Healed injury in a nektobenthic trilobite: “Octopus-like” predatory style in Middle Ordovician?

Main Article Content

Oldrich Fatka
Petr Budil
Radek Mikuláš

Abstract

The Lower Paleozoic sediments of the Barrandian area are globally renowned as a classical example of well-preserved skeletal marine fauna, including abundant remains of trilobites. Several tens of morphologically anomalous exoskeletons of trilobites have been collected and documented from Cambrian to Devonian clastic sediments and carbonates. One of them, an exceptionally well preserved, articulated and partly enrolled exoskeleton of the Ordovician nektobenthic trilobite Parabarrandia bohemica (NOVÁK, 1884) exhibits a prominent palaeopathological anomaly in its pygidium. We interpret this anomaly as a healed traumatic injury and attribute this damage to a failed predatory attack. The subsequently healed injury is classified as the ichnogenus Oichnus BROMLEY, 1981. The structure on the pygidium is strongly reminiscent of injuries caused by octopods and a large cephalopod is proposed as a potential durophagous predator responsible for the herein described trilobite injury. However, an attack from an unknown arthropod while the trilobite was in a soft-shelled stage cannot be excluded. 

Downloads

Download data is not yet available.

Article Details

Section
Original Scientific Papers

References

ALPERT, S.P. & MOORE, J.N. (1975): Lower Cambrian trace fossil evidence for predation on trilobites.– Lethaia, 8/3, 223–230. doi: 10.1111/j.1502-3931.1975.tb00926.x

ARNOLD, J.M. & ARNOLD, K.O. (1969): Some aspects of hole-boring predation by Octopus vulgaris.– Am. Zoologist, 9/3, 991–996. doi: 10.1093/icb/9.3.991

AUBRECHTOVÁ, M. (2015): A revision of the Ordovician cephalopod Bactrites sandbergeri Barrande: Systematic position and palaeobiogeography of Bactroceras.– Geobios, 48/3, 193–211. doi: 10.1016/j.geobios.2015.03.002

AUBRECHTOVÁ, M. & TUREK V. (2018): Lituitid cephalopods from the Middle Ordovician of Bohemia and their paleobiogeographic affinities.– Bull. Geosci., 93/3, 401–417. doi: 10.314/bull.geosci.1707

BABCOCK, L.E. (1993): Trilobite malformations and the fossil record of behavioural asymmetry.– J. Paleontol., 67/2, 217–229. doi: 10.1017/S0022336000032145

BABCOCK, L.E. (2003): Trilobites in Paleozoic predator-prey systems, and their role in reorganization of early Paleozoic ecosystems.– In: KELLEY, P., KOWALEWSKI, M. & HANSEN, T.A. (eds.): Predator–Prey Interactions in the Fossil Record. Plenum Publishers, New York, 55–92. doi: 10.1007/978-1-4615-0161-9_4

BABCOCK, L.E. (2007): Role of malformations in elucidating trilobite paleobiology: a historical synthesis.– In: MIKULIC, D.G., LANDING, E. & KLUESSENDORF, J. (eds.): Fabulous Fossils–300 Years of Worldwide Research on Trilobites. New York State Museum, New York, 507, 3–19.

BARRANDE, J. (1846): Notice préliminaire sur le Systême Silurien et les trilobites de Bohême.– C. L. Hirschfeld, libraire, Leipsic, 97 p.

BARRANDE, J. (1867): Systême Silurien du centre de la Bohême. Ser. 1.– Praha and Paris, 712 p.

BARRANDE, J. (1872): Systême Silurien du centre de la Bohême. Supplement I. Trilobites, Crustace`s divers et Poisson.– Praha and Paris, 647 p.

