Is evidence of predation on trilobites common?

[joaoarguello3]

I have a question that came up a few days ago. I was taking a look at some common trilobites on online sales sites (some of the most common trilobites for sale in the genus Elrathia) and came across some specimens that were allegedly attacked by anomalocaris. I have various doubts. How common are trilobite fossils that suffered from predator attacks? Is it possible to know which animal was the one that carried out the attack on the trilobite? Could they be poorly preserved or molted specimens of trilobites?

 

I leave some images of the alleged trilobites that suffered the attacks

[piranha]

There are numerous records of predation on trilobites.

 

However, the evidence strongly suggests that Anomalocaris was only capable of consuming a 'soft-shelled' diet.

 

 

There are few predatory EBS taxa that could have produced the documented injuries to both Redlichia species. Anomalocaris aff. canadensis Whiteaves, 1892 (Daley et al., 2013; Paterson et al., 2020) and Redlichia rex itself (Holmes et al., 2020) are the most likely candidates, especially given their large size. Anomalocaris Whiteaves, 1892 and other radiodonts were traditionally considered predators of Cambrian trilobites (Rudkin, 1979; Briggs and Whittington, 1985; Whittington and Briggs, 1985; Babcock and Robison, 1989; Nedin, 1999); but see Bicknell and Paterson (2018) regarding evidence to the contrary. Although the frontal appendages and oral cone of A. aff. canadensis appear to be capable of grasping and masticating large prey items (Daley et al., 2013; Paterson et al., 2016; fig. 3j, k), it is unlikely that these nonbiomineralised feeding structures (Daley and Bergström, 2012) were strong enough to inflict the damage observed on many of the trilobites documented here, especially the large specimens of R. rex. Furthermore, the gnathobase-like structures of some radiodonts (e.g. Cong et al., 2017, 2018) are unknown in the Emu Bay Shale. While it is possible that A. aff. canadensis may have been able to consume newly moulted, ‘softshelled’ Redlichia individuals, this does not explain the presence of fully calcified Redlichia fragments found within large coprolites from the EBS Konservat-Lagerstätte (Daley et al., 2013); discussed further below.

 

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.
Palaeogeography, Palaeoclimatology, Palaeoecology, 591(110877):1-20

 

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Anomalocaridids are hypothesized to have consumed trilobites. Other than their large size, their midgut glands, and malformed trilobites, there is little direct evidence that they did so. New taphonomic, compositional, and modelling evidence suggests that anomalocaridid mouths were soft, could not close completely or chew, had biting kinematics incompatible with many trilobite malformations, and were well suited to manipulate or suck soft prey. Anomalocaridid mouth plates and their tips are never broken, nor are tips worn. If plates were hard, and were used to manipulate, puncture, crush, or masticate biomineralized prey, they would be expected to show evidence of abrasion or breakage. Absence of this evidence is striking given the frequency (0.01-1%) of healed malformations in extant marine arthropods, most of which are due to prey manipulation or feeding. Moreover, anomalocaridid plates and their biting tips are commonly wrinkled, exhibit preburial shearing and tearing, and mantle or are deformed by biomineralized fossils such as brachiopods, trilobites, and Scenella. Plates are preserved as organic carbon and exhibit fracture patterns typical of desiccating arthropod cuticle. Thus anomalocaridid plates, including their tips, were unmineralized and pliable in life.

 

Computer aided design modelling of the kinematics of mouth opening and closure, together with comparison with muscle movements used by modern circular-mouthed organisms, suggests several plausible models for anomalocaridid mouth movement. These include sphincter-like constricting closure of the circlet of plates, and full- or half-eversion or inversion of the circlet; the latter two movements generate sufficient subambient pressure for suction feeding. In all closure modes, laterally-adjacent opposing plates intersect one another when the mouth closes, which prevents the circlet from closing more than half-way. Orientations of plate tips are consistent with a partial mouth closure model; if full closure was possible, opposing plate tips would not articulate or interlock with one another, as is expected from teeth optimized to masticate or puncture, or teeth which intersect at tooth tips to crush, puncture, or break.

