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Early Palaeozoic jawed polychaetes with focus on polychaetaspids and ramphoprionids from the Silurian of Gotland, Sweden

Eriksson, Mats LU (2000) In Lund Publications in Geology 151.
Abstract (Swedish)
Popular Abstract in Swedish

Käkförsedda havsborstmaskar (polychaeter) var artrika och vanliga i de tidigpaleozoiska haven. Maskarnas käkar, benämda scolecodonter i den vetenskapliga litteraturen, är mycket vanliga mikrofossil i sedimentära bergarter, främst kalkstenar av denna ålder. Mycket pekar därför på att de ofta utgjorde en väsentlig del av bottenfaunan. Trots mångfalden av scolecodonter har relativt lite forskning gjorts på dessa fossil. Ett av skälen är att systematiken har varit och är i viss mån fortfarande mycket oklar. Detta beror delvis på att parataxonomi har varit förhärskande, det vill säga att olika fossila delar från en och samma art har beskrivits och namngivits var för sig baserat på olikheter i deras... (More)
Popular Abstract in Swedish

Käkförsedda havsborstmaskar (polychaeter) var artrika och vanliga i de tidigpaleozoiska haven. Maskarnas käkar, benämda scolecodonter i den vetenskapliga litteraturen, är mycket vanliga mikrofossil i sedimentära bergarter, främst kalkstenar av denna ålder. Mycket pekar därför på att de ofta utgjorde en väsentlig del av bottenfaunan. Trots mångfalden av scolecodonter har relativt lite forskning gjorts på dessa fossil. Ett av skälen är att systematiken har varit och är i viss mån fortfarande mycket oklar. Detta beror delvis på att parataxonomi har varit förhärskande, det vill säga att olika fossila delar från en och samma art har beskrivits och namngivits var för sig baserat på olikheter i deras utseende. Med nuvarande kunskap kan och bör därför vetenskapliga namn som ställts upp på detta vis revideras och sedermera förkastas. Integrering av systematik baserad på mer eller mindre intakta käkapparater och systematik baserad på isolerade käkar resulterar i en mer tillförlitlig bild över de fossila polychaetfaunorna. Vid denna undersökning av tidigpaleozoiska käkförsedda polychaeter har sådan systematik använts. Scolecodonter utgör några av de vanligaste mikrofossilen i den siluriska lagerföljden på Gotland. Baserat på mycket rika kollektioner kan cirka hundra polychaetarter tillhörande ett dussin familjer urskiljas. Två familjer, Ramphoprionidae och Polychaetaspidae, var av största intresse i denna studie. Polychaetaspidae utgör en av de vanligaste och mest mångformiga familjerna i Gotlands siluriska berggrund. Tio arter tillhörande tre släkten, Oenonites Hinde, Kozlowskiprion Kielan-Jaworowska och Dubichaetaspis Eriksson, har identifierats och beskrivits. Av dessa var sju arter och ett släkte, Dubichateaspis, tidigare okända. Ramphoprioniderna tycks däremot varken vara rikligt förekommande eller särskilt mångformiga, men utgör hur som helst en karakteristisk del av faunorna. I speciella miljöer kunde de vara en framträdande grupp. Sex namngivna arter tillhörande fyra släkten, Protarabellites Stauffer, Ramphoprion Kielan-Jaworowska, “Pararamphoprion” Männil & Zaslavskaya, och Megaramphoprion Eriksson, har identifierats och beskrivits. Av dessa var fem arter och ett släkte, Megaramphoprion, tidigare okända. Vidare har ett fåtal exemplar beskrivits under öppen nomenklatur och de har alltså inte tilldelats något formellt vetenskapligt namn i avvaktan på fortsatta studier. Undersökningar av mindre provkollektioner från silurisk berggrund i Skåne och västra England indikerar att flertalet ramphoprionidarter hade relativt vid geografisk spridning. I likhet med nulevande polychaeter var emellertid många av de undersökta arterna begränsade i sin utbredning av miljöfaktorer; många var stenotopa och således starkt bundna till vissa miljöer. En ny familj, Hadoprionidae, har identifierats och beskrivits från överordoviciska lagerföljder i Indiana, Nordamerika. En art av det nya släktet Hadoprion Eriksson & Bergman, har beskrivits. Käkapparaten tillhörande denna art, H. cervicornis (Hinde), har tidigare beskrivits under fyra släktesnamn och åtta artnamn. Hadoprionider har även identifierats i silurisk berggrund från norra Europa. En partikelaccelerator har använts för kemiska analyser, och anrikningar av tungmetaller har påvisats i käkar av fossila och nulevande polychaeter. Metallerna, främst järn, zink och koppar, var företrädelsevis koncentrerade till de främre delarna av käkarna. Hos flertalet andra marina och terrestriska nulevande djurgrupper har snarlika anrikningar rapporterats i strukturer som är utsatta för hög påfrestning och/eller slitage. Detta indikerar att metallerna stärkte strukturerna. Metallackumulationerna verkar ibland ha bidragit till det dåliga bevaringstillståndet hos vissa fossila scolecodonter. (Less)
Abstract
