Рожнов Владимирович - Academia.edu (original) (raw)
Papers by Рожнов Владимирович
Despite more than 150 years of study of crinoids from the Moscow Region there are numerous undesc... more Despite more than 150 years of study of crinoids from the Moscow Region there are numerous undescribed taxa from well-known localities as well as others from poorly known localities. In recent years, through the acquisition of new collections as well as new discoveries, the holdings of Carboniferous crinoids of the Paleontological Institute, Russian Academy of Science have been greatly increased. This has allowed a more detailed study of the faunas, which is in pro-gress. Among the crinoids in the collection there are representatives of the family Pirasocrinidae Moore & Laudon, 1943, that are abundant in the Pennsylvanian of the USA, and previously unknown in the Carboniferous of the Moscow Region, as well as representatives of the genera Allosocrinus Strimple, 1949, Cibolocrinus Weller, 1909 and Elibatocrinus Moore, 1940, also previously unknown in the Moscow Region. There is also the first recognized Pennsylvanian member of the family Taxocrinidae Angelin, 1878. The stratigraphic ...
Вестник Российской академии наук, 2017
Вестник Российской академии наук, 2017
Paleontological Journal, 2007
WOGOGOB-2004 8th Meeting on the Working Group on the Ordovician Geology of Baltoscandia May 13–18, 2004, Tallinn and Tartu, Estonia Organising Comittee, 2004
In the abandoned Aluvere quarry near Rakvere, south of the Tallinn–Narva road, the limestone succ... more In the abandoned Aluvere quarry near Rakvere, south of the Tallinn–Narva road, the limestone succession of the Kahula Formation, Haljala Stage (Caradoc) is exposed. In the southern wall of the quarry 6 m of limestone can be studied, characterising the Aluvere and Pagari members of the Kahula Formation (Jõhvi Substage of the Haljala Stage; Fig. 1). The limestone can be classified as wackestone to packstone with a varying content (10–25%) of siliciclastic mud. This siliciclastics content varies rhythmically, as 10–20 cm thick cycles, ...
Paleontological Journal, 2006
Without Abstract
Compiled and edited by David A.T. Harper and Maureen McCorry STATENS NATURHISTORISKE MUSEUM – GEO... more Compiled and edited by David A.T. Harper and Maureen McCorry STATENS NATURHISTORISKE MUSEUM – GEOLOGISK MUSEUM DET NATURVIDENSKABELIGE FAKULTET KØBENHAVNS UNIVERSITET Absolutely final meeting of IGCP 503: Ordovician palaeogeography and palaeoclimate Copenhagen 2009 August 31 – September 4 1 Absolutely final meeting of IGCP 503: Ordovician palaeogeography and palaeoclimate
Zoosymposia
Three incomplete thecae of the stylophoran Lagynocystis cf. pyramidalis (Barrande, 1887) are desc... more Three incomplete thecae of the stylophoran Lagynocystis cf. pyramidalis (Barrande, 1887) are described from the Upper Ordovician of the Baltic Paleobasin for the first time. These specimens of Lagynocystis are the first records of this genus from the Ordovician outside peri-Gondwana, thus significantly expanding its paleogeographical distribution of this genus. Due to the preservation of the specimens the microstructure of the stereom is studied for the first time in this genus.
Zoosymposia
The monotypic genus Heckerites Rozhnov, 1987, that was found in the Upper Ordovician of Estonia, ... more The monotypic genus Heckerites Rozhnov, 1987, that was found in the Upper Ordovician of Estonia, is redescribed on the basis of new findings. The morphology of the ambulacral system, peristome, the structure and the position of the hydropore, gonopore, and periproct are described in detail. In the morphology of this genus the features of eocrinoids and paracrinoids are unusually combined. Nevertheless, the analysis of these features points to a possible assignment of this genus, and hence the monotypic family Heckeritidae Rozhnov, 1987 based on this genus, to paracrinoids.
