|Pterobranchites Kozlowski, 1967 - an aberrant graptolite?
The periderm of Ordovician Pterobranchites
antiquus Kozlowski, 1967 has been examined
with SEM. Four components have been
recognized within the thecal wall: outer lining,
cortex, fusellum and inner lining. The cortical
material is composed of thick, straight,
unbranched fibrils arranged in several layers as in
cortical layer of the graptolite periderm. P.
antiquus, previously referred to cephalodiscid
pterobranchs, is identified as an aberrant
graptolite of uncertain taxonomic position.
Pterobranchites antiquus Kozlowski, 1967.
Llandeilo, deep boring Krzyze 4.
SEM micrograph of four components of the periderm:
O - outer layer, C - cortical layer, F - fusellar layer, I -
|Acta Palaeontologia Polonica 29, 1/2, 83-89