The end of the Ordovician witnessed major perturbations in the ecosystem, seriously affecting glo... more The end of the Ordovician witnessed major perturbations in the ecosystem, seriously affecting global marine biodiversity. Nevertheless, some marine organism groups and their crisis-bound palaeogeographic distribution are still understudied. Among the outliers are eunicid polychaetes, even though they flourished and diversified extensively during the Ordovician. A collection of seven genera of jaw-bearing polychaetes, including the new ramphoprionid genus Spitiprion Tonarová, Suttner, & Hints, with type new species of Spitiprion khannai Tonarová, Suttner, & Hints, is described here from Katian (Upper Ordovician) deposits of Spiti, northern India. The new species is preserved as isolated maxillae and a jaw cluster, and 3D models of the maxillary apparatus are reconstructed based on submicron-CT. Along with the scolecodonts, a low-diversity assemblage of chitinozoans was recovered, comprising five genera. The most common chitinozoan species are Acanthochitina cf. cancellata and Spinachitina suecica.
Early Palaezoic Biogeography and Palaeogeography, 2013
ABSTRACT Eunicidan polychaetes formed a significant part of Early Palaeozoic marine invertebrate ... more ABSTRACT Eunicidan polychaetes formed a significant part of Early Palaeozoic marine invertebrate communities, as shown by the abundance and diversity of scolecodonts (polychaete jaws) in the fossil record. In this study we summarize the early radiation and biodiversity trends and discuss the palaeobiogeography of these fossils. The oldest (latest Cambrian–Early Ordovician) representatives had primitive, usually symmetrical, placognath/ctenognath type jaw apparatuses. The first more advanced taxa, possessing labidognath-type jaw apparatuses or placognath apparatuses with compound maxillae, are first recorded in the Middle Ordovician. The most significant increase in generic diversity occurred in the Darriwilian, when many common taxa appeared and diversified. The Ordovician and Silurian scolecodont occurrences allow some palaeobiogeographical units and distribution patterns to be explored and outlined. The most robust data presently at hand derive from successions in Baltica and Laurentia. That information, together with new records from other palaeocontinents, reveals a wide distribution for the most frequent and species-rich genera and families, similar to the biogeographical patterns of extant polychaetes. Like many other benthic and pelagic fossil groups, scolecodont-bearing polychaetes show an increased cosmopolitan character in the Silurian as compared with the Ordovician. Species-level endemism appears to be relatively common, inferring a potential for scolecodonts as biogeographical tools in the future.
A rich assemblage of Middle Devonian (late Eifelian) polychaete jaws (scolecodonts) from the Blan... more A rich assemblage of Middle Devonian (late Eifelian) polychaete jaws (scolecodonts) from the Blankenheimerdorf section in the type Eifel area, western Germany, is described. The top part of the section also reflects the onset of the global Kacak Event. The sediments of the section were deposited in a shallow to deep subtidal environment on the southern Avalonian margin. The habitat was obviously favourable for jaw-bearing polychaetes, which are represented by 18 species belonging to 9 genera. The assemblage is dominated by polychaetaspids, followed by mochtyellids, paulinitids and kielanoprionids. Notably, this study documents one of the oldest records of kielanoprionids, a polychaete family common since the Middle Devonian and closely related to the extant Hartmaniellidae. This may indicate that a prominent change in jawed polychaete evolution occurred during the Early–Middle Devonian transition. Moreover, we present new information on polychaete palaeobiogeography, which when compared with previously described Devonian scolecodonts shows that very similar polychaete faunas with many species in common were widespread in today's Europe and North America.
Arevision of the large scolecodont collections of Žebera (1935) and Šnajdr (1951) has been accomp... more Arevision of the large scolecodont collections of Žebera (1935) and Šnajdr (1951) has been accomplished using among other techniques, electron microscopy. The preliminary results showed a high level of morphological variability in the first and second maxillae of Kettnerites kosoviensis ŽEBERA, 1935 which represents the type species of the genus Kettnerites ŽEBERA, 1935.
ABSTRACT The impact of the Llandovery–Wenlock Ireviken Event (IE) on the jawed polychaete faunas ... more ABSTRACT The impact of the Llandovery–Wenlock Ireviken Event (IE) on the jawed polychaete faunas is explored in this study, based on new data on scolecodonts from the Viki drill core of western Estonia. A distinct faunal reorganisation is observed, with the most abrupt changes recorded between datum points 4 and 6 of the IE, which coincides with the major turnover interval of other fossil groups. Based on what is now known, polychaetaspids and mochtyellids suffered most severely during the event, whereas the members of other families seem to have been less affected.