Zoosymposia
Despite more than 150 years of study of crinoids from the Moscow Region there are numerous undesc... more Despite more than 150 years of study of crinoids from the Moscow Region there are numerous undescribed taxa from well-known localities as well as others from poorly known localities. In recent years, through the acquisition of new collections as well as new discoveries, the holdings of Carboniferous crinoids of the Paleontological Institute, Russian Academy of Science have been greatly increased. This has allowed a more detailed study of the faunas, which is in progress. Among the crinoids in the collection there are representatives of the family Pirasocrinidae Moore & Laudon, 1943, that are abundant in the Pennsylvanian of the USA, and previously unknown in the Carboniferous of the Moscow Region, as well as representatives of the genera Allosocrinus Strimple, 1949, Cibolocrinus Weller, 1909 and Elibatocrinus Moore, 1940, also previously unknown in the Moscow Region. There is also the first recognized Pennsylvanian member of the family Taxocrinidae Angelin, 1878. The stratigraphic ...
Palaeoworld
Abstract The study of the Ordovician holdfasts of the Baltic Paleobasin revealed an explosive inc... more Abstract The study of the Ordovician holdfasts of the Baltic Paleobasin revealed an explosive increase in the morphological diversity of echinoderms of the Baltic Paleobasin, up to 12 major morphological types in the Volkhov Regional Stage (Dapingian), reflecting an explosive growth in the taxonomic and morphological diversity of stalked echinoderms in general, but primarily crinoids. A sudden increase in the size and diversity of holdfasts at that time suggests a considerable increase in calcite production by stalked echinoderms and their adaptation to a wide distribution of a new type of substrate — hardgrounds and firm coarse-grained bioclastic substrates. The possibility of wide distribution of such substrates was due to a considerable increase, of at least an order of magnitude, in the carbonate productivity of benthic communities, whereas the rapid distribution of a new type of substrate and an explosive increase in the diversity and abundance of their inhabitants in the Baltic Basin was related to the appearance of positive feedbacks between the living and non-living components of this ecosystem. The existence of this positive feedback was due to cyanobacterial communities, the development of a biofilm on the substrate, and mineralization of an extracellular polymer substance, which led to the formation of hardgrounds and consolidation of the surface of the bioclastic substrates. The appearance in the Middle Ordovician of positive feedback between the expansion of the bioclastic substrates and an increase in carbonate production by their inhabitants, resulted in the Ordovician substrate revolution and explosive diversification of Ordovician benthic animals. Cyanobacterial films episodically appearing on the substrate, were an essential factor in the formation of this feedback.
Herald of the Russian Academy of Sciences, 2010
Natural Science, 2014
Echinoderm radial symmetry has first appeared in the ambulacral system, when the ambulacral chann... more Echinoderm radial symmetry has first appeared in the ambulacral system, when the ambulacral channel assumed the shape of a closed ring or a horseshoe with approximated ends, and then spread onto other organ systems. Its origin was a natural consequence of a steady increase of the original asymmetry of bilaterally-asymmetric three-segmented ancestors of echinoderms, culminated by closing of the ancestral linear metamerism into radiality. The evolutionary transformation from a simple pouchlike hydrocoel with one side channel to an elongated hydrocoel (located under the oesophagus) with two side channels, and finally to a nearly closed horseshoeshaped hydrocoel with three radial channels can be reconstructed based on the theca structure and the number of ambulacra in the row Soluta-Cincta-Helicoplacoidea. After the hydrocoel with three outbound ambulacral channels circled around the oesophagus as a horseshoe, it either closed into a ring, or its ends became closely approximated. This has determined the primary triradiate symmetry, which quickly transformed into pentaradial symmetry of the 2-1-2 type as a result of branching of two of the three primary radial channels. This occurred no earlier than the Late Vendian, when the first bilaterians appeared to have begun to acquire body appendages, and no later than the Early Cambrian, when the first skeletal remains of echinoderms entered the fossil record (in the Atdabanian). The 2-1-2 pentaradial symmetry evolved into the true pentaradiality as a result of shifting the timing of tentacle branching to earlier stages of ontogenesis and even spreading of the five tentacle primordia over the ambulacral ring. This occurred during the Ordovician.