BERTLING, M. (1992): Arachnostega n. ichnog – burrowing traces in internal moulds of boring bivalves (Late Jurassic, Northern Germany).– Paläontol. Z., 66/1–2, 177–185. doi: 10.1007/BF02989487

BERTLING, M., BRADDY, S.J., BROMLEY, R.G., DEMATHIEU, G.R., GENISE, J., MIKULÁŠ, R., NIELSEN, J.K., NIELSEN, K.S.S., RINDSBERG, A.K., SCHLIRF, M. & UCHMAN, A. (2006): Names for trace fossils: a uniform approach.– Lethaia, 39/3, 265–286. doi: 10.1080/00241160600787890

BEYRICH, E. (1845): Über einige böhmische Trilobiten.– G. Reimer, Berlin, 47 p.

BICKNELL, R.D.C., HOLMES, J.D., PATES, S., GARCÍA-BELLIDO, D.C. & PATERSON, J.R. (2022): Cambrian carnage: Trilobite predator-prey interactions in the Emu Bay Shale of South Australia.– Palaeogeogr. Palaeoclimatol. Palaeoecol., 591, 110877. doi: 10.1016/j.palaeo.2022.110877

BICKNELL, R.D.C., PATES, S. & BOTTON, M.L. (2018): Abnormal xiphosurids, with possible application to Cambrian trilobites.– Palaeontol. Electron., 21/2, 1–17. doi: 10.26879/866

BICKNELL, R.D.C., SMITH, P.M., BRUTHANSOVÁ, J. & HOLLAND, B. (2021): Malformed trilobites from the Ordovician and Devonian.– PalZ. doi:10.1007/s12542-021-00572-9

BICKNELL, R.D.C. & PATES, S. (2020): Exploring abnormal Cambrian-aged trilobites in the Smithsonian collection.– PeerJ, 8, e8453. doi: 10.7717/peerj.8453

BICKNELL, R.D.C. & PATERSON, J.R. (2018): Reappraising the early evidence of durophagy and drilling predation in the fossil record: implications for escalation and the Cambrian Explosion.– Biol. Rev., 93/2, 754–784. doi: 10.1111/brv.12365

BICKNELL, R.D.C. & SMITH, P.M. (2021): Teratological trilobites from the Silurian (Wenlock and Ludlow) of Australia.– Sci. Nat., 108, 58. doi: 10.1007/s00114-021-01766-6

BOECK, C.P.B. (1827): Notitser til Laeren om Trilobiterne.– Magazin for Naturvidenskaberne, 1, 11–44.

BOYLE, P.R. & KNOBLOCH, D. (1981): Hole boring of crustacean prey by the octopus Eledone cirrhosa (Mollusca, Cephalopoda).– J. Zool., 193, 1–10. doi: 10.1111/j.1469-7998.1981.tb01486.x

BRADY, S.J. (2001): Eurypterid palaeoecology: palaeobiological, ichnological and comparative evidence for a “mass-moult-mate” hypothesis.– Palaeogeogr. Palaeoclimatol. Palaeoecol., 172, 115–132. doi: 10.1016/S0031-0182(01)00274-7

BRETT, C.E. & WALKER, S.E. (2002): Predators and predation in Paleozoic marine environments.– In: KOWALEWSKI, M. & KELLEY, P.H. (eds.): The Fossil Record of Predation. Spec. Pap. in Paleontol., 8, 93–118.

BROMLEY, R.G. (1981): Concepts in ichnology illustrated by small round holes in shells.– Acta Geol. Hisp., 16, 55–64.

BROMLEY, R.G. (1993): Predation habits of octopus past and present and a new ichnospecies, Oichnus ovalis.– Bull. Geol. Soc. Den., 40/1–2, 167–173.

BRUTHANSOVÁ, J. (2004): Exuviation of selected Bohemian Ordovician trilobites.– Spec. Pap. Palaeont., 70, 293–308.

BRUTHANSOVÁ, J. & BUDIL, P. (2003): Exuviation of the genus Placoparia Hawle et Corda, 1847 (Trilobita, Czech Republic, Prague Basin, Ordovician).– In: ALBANESI, G.L., BERESI, M.S. & PERALTA, S.H. (eds.): Ordovician from the Andes. INSUGEO, Ser. Correlación Geol., 17, 267–269.