 

Although bilaterally-oriented trilobite malformations can plausibly be explained by a closure of a circular mouth, most trilobite malformations are arc- or U-shaped. Suction-, eversion-, and sphincter-movement of anomalocaridid jaws cannot produce U-shaped bite marks; these are better explained by predators who had opposable jaws or claws. Finite Element Analysis, and modelling of anomalocaridid plates using cuticle yield strengths from modern shrimp (Pandalus) and lobster (Homarus), illustrate that plates could withstand maximum forces of up to 6.2 and 13.0 N, should they have bitten into the thoracic segments of a trilobite. The most commonly malformed Cambrian trilobites had maximum skeletal yield strengths ranging from 3.7–37.1 N, suggesting that only weakly mineralized taxa, such as Elrathia kingii, could have been broken by an anomalocaridid bite.

 

Anomalocaridids may have bitten some soft trilobites, but it is more likely that they were suctorial feeders, perhaps using their preoral appendages to comb soft-bodied invertebrates from the benthos. This feeding strategy makes sense given the recent discovery of multiple rows of inwardly pointing serrated plates inside some anomalocaridids’ oral cavity; these may have prevented prey from exiting the mouth, or may have been part of a buccal cavity or eversible grasping organ.

 

Hagadorn, J.W. 2009
Taking a Bite Out of Anomalocaris. pp. 33-34
Walcott 2009: An International Conference on the Cambrian Explosion. Abstract Volume.

 

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Anomalocaridids have a circular mouth consisting of 32 inwardly-facing pointed plates that cap a plate-studded esophageal area. How these structures functioned or what they were used to eat is not understood. To address these knowledge gaps, we constructed CAD models of an anomalocaridid mouth and twelve possible trilobite ‘prey’, and characterized their response to different biting kinematics and stresses.

 

In life, anomalocaridid mouth plates were connected along their long edges by flexible tissue, and mouth plates, esophageal plates and preoral appendages were composed of unmineralized cuticle. The mouth could close like a sphincter, and its plates could have moved synchronously or moved asynchronously with opening initiated by four large cardinal plates. Whether moving in an inverted, everted, or in-plane position, a rapidly closing anomalocaridid mouth could generate sufficient external pressure change to allow suctorial feeding - yet no anomalocaridid mouth could close more than half-way.

 

To test the hypothesis that anomalocaridids ate trilobites, we conducted finite element analyses of how different biting stresses would deform and cause failure of twelve commonly malformed Cambrian trilobites. A spectrum of trilobite sizes, shapes, thicknesses, and ornamentation were subjected to both horizontal and vertical bite-impact angles, using the known range of anomalocaridid plate tip sizes. Young’s modulus, Poisson’s ratio, and ultimate tensile strength were derived from strain measurements on modern marine arthropod cuticle ranging from freshly molted Callinectes sapidus to well sclerotized claws of Homarus americanus. These cuticle material properties were applied to each possible combination of anomalocaridid biting geometry and trilobite type. In the absence of significant bending stresses, cuticle failure always occured at the locus of bite impact in all trilobites modeled; where bending stresses predominated, failure occurred near the axial furrow. FEA suggests that although tiny or protaspid trilobites could be eaten whole by most anomalocaridids, and some freshly molted trilobites could possibly be deformed by interacting with anomalocaridid mouth plates or preoral appendages, anomalocaridid mouth plates would break before most trilobite thoracic cuticle would fail.

 

Hagadorn, J.W. 2010

Putting Anomalocaris on a Soft-Food Diet?