Comparison of thecal plating of Rhipidocystis and Cryptocrinites shows that these genera have bee... more Comparison of thecal plating of Rhipidocystis and Cryptocrinites shows that these genera have been closely related. Some differences in the plating were caused by the process of theca flattening in Rhipidocystis. The bend of the theca in both genera in the same plane of symmetry but in opposite directions as well as the different position of anus resulted from the process of heterochrony.
Paleontological Journal
The supplement is published only in English by MAIK "Nauka /Interperiodica" (Russia).
Paleontological Journal, 2014
One of the earliest isorophid edrioasteroids from the upper Middle Cambrian-lower Upper Cam brian... more One of the earliest isorophid edrioasteroids from the upper Middle Cambrian-lower Upper Cam brian (upper part of Series 3-lower part of the Furongian Series) of northern Iran is described. It has unusual branched ambulacra, which extend beyond the theca almost to the marginal rim. These unusual features reflect the latent possibility of appearance of separated from the theca and even branching food gathering appendages, such as arms in crinoids and brachials in blastozoans, in common ancestor of all radially sym metrical echinoderms.
![Research paper thumbnail of [From Vendian to Cambrian: the beginning of morphological disparity of modern Metazoan phyla]](https://attachments.academia-assets.com/78062967/thumbnails/1.jpg)
](Ontogenez
Continuity of the transition from Precambrian to the Phanerozoic metazoan fauna at the phylum lev... more Continuity of the transition from Precambrian to the Phanerozoic metazoan fauna at the phylum level is analyzed. The discrete traces of feeding on bacterial mats by Dickinsonia and similar organisms are explained by extracorporeal digestion, characteristic ofa placozoan level of organization, as in the extant Trichoplax. The absence of a morphologically developed anterior end of the body, of food-gathering appendages of any kind, and of appendages responsible for movement suggest that these animals were at this level of organization. Probably, an expanded placozoan level of organization can be assumed for most vendian animals. Against this background, new characters emerged in the Cambrian to be included in the body plan of extant animal phyla. The relationships between the morphological archetype (body plan) and morphogenetic archetype are considered. It is shown that major features of a morphogenetic archetype could be retained from the time the taxon was formed.
Despite more than 150 years of study of crinoids from the Moscow Region there are numerous undesc... more Despite more than 150 years of study of crinoids from the Moscow Region there are numerous undescribed taxa from well-known localities as well as others from poorly known localities. In recent years, through the acquisition of new collections as well as new discoveries, the holdings of Carboniferous crinoids of the Paleontological Institute, Russian Academy of Science have been greatly increased. This has allowed a more detailed study of the faunas, which is in pro-gress. Among the crinoids in the collection there are representatives of the family Pirasocrinidae Moore & Laudon, 1943, that are abundant in the Pennsylvanian of the USA, and previously unknown in the Carboniferous of the Moscow Region, as well as representatives of the genera Allosocrinus Strimple, 1949, Cibolocrinus Weller, 1909 and Elibatocrinus Moore, 1940, also previously unknown in the Moscow Region. There is also the first recognized Pennsylvanian member of the family Taxocrinidae Angelin, 1878. The stratigraphic ...
Вестник Российской академии наук, 2017
Вестник Российской академии наук, 2017
Paleontological Journal, 2007
WOGOGOB-2004 8th Meeting on the Working Group on the Ordovician Geology of Baltoscandia May 13–18, 2004, Tallinn and Tartu, Estonia Organising Comittee, 2004
In the abandoned Aluvere quarry near Rakvere, south of the Tallinn–Narva road, the limestone succ... more In the abandoned Aluvere quarry near Rakvere, south of the Tallinn–Narva road, the limestone succession of the Kahula Formation, Haljala Stage (Caradoc) is exposed. In the southern wall of the quarry 6 m of limestone can be studied, characterising the Aluvere and Pagari members of the Kahula Formation (Jõhvi Substage of the Haljala Stage; Fig. 1). The limestone can be classified as wackestone to packstone with a varying content (10–25%) of siliciclastic mud. This siliciclastics content varies rhythmically, as 10–20 cm thick cycles, ...