BRUTHANSOVÁ, J., FATKA, O., BUDIL, P. & KRÁL, J. (2007): 200 years of trilobite research in the Czech Republic.– In: MIKULIC, D.G., LANDING, E. & KLUESSENDORF, J. (eds.): Fabulous Fossils–300 Years of Worldwide Research on Trilobites. New York State Museum, New York, 507, 51–80.

BUDIL, P., KRAFT, P., KRAFT, J. & FATKA, O. (2007): Faunal associations of the Šárka Formation (Middle Ordovician, Darriwilian, Prague Basin, Czech Republic).– Acta Palaeontol. Sinica, 46/Suppl., 64–70.

BUDIL, P., FATKA, O., RAK, Š. & ZWANZIG, M. (2010): Two unique Middle Ordovician trilobites from the Prague Basin, Czech Republic.– J. National Mus., Nat. Hist., 179/8, 95–104.

CHLUPÁČ, I. (1970): Phyllocarid crustaceans of the Bohemian Ordovician.– Sbor. geol. Věd, Paleontol., 12, 41–75.

CHILDRESS, M.J. & HERRNKIND, W.F. (1997): Den sharing by juvenile Caribbean spiny lobsters (Panulirus argus) in nursery habitat: Cooperation or coincidence?– Mar. Freshwater Res., 48/8, 751–758. doi: 10.1071/MF97158

COLMENAR, J., PEREIRA, S., PIRES, M., DA SILVA, C.M., SÁ, A.A. & YOUNG, T.P. (2017): A Kralodvorian (upper Katian, Upper Ordovician) benthic association from the Ferradosa Formation (central Portugal) and its significance for the redefinition and subdivision of the Kralodvorian Stage.– Bull. Geosci., 92/4, 443–464. doi: 10.3140/bull.geosci.1643

DAVID, M. & BUDIL, P. (2015): Complementary description of the Middle Ordovician trilobite associations at Praha-Vokovice.– Folia Mus. rer. natur. Bohem, occident., Geol. Paleobiol., 49/1–2, 1–7. doi: 10.1515/fbgp-2015-0001

DE BAETS, K., BUDIL, P., FATKA, O. & GEYER, G. (2022): Trilobites as hosts for parasites: from paleopathologies to ethiologies.– In: DE BAETS, K. & HUNTLEY, J.W. (eds.): The Evolution and Fossil Record of Parasitism. Topics in Geobiology, 50, 173–201. doi: 10.1007/978-3-030-52233-9_6

EKDALE, A.A. (1985): Paleoecology of the marine endobenthos.– Palaeogeogr. Palaeoclimatol. Palaeoecol., 50/1, 63–81. doi: 10.1016/S0031-0182(85)80006-7

FATKA, O. & BUDIL, P. (2014): Sheltered gregarious behavior of Middle Ordovician harpetid trilobites.– Palaios, 29/9, 495–500. doi: 10.2110/palo.2013.031

FATKA, O., BUDIL, P. & GRIGAR, L. (2015): A unique case of healed injury in a Cambrian trilobite.– Ann. Paléontol., 101/4, 295–299. doi: 10.1016/j.annpal.2015.10.001

FATKA. O., LEROSEY-AUBRIL, R., BUDIL, P. & RAK, Š. (2013): Fossilised guts in trilobites from the Upper Ordovician Letná Formation (Prague Basin, Czech Republic).– Bull. Geosci., 88/1, 95–104. doi: 10.3140/bull.geosci.1329

FATKA, O., BUDIL, P. & ZICHA, O. (2021): Exoskeletal and eye repair in Dalmanitina socialis (Trilobita): An example of blastemal regeneration in the Ordovician? Int. J. Paleopathol., 34, 113–121. doi: 10.1016/j.ijpp.2021.05.011

