Olaf Elicki

Cambrian brachiopods from Sardini" are investigated for Ihe first tim" in Ihi5 paper. The specimcns eome frotll nodular limestones of the late Early to Middlc Cambriall Campo Pisano Formalion of Gutturu Pala (soulhweilern Sardinia). The brachiopod fauna consislS of lingulids 3nd acrotretids and yields twO new acrOlretid spccics, dcscribcd hefe;1S OpiJ/hotrcta Iardica n. sp. and Va"daIOIrf'ta prodi1!is n. sI'. Malerial allribuled 10 Ih" genus Schmidtites is reponcd here for the firsl time from bOlh Ihe Middle Cambrian and western Gondwana. Th" genus LinlIamollrlla i!i reponed for Ihe first lime from the Middlc Cambrian and from outside North Amcrica. Wherea5 most braehiopods frOIll Gutturu I'ala bioslr:lligraphically indicale a rathcr undifferenciat"d Middl" C;1mbrian age. the laSt mentioned genus points 10 a late Middle Cambrian age for the upp"rmosl part of the Campo Pisano Formation.

The Campo Pisano Formation of southwestern Sardinia is represented by an offshore carbonate succession spanning the latest Early to late Middle Cambrian. Paleogeographically, the fauna is characteristic of western Perigondwana, and indicates faunal relations to France, Spain, and Turkey. Microfaunal paleoecology reflects drowning of an isolated carbonate platform at tropical latitudes. Sessile epibenthic filter feeders dominate at the base, succeeded

Im vorliegenden Artikel wird der derzeitige Kenntnisstand über die unterkambri-schen Trilobitenfaunen der Gegend um Görlitz (Sachsen) mitgeteilt. Zusätzlich zu den seit langem bekannten Arten werdenCalodiscus cf.lobatus undFerrakia saxonica n. sp. aus den untersuchten Schichten vorgestellt. Die Olenelloiden, die bisher als zwei eigenständige Arten angesehen wurden, werden als identische Art interpretiert.Lusatiops bederkei wird nur durch verformte Stücke vonL. lusaticus repräsentiert. Die stratigraphische Aussagekraft der Trilobiten und Probleme, die aufgrund der biostratigraphischen Daten auftreten, sowie die Korrelationen der Abfolgen werden diskutiert. The present article reviews recent advances in the knowledge of the Lower Cambrian trilobite faunas of the Görlitz area, Saxonia, eastern Germany. New additions to the fauna areCalodiscus cf.lobatus (Hall) andFerralsia saxonica n. sp. The olenelloid trilobites, previously thought to represent two distinct species, are re-evaluated and interpreted as belonging to one species.Lusatiops bederkei is actually represented by deformed specimens ofL. lusaticus. Furthermore, the stratigraphic significance of the trilobites and problems associated with the biostratigraphic data and the correlation of the rocks are discussed.

Geological, papaeontological and microfacies studies in the Lower Cambrian carbonate complex of the Görlitz Synclinorium (eastern Germany/Saxony/Lusatian region) provide new data for the fossil content, depositional history and palaeogeography. The Lower Cambrian of the Görlitz Synclinorium belongs to the facies zones 5, 7 and 8 ofWilson (1975)-platform rim with connections to the open ocean and to the restricted platform areas. An extraordinarily rich fauna was found with elements which are in some cases new for Europe (Rhombocorniculum cancellatum Cobbold,Fordilla sibirica Krasilova, Calodiscus lobatus Hall,Archaeooides granulatus Qian,Archiasterella pentactina Sdzuy,Allonia sp.,Obliquatheca aldanica Sysoiev,Conotheca circumflexa Missarzhevsky,Microcornus elongatus Missarzhevsky,Lenalituus sp.,Pelagiella cf.lorenzi Kobayashi,Beshtashella sp.,Comluella sp.,Cambroclavithidae gen. et sp. indet., Helcionellidae gen. et sp., indet. Eocrinoidea gen. et sp. indet.) This fauna indicates Lower Cambrian (higher Atdabanian/Botomian) age and reveals palaeobiogeographical connections to the Siberian Platform, to the Mediterranean area and to China. A somewhat new stratigraphical subdivision of the Lower Cambrian sequence (Zwetau Formation) is described. New units are established within the Ludwigsdorf Member (the carbonatic lower part of the sequence), the ‘Lower Ludwigsdorf Member’ (massive dolostone) and the ‘Upper Ludwigsdorf Member’ (bedeed limestones and their equivalents). The subsequentLusatiops Member is subdivided intoSerrodiscus Bed (claystones) andLusatiops Bed (siltstones).

