R e f e r e n c e s:

Mierzejewski, P. 1982. The nature of pre-Devonian tracheid-like tubes. - Lethaia 15, 148.
Mierzejewski, P. 1985. New aberrant sessile graptolites from glacial boulders. -
Acta
Palaeontologica Polonica
30, 3/4, 191-199.
Type species: Maenniligraptus ursulae Mierzejewski, 1985
Maenniligraptus Mierzejewski, 1985 is a sessile graptolite, whose order and family
remains uncertain (for discussion see
here). This genus was erected for the species
Maenilligraptus ursulae, described on the basis of chemically isolated material from an
Ordovician? Baltic drift boulder.
   The genus is named in honour of the late Dr.
Ralph Männil (1927-1989), an Estonian
geologist and student of acid-resistant microfossils.
 
D i a g n o s i s:
                          Encrusting graptolite. Thecae (autothecae? bithecae?) tubular and
creeping, devoid of erect parts and any apertural apparatus. Diameter of thecae 100-130
micrometers. Stolons bifurcate and trifurcate. In the middle of the stolonal triad there is a
secondary stolothecal or thecal stolon. Numerous annular and helical thickenings are
distributed irregularly along the stolons. Stolothecae occur in the deeper parts of the
rhabdosome.
Graptolite Net >>     Graptolites & Graptoliters >>
Maenniligraptus ursulae Mierzejewski, 1985. Ordovician? Glacial boulder, Baltic coast. 1. Fragment of the
rhabdosome with two thecae. SEM micrograph.
2. Bifurcation of the stolon; s - main stolothecal stolon, s - thecal stolon with
inner circular and spiral thickenings. Light micrograph, transmitted light.
3. Margin of the thecal aperture. Note unconformity
between fibrils of ectocortical bandages on the eroded periderm surface. SEM micrograph.
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Class Graptolithoidea, Order and Family unknown