FATKA, O. & MERGL, M. (2009): The “microcontinent” Perunica: status and story 15 years after conception. In: BASSETT, M.G. (ed.): Early Palaeozoic Peri-Gondwanan Terranes: New Insights from Tectonics and Biogeography. Geol. Soc. London, Spec. Publ., 325, 65–102. doi:10.1144/SP325.4

FATKA, O., SZABAD, M. & BUDIL, P. (2009): Malformed agnostids from the middle Cambrian Jince Formation of the Příbram–Jince Basin, Czech Republic.– Bull.Geosci., 84/1, 121–126. doi: 10.3140/bull.geosci.1107

FATKA, O. & VODIČKA, J. (in press): Putative Ordovician green alga Krejciella reinterpreted as a tube of hemichordate.– Palaeontol. Electron.

FERNÁNDEZ-ÁLVAREZ, F.Á., MACHORDOM, A., GARCÍA-JIMÉNEZ, R., SALINAS-ZAVALA, C.A. & VILLANUEVA, R. (2018): Predatory flying squids are detritivores during their early planktonic life.– Sci. Rep., 8, 3440. doi: 10.1038/s41598-018-21501-y

FORTEY, R.A. (1985): Pelagic trilobites as an example of deducing the life habits of extinct arthropods.– T. Roy. Soc. Edin-Earth., 76/2–3, 219–230. doi: 10.1017/S0263593300010452

FORTEY, R.A. (2004): The lifestyles of the trilobites.– Am. Sci., 92/5, 446–453. doi: 10.1511/2004.5.446

FORTEY, R.A. & OWENS, R.M. (1987): The Arenig Series in South Wales.– Bull. Brit. Mus. (Nat. Hist.) Geol. Ser., 41/3, 69–307.

FORTEY, R.A. & OWENS, R.M. (1999): Feeding habits in trilobites.– Palaeontology, 42/3, 429–465. doi: 10.1111/1475-4983.00080

GIBB, S., CHATTERTON, B.D.E. & GINGRAS, M.K. (2010): Rusophycus carleyi (James, 1885), trace fossils from the Lower Ordovician of Southern Morocco, and the trilobites that made them.– Ichnos, 17/4, 271–283. doi: 10.1080/10420940.2010.535452

GUTIÉRREZ-MARCO, J.C., SÁ, A.A., GARCÍA-BELLIDO, D.C. & RÁBANO, I. (2017): The Bohemo-Iberian regional chronostratigraphical scale for the Ordovician System and palaeontological correlations within South Gondwana.– Lethaia, 50/2, 258–295. doi: 10.1111/let.12197

HALL, J. (1847): Paleontology of New York, vol. 1. Van Benthuysen, Albany, 338 p.

HARPER, E.M. (2002): Plio-Pleistocene octopod drilling behavior in scallops from Florida.– Palaios, 17/3, 292–295. doi: 10.1669/0883-1351(2002)017<0292:PPODBI>2.0.CO;2

HAVLÍČEK, V. & VANĚK, J. (1966): The biostratigraphy of the Ordovician of Bohemia.– Sbor. geol. Věd, Paleontol., 8, 7–69.

HAVLÍČEK, V. & VANĚK, J. (1990): Ordovician invertebrate communities in black– shale lithofacies (Prague Basin, Czechoslovakia).– Věst. Ústřed. úst. geol., 65/4, 223–236.

HAVLÍČEK, V. & VANĚK, J. (1996): Dobrotivian/Berounian boundary interval in the Prague Basin with a special emphasis on the deepest part of the trough (Ordovician, Czech Republic).– Věst. Ústřed. úst. geol., 71/3, 225–243.

HAWLE, I. & CORDA, A.J.C. (1847): Prodrom einer Monographie der böhmischen Trilobiten.– Abh. K. Böhm. Ges. Wiss., 5, 117–292.

HENNINGSMOEN, G. (1975): Moulting in trilobites.– Fossils and Strata, 4, 179–200.