GSA Denver Annual Meeting - Paper No. 125-1

 

 

Additional References:

 

Alpert, S.P., Moore, J.N. 1975
Lower Cambrian Trace Fossil Evidence for Predation on Trilobites.
Lethaia, 8(3):223-230

 

Babcock, L.E. 2011
Interpreting Early Arthropod Predator-Prey Relationships and Feeding From Body Fossils, Trace Fossils, and Taphonomic Experimentation.
GSA 186241 (20-22 March 2011) Paper No. 2-1

 

Babcock, L.E. 2003
Trilobites in Paleozoic Predator-Prey Systems, and their Role in Reorganization of Early Paleozoic Ecosystems.
Topics in Geobiology, 20:55-92

 

Babcock, L.E., Robison, R.A. 1989
Asymmetry of Predation on Trilobites.
28th International Geological Congress Abstracts

 

Babcock, L.E., Robison, R.A. 1989
Preferences of Palaeozoic Predators.
Nature, 337:695-696

 

Beasecker, J., Brandt, D.S. 2022
Predatory Trilobites: Combining Morphological and Ichnological Data.

Geological Society of America Abstracts with Programs, Joint 56th

Annual North-Central/ 71st Annual Southeastern Section Meeting, 54(4):36-1/373423

 

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.
Palaeogeography, Palaeoclimatology, Palaeoecology, 591(110877):1-20

 

Bicknell, R.D.C., Holmes, J.D., Edgecombe, G.D., Losso, S.R., Ortega-Hernández, J., Wroe, S., Paterson, J.R. 2021

Biomechanical Analyses of Cambrian Euarthropod Limbs Reveal their Effectiveness in Mastication and Durophagy.

Royal Society of London, Proceedings, Series B, 288(20202075):1-8

 

Bicknell, R.D.C., Ledogar, J.A., Wroe, S., Gutzler, B.C., Watson III, W.H., Paterson, J.R.B 2018

Computational iomechanical Analyses Demonstrate Similar Shell-Crushing Abilities in Modern and Ancient Arthropods.

Royal Society of London, Proceedings Series B, 285(20181935):1-8

 

Bicknell, R.D.C., Paterson, J.R. 2018
South Australian Cambrian trilobite injuries: A New Approach to Explore the Early Evolution of Predation and Lateralisation.

International Conference on Ediacaran and Cambrian Sciences. 12th-16th August 2018, Xi'an, pp. 60-61

 

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.

Biological Reviews, 93(2):754-784

 

Bicknell, R.D.C., Pates, S., Botton, M.L. 2018

Abnormal Xiphosurids, With Possible Application to Cambrian Trilobites.

Palaeontologia Electronica, 21(2-19A):1-17

 

Bicknell, R.D., Paterson, J.R., Hopkins, M.J. 2019
A Trilobite Cluster from the Silurian Rochester Shale of New York: Predation Patterns and Possible Defensive Behavior.
American Museum of Natural History, Novitates, 3937:1-16

 

Birkenmajer, K. 1977
Trace Fossil Evidence for Predation on Trilobites from Lower Cambrian of South Spitsbergen.
Norsk Polarinstitutt Årbok, 1976:187-194

 

Brandt, D.S. 2011
Trilobites as Predators: Melding the Morphological and Ichnological Data.

GSA 185009 (20-22 March 2011) Paper No. 2-2

 

Brandt, D.S. 2013
Ichnologic Evidence for Predatory Trilobites:  How Literally Can We Read the Record?
GSA 218616 (North-Central Section - 47th Annual Meeting 2-3 May 2013) Paper No. 27-4

 

Briggs, D.E.G., Whittington, H.B. 1985

Terror of the Trilobites.

American Museum of Natural History Magazine, 94(12):34-39

 

Capasso, L., Caramiello, S. 1996
A Healed Injury in a Cambrian Trilobite.
Journal of Paleopathology, 8(3):181-184

 

Conway Morris, S., Jenkins, R.J.F. 1985
Healed Injuries in Early Cambrian Trilobites from South Australia.
Alcheringa, 9(3):167-17

 

Daley, A.C., Paterson, J.R., Edgecombe, G.D., García-Bellido, D.C., Jago, J.B. 2013
New Anatomical Information on Anomalocaris from the Cambrian Emu Bay Shale of

South Australia and a Reassessment of its Inferred Predatory Habits.

Palaeontology, 56(5):971-990

 

Eaton, K.J. 2019
Lethal and Sublethal Predation on Cambrian Trilobites from North America.
BSc Thesis, Ohio State University, 24 pp.