The lower Silurian strata of the Prague Basin, as well as in many other regions, are primarily re... more The lower Silurian strata of the Prague Basin, as well as in many other regions, are primarily represented by black shales, with limited to no record of benthic life. In this paper, we describe an exceptional late Aeronian volcanic-carbonate succession from the Hýskov locality near Beroun, which contains a diverse and well-preserved fossil assemblage and specific microfacies features. The studied section is mostly represented by well-washed, poorly sorted skeletal grainstones, rudstones and floatstones along with volcaniclastic material. The environment is interpreted as agitated, above storm wave base, and with rapid sedimentation and burial. The collection of acid-resistant microfossils includes abundant scolecodonts, conodonts and chitinozoans, of which only the chitinozoans have previously been studied. The scolecodonts recovered represent at least 14 polychaete genera and 20 species. The fauna bears a great similarity to the early Silurian assemblages previously reported from B...
A rich assemblage of Middle Devonian (late Eifelian) polychaete jaws (scolecodonts) from the Blan... more A rich assemblage of Middle Devonian (late Eifelian) polychaete jaws (scolecodonts) from the Blankenheimerdorf section in the type Eifel area, western Germany, is described. The top part of the section also reflects the onset of the global Kačák Event. The sediments of the section were deposited in a shallow to deep subtidal environment on the southern Avalonian margin. The habitat was obviously favourable for jaw-bearing polychaetes, which are represented by 18 species belonging to 9 genera. The assemblage is dominated by polychaetaspids, followed by mochtyellids, paulinitids and kielanoprionids. Notably, this study documents one of the oldest records of kielanoprionids, a polychaete family common since the Middle Devonian and closely related to the extant Hartmaniellidae. This may indicate that a prominent change in jawed polychaete evolution occurred during the Early–Middle Devonian transition. Moreover, we present new information on polychaete palaeobiogeography, which when compared with previously described Devonian scolecodonts shows that very similar polychaete faunas with many species in common were widespread in today's Europe and North America.
The end of the Ordovician witnessed major perturbations in the ecosystem, seriously affecting glo... more The end of the Ordovician witnessed major perturbations in the ecosystem, seriously affecting global marine biodiversity. Nevertheless, some marine organism groups and their crisis-bound palaeogeographic distribution are still understudied. Among the outliers are eunicid polychaetes, even though they flourished and diversified extensively during the Ordovician. A collection of seven genera of jaw-bearing polychaetes, including the new ramphoprionid genus Spitiprion Tonarová, Suttner, & Hints, with type new species of Spitiprion khannai Tonarová, Suttner, & Hints, is described here from Katian (Upper Ordovician) deposits of Spiti, northern India. The new species is preserved as isolated maxillae and a jaw cluster, and 3D models of the maxillary apparatus are reconstructed based on submicron-CT. Along with the scolecodonts, a low-diversity assemblage of chitinozoans was recovered, comprising five genera. The most common chitinozoan species are Acanthochitina cf. cancellata and Spinachitina suecica.
Early Palaezoic Biogeography and Palaeogeography, 2013
ABSTRACT Eunicidan polychaetes formed a significant part of Early Palaeozoic marine invertebrate ... more ABSTRACT Eunicidan polychaetes formed a significant part of Early Palaeozoic marine invertebrate communities, as shown by the abundance and diversity of scolecodonts (polychaete jaws) in the fossil record. In this study we summarize the early radiation and biodiversity trends and discuss the palaeobiogeography of these fossils. The oldest (latest Cambrian–Early Ordovician) representatives had primitive, usually symmetrical, placognath/ctenognath type jaw apparatuses. The first more advanced taxa, possessing labidognath-type jaw apparatuses or placognath apparatuses with compound maxillae, are first recorded in the Middle Ordovician. The most significant increase in generic diversity occurred in the Darriwilian, when many common taxa appeared and diversified. The Ordovician and Silurian scolecodont occurrences allow some palaeobiogeographical units and distribution patterns to be explored and outlined. The most robust data presently at hand derive from successions in Baltica and Laurentia. That information, together with new records from other palaeocontinents, reveals a wide distribution for the most frequent and species-rich genera and families, similar to the biogeographical patterns of extant polychaetes. Like many other benthic and pelagic fossil groups, scolecodont-bearing polychaetes show an increased cosmopolitan character in the Silurian as compared with the Ordovician. Species-level endemism appears to be relatively common, inferring a potential for scolecodonts as biogeographical tools in the future.