HENRY, J.-L. (1989): Paléoenvironnements et dynamique de faunes de Trilobites dans l’Ordovicien (Llanvirn Supérieur-Caradoc basal) du Massif Armoricain (France).– Palaeogeogr. Palaeoclimatol. Palaeoecol., 73/1–2, 139–153. doi: 10.1016/0031-0182(89)90049-7

HOLM, G. (1891): Om mynningen Lituites.– Geol. Fören. Stock. För., 13, 736–776. doi: 10.1080/11035899109445850

HORNÝ, R.J. (1996): Grandostoma: An additional bellerophontiform mollusc with circumbilical retractor muscle attachment areas (Gastropoda, Bellerophontoidea).– J. Czech Geol. Soc., 41/3-4, 223–228.

HORNÝ, R.J. (1997a): Shell breakage and repair in explanate bellerophontoidean gastropods from the Middle Ordovician of Bohemia.– Věst. Čes. geol. úst., 72/2, 157–168.

HORNÝ, R.J. (1997b): Shell breakage and repair in Sinuitops neglecta (Mollusca, Tergomya) from the Middle Ordovician of Bohemia.– Čas. Nár. Muz., Ř. přírodověd., 166/1-4, 137–142.

HORNÝ, R.J. (1997c): Ordovician Tergomya and Gastropoda of the Anti-Atlas (Morocco).– Acta Musei Nat. Pragae, Series B, Nat. Hist., 53/3-4, 37–78.

JACOBSEN, A.R. & BROMLEY, R.G. (2009): New ichnotaxa based on tooth impressions on dinosaur and whale bones.– Geol. Q., 53/4, 373–382.

JAGO, J.B. & HAINES, P.W. (2002): Repairs to an injured early middle Cambrian trilobite, Elkedra area, Northern Territory.– Alcheringa, 26/1, 19–21. doi: 10.1080/03115510208619241

KRAFT, J. (1972): Type specimens of fossils in the West-Bohemian Museum in Plzeň and in the Regional Museum of Dr. B. Horák in Rokycany. Part I – Trilobita.– Folia Mus. rer. natur. Bohem, occident., Geol., 1, 1–11.

KRAFT, P., BRUTHANSOVÁ, J. & MIKULÁŠ, R. (2020): Feeding traces related to shells from the Prague Basin, Czech Republic (Tremadocian to early Darriwilian, Ordovician).– Palaeogeogr. Palaeoclimatol. Palaeoecol., 537, 109399. doi: 10.1016/j.palaeo.2019.109399

KRÖGER, B. (2011): Size matters – Analysis of shell repair scars in endocerid cephalopods.– Foss. Rec., 14/2, 109–118. doi: 10.1002/mmng.201100001

LAJBLOVÁ, K. & KRAFT, P. (2014): The earliest ostracods from the Ordovician of the Prague Basin, Czech Republic.– Acta Geol. Pol., 64/4, 367–392. doi: 10.2478/agp-2014-0021

LEFEBVRE, B. (2007): Early Palaeozoic palaeobiogeography and palaeoecology of Stylophoran Echinoderms.– Palaeogeogr. Palaeoclimatol. Palaeoecol., 245/1, 156–199. doi: 10.1016/j.palaeo.2006.02.021

MANDA, Š. (2008): Trocholites Conrad, 1838 (Nautiloidea, Tarphycerida) in the Middle Ordovician of the Prague Basin and its palaeobiogeographical significance.– Bull. Geosci., 83/3, 327–334. doi: 10.3140/bull.geosci.2008.03.327

MAREK, L. (1961): The trilobite family Cyclopygidae Raymond in the Ordovician of Bohemia.– Rozpr. Ústřed. úst. geol., 28, 1–84.

