An Enigmatic Epibiont on Ordovician Graptolites,
Helicotubulus Mierzejewski et Kulicki, 2003
by  Countess Maja Korwin-Kossakowska

So far, only few fossils have been recognized as epibionts on graptolites (e.g. Kozłowski 1967, 1970;
Mierzejewski 1978; Urbanek & Mierzejewski 1982; Bates & Loydell 2000). As a rule, they are
interpreted as commensals or parasites of graptolite colonies.

To the right is an example of a Middle
Ordovician problematic organic fossil twisted
around stipes of the sessile graptolite
Mastigograptus. Primarily, this form was
described by Kozłowski (1967) from a glacial
boulder of Baltic origin under the name
Helicosyrinx dextrogyra and assigned
tentatively to the Phoronida.
  
       Mierzejewski and Kulicki (2003) found
that the name Helicosyrinx Kozłowski, 1967
is preoccupied by the generic name of the
opisthobranch gastropod Helicosyrinx Baur,
1864.  They  introduced the name
Helicotubulus for the phoronid-like form in
question.

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Kozłowski, R. 1967. Sur certain fossiles à test organique.
- Acta Palaeontologica Polonica 12: 99-132

Mierzejewski, P. & Kulicki, C. 2003. Helicotubulus, a
replacement name for Helicosyrinx Kozłowski, 1967 (?
Phoronoidea) preoccupied by Helicosyrinx Baur, 1864
(Mollusca, Gastropoda).  - Acta Palaeontologica Polonica
48: 446.