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Selected cephalopods from the Ordovician of the Prague Basin (Bohemia) and Baltica (Estonia and Sweden): taxonomy, paleobiogeography and paleoecology
Aubrechtová, Martina ; Košťák, Martin (advisor) ; Klug, Christian (referee) ; King, Andrew H. (referee)
This dissertation thesis is a summary of five studies published in peer- reviewed, impacted scientific journals. All of the publications are taxonomic revisions of previously unknown or little known collections of fossil cephalopods from the Early Paleozoic strata of Bohemia, Estonia and Sweden. Paleogeogra- phical and stratigraphical distributions of the respective taxa were summarized, refined and compared with contemporary fossil assemblages known from other regions. Implications on the paleoecology of the cephalopods and original envi- ronmental conditions were made. The text of the thesis is divided into three main parts. In the first part, the morphology of cephalopods is explained, stressing out the most important diagnostic characters used for their descriptions. The current systematics of the Cephalopoda is overviewed and the main cephalopod groups during the Ordovician are briefly introduced. The second part of the thesis describes the geological development and settings of the regions, from which the studied fossil cephalopods originate. The third and final part of the thesis provides a discussion and interpretation of the results of the published studies in the context of the previously published research. The genus Bactroceras Holm, 1898 and some members of the order Litui- tida were studied...
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Selected cephalopods from the Ordovician of the Prague Basin (Bohemia) and Baltica (Estonia and Sweden): taxonomy, paleobiogeography and paleoecology
Aubrechtová, Martina ; Košťák, Martin (advisor) ; Klug, Christian (referee) ; King, Andrew H. (referee)
This dissertation thesis is a summary of five studies published in peer- reviewed, impacted scientific journals. All of the publications are taxonomic revisions of previously unknown or little known collections of fossil cephalopods from the Early Paleozoic strata of Bohemia, Estonia and Sweden. Paleogeogra- phical and stratigraphical distributions of the respective taxa were summarized, refined and compared with contemporary fossil assemblages known from other regions. Implications on the paleoecology of the cephalopods and original envi- ronmental conditions were made. The text of the thesis is divided into three main parts. In the first part, the morphology of cephalopods is explained, stressing out the most important diagnostic characters used for their descriptions. The current systematics of the Cephalopoda is overviewed and the main cephalopod groups during the Ordovician are briefly introduced. The second part of the thesis describes the geological development and settings of the regions, from which the studied fossil cephalopods originate. The third and final part of the thesis provides a discussion and interpretation of the results of the published studies in the context of the previously published research. The genus Bactroceras Holm, 1898 and some members of the order Litui- tida were studied...
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Taxonomic position of the species Bactroceras sandbergeri (Barr.,1867) from the Czech Ordovician
Aubrechtová, Martina ; Marek, Jaroslav (advisor) ; Turek, Vojtěch (referee)
Taxonomic position of the cephalopod Bactroceras sandbergeri (Barr., 1867) from the Ordovician of the Prague Basin was subjected to wide discussions and disputes in the past. The species was first classified within the genus Bactrites. Later, a separate, monotypic genus Eobactrites was defined. At present, the species is assigned to the genus Bactroceras. It belongs to the family Baltoceratidae, the genera of which are supposed to represent the oldest orthoceridans. The order Orthocerida is one of the most successful and most diversified cephalopod groups of the Paleozoic Era. In this thesis, a revision of Bactroceras sandbergeri has been made after a detailed study of about one hundred specimens. Attention was paid to those features, that are missing in the original species descriptions or that were neglected in the past. Special attention was paid mainly to muscle scars, structure of the siphuncle and morphology of the embryonic shell. The embryonic shell was originally described as Tretoceras parvulum Barrande, 1868. In addition, Orthoceras naufragum Barrande, 1870 was synonymized with the studied species and the species Orthoceras interpolatum Barrande, 1870 was assigned to the genus Bactroceras. Key words: Cephalopoda, Ordovician, Czech Republic, Barrandian area
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