MERGL, M., FATKA, O. & BUDIL, P. (2008): Lower and Middle Ordovician trilobite associations of Perunica: from shoreface endemicity to offshore uniformity (Prague Basin, Czech Republic).– In: RÁBANO, I., GOZALO, R. & GARCÍA-BELLIDO, D. (eds.): Advances in trilobite research. Cuadernos del Museo Geominero, 9, 275–282.

MIKULÁŠ, R. & BUDIL, P. (2013): The ichnofossil Rusophycus cf. cryptolithi Osgood, 1970 as a trace of the trilobite Deanaspis goldfussi (Barrande, 1846) from the Letná Formation (Upper Ordovician, Barrandian area, Czech Republic).– Geosci. Res. Rep. 2012, 192–194.

MIKULÁŠ, R., KADLECOVÁ, E., FEJFAR, O. & DVOŘÁK, Z. (2006): Three new ichnogenera of biting and gnawing traces on reptilian and mammalian bones: a case study from the Miocene of the Czech Republic.– Ichnos, 13/3, 113–127. doi: 10.1080/10420940600850729

MIRONENKO, A.A. (2020): Endocerids: suspension feeding nautiloids?– Hist. Biol., 32/2, 281–289. doi: 10.1080/08912963.2018.1491565

MORAVEC, J.K. (2006): A pathologic pygidium of the Eccoptochile clavigera (Beyrich, 1845) (Trilobita) from the Letná Formation of the Bohemian Ordovician in the Prague Basin (Barrandian).– Geosci. Res. Rep., 2005, 91. [in Czech with English summary]

NETO DE CARVALHO, C. & BAUCON, A. (2016): Giant trilobite burrows and their paleobiological significance (Lower-to-Middle Ordovician from Penha Garcia, Portugal).– Comun. Geol., 103, 71–82.

NIXON, M. (1979): Has Octopus vulgaris a second radula?– J. Zool., 187/3, 291–296. doi: 10.1111/j.1469-7998.1979.tb03370.x

NIXON, M. (1980): The salivary papilla of Octopus as an accessory radula for drilling shells.– J. Zool., 190/1, 53–57. doi: 10.1111/j.1469-7998.1980.tb01422.x

NIXON, M. (1984): Is there external digestion by Octopus?– J. Zool., 202/3, 441–447. doi: 10.1111/j.1469-7998.1984.tb05094.x

NIXON, M. (1988): The feeding mechanisms and diets of cephalopods - Living and fossil.– In: WIEDMANN, J. & KULLMANN, J. (eds.): Cephalopods Present and Past. 2nd International Cephalopod Symposium, E. Schweizerbart’sche Verlagsbuchhandlung, Stuttgart, 642–652.

NIXON, M. & MACONNACHIE, E. (1988): Drilling by Octopus vulgaris (Mollusca: Cephalopoda) in the Mediterranean.– J. Zool., 216/4, 687–716. doi: 10.1111/j.1469-7998.1988.tb02466.x

NOVÁK, O.P. (1884): Studien an Hypostomen Böhmischer Trilobiten Nr. II.– Sitzber. K. Böhm. Ges. Wiss., 212–229.

OWEN, A.W. (1985): Trilobite abnormalities.– T. Roy. Soc. Edin-Earth, 76/2–3, 255–272. doi: 10.1017/S0263593300010488

OWENS, R.M. & SERVAIS, T. (2007): The Ordovician of the Condroz Inlier, Belgium: Trilobites from the southeastern margin of Avalonia.– Palaeogeogr. Palaeoclimatol. Palaeoecol., 245/1-2, 272–294. doi: 10.1016/j.palaeo.2006.02.025

PATES, S. & BICKNELL, R.D.C. (2019): Elongated thoracic spines as potential predatory deterrents in olenelline trilobites from the lower Cambrian of Nevada. Palaeogeogr. Palaeoclimatol. Palaeoecol., 516, 295–306. doi: 10.1016/j.palaeo.2018.12.013

PERNER, J. (1903): Systême Silurien du centre de la Bohême. Gastéropodes 4/1.– Praha and Paris, 164 p.

