Heliodiscoaster deflandrei * Heliodiscoaster irregularis * Heliodiscoaster rumanus * Hemidiscoaster triradiatus aquitanicus * Perforocalcinella * Perforocalcinella fusiformis * Perforocalcinella petali * Tansinius * Tansinius angularis * Tansinius irregularis * Tansinius olteniae * Tansinius rectangularis * Tansinius stefanescui *

Distinguishing features: Typically spherically-radiate calcite bodies, formed of largish tapering, radiate elements with radial c-axes. Larger and less regularly-shaped than typical nannofossils.

Geological Range:
Last occurrence (top): Extant Data source:
First occurrence (base): within Jurassic Period (145.01-201.30Ma, base in Hettangian stage). Data source:


Bona, J. (1964). Coccolithophorida-vizsgalatok a meceski retegekben (Coccolithopohriden-Unntersuchungen in der neogen Schichtenfolge des Meeskggerbirges). Földt. Közl., 94: 121-131. GS

Deflande & Delfandre-Rigaud 1956 [sorry, not in our bibliography yet]

Filipescu, M. & Hanganu, E. (1960). Sur les Discoastérides du Tertiare du N-O de l'Olténie. Rev. Géol Géogr. Acad. Rep. Pop. Roumanie, 4(2): 217-232. GS

Hoffmann, N. (1970). Taxonomische Untersuchungen an Coccolithen aus der Kreide Norddeutchlands anhand elektronenmikroskopischer Aufnamen. Hercynia, 7(1-3): 163-198. GS

Lukowiak et al 2016 [sorry, not in our bibliography yet]

Varol, O. & Houghton, S.D. (1996). A review and classification of fossil didemnid ascidian spicules. Journal of Micropalaeontology, 15: 135-149. GS

Varol, O. (2006). Didemnid ascidian spicules from the Arabian Peninsula. Journal of Nannoplankton Research, 28(1): 35-56. GS


Ascidian spicules compiled by Jeremy R. Young viewed: 25-5-2019

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Comments (2)

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magdalena lukowiak (Warsaw, Poland)
Thanks guys for such a possitive reactions to our latest paper! :) we are glad that you liked it. If you are interested in fossil ascidian spicules, I also recommend my article from 2012: _ukowiak, M. 2012. First Record of Late Eocene Ascidians (Ascidiacea, Tunicata) from Southeastern Australia: Journal of Paleontology 86 (3): 521–526
If any of you want a pdf of this paper, please, do not hesitate to write to me. Cheers!
Ines Galovic (Croatian Geological Survey, Croatia)
Very nice article about ascidian spicules at Researchgate published in April 2016 in Geobios. Unfortunatelly I couldn't add a link here. :(
Jeremy Young (UCL, UK)
thanks for the tip - I just found it and and yes it is a nice paper , i will add mention of it on the page as it has modern references etc.

Lukowiak, M.; Dumitriu, S. & Ionesi, V., (2016). First fossil record of early Sarmatian didemnid ascidian spicules (Tunicata) from Moldova. Geobios, 49: 201-209.
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