Portal of Graptolites and Pterobranchs sponsored by "M.M. PLUS M." SZTANDARY
Rhabdopleurites primaevus Kozłowski, 1967from the lower Llanvirn of Öland, Sweden  

by Piotr Mierzejewski

Graptolite Net
edited by
Piotr Mierzejewski, the Count of Calmont DRG, FRC
    The specimen figured on SEM micrograph is a fragment of
strongly flattened zooidal tube measuring 0.760 mm in lenght
and ca. 0.340 mm in width. It is composed of delicate, flexible,
light-brown and translucent periderm. The fusellar increments
are usually ring-like, only exhibit an oblique suture and vary from
30 to 61 micrometers in width. The fusellar collars are weak
and indistinct; some appear to be empty.

This form agrees closely in shape and dimensions with those
from Ordovician glacial boulders described by Kozłowski (1967,
1970) and Mierzejewski (

Fusellar tubes of
Rhabdopleurites primaevus have been
described by Andres (1961). They were originally described as
thecae of the graptolite
Mastigograptus but his
misidentification was corrected later (Andres 1977).               

Fusellar stolonal tubes with stolons of
Rhabdopleurites were
found by Skevington (1965) in Lower Ordovician of Öland who
assigned them erroneously to the
Graptovermida. Their
rhabdopleurid nature was recognized by Andres (1977) and
Mierzejewski (
1977, 1986).

The ultrastructure of this form was studied with TEM by
Mierzejewski (
1986) and with SEM by Mierzejewski & Kulicki
Rhabdopleurites primaevus Kozłowski
Fragment of zooidal tube in SEM.