Recent publications (9)

Männik, R. 2024. Siluri ajastu Lau sündmuse mõju mikrofossiilidele Bebirva 111 puuraugus Leedus [Bakalaureusetöö. Juhendajad: O. Hints ja T. Meidla]. 1-54. PDF
Tonarová, P., Suttner, T., Hints, O., Liang, Y., Zemek, M., Kubajko, M., Zikmund, T., Kaiser, J., Kido, E. 2024. Late Ordovician scolecodonts and chitinozoans from the Pin Valley in Spiti, Himachal Pradesh, northern India. Acta Palaeontologica Polonica, 69 (2), 199-215. PDF
Gueriau, P., Parry, L. A., Rabet, N. 2023. Gilsonicaris from the Lower Devonian Hunsrück slate is a eunicidan annelid and not the oldest crown anostracan crustacean. Biology Letters, 19 (8), . PDF
Hints, O., Ainsaar, L., Lepland, A., Liiv, M., Männik, P., Meidla, T., Nõlvak, J., Radzevičius, S. 2023. Paired carbon isotope chemostratigraphy across the Ordovician–Silurian boundary in central East Baltic: Regional and global signatures. Palaeogeography, Palaeoclimatology, Palaeoecology, 624, 1-17.
Hints, O., Tonarová, P. 2023. A diverse Hirnantian scolecodont assemblage from northern Estonia and resilience of polychaetes to the end-Ordovician mass extinction. Estonian Journal of Earth Sciences, 72 (1), 46-49. PDF
Tonarová, P., Suttner, T. J., Kubajko, M., Hints, O. 2023. Late Ordovician jawed polychaete fauna from the Spiti Valley, northern India. Estonian Journal of Earth Sciences, 72 (1), 160-160. PDF
Tonarová, P., Vodrážková, S., Hints, O., Nõlvak, J., Kubajko, M., Čáp, P. 2023. Latest Ordovician jawed polychaetes, chitinozoans and depositional environments of the Levín section, Prague Basin, Czech Republic. Geobios, 81, 179-198.
Bek, J., Štorch, P., Tonarová, P., Libertín, M. 2022. Early Silurian (mid-Sheinwoodian) palynomorphs from the Loděnice-Špičatý vrch, Prague Basin, Czech Republic. Bulletin of Geosciences, 97 (3), 385-396. PDF
Shcherbakov, D. E., Tzetlin, A. B., Zhuravlev, A. Y. 2022. Boreognathus pogorevichi, a remarkable new polychaete annelid from the lower Permian of the Pechora Basin, Russia. Papers in Palaeontology, 8 (5), e1461.

About scolecodonts

Scolecodonts (worm jaws in Latin) are tiny jaws of polychaete annelids of the order Eunicida - a diverse and abundant group of worms which has been inhabiting different marine environments in the past 500 Million years.

Some examples of scolecodonts from the Ordovician and Silurian of Baltic region.

Composed of highly resistant organic substance, the scolecodonts are frequently found as fossils from the rocks as old as the late Cambrian. Since the worms themselves were soft-bodied and hence extreamly rarely preserved in the fossil record, their jaws constitute the main evidence of polychaetes in the geological past, and the only way to restore the evolution of this important group of animals. Small size of scolecodonts, usually less than 1 mm, puts them into a microfossil category. They are common by-product of conodont, chitinozoan and acritarch samples, but sometimes they occur in the sediments where other fossils are very rare or absent.

In fact, the scolecodonts derive from rather complex jaw apparatuses consisting of numerous differently shaped, usually paired elements. Occassionally, if right collecting techniques are employed, entirely preserved jaw apparatuses can be found. Usually, however, indirect methods need to be used to reconstruct different individual jaws back into jaw apparatuses representing particular (natural) genera and species. In the early stage of scolecodont research, every single jaw was taken as a separate species with its own binominal name. This made artificially the number of taxa very large and caused high demand of large-scale revisions by later students.

jaw apparatuses
Five types of jaw apparatuses. See Kielan-Jaworowska (1966) and Szaniawski (1996) for further details.

Fossil scolecodonts are rather poorly studied - that's because of common belief of hopelessly confusing taxonomy and, on the other hand, rather slow evolution and strong facies dependance which makes the jaw-bearing polychaetes them less attractive for biostratigraphy. Currently there are only some five persons with noteworthy experience in fossil scolecodont research, and even less who are actively publishing on the subject.