Geological history and applications

Scolecodonts first appeared in the Lower Ordovician and diversified rapidly (Underhay & Williams 1995) and had their acme in the Palaeozoic. Most work on fossils has been conducted on material from glacial erratics in Poland (Kielan-Jaworowska 1966; Szaniawski 1968) and on outcrop and borehole material from the Baltic region (e.g. Nakrem et al. 2001; Erikson 2002). They are uncommon in the Mesozoic and Cenozoic (Jansonius & Craig 1971; Schäfer 1972; Szaniawski 1974; Germeraad 1980; Courtinat et al. 1990; Head 1993) and persist into the Recent. Bergman (1995) and Baudu & Paris (1995) have documented some facies restriction in Silurian and Devonian scolecodonts.

Scolecodonts are primarily used in biostratigraphy from the Ordovician to Permian and in thermal maturity studies (e.g. Goodarzi & Higgins 1988; Bertrand 1990; Bertrand & Malo 2001 for a case study). A useful introduction is to be found in Szaniawski (in Jansonius and McGregor 1996, vol. 1, pp. 337-355).

Mill

Mill

Muscle scar

Inner slope

Xanioprion walliseri

Xanioprion walliseri

Muscle scar

Opening of the pulp cavity

Ligament scar

Width

Dentary Inner margin

Inner wing Inner slope

Ligament scar

Width

Attachment lamella

Inner slope

Denticles

Shaft

Denticles

Plate

Shaft

Sinus

Ramus

Sinus

Shank

Fig. 12.1 Descriptive terminology of scolecodonts. (a) Diagrammatic representation of the complete apparatus of Xanioprion walliseri. (b) Diagrammatic sagittal section through Eunice siciliensis showing the relationship of the mandible (Md), maxillae (I-IV) and carriers. (c)-(e) Morphological terminology applied to maxillae. (f) Morphological terminology applied to mandible. (g), (h) Morphological terminology applied to carriers. l, Left; r, right. ((a) After Kielan-Jaworowska 1966; (b) modified from Traverse 1988; (c)-(h) redrawn after Szaniawski in Jansonius and McGregor 1996, vol. 1.)

REFERENCES

Baudu, V. & Paris, F. 1995. Relationships between organic-walled microfossils and paleoenvironments - examples of two Devonian formations from the Armorican Massif and Acquitaine. Review of Palaeobotany and Palynology 87, 1-14.

Bergman, C.F. 1995. Symmetroprion spatiosus (Hinde), a jawed polychaete showing preference for reef environments in the Silurian of Gotland. Geologiska Foereningens i Stockholm Foerhandlingar 127, 143-150.

Bertrand, R. 1990. Correlations among the reflectances of vitrinite, chitinozoans, graptolites and scolecodonts. Organic Geochemistry 15, 565-574.

Bertrand, R. & Malo, M. 2001. Source rock analysis, thermal maturation and hydrocarbon generation in the Siluro-Devonian rocks of the Gaspe Belt basin, Canada. Bulletin. Canadian Petroleum Geology 49, 238-261.

Clarke, R.B. 1969. Systematics and phylogeny: Annelida, Echiura, Sipuncula. In: Florkin, M. & Scheer, T. (eds) Chemical Zoology IV, Annelida, Echiura, Sipuncula. Academic Press, New York, pp. 1-68.

Colbath, G.K. & Larson, S.K. 1980. On the chemical composition of fossil polychaete jaws. Journal Paleontology 54, 485-488.

Courtinat, B., Crumiere, J.P. & Meon, H. 1990. Upper Cenomanian organoclasts from the Vocontian Basin (France) - Scolecodonts. Geobios 23, 387-397.

Edgar, D.R. 1984. Polychaetes of the lower and middle Paleozoic: a multi-element analysis and phylogenetic outline. 6th International Palynology Conference, Calgary, abstracts, 39.

Erikson, M. 2002. The palaeobiogeography of Silurian ramphoprionid Polychaete annelids. Palaeontology 45, 985-996.

Germeraad, J.H. 1980. Dispersed scolecodonts from Cenozoic strata of Jamaica. Scripta Geologica 54, 1-24.

Goodarzi, F. & Higgins, A.C. 1988. Optical properties of scolecodonts and their use as indicators of thermal maturity. Marine and Petroleum Geology 4, 353-359.

Head, M.J. 1993. Dinoflagellates, sporomorphs and other palynomorphs from the Upper Pliocene St Erth Beds of Cornwall, southwestern England. Journal of Paleontology 67, 1-62.

Jansonius, J. & Craig, J.H. 1971. Scolecodonts: I. Descriptive terminology and revision of systematic nomenclature: II. Lectotypes, new names for homonyms, index of species. Bulletin. Canadian Petroleum Geology 19, 251-302.

Jansonius, J. & McGregor, D.C. (eds) 1996. Palynology, Principles and Applications, vols. 1-3. American Association of Stratigraphic Palynologists Foundation, pp. 337355.

Kielan-Jaworowska, Z. 1966. Polychaete jaw apparatuses from the Ordovician and Silurian of Poland and a comparison with modern forms. Palaeontologia Polonica 16, 1-152.

Nakrem, H.A., Szaniawski, H. & Mork, A. 2001. Permian-Triassic scolecodonts and conodonts from the Svalis Dome, central Barents Sea, Norway. Acta Palaeontologica Polonica 46, 69-86.

Schäfer, W. 1972. Ecology and Palaeoecology of Marine Environments. University of Chicago Press, Chicago.

Szaniawski, H. 1968. Three new polychaete jaw apparatuses from the Upper Permian of Poland. Acta Palaeontologica Polonica 13, 255-280.

Szaniawski, H. 1974. Some Mesozoic scolecodonts congeneric with Recent forms. Acta Palaeontologica Polonica 19, 179-195.

Tasch, P. & Stude, J.R. 1965. A scolecodont natural assemblage from the Kansas Permian. Transaction. Kansas Academy of Science 67, 4.

Traverse, A. 1988. Paleopalynology. Unwin Hyman, Boston.

Underhay, N.K. & Williams, S.H. 1995. Lower Ordovician scolecodonts from the Cow-Head Group, Western Newfoundland. Canadian Journal of Earth Sciences 32, 895-901.

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