Asterozoan pedicellariae and ossicles revealed from the Middle Ordovician of Baltica

Tinn, Oive; Ainsaar, Leho

doi:10.4202/app.2012.0034

Cited by 2 publications

(2 citation statements)

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“…Because of their stratigraphic range and palaeobiogeographic distribution in the Ordovician, asterozoans are more likely candidates: their oldest known representatives have been documented in Lower Ordovician deposits (Thoral 1935;Blake 2013;Jell 2014;Blake & Guensburg 2015), and their presence is recorded in Baltica at least from the Dapingian, i.e., as early as the oldest known occurrence of Bolboporites (Pisera 1994;Hansen et al 2005;Rozhnov 2005;Blake & Rozhnov 2007;Tinn & Ainsaar 2014). However, Bolboporites clearly does not show any character supporting its interpretation as an isolated asterozoan spine.…”

Section: Bolboporites As An Infrabasal Conementioning

confidence: 99%

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Reinterpretation of the enigmatic Ordovician genus Bolboporites (Echinodermata)

et al. 2019

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Bolboporites is an enigmatic Ordovician cone-shaped fossil, the precise nature and systematic affinities of which have been controversial over almost two centuries. For the first time, a wide range of techniques (CT-scan, SEM, cathodoluminescence, XPL, UV epifluorescence, EBSD, FT-IR and XRF spectrometry) were applied to well-preserved specimens of Bolboporites from Norway and Russia. Our main finding confirms its echinoderm affinities, as shown by its stereomic microstructure and by the first definitive evidence of its monocrystalline nature. Each cone consists in a single, microporous calcitic crystal with a narrow longitudinal internal canal. These results are combined with all previous data on Bolboporites to critically discuss five alternative interpretations of this fossil, namely theca, basal cone, spine, columnal, and holdfast, respectively. The most parsimonious scenario considers Bolboporites as an isolated spine, which was articulated in life by a short biserial appendage to the body wall of an unknown echinoderm, possibly of echinozoan affinities.

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Section: Bolboporites As An Infrabasal Conementioning

confidence: 99%

“…However, Bolboporites clearly does not show any character supporting its interpretation as an isolated asterozoan spine. The skeletal morphology of Ordovician asterozoans is strongly constrained and, even when preserved as isolated remains, their plates are highly diagnostic (Pisera 1994;Tinn & Ainsaar 2014).…”

Section: Bolboporites As An Infrabasal Conementioning

confidence: 99%