 

Eaton, K.J., Babcock, L.E. 2019
Patterns of Lethal and Sublethal Predation on Cambrian Stage 3-Drumian Stage Trilobites from the Great Basin, USA.
North American Paleontological Convention, Abstracts & Posters

 

Fatka, O., Budil, P., Grigar, L. 2015
A Unique Case of Healed Injury in a Cambrian Trilobite.
[Un Cas Unique de Blessure Vicatrisée Chez un Trilobite Cambrien.]
Annales de Paléontologie, 101(4):295-299

 

Fatka, O., Budil, P., Mikuláš, R., Micka, V., Szabad, M., Vokáč, V., Laibl, L., Grigar, L. 2012
Evidence of Lethal Durophagous Predation in Cambrian Conocoryphid Trilobites from the Barrandian area (Czech Republic). p. 26
In: 13th Czech-Slovak-Polish Palaeontological Conference. Book of contributions. October, 18th–19th, 2012. Masarykova Univerzita.

 

Fatka, O., Budil, P., Mikuláš, R., Micka, V., Szabad, M., Vokáč, V., Laibl, L., Grigar, L. 2012
Evidence of Predation in Cambrian Trilobites from the Barrandian Area (Czech Republic).
Terra Nostra (Bonn) 2012-3:53

 

Fatka, O., Budil, P., Mikuláš, R. 2022
Healed Injury in a Nektobenthic Trilobite: “Octopus-like” Predatory Style in Middle Ordovician?

Geologia Croatica, 75(2):189-198

 

Fatka, O., Budil, P., Mikuláš, R., Zicha, O. 2022.

Healed Injuries in Two Ordovician Trilobites.

21st Slovak-Czech-Polish Paleontological Conference, 21:121-122

 

Hagadorn, J.W. 2009
Taking a Bite Out of Anomalocaris. pp. 33-34
Walcott 2009: An International Conference on the Cambrian Explosion. Abstract Volume.

 

Hagadorn, J.W. 2010

Putting Anomalocaris on a Soft-Food Diet?

GSA Denver Annual Meeting - Paper No. 125-1

 

Hughes, H.E., Thomas, A.T. 2017
Taphonomy and Predation of Dalmanites in the Wenlock of Shropshire.
Abstracts: 6th International Conference on Trilobites and their Relatives, Tallinn, Estonia

 

Jensen, S. 1990
Predation by Early Cambrian Trilobites on Infaunal Worms; Evidence from the Swedish Mickwitzia Sandstone.
Lethaia, 23(1):29-42  

 

Koppka, J. 2016
Regenerierte Schalenverletzungen bei Flexicalymene retrorsa aus dem Ordovizium von Ohio, USA.
[Healed Shell Injuries of Flexicalymene retrorsa from the Ordovician of Ohio, USA.]
3rd German Conference on Trilobites. [Berlin, October, 8th and 9th 2016]. Abstracts of Lectures.

 

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

 

Mcmenamin, M.A.S. 2003
Origin and Early Evolution of Predators.
Topics in Geobiology, 20:379-400

 

McMenamin, M.A.S. 2012
Cambrian Cannibals: Agnostid Trilobites and the Earliest Known Case of Arthropod Cannibalism.
21st Century Science, Spring-Summer 2012:67-70

 

Mikuláš, R., Fatka, O., Szabad, M. 2010
Substrate as a Test of Behaviour and as the Ichnotaxonomical Problem: Predation and Scavenging Traces on Trilobite Exoskeletons, Middle Cambrian, Czech Republic. pp. 39-40 In: IV Workshop on Ichnotaxonomy. Russian Academy of Sciences, Geological Institute, Borissak Paleontological Institute

 

Nedin, C. 1997
Anomalocaris Predation on Mineralized and Non-Mineralized Trilobites from the Early Cambrian Emu Bay Shale, South Australia.
2nd International Trilobite Conference (Brock University, St. Catharines, Ontario, August 22-24, 1997) Abstracts Volume.

 

Nedin, C. 1999
Anomalocaris Predation on Nonmineralized and Mineralized Trilobites.

