Frontal auxiliary impressions in the Ordovician trilobite Dalmanitina Reed, 1905 from the Barrandian area, Czech Republic


Authors: Fatka O Budil P

Published in: Bulletin of Geosciences, volume 96, issue 4; pages: 481 - 491; Received 10 July 2020; Accepted in revised form 11 August 2021; Online 29 August 2021

Keywords: Trilobites, frontal auxiliary impressions, soft-tissue preservation, Letná Formation, Upper Ordovician, Czech Republic,

full text (PDF, 6.34 MB)

Export to RIS



Fossils preserved in Cambrian to Devonian sediments of the Barrandian area (Czech Republic) have contributed significantly to our knowledge of numerous invertebrate groups. With respect to trilobites, important data has been discovered on the construction of eyes, healing of exoskeletal injuries, as well as on the morphology of soft parts. The generally rarely preserved frontal auxiliary impressions (FAIs) on the glabellar surface of trilobites were first described in Devonian examples from this area in the mid-nineteenth century by Barrande. Such impressions have only rarely been documented in a few trilobite species in the Lower Palaeozoic of the Barrandian area. Here we describe twelve exceptionally preserved holaspid cephalic shields of Dalmanitina socialis Barrande, 1846. These specimens are internal moulds and were collected at three localities in the Upper Ordovician Letná Formation. This material documents a high level of variability in the disposition of FAIs within the glabella. However, the FAIs show a common pattern at the anterior glabellar margin and are arranged in two pairs around a medial impression and are also associated with a third pair situated more posterolaterally. This current study is the first to focus on the distribution of FAIs within the Dalmanitidae. Dalmanitina socialis specimens with FAIs from the Letná Formation indicate that the depositional environment at the several localities in that unit was favourable to exceptional preservation. Excellently preserved cephalic shields of Dalmanitina demonstrate the presence of the posterior median impression (pmi) of Eldredge (1972) and enable new terminology to be proposed for other FAIs.


Barrande, J. 1846. Notice préliminaire sur le Systeme silurien et les trilobites de Boheme. 97 pp. Hirschfeld, Leipzig.

Barrande, J. 1852. Systeme silurien du centre de la Boheme. lere partie: Recherches paléontologiques. Vol. 1. Crustacés: Trilobites. 935 pp. Privately published, Prague & Paris.View article

Barrande, J. 1872. Systeme silurien du centre de la Boheme. lere partie: Recherches paléontologiques. Supplément au Vol. I. Trilobites, crustacés divers et poissons. 647 pp. Privately published, Prague & Paris.

Bergström, S.M., Chen, X., Gutiérrez-Marco, J.C. & Dronov, A. 2009. The new chronostratigraphic classification of the Ordovician System and its relations to major regional series and stages and to δ13C chemostratigraphy. Lethaia 42(1), 97-107.View article

Born, A. 1919. Zur Organisation der Trilobiten. I. Das Kopfschild von Chasmops odini Eichw. Senckenbergiana 1(5), 159-171.

Budil, P. & Fatka, O. 2020. Ordovician trilobites with soft-parts in West Gondwana and European peri-Gondwana: a review. Geological Society of London, Special Publication 485.View article

Budil, P., Fatka, O., Kolář, P. & David, M. 2011. Arthrorhachis Hawle & Corda, 1847 (Agnostida) in the Prague Basin (Barrandian area, Czech Republic) revisited. Bulletin of Geosciences 85(4), 707-724.View article

Budil, P., Hörbinger, F. & Mencl, R. 2009. Lower Devonian dalmanitid trilobites of the Prague Basin (Czech Republic). Earth and Environmental Science Transactions of the Royal Society of Edinburgh 99(2), 61-100.View article

Budil, P., Thomas, A.T. & Hörbinger, F. 2008. Exoskeletal architecture, hypostomal morphology and mode of life of Silurian and Lower Devonian dalmanitid trilobites. Bulletin of Geosciences 83(1), 1-10.View article

Carvalho, M.G.P., Edgecombe, G.D. & Smith, L. 2003. New calmoniid Trilobites (Phacopina: Acastoidea) from the Devonian of Bolivia. American Museum Novitates 3407, 1-17.View article

Chatterton, B.D.E. & Ludvigsen, R. 2004. Early Silurian of Anticosti Island, Québec, Canada. Palaeontographica Canadiana 22, 1-264.

Chlupáč, I. 1988. The enigmatic arthropod Duslia from the Ordovician of Czechoslovakia. Palaeontology 31(3), 611-620.

Chlupáč, I. 1999a. Some problematical arthropods from the Upper Ordovician Letná Formation of Bohemia. Journal of the Czech Geological Society 44(1-2), 79-87.

Chlupáč, I. 1999b. Unusual arthropods from the Bohemian Ordovician - a review. Acta Universitatis Carolinae, Geologica 43(1-2), 393-396.

Drage, H.B., Laibl, L. & Budil, P. 2018. Postembryonic development of Dalmanitina, and the evolution of facial suture fusion in Phacopina. Paleobiology 44(4), 638-659.View article

Dunlop, J.A., Altringham, J.D. & Mill, P. 1992. Coupling between the heart and sucking stomach during ingestion in a tarantula. Journal of Experimental Biology 166, 83-93.

Edgecombe, G.D. 1993. Silurian acastacean trilobites of the Americas. Journal of Paleontology 67(4), 535-548.View article

Edgecombe, G.D. 1994. Calmoniid trilobites from the Devonian Fox Bay Formation, Falkland Islands: systematics and biogeography. Bulletin of the New York State Museum and Science Service 481, 55-68.

Edgecombe, G.D. & Fortey, R.A. 2000. Silurian trilobites from the El Carmen Formation, Bolivia. Senckenbergiana lethaea 79(2), 329-355.

Eldredge, N. 1971. Patterns of cephalic musculature in the Phacopina (Trilobita) and their phylogenetic significance. Journal of Paleontology 45(1), 52-67.

Eldredge, N. 1972. Morphology and relationships of Bouleia Kozłowski, 1923 (Trilobita, Calmoniidae). Journal of Paleontology 46(1), 140-151.

Eldredge, N. 1979. Cladism and common sense, 165-198. In Cracraft, J. & Eldredge, N. (eds) Phylogenetic analysis and paleontology. Columbia University Press, New York.View article

Eldredge, N. & Braniša, L. 1980. Calmonid trilobites of the Lower Devonian Scaphiocoelia zone of Bolivia, with remarks on related species. Bulletin of the American Museum of Natural History 165(2), 181-289.

Emmrich, H.F. 1839. De Trilobitis: Dissertatio petrefactologica quam consensu & auctoritate amplissimi philosophorum ordinis in Alma litterarum Universitate Frederica Guildma pro summis in philosophia honoribus. 56 pp. Nietack, Berlin.

Fatka, O., Lerosey-Aubril, R., Budil, P. & Rak, Š. 2013. New examples of fossilised guts in trilobites from the Upper Ordovician Letná Formation (Prague Basin, Czech Republic). Bulletin of Geosciences 88(1), 95-104.View article

Gutiérrez-Marco, J.C., Pereira, S., García-Bellido, D.C. & Rábano, I. 2019. Ordovician trilobites from the Tafilalt Lagerstätte: new data and reappraisal of the Bou Nemrou assemblage. Geological Society of London, Special Publications 485.View article

Hammann, W. 1972. Neue propare Trilobiten aus dem Ordovizium Spaniens. Senckenbergiana lethaea 53(5), 371-381.

Hammann, W. 1974. Phacopina und Cheirurina (Trilobita) aus dem Ordovizium von Spanien. Senckenbergiana lethaea 55(1-5), 1-151.

Harrington, H.J. 1959. General description of Trilobita, 38-117. In Moore, R.C. (ed.) Treatise on invertebrate paleontology. Part O. Arthropoda 1. Geological Society of America & University of Kansas Press, Boulder, Colorado & Lawrence, Kansas.

Havlíček, V. & Marek, L. 1973. Bohemian Ordovician and its international correlation. Časopis pro Mineralogii a Geologii 18(3), 225-232.

Havlíček, V. & Vaněk, J. 1966. The biostratigraphy of the Ordovician of Bohemia. Sborník geologických věd, Paleontologie 8, 7-69.

Havlíček, V. & Vaněk, J. 1990. Ordovician invertebrate communities in black-shale lithofacies (Prague Basin, Czechoslovakia). Věstník Ústředního ústavu geologického 65(4), 223-236.

Henry, J.-L. 1965. Révision de deux Zeliszkellinae (trilobites) des ’schistes a Calymenes’ (Llandeilien) du Massif Armoricain. Bulletin de la Société Géologique de France (Series 7) 6, 139-145.

Henry, J.-L. 1968. Crozonaspis struvei n.g. n.sp., Zeliszkellinae (Trilobita) de l’Ordovicien moyen de Bretagne. Senckenbergiana Lethaea 49(5-6), 367-381.

Henry, J.-L. 1980. Trilobites ordoviciens du Massif Armoricain. Mémoires de la Société Géologique et Minéralogique de Bretagne 22, 1-250.

Henry, J.-L. 1989. Paléoenvironnements et dynamique de faunes de trilobites dans l’Ordovicien (Llanvirn supérieur-Caradoc basal) du Massif Armoricain (France). Palaeogeography, Palaeoclimatology, Palaeoecology 73(1-2), 139-153.

Henry, J.-L. & Morzadec, P. 1968. Sur la présence du sous-genre Phacopidella (Prephacopidella) Destombes, 1963 (trilobite) dans les schistes ordoviciens du Portugual. Compte Rendu Sommaire des Séances de la Société Géologique de France 5, 158-159.

Henry, J.-L., Nion, J., Paris, F. & Thadeu, D. 1974. Chitinozoaires, ostracodes et trilobites de l’Ordovicien du Portugal (serra de Buçaco) et du massif Armoricain: essai de comparaison et signification paléogéographique. Comunicaçoes dos Serviços Geológicos de Portugal 57, 303-345.

Jahn, J.J. 1893. Duslia, eine neue Chitonidegattung aus dem böhmischen Untersilur, nebst einigen Bemerkungen über die Gattung Triopus Barr. Sitzungsberichte der Kaiserlichen Akademie der Wissenschaften 102, 591-603.

Lerosey-Aubril, R., Hegna, T.A. & Olive, S. 2011. Inferring internal anatomy from the trilobite exoskeleton: the relationship between frontal auxiliary impressions and the digestive system. Lethaia 44(2), 166-184.View article

Lerosey-Aubril, R. & Peel, J.S. 2018. Gut evolution in early Cambrian trilobites and the origin of predation on infaunal macroinvertebrates: evidence from muscle scars in Mesolenellus. Palaeontology 61(5), 747-760.View article

Marples, B.J. 1983. Observations on the structure of the fore-gut of spiders. Bulletin of the British Arachnological Society 6(1), 46-52.

Nion, J. & Henry, J.-L. 1966. Phacopidella (Prephacopidella) hupei nov. sp., nouveau trilobite de l’Ordovicien du Finistere. Bulletin de la Société Géologique de France (Series 7) 8, 884-890.

Rak, Š., Ortega-Hernández, J. & Legg, D.A. 2013. A revision of the Late Ordovician marrellomorph arthropod Furca bohemica from Czech Republic. Acta Palaeontologica Polonica 58(3), 615-628.View article

Ramsköld, L. & Edgecombe, G.D.E. 1993. Silurian (Ludlow) acastid trilobites from Gotland and Scania, Sweden. Paläontologische Zeitschrift 67(3), 261-285.View article

Reed, F.R.C. 1905. The classification of the Phacopidae. Geological Magazine 42, 172-178, 224-228.View article

Robardet, M., Henry, J.-L., Nion, J., Paris, F. & Pillet, J. 1972. La Formation du Pont-de-Caen (Caradocien) dans les synclinaux de Domfront et de Sées (Normandie). Annales de la Société Géologique du Nord 92, 117-137.

Richter, R. 1923. Von Bau und Leben der Trilobiten III. Die Beziehung von Glatze und Magen. IV. Die Versteifungen der Schale und daraus hervorgehende Konvergenzen. Palaeontologia Hungarica 1, 77-108.

Šnajdr, M. 1956. Trilobiti drabovských a letenských vrstev českého ordoviku (Trilobites from the Drabov and Letná beds of the Ordovician of Bohemia). Sborník Ústředního ústavu geologického, Oddíl paleontologický 22 (1955), 477-533.

Šnajdr, M. 1982a. Bohemian representatives of the trilobite genera Kloucekia Delo, Phacopidina Bancroft, Sokhretia Hupé and Dalmanitina Reed. Věstník Ústředního ústavu geologického 57(3), 179-182.

Šnajdr, M. 1982b. New trilobites from the Bohdalec Formation (Berounian) in the Barrandian. Věstník Ústředního ústavu geologického 57(4), 227-230.

Šnajdr, M. 1987. New Bohemian Ordovician Dalmanitidae and Calmonidae (Trilobita). Věstník Ústředního ústavu geologického 62(5), 271-277.

Šnajdr, M. 1990. Bohemian trilobites. 265 pp. Czech Geological Survey, Prague.

Vaněk, J. & Vokáč V. 1997. Trilobites of the Bohdalec Formation (Upper Berounian, Ordovician, Prague Basin, Czech Republic). Palaeontologia Bohemiae 3, 20-50.

Wendruff, A.J., Babcock, L.E., Kluessendorf, J. & Mikulic, D.G. 2020. Paleobiology and taphonomy of exceptionally preserved organisms from the Waukesha Biota (Silurian), Wisconsin, USA. Palaeogeography, Palaeoclimatology, Palaeocology 546, art. 109631.View article

Whittington, H.B. & Kelly, S.R.A. 1997. Morphological terms applied to Trilobita, 313-329. In Kaesler, R.L. (ed.) Treatise on invertebrate paleontology, Part O, Arthropoda 1, Trilobita, revised, Volume 1: Introduction, Order Agnostida, Order Redlichiida. Geological Society of America & University of Kansas Press, Boulder, Colorado & Lawrence, Kansas.

Wolfart, R. 1968. Die Trilobiten aus dem Devon Boliviens und ihre Bedeutung für Stratigraphie und Tiergeographie. Beihefte zum Geologischen Jahrbuch 74, 5-201.