Paleontological Journal, 2006
Without Abstract
Compiled and edited by David A.T. Harper and Maureen McCorry STATENS NATURHISTORISKE MUSEUM – GEO... more Compiled and edited by David A.T. Harper and Maureen McCorry STATENS NATURHISTORISKE MUSEUM – GEOLOGISK MUSEUM DET NATURVIDENSKABELIGE FAKULTET KØBENHAVNS UNIVERSITET Absolutely final meeting of IGCP 503: Ordovician palaeogeography and palaeoclimate Copenhagen 2009 August 31 – September 4 1 Absolutely final meeting of IGCP 503: Ordovician palaeogeography and palaeoclimate
Zoosymposia
Three incomplete thecae of the stylophoran Lagynocystis cf. pyramidalis (Barrande, 1887) are desc... more Three incomplete thecae of the stylophoran Lagynocystis cf. pyramidalis (Barrande, 1887) are described from the Upper Ordovician of the Baltic Paleobasin for the first time. These specimens of Lagynocystis are the first records of this genus from the Ordovician outside peri-Gondwana, thus significantly expanding its paleogeographical distribution of this genus. Due to the preservation of the specimens the microstructure of the stereom is studied for the first time in this genus.
Zoosymposia
The monotypic genus Heckerites Rozhnov, 1987, that was found in the Upper Ordovician of Estonia, ... more The monotypic genus Heckerites Rozhnov, 1987, that was found in the Upper Ordovician of Estonia, is redescribed on the basis of new findings. The morphology of the ambulacral system, peristome, the structure and the position of the hydropore, gonopore, and periproct are described in detail. In the morphology of this genus the features of eocrinoids and paracrinoids are unusually combined. Nevertheless, the analysis of these features points to a possible assignment of this genus, and hence the monotypic family Heckeritidae Rozhnov, 1987 based on this genus, to paracrinoids.
Zoosymposia
Despite more than 150 years of study of crinoids from the Moscow Region there are numerous undesc... more Despite more than 150 years of study of crinoids from the Moscow Region there are numerous undescribed taxa from well-known localities as well as others from poorly known localities. In recent years, through the acquisition of new collections as well as new discoveries, the holdings of Carboniferous crinoids of the Paleontological Institute, Russian Academy of Science have been greatly increased. This has allowed a more detailed study of the faunas, which is in progress. Among the crinoids in the collection there are representatives of the family Pirasocrinidae Moore & Laudon, 1943, that are abundant in the Pennsylvanian of the USA, and previously unknown in the Carboniferous of the Moscow Region, as well as representatives of the genera Allosocrinus Strimple, 1949, Cibolocrinus Weller, 1909 and Elibatocrinus Moore, 1940, also previously unknown in the Moscow Region. There is also the first recognized Pennsylvanian member of the family Taxocrinidae Angelin, 1878. The stratigraphic ...
Palaeoworld
Abstract The study of the Ordovician holdfasts of the Baltic Paleobasin revealed an explosive inc... more Abstract The study of the Ordovician holdfasts of the Baltic Paleobasin revealed an explosive increase in the morphological diversity of echinoderms of the Baltic Paleobasin, up to 12 major morphological types in the Volkhov Regional Stage (Dapingian), reflecting an explosive growth in the taxonomic and morphological diversity of stalked echinoderms in general, but primarily crinoids. A sudden increase in the size and diversity of holdfasts at that time suggests a considerable increase in calcite production by stalked echinoderms and their adaptation to a wide distribution of a new type of substrate — hardgrounds and firm coarse-grained bioclastic substrates. The possibility of wide distribution of such substrates was due to a considerable increase, of at least an order of magnitude, in the carbonate productivity of benthic communities, whereas the rapid distribution of a new type of substrate and an explosive increase in the diversity and abundance of their inhabitants in the Baltic Basin was related to the appearance of positive feedbacks between the living and non-living components of this ecosystem. The existence of this positive feedback was due to cyanobacterial communities, the development of a biofilm on the substrate, and mineralization of an extracellular polymer substance, which led to the formation of hardgrounds and consolidation of the surface of the bioclastic substrates. The appearance in the Middle Ordovician of positive feedback between the expansion of the bioclastic substrates and an increase in carbonate production by their inhabitants, resulted in the Ordovician substrate revolution and explosive diversification of Ordovician benthic animals. Cyanobacterial films episodically appearing on the substrate, were an essential factor in the formation of this feedback.