PERNER, J. (1918): Trilobites of D-d1γ from the surrounding of Prague.– Palaeont. Bohem., 9, 1–55. [in Czech]

PERŠÍN, J. & BUDIL, P. (2009): New observations on Šárka and Dobrotivá Formation (Ordovician, Darriwilian Stage) in northwestern and northern surroundings of Prague.– Český kras, 35, 25–35. [in Czech with English summary]

PIRRONE, C.A., BUATOIS, L. & BROMLEY, R.G. (2014): Ichnotaxobases for Bioerosion Trace Fossils in Bones. J. Paleont., 88/1, 195–203. doi: 10.1666/11-058

POLECHOVÁ, M. (2013): Bivalves from the Middle Ordovician Šárka Formation (Prague Basin, Czech Republic).– Bull. Geosci., 88/2, 427–461. doi: 10.3140/bull.geosci.1426

PRANTL, F. (1948): Malformations in the genus Crotalocephalus Salter.– Rozpr. Čes. akad. věd Um., Tř. II, 57/1, 1–14. [in Czech]

PRANTL, F. (1954): Teratology of the species Harpes venulosus Hawle a Corda.– Čas. Nár. Muz., Ř. přírodověd., 123/1, 121. [in Czech]

PRANTL, F. & PŘIBYL, A. (1954): On the Bohemian representatives of the family Harpetidae (Hawle & Corda).– Rozpr. Ústřed. úst. geol., 18, 1–170 [in Czech with Russian and English summary]

PŘIBYL, A. & VANĚK, J. (1969): Trilobites of the family Trinucleidae Hawle et Corda, 1847 from the Ordovician of Bohemia.– Sbor. geol. Věd, Paleontol., 11, 85–137.

PŘIBYL, A. & VANĚK, J. (1976): Palaeoecology of Berounian trilobites from the Barrandian area (Bohemia, Czechoslovakia).– Rozpr. Českoslov. akad. věd, Ř. matemat. přírod. věd, 86/5, 1–40.

RÁBANO, I. & ARBIZU, M. (1999): Exoskeletal abnormalities in trilobites from Spain.– Rev. Esp. Paleont. vol. extr Homenaje al Prof. J. Truylos, 109–113. [in Spanish]

RÁBANO, I., SÁ, A.A., GUTTIÉREZ-MARCO, J.C. & GARCÍA-BELLIDO, D.C. (2010): Two more Bohemian trilobites from the Ordovician of Portugal and Morocco.– Bull. Geosci., 85/3, 415–424. doi: 10.3140/bull.geosci.1173

RACHEBOEUF, P.R. & CRASQUIN, S. (2010): The Ordovician caryocaridid phyllocarids (Crustacea): Diversity and evolutionary tendencies.– N. Jb. Geol. Paläont., Abh, 257(2), 237–248. doi: 10.1127/0077-7749/2010/0075

RUDKIN, D.M. (1979): Healed injuries in Ogygopsis klotzi (Trilobita) from the Middle Cambrian of British Columbia.– Roy. Ontario Museum, Life Sci. Occasional Pap., 32, 1–8.

RUDKIN, D.M. (1984): Exoskeletal abnormalities in four trilobites.– Can. J. Earth Sci., 22, 479–483.

SALTER, J.W. in MURCHISON R.I. (1859): Siluria. The history of the oldest known rocks containing organic remains, with a brief description of the distribution of gold over the earth. 3rd edn.– London, 592 p.

SCHLOTHEIM, E.F. (1823): Nachträge zur Petrefactenkunde, zweyte Abtheilung.– Becker, Gotha, 114 p.

ŠNAJDR, M. (1956): The trilobites from the Drabov and Letná beds of the Ordovician of Bohemia.– Sbor. Ústřed. úst. geol., odd. paleontol., 22, 477–533. [in Czech with English summary]

ŠNAJDR, M. (1978a): Anomalous carapaces of Bohemian paradoxid trilobites. -Sbor. geol. Věd, Paleontol., 20, 7–31.