Jawed polychaete annelid worms were abundant and diverse in the early Palaeozoic seas and their jaws (scolecodonts) are common microfossils in sedimentary rocks of that age. Despite their abundance, relatively little work has been focused on these fossils. One reason for this is that their taxonomy has been, and to some extent still is, in a state of disorder, mainly because of a parataxonomic treatment. In the present state of knowledge, however, parataxonomy and paranomenclatural names can and therefore must be rejected from the research field. Integration of element-based and apparatus-based taxonomies results in great progress and a more reliable picture of the fossil jawed polychaete faunas. Such a taxonomic approach has been applied... (More)
Jawed polychaete annelid worms were abundant and diverse in the early Palaeozoic seas and their jaws (scolecodonts) are common microfossils in sedimentary rocks of that age. Despite their abundance, relatively little work has been focused on these fossils. One reason for this is that their taxonomy has been, and to some extent still is, in a state of disorder, mainly because of a parataxonomic treatment. In the present state of knowledge, however, parataxonomy and paranomenclatural names can and therefore must be rejected from the research field. Integration of element-based and apparatus-based taxonomies results in great progress and a more reliable picture of the fossil jawed polychaete faunas. Such a taxonomic approach has been applied here during the investigation of early Palaeozoic jawed polychaetes. In the Silurian succession (latest Llandovery to latest Ludlow) of the island of Gotland, situated east of the Swedish mainland in the Baltic Sea, scolecodonts are among the most common microfossils. Based on extensive collections, approximately one hundred polychaete species of a dozen families can be identified in the entire succession. Two families, Polychaetaspidae and Ramphoprionidae, were of prime interest in this study. Polychaetaspidae comprises one of the most abundant and taxonomically diverse families in the Silurian of Gotland. Ten species belonging to three genera, Oenonites Hinde, Kozlowskiprion Kielan-Jaworowska, and Dubichaetaspis Eriksson, have been identified and described here. Of these, seven species and one genus, Dubichaetaspis, were previously unknown. In contrast to the polychaetaspids, the ramphoprionids are neither particularly diverse nor abundant. Nevertheless, they comprise a characteristic part of the faunas, at certain localities constituting a major faunal element. Six named species belonging to four genera, Protarabellites Stauffer, Ramphoprion Kielan-Jaworowska, “Pararamphoprion” Männil & Zaslavskaya, and Megaramphoprion Eriksson, have been identified and described. Of these, five species and one genus, Megaramphoprion, were previously unknown. A few specimens were described under open nomenclature pending further investigations. Studies of smaller scolecodont collections from the Silurian of Skåne (Scania), southern Sweden, and western England indicate that most ramphoprionids had a fairly wide geographical distribution. Like extant polychaetes, many of the investigated polychaetes were environmentally controlled; many species were stenotopic, showing strong preference for particular environments. A new monogeneric family, Hadoprionidae, has been identified and described from rich collections from the Cincinnatian (upper Ordovician) of Indiana, North America. One species of the new genus, Hadoprion, was identified. The jaw apparatus of H. cervicornis (Hinde) has formerly been described under four generic and eight specific names. Hadoprionids have also been identified in Silurian strata of northern Europe. Chemical analyses applying a nuclear microprobe, Particle Induced X-ray Emission (PIXE) and Scanning Transmission Ion Microscopy (STIM) analytical techniques, demonstrated enrichments of heavy metals in jaws of fossil and extant polychaetes. The metals, particularly Fe, Zn, and Cu, were predominantly concentrated in the anterior region of the jaws. Closely similar enrichments have been reported in structures exposed to high stress and/or abrasional forces of various other, marine and terrestrial, Recent higher taxa. This indicates that the metals have functional significance. Occasionally, such metal accumulations seem to have been responsible for the present damaged condition of some fossil scolecodonts. (Less)
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author
opponent
  • Professor Szaniawski, Hubert, Warsaw, Poland
organization
publishing date
type
Thesis
publication status
published
subject
keywords
fysisk geografi, Geologi, physical geography, Geology, chemistry, palaeobiogeography, palaeoecology, taxonomy, apparatus reconstructions, Silurian, Recent, Ordovician, early Palaeozoic, scolecodonts, Annelida, polychaeta
in
Lund Publications in Geology
volume
151
pages
105 pages
publisher
Department of Geology, Lund University
defense location
Dept. of Geology, 3rd floor
defense date
2000-09-29 10:15
external identifiers
  • other:ISRN: SE-LUNBDS/NBGH-00/1024+19S
ISSN
0281-1316
ISBN
91-86746-36-7
language
English
LU publication?