Herald of the Russian Academy of Sciences, 2010
Natural Science, 2014
Echinoderm radial symmetry has first appeared in the ambulacral system, when the ambulacral chann... more Echinoderm radial symmetry has first appeared in the ambulacral system, when the ambulacral channel assumed the shape of a closed ring or a horseshoe with approximated ends, and then spread onto other organ systems. Its origin was a natural consequence of a steady increase of the original asymmetry of bilaterally-asymmetric three-segmented ancestors of echinoderms, culminated by closing of the ancestral linear metamerism into radiality. The evolutionary transformation from a simple pouchlike hydrocoel with one side channel to an elongated hydrocoel (located under the oesophagus) with two side channels, and finally to a nearly closed horseshoeshaped hydrocoel with three radial channels can be reconstructed based on the theca structure and the number of ambulacra in the row Soluta-Cincta-Helicoplacoidea. After the hydrocoel with three outbound ambulacral channels circled around the oesophagus as a horseshoe, it either closed into a ring, or its ends became closely approximated. This has determined the primary triradiate symmetry, which quickly transformed into pentaradial symmetry of the 2-1-2 type as a result of branching of two of the three primary radial channels. This occurred no earlier than the Late Vendian, when the first bilaterians appeared to have begun to acquire body appendages, and no later than the Early Cambrian, when the first skeletal remains of echinoderms entered the fossil record (in the Atdabanian). The 2-1-2 pentaradial symmetry evolved into the true pentaradiality as a result of shifting the timing of tentacle branching to earlier stages of ontogenesis and even spreading of the five tentacle primordia over the ambulacral ring. This occurred during the Ordovician.
Comparison of thecal plating of Rhipidocystis and Cryptocrinites shows that these genera have bee... more Comparison of thecal plating of Rhipidocystis and Cryptocrinites shows that these genera have been closely related. Some differences in the plating were caused by the process of theca flattening in Rhipidocystis. The bend of the theca in both genera in the same plane of symmetry but in opposite directions as well as the different position of anus resulted from the process of heterochrony.
Paleontological Journal
The supplement is published only in English by MAIK "Nauka /Interperiodica" (Russia).
Paleontological Journal, 2014
One of the earliest isorophid edrioasteroids from the upper Middle Cambrian-lower Upper Cam brian... more One of the earliest isorophid edrioasteroids from the upper Middle Cambrian-lower Upper Cam brian (upper part of Series 3-lower part of the Furongian Series) of northern Iran is described. It has unusual branched ambulacra, which extend beyond the theca almost to the marginal rim. These unusual features reflect the latent possibility of appearance of separated from the theca and even branching food gathering appendages, such as arms in crinoids and brachials in blastozoans, in common ancestor of all radially sym metrical echinoderms.
Ontogenez
Continuity of the transition from Precambrian to the Phanerozoic metazoan fauna at the phylum lev... more Continuity of the transition from Precambrian to the Phanerozoic metazoan fauna at the phylum level is analyzed. The discrete traces of feeding on bacterial mats by Dickinsonia and similar organisms are explained by extracorporeal digestion, characteristic ofa placozoan level of organization, as in the extant Trichoplax. The absence of a morphologically developed anterior end of the body, of food-gathering appendages of any kind, and of appendages responsible for movement suggest that these animals were at this level of organization. Probably, an expanded placozoan level of organization can be assumed for most vendian animals. Against this background, new characters emerged in the Cambrian to be included in the body plan of extant animal phyla. The relationships between the morphological archetype (body plan) and morphogenetic archetype are considered. It is shown that major features of a morphogenetic archetype could be retained from the time the taxon was formed.