ŠNAJDR, M. (1978b): Pathological neoplasms in the fringe of Bohemoharpes (Trilobita). -Věst. Ústř. Úst. geol., 53/4, 301–305.

ŠNAJDR, M. (1979a): Two trinucleid trilobites with repair of traumatic injury.– Věst. Ústřed. úst. geol., 54/1, 49–50.

ŠNAJDR, M. (1979b): Note on the regenerative ability of injured trilobites.– Věst. Ústřed. úst. geol., 54/3, 171–173.

ŠNAJDR, M. (1980): Pathological exoskeletons of two Ordovician trilobites (Czechoslovakia).– Čas. Nár. Muz., Ř. přírodověd., 148/3-4, 173–176. [in Czech with English summary]

ŠNAJDR, M. (1981): Bohemian Proetidae with malformed exoskeletons (Trilobita).– Sbor. geol. Věd, Paleontol., 24, 37–61.

ŠNAJDR, M. (1985): Anomalous exoskeletons of Bohemian encrinurine trilobites.– Věst. Ústřed. úst. geol., 60/5, 303–306.

ŠNAJDR, M. (1990a): Bohemian trilobites.– Czech Geological Survey, Praha, 265 p.

ŠNAJDR, M. (1990b): Five extremely malformed scutelluid pygidia (Styginidae, Trilobita).– Věst. Ústřed. úst. geol., 65/2, 115–118.

SPEYER, S.E. & BRETT, C.E. (1985): Clustered trilobite assemblages in the Middle Devonian Hamilton Group.– Lethaia, 18/2, 85–103. doi: 10.1111/j.1502-3931.1985.tb00688.x

UCHMAN, A. (1999): Ichnology of the Rhenodanubian Flysch (Lower Cretaceous-Eocene) in Austria and Germany.– Beringeria, 25, 67–173.

VERMEIJ, G.J. (2002): Evolution in the consumer age: Predators and the history of life.– In: KOWALEWSKI, M. & KELLEY, P.H. (eds.), The Fossil Record of Predation. Paleontol. Soc., Spec. Pap., 8, 375–394. doi: 10.1017/S1089332600001169

VALLON, L.H., RINDSBERG, A.K. & BROMLEY, R.G. (2016): An updated classification of animal behaviour preserved in substrates.– Geodin. Acta, 28/1–2, 5–20. doi: 10.1080/09853111.2015.1065306

VALLON, L.H., SCHWEIGERT, G., BROMLEY, R.G., RÖPER, M. & EBERT, M. (2015): Ecdysichnia – a new ethological category for trace fossils produced by moulting.– Ann. Soc. Geol. Pol., 85, 433–444. doi:10.14241/asgp.2015.027

VOKÁČ, V. (1996): On some abnormities of trilobite exoskeletons from Central Bohemian Palaeozoikum).– Palaeontol. Bohem., 2, 20–22. [in Czech with English summary]

VOKÁČ, V. & GRIGAR, L. (2010): Occurence of the fossiliferous Ordovician Dobrotivá Formation (Upper Darriwilian to Lower Sandbian?) at Tymákov (western part of the Prague Basin, Barrandian Area, Czech Republic).– Erica, 17, 159–163, [in Czech with English summary]

WHITTINGTON, H.B. & BRIGGS, D.E.G. (1985): The largest Cambrian animal, Anomalocaris, Burgess Shale, British Columbia.– Philos. T. R. Soc. B, 309, 569–609. doi: 10.1098/rstb.1985.0096

WISSHAK, M., KROH, A., BERTLING, M., KNAUST, D., NIELSEN, J.K., JAGT, J.W.M., NEUMANN, C. & NIELSEN, K.S.S. (2015): In defence of an iconic ichnogenus – Oichnus Bromley, 1981.– Ann. Soc. Geol. Pol., 85/3, 445–451.