A rich assemblage of Middle Devonian (late Eifelian) polychaete jaws (scolecodonts) from the Blan... more A rich assemblage of Middle Devonian (late Eifelian) polychaete jaws (scolecodonts) from the Blankenheimerdorf section in the type Eifel area, western Germany, is described. The top part of the section also reflects the onset of the global Kacak Event. The sediments of the section were deposited in a shallow to deep subtidal environment on the southern Avalonian margin. The habitat was obviously favourable for jaw-bearing polychaetes, which are represented by 18 species belonging to 9 genera. The assemblage is dominated by polychaetaspids, followed by mochtyellids, paulinitids and kielanoprionids. Notably, this study documents one of the oldest records of kielanoprionids, a polychaete family common since the Middle Devonian and closely related to the extant Hartmaniellidae. This may indicate that a prominent change in jawed polychaete evolution occurred during the Early–Middle Devonian transition. Moreover, we present new information on polychaete palaeobiogeography, which when compared with previously described Devonian scolecodonts shows that very similar polychaete faunas with many species in common were widespread in today's Europe and North America.
Arevision of the large scolecodont collections of Žebera (1935) and Šnajdr (1951) has been accomp... more Arevision of the large scolecodont collections of Žebera (1935) and Šnajdr (1951) has been accomplished using among other techniques, electron microscopy. The preliminary results showed a high level of morphological variability in the first and second maxillae of Kettnerites kosoviensis ŽEBERA, 1935 which represents the type species of the genus Kettnerites ŽEBERA, 1935.
ABSTRACT The impact of the Llandovery–Wenlock Ireviken Event (IE) on the jawed polychaete faunas ... more ABSTRACT The impact of the Llandovery–Wenlock Ireviken Event (IE) on the jawed polychaete faunas is explored in this study, based on new data on scolecodonts from the Viki drill core of western Estonia. A distinct faunal reorganisation is observed, with the most abrupt changes recorded between datum points 4 and 6 of the IE, which coincides with the major turnover interval of other fossil groups. Based on what is now known, polychaetaspids and mochtyellids suffered most severely during the event, whereas the members of other families seem to have been less affected.
The lower Silurian strata of the Prague Basin, as well as in many other regions, are primarily re... more The lower Silurian strata of the Prague Basin, as well as in many other regions, are primarily represented by black shales, with limited to no record of benthic life. In this paper, we describe an exceptional late Aeronian volcanic-carbonate succession from the Hýskov locality near Beroun, which contains a diverse and well-preserved fossil assemblage and specific microfacies features. The studied section is mostly represented by well-washed, poorly sorted skeletal grainstones, rudstones and floatstones along with volcaniclastic material. The environment is interpreted as agitated, above storm wave base, and with rapid sedimentation and burial. The collection of acid-resistant microfossils includes abundant scolecodonts, conodonts and chitinozoans, of which only the chitinozoans have previously been studied. The scolecodonts recovered represent at least 14 polychaete genera and 20 species. The fauna bears a great similarity to the early Silurian assemblages previously reported from B...
A rich assemblage of Middle Devonian (late Eifelian) polychaete jaws (scolecodonts) from the Blan... more A rich assemblage of Middle Devonian (late Eifelian) polychaete jaws (scolecodonts) from the Blankenheimerdorf section in the type Eifel area, western Germany, is described. The top part of the section also reflects the onset of the global Kačák Event. The sediments of the section were deposited in a shallow to deep subtidal environment on the southern Avalonian margin. The habitat was obviously favourable for jaw-bearing polychaetes, which are represented by 18 species belonging to 9 genera. The assemblage is dominated by polychaetaspids, followed by mochtyellids, paulinitids and kielanoprionids. Notably, this study documents one of the oldest records of kielanoprionids, a polychaete family common since the Middle Devonian and closely related to the extant Hartmaniellidae. This may indicate that a prominent change in jawed polychaete evolution occurred during the Early–Middle Devonian transition. Moreover, we present new information on polychaete palaeobiogeography, which when compared with previously described Devonian scolecodonts shows that very similar polychaete faunas with many species in common were widespread in today's Europe and North America.
Uploads
Papers by Petra Tonarova