New issue of Fossils & Strata

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Another hefty issue of Fossils & Strata has just come out of the printing
presses: No. 38, Arne Thorshøj Nielsen's monumental monograph on Lower
Ordovician trilobites from southern Scandinavia. It costs USD 75.00 plus
postage & handling (no, that's not expensive, it's a big book!) and can be
ordered from Scandinavian University Press, P.O. Box 2959, Toyen, Oslo,
Norway (WWW home page at http://193.69.40.2/; e-mail to
subscription@scup.no).


Nielsen, A.T. 1995 09 20: Trilobite systematics, biostratigraphy and
palaeoecology of the Lower Ordovician Komstad Limestone and Huk Formations,
southern Scandinavia. Fossils and Strata, No. 38, pp. 1-374. Oslo. ISSN
0300-9491. ISBN 82-00-37658-3.

ABSTRACT: The upper Arenigian to lower Llanvirnian Komstad Limestone
Formation is a tongue of the Baltoscandian 'Orthoceratite limestone',
intercalated in the predominantly shaly Ordovician succession of
Scania-Bornholm, southernmost Scandinavia. The Formation is 2-5 m thick on
Bornholm, 10 to more than 15 m in southeastern Scania, 3 to more than 4.5 m
in central western Scania, and from there thins towards northwestern
Scania, where it wedges out. The stratigraphically equivalent Huk Formation
of the Oslo area has been studied only at Slemmestad, where it comprises
the 1.5 m thick Hukodden Limestone Member ('Megistaspis Limestone'), the
4.4 m thick Lysaker Member ('Asaphus Shale'), and the 2.6 m thick
Svartodden Limestone Member ('Endoceras Limestone'). The 'Skelbro Limestone
Formation' of Bornholm is abandoned and merged with the Komstad Limestone
Formation. The Killeröd quarry is proposed as a paratype section for the
Komstad Limestone Formation. Based on collections of about 8000 trilobites,
the Komstad Limestone and Huk Formations are assigned to the Zones of
Megistaspis polyphemus (former M. lata), M. simon, M. limbata, Asaphus
expansus, and A. 'raniceps' of the Volkhov and Kunda Stages. The Komstad
Limestone Formation is diachronous. The correlation of trilobite and
graptolite zones is briefly discussed. The Yapeenian-Darriwilian boundary
approximates the M. simon - M. limbata zonal boundary. The Arenig-Llanvirn
boundary corresponds to a level slightly above base of the A. 'raniceps'
Zone. Inferences on the autecology of the most common trilobite groups are
summarised. Five recurrent trilobite biofacies are defined: the benthic
assemblage succession Nileus->Geragnostus->Symphysurus->Megistaspis
represents a depth transect, whereas the Cyclopyge assemblage was pelagic.
The correlation of palaeoenvironmental changes as revealed by the
alternation of biofacies, i.e. ecostratigraphy, improves stratigraphical
resolution significantly. A relative-sea-level curve is reconstructed on
this basis. The deposition of the Komstad Limestone and Huk Formations was
connected to a series of sea-level falls, shifting the limestone deposition
stepwise into the western facies belts. Systematic descriptions are
presented of Ampyx, Asaphus, Cnemidopyge, Dysplanus, Globampyx, Hallanta,
Illaenus, Lonchodomas, Megistaspis, Nileus, Niobe, Ottenbyaspis, Panderia,
Parillaenus, Raymondaspis, and Stygina, including eighteen new species and
subspecies, viz. Megistaspis (Megistaspis) geminus n.sp., Nileus depressus
schranki n.subsp., N. d. serotinus n.subsp., N. d. parvus n.subsp., N.
planiceps n.sp., N. latifrons n.sp., N. implexus n.sp., Niobe (Niobe)
tjernviki n.sp., Lonchodomas volborthi schmidti n.subsp., Dysplanus
acutigenia vetustus n.subsp., Illaenus fornicatus n.sp., I. schuberti
n.sp., Lonchodomas tenuis n.sp., Rhombampyx frater n.sp., Raymondaspis
(Turgicephalus) whittingtoni n.sp., R. (T.) neglecta n.sp., R.
(Raymondaspis) scitula n.sp., and R. (R.) insignis n.sp. Nineteen forms,
including several new species, are treated under open nomenclature.


Stefan Bengtson
Editor, Fossils & Strata

Stefan Bengtson                      _/        _/ _/_/_/    _/        _/
Department of Palaeozoology         _/_/      _/ _/    _/  _/_/    _/_/
Swedish Museum of Natural History  _/  _/    _/ _/    _/  _/  _/ _/ _/
Box 50007                         _/    _/  _/ _/_/_/    _/    _/  _/
S-104 05 Stockholm               _/      _/_/ _/   _/   _/        _/
Sweden                          _/        _/ _/     _/ _/        _/

tel. +46-8 666 42 20
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