yes
id
7bbc5045-f4aa-4c84-92d5-18803eef060d (old id 40671)
date added to LUP
2007-06-20 12:58:34
date last changed
2016-09-19 08:44:52
@phdthesis{7bbc5045-f4aa-4c84-92d5-18803eef060d,
  abstract     = {Jawed polychaete annelid worms were abundant and diverse in the early Palaeozoic seas and their jaws (scolecodonts) are common microfossils in sedimentary rocks of that age. Despite their abundance, relatively little work has been focused on these fossils. One reason for this is that their taxonomy has been, and to some extent still is, in a state of disorder, mainly because of a parataxonomic treatment. In the present state of knowledge, however, parataxonomy and paranomenclatural names can and therefore must be rejected from the research field. Integration of element-based and apparatus-based taxonomies results in great progress and a more reliable picture of the fossil jawed polychaete faunas. Such a taxonomic approach has been applied here during the investigation of early Palaeozoic jawed polychaetes. In the Silurian succession (latest Llandovery to latest Ludlow) of the island of Gotland, situated east of the Swedish mainland in the Baltic Sea, scolecodonts are among the most common microfossils. Based on extensive collections, approximately one hundred polychaete species of a dozen families can be identified in the entire succession. Two families, Polychaetaspidae and Ramphoprionidae, were of prime interest in this study. Polychaetaspidae comprises one of the most abundant and taxonomically diverse families in the Silurian of Gotland. Ten species belonging to three genera, Oenonites Hinde, Kozlowskiprion Kielan-Jaworowska, and Dubichaetaspis Eriksson, have been identified and described here. Of these, seven species and one genus, Dubichaetaspis, were previously unknown. In contrast to the polychaetaspids, the ramphoprionids are neither particularly diverse nor abundant. Nevertheless, they comprise a characteristic part of the faunas, at certain localities constituting a major faunal element. Six named species belonging to four genera, Protarabellites Stauffer, Ramphoprion Kielan-Jaworowska, “Pararamphoprion” Männil & Zaslavskaya, and Megaramphoprion Eriksson, have been identified and described. Of these, five species and one genus, Megaramphoprion, were previously unknown. A few specimens were described under open nomenclature pending further investigations. Studies of smaller scolecodont collections from the Silurian of Skåne (Scania), southern Sweden, and western England indicate that most ramphoprionids had a fairly wide geographical distribution. Like extant polychaetes, many of the investigated polychaetes were environmentally controlled; many species were stenotopic, showing strong preference for particular environments. A new monogeneric family, Hadoprionidae, has been identified and described from rich collections from the Cincinnatian (upper Ordovician) of Indiana, North America. One species of the new genus, Hadoprion, was identified. The jaw apparatus of H. cervicornis (Hinde) has formerly been described under four generic and eight specific names. Hadoprionids have also been identified in Silurian strata of northern Europe. Chemical analyses applying a nuclear microprobe, Particle Induced X-ray Emission (PIXE) and Scanning Transmission Ion Microscopy (STIM) analytical techniques, demonstrated enrichments of heavy metals in jaws of fossil and extant polychaetes. The metals, particularly Fe, Zn, and Cu, were predominantly concentrated in the anterior region of the jaws. Closely similar enrichments have been reported in structures exposed to high stress and/or abrasional forces of various other, marine and terrestrial, Recent higher taxa. This indicates that the metals have functional significance. Occasionally, such metal accumulations seem to have been responsible for the present damaged condition of some fossil scolecodonts.},
  author       = {Eriksson, Mats},
  isbn         = {91-86746-36-7},
  issn         = {0281-1316},
  keyword      = {fysisk geografi,Geologi,physical geography,Geology,chemistry,palaeobiogeography,palaeoecology,taxonomy,apparatus reconstructions,Silurian,Recent,Ordovician,early Palaeozoic,scolecodonts,Annelida,polychaeta},
  language     = {eng},
  pages        = {105},
  publisher    = {Department of Geology, Lund University},
  school       = {Lund University},
  series       = {Lund Publications in Geology},
  title        = {Early Palaeozoic jawed polychaetes with focus on polychaetaspids and ramphoprionids from the Silurian of Gotland, Sweden},
  volume       = {151},
  year         = {2000},
}