New data on Cambrian small shelly fossils from Germany and Sardinia, and Spain are discussed with respect to their stratigraphical, paleogeographical, and paleoecological value. It is shown that these small shelly assemblages represent very useful tools for reconstruction of geological processes and of the Perigondwanan history in the Mediterranean area, especially, if trilobites are absent or hard to recover from the rocks. The German and Sardinian assemblages reflect distinct ecological conditions on shallow platform and shelf areas and mirror any changes in these habitats. Thus, lateral and vertical transitions from restricted inner platform to deep subtidal conditions are documented by characteristic successions of Sardinian assemblages. German assemblages show clearly distinct paleogeographic/ecological developments. The reorganization of the ecosystems is linked to shelf-wide processes which can be stratigraphically correlated in their single phases (e.g., drowning of platforms, breakup of the Perigondwanan realm, origin of terranes). Broader paleogeographic relationships of small shelly fossils to the Far East and Australia are proposed and support earlier controversial assumptions based on trilobites. Because of the small shelly fossils distribution patterns, a pre-Late Cambrian separation of terranes from the so called European shelf of western Gondwana is unlikely. During the Early to Middle Cambrian a rather uniform and weakly differentiated facies belt across most of the European shelf is indicated, and this contradicts earlier concepts of more-or-less isolated depositional basins. Despite recent progress in knowledge of Mediterranean small shelly fossil assemblages, further improvements will lead to a better understanding and a much more detailed picture of the Cambrian history of Perigondwana and its relationships to other paleocontinents.

Cambrian bivalves from the Middle East are reported here for the first time. They come from early “Middle Cambrian” and latest “Early Cambrian” limestones of the lower Çal Tepe Formation at the type locality (near Seydişehir, western Taurides). The majority of the new findings consists of Pojetaia runnegari Jell, 1980, but a few specimens of Fordilla sp. represent the first report of this genus from “Middle Cambrian” strata. Based on a compilation of the hitherto reported, but mostly revised Cambrian bivalves, the today widely accepted taxa are discussed. The genera Pojetaia Jell, 1980 and Fordilla Barrande, 1881 are critically evaluated, and three valid species are included in Pojetaia: P. runnegari Jell, 1980, P. sarhroensis Geyer and Streng, 1998, and—with limitations—P. ostseensis Hinz-Schallreuter, 1995. Fordilla also includes three species: F. troyensis Barrande, 1881, F. sibirica Krasilova, 1977, and F. germanica Elicki, 1994. The Cambrian genera Tuarangia MacKinnon, 1982, Camya Hinz-Schallreuter, 1995, and Arhouriella Geyer and Streng, 1998 most probably belong to the class Bivalvia. Palaeoecologically, the Cambrian bivalves of the Western Perigondwanan shelf seem to occur in a relatively small window of low-energy, subtidal, open-marine, warm-water conditions on a muddy carbonate ramp or platform with reduced sedimentation rate. The frequently interpreted infaunal mode of life of Pojetaia and Fordilla is questioned by observations of similarly organized modern bivalves. The palaeogeographical distribution of Pojetaia and Fordilla is discussed with respect to their early ontogeny and to differences in the recent state of knowledge on shelly fossils from Cambrian carbonate successions of Perigondwana. Erstmals für den Mittleren Osten werden Funde kambrischer Muscheln gemeldet. Sie entstammen Kalksteinen untermittelkambischer und höchstunterkambrischer Bereiche der tieferen Çal Tepe Formation an der Typuslokalität Çal Tepe (nahe Seydişehir) im westlichen Taurusgebirge. Die Muscheln werden überwiegend durch die Art Pojetaia runnegari Jell, 1980 und untergeordnet durch Fordilla sp. repräsentiert. Letztere stellt den ersten Nachweis dieser Gattung im „Mittelkambrium” überhaupt dar. Ausgehend von einer Zusammenstellung der bisher beschriebenen und größtenteils wieder revidierten kambrischen Muscheln, werden die heute weitgehend akzeptierten Formen diskutiert. Insbesondere für die Gattungen Pojetaia Jell, 1980 und Fordilla Barrande, 1881 und deren Arten werden taxonomisch verwendbare Merkmale kritisch bewertet. Danach ergeben sich im Bestand von Pojetaia folgende gültige Arten: P. runnegari Jell, 1980, P. sarhroensis Geyer and Streng, 1998 und—mit Einschränkung—P. ostseensis Hinz-Schallreuter, 1995. In der Gattung Fordilla werden die Arten F. troyensis Barrande, 1881, F. sibirica Krasilova, 1977 und F. germanica Elicki, 1994 geführt. Als höchstwahrscheinlich den Bivalvia zuzuordnende, weitere kambrische Gattungen werden Tuarangia MacKinnon, 1982, Camya Hinz-Schallreuter, 1995 und Arhouriella Geyer and Streng, 1998 angesehen. Paläoökologisch scheinen die kambrischen Muscheln des Perigondwana-Schelfs innerhalb eines relativ schmalen Fensters aufzutreten, welches niedrigenergetische, subtidale, offenmarine Warmwasserverhältnisse auf einer feinkörnigen Karbonatrampe oder -plattform mit geringer Sedimentationsrate repräsentiert. Die zumeist interpretierte, infaunale Lebensweise von Pojetaia und Fordilla erscheint im Vergleich mit ähnlich gebauten rezenten Muscheln als nicht hinreichend belegt. Die paläogeographische Verbreitung von Pojetaia und Fordilla wird mit Blick auf deren frühe Ontogenese und hinsichtlich des Bearbeitungsstandes von Schalenfossilien kambrischer Karbonatfolgen Perigondwanas diskutiert.