Geology, 27(11):987-990

 

Owen, A.W. 1985
Trilobite Abnormalities. 
Transactions of the Royal Society of Edinburgh: Earth Sciences, 76:255-272

 

Pates, S., Bicknell, R.D.C., Daley, A.C., Zamora, S. 2017

Quantitative Analysis of Repaired and Unrepaired Damage to Trilobites from the Cambrian (Stage 4, Drumian) Iberian Chains, NE Spain.

Palaios, 32(12):750-761

 

Pratt, B.R. 1997
Broken Upper Cambrian Trilobite Exoskeletons: Indicator of the Ravages and Extinction of a Soft-Bodied Predator in Deep Water.
2nd International Trilobite Conference (Brock University, St. Catharines, Ontario, August 22-24, 1997) Abstracts Volume.

 

Pratt, B.R. 1993
Whither the Burgess Shale fauna? Its Extinction at the Marjuman-Steptoean

Boundary (Early Late Cambrian) Suggested by Patterns of Trilobite Predation.
GSA Abstracts with Programs, 25(6):458

 

Pratt, B.R. 1998
Probable Predation on Upper Cambrian Trilobites and its Relevance for the Extinction of Soft-Bodied Burgess Shale-Type Animals.
Lethaia, 31(1):73-88

 

Rudkin, D.M. 1979
Healed Injuries in Ogygopsis klotzi (Trilobita) from the Middle Cambrian of British Columbia.
Royal Ontario Museum, Life Sciences Occasional Paper, 32:1-8

 

Rudkin, D.M. 1985
Exoskeletal Abnormalities in Four Trilobites. 
Canadian Journal of Earth Sciences, 22(3):479-483

 

Rustán, J.J., Balseiro, D., Waisfeld, B., Foglia, R.D.; Vaccari, N.E. 2011
Infaunal Molting in Trilobita and Escalatory Responses Against Predation.

Geology, 39(5):495-498

 

Selly, T., Huntley, J.W., Shelton, K.L., Schiffbauer, J.D. 2015
Caught in the Act: Ichnofossil Record of Selective Predation by Cambrian Trilobites.
GSA 262553 (Annual Meeting in Baltimore, Maryland, USA 1-4 November 2015) Paper No. 20-12

 

Selly, T., Huntley, J.W., Shelton, K.L., Schiffbauer, J.D. 2016
Ichnofossil Record of Selective Predation by Cambrian Trilobites.
Palaeogeography, Palaeoclimatology, Palaeoecology, 444:28-38

 

Tarhan, L.G., Jensen, S., Droser, M.L. 2012
Furrows and Firmgrounds: Evidence for Predation and Implications for Palaeozoic

Substrate Evolution in Rusophycus Burrows from the Silurian of New York.
Lethaia, 45(3):329-341

 

Vinn, O. 2018
Traces of Predation in the Cambrian.
Historical Biology, 30(8):1043-1049

 

Vorwald, G.R. 1982
Healed Injuries in Trilobites—Evidence for a Large Cambrian Predator.
Geological Society of America Abstracts with Programs 14:639

 

Zacaï, A., Vannier, J., Lerosey-Aubril, R. 2016

Reconstructing the Diet of a 505-Million-Year-Old Arthropod: Sidneyia inexpectans from the Burgess Shale Fauna.

Arthropod Structure & Development, 45(2):200-220

 

Zamora, S., Mayoral, E., Esteve, J., Gámez-Vintaned, J.A., Santos, A. 2011

Exoskeletal Abnormalities in Paradoxidid Trilobites from the Cambrian of Spain, and a New Type of Bite Trace.

Czech Geological Survey, Bulletin of Geosciences, 86(3):665-673

 

Zhu, M.Y., Vannier, J., Van Iten, H., Zhao, Y.L. 2004
Direct Evidence for Predation on Trilobites in the Cambrian.
Royal Society of London, Proceedings, Series B, 271(Supp.5 to Issue 1):277-280

[piranha]

Listed below is a summary of published examