Exoskeletal structures and ultrastructures in Lower Devonian dalmanitid trilobites of the Prague Basin (Czech Republic)


Authors: Budil P, Hörbinger F

Published in: Bulletin of Geosciences, volume 82, issue 1; pages: 27 - 36; Received 17 January 2007; Accepted in revised form 7 March 2007;

Keywords: Trilobita, Dalmanitidae, exoskeleton microstructure,

full text (PDF, 0.65 MB)

Export to RIS



Our current studies of the exoskeletal structures and ultrastructures in Lower Devonian dalmanitid trilobites of the Prague Basin are briefly described and discussed. The interior of the exoskeleton in most specimens from the Prague Basin is recrystallised and largely filled with very fine homogeneous sparitic cement. The ultrastructures sensu stricto, e.g., the lamination, layers forming the exoskeleton, and the fine pores or “Osmólska” cavities, are mostly imperceptible even at higher magnifications. However, ultrastructural relics were observed in some polished thin sections and exoskeletal fragments using electron microscopy. Larger structures, especially the eyes, the megapores penetrating the exoskeleton, and the surface sculptures (prosopon sensu Gill 1949), are relatively well preserved and show very fine details. The biological significance of megapores is briefly discussed. Modification of the inner parts of the exoskeletons by diagenetic processes, obscuring most of the fine internal structures, is evident.


Barrande, J. 1846. Notice préliminaire sur Systeme Silurien et les trilobites de Boheme. 96 pp. Leipzig.

Barrande, J. 1852. Systeme Silurien du centre de la Boheme. Iere partie. Recherches paléontologiques. I. Trilobites. 935 pp. Praha and Paris.

Brongniart, A. 1822. Les trilobites, 1–65. In Brongniart, A. & Desmarest, A.G. (eds) Histoire naturelle des crustacés fossiles: Les trilobites. Paris.

Bruton, D. & Haas, W. 2003. The puzzling eye of Phacops. Special Papers in Palaeontology 70, 349–361.

Budil, P., Hörbinger, F. & Menzel, R. S 2008. Lower Devonian dalmanitid trilobites of the Prague Basin (Czech Republic). Transactions of the Royal Society of Edinburgh. 99, 61-100.View article

Campbell, K.S.W. 1967. Henryhouse trilobites. Bulletin of Oklahoma Geological Survey 115, 1–68.

Campbell, K.S.W. 1975. The functional anatomy of phacopid trilobites: musculature and eyes. Journal and Proceedings, Royal Society of New South Wales 108, 168–188.

Campbell, K.S.W. 1977. Trilobites of the Haragan, Bois d’Arc and Frisco Formations (Early Devonian), Arbuckle Mountains region, Oklahoma. Bulletin of the Oklahoma Geological Survey 123, 1–139.

Chlupáč, I. 1977. The phacopid trilobites from the Silurian and Devonian of Czechoslovakia. Rozpravy Ústředního ústavu geologického 43, 1–172.

Clarkson, E.N.K. 1967. Fine structure of the eye in two species of Phacops (Trilobita). Palaeontology 10, 603–616.

Clarkson, E.N.K. 1968. Structure of the eye of Crozonaspis struvei (Trilobita, Dalmanitidae, Zeliszkellinae). Senckenbergiana Lethaea 49, 367–381.

Clarkson, E.N.K. 1969. On the schizochroal eyes of three species of Reedops (Trilobita: Phacopidae) from the Lower Devonian of Bohemia. Transactions of the Royal Society of Edinburgh 68(8), 183–205.

Clarkson, E.N.K. 1971. On the early schizochroal eyes of Ormathops (Trilobita, Zeliszkellinae). Mémoires du Bureau de recherches géologiques et minieres 73, 51–63.

Clarkson, E.N.K. & Levi-Setti, R. 1975. Trilobite eyes and the optics of Des Cartes and Hughes. Nature 254(5502), 663–667.View article

Dalingwater, J.E. 1973. Trilobite cuticle microstructure and composition. Palaeontology 16, 827–839.

Dalingwater, J.E. & Miller, J. 1977. The laminae and cuticular organization of the trilobite Asaphus raniceps. Palaeontology 20, 21–32.

Dalingwater, J.E., Hutchinson, S.J., Mutvei, H. & Siveter, D.J. 1991. Cuticular ultrastructure of the trilobite Ellipsocephalus polytomus from the Middle Cambrian of Öland, Sweden. Palaeontology 34, 205–217.

Dalingwater, J.E., Hutchinson, S.J., Mutvei, H. & Siveter, D.J. 1993. Cuticular ultrastructure of some Silurian calymenid trilobites from the Welsh Borderland and Gotland. Palaeontographica, Abteilung A 229, 37–49.

Dalman, J.W. 1826. Om palaeaderna, eller de sa kallade trilobiterna. Konliga Svenska Vetenskaps-Akademiens Handlingar 1826, 113–294.

Delo, D.M. 1935. A revision of the phacopid trilobites. Journal of Paleontology 9(5), 402–420.

Fortey, R. & Owens, R. 1999. The trilobite exoskeleton, 538–562. In Savazzi, E. Functional Morphology of the Invertebrate Skeleton. John Wiley and Sons Ltd., London.

Fortey, R.A. & Wilmot, N.V. 1991. Trilobite cuticle thickness in relation to palaeoenvironment. Paläeontologische Zeitschrift 65, 141–151.

Gill, E.D. 1949. Prosopon, a term proposed to replace the biologically erroneous term ornament. Journal of Paleontology 23, 572.

Hawle, I. & Corda, A.J.C. 1847. Prodrom einer Monographie der Böhmischen Trilobiten. 176 pp. Praha.

Horváth, G. & Clarkson, E.N.K. 1993. Computation Reconstruction of the Probable Change of Form of the Corneal Lens and Maturation of Optics in the Post-ecdysial Development of the Schizochroal Eye of the Devonian Trilobite Phacops rana milleri Stewart 1827. Journal of Theoretical Biology 160(3), 271–405.View article

Kácha, P. & Petr, V. 1995. Camouflage and mimicry in fossils, I.: General part. Acta Musei nationalis Pragae, Series B – historia naturalis 51(1–4), 53–82.

Kaesler, R.L. 1997. Ed. Treatise on Invertebrate Paleontology, Part O, Arthropoda 1 Trilobita. 535 pp. Geological Society of America, University of Kansas Press, Lawrence, Boulder.

Kasan, D. 1997. Variabilita tuberkulace trilobitů podrodu Phacops (Boeckops) Chlupáč, 1971 a rodu Chotecops Chlupáč, 1971 devonu Barrandienu. 72 pp. Master thesis, Charles University, Praha.

Levi-Setti, R. 1993. Trilobites. Second edition. 342 pp. The University of Chicago Press, Chicago.

Lieberman, B.S. & Kloc, G.J. 1997 Evolutionary and biogeographic patterns in the Asteropyginae (Trilobita, Devonian) Delo, 1935. Bulletin of the American Museum of Natural History 232, 1–127.

Lindström, G. 1901. Researches on the visual organs of the trilobites. Konliga Svenska Vetenskaps-Akademiens Handlingar 34(8), 1–86.

Meslinger, K. 1987. Fine structure of scorpion trichobothria (Arachnida, Scorpiones). Zoomorphology 107, 49–57.View article

McAllister, J.E. & Brand, U. 1989. Primary and diagenetic microstructures in trilobites. Lethaia 22, 101–111.View article

Miller, J. 1976. The sensory fields and life mode of Phacops rana (Green, 1832) (Trilobita). Transactions of the Royal Society of Edinburgh 69(16), 337–367.

Miller, J. & Clarkson, E.N.K. 1980. The postecdysial development of the cuticle and the eye of the Devonian trilobite Phacops rana milleri Stewart 1927. Philosophical Transactions of the Royal Society of London, Series B 288, 461–480.View article

Mutvei, H. 1981. Exoskeletal structure in the Ordovician trilobite Flexicalymene. Lethaia 14, 225–234.View article

Osmólska, H. 1975. Fine morphological characters of some Upper Palaeozoic trilobites. Fossils and Strata 4, 201–207.

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

Richter, R. & Richter, E. 1925. Unterlagen zum Fossilium Catalogus. Trilobitae III. Senckenbergiana 7(6), 239–244.

Šnajdr, M. 1980. Bohemian Silurian and Devonian Proetidae (Trilobita). Rozpravy Ústředního ústavu geologického 45, 1–324.

Šnajdr, M. 1985. Bohemian representatives of the subfamily Odontochilinae subf. nov. Věstník Ústředního Ústavu geologického 60, 165–169.

Šnajdr, M. 1987. Bohemian Lower Devonian Odontochilinae (Trilobita). Sborník geologických věd, Paleontologie 28, 9–60.

Stormer, L. 1930. Scandinavian Trinucleidae: With special references to Norwegian species and varieties. Skrifter Utgitt av Der Norsk Geologisk Tidsskrift 19, 143–274.

Stormer, L. 1980. Sculpture and microstructure of the exoskeleton in chasmopid and phacopid trilobites. Palaeontology 23, 237–271.

Teigler, D.J. & Towe, K.M. 1975. Microstructure and composition of the trilobite exoskeleton. Fossils and Strata 4, 137–149.

Wilmot, N.V. 1990a. Cuticular structure of the agnostine trilobite Homagnostus obesus. Lethaia 23, 87–92.View article

Wilmot, N.V. 1990b. Primary and diagenetic microstructures in trilobite exoskeletons. Historical Biology 4, 51–65.View article

Wilmot, N.V. & Fallick, A.E. 1989. Original mineralogy of trilobite exoskeletons. Palaeontology 32, 297–304.

Whiteley, T.E., Kloc, G.J. & Brett, C.E. 2002. Trilobites of New York. 202 pp. Cornell University Press, Ithaca.

Zenker, J.C. 1833. Beiträge zur Naturgesichte der Urwelt. Organische Reste (Petrefacten) aus der Altenbruger Braunkohlen-Formation, dem Blankenburger Quadersandstein, Jenaischen bunten Sandstein und Böhmischen Uebergangsgebirge. 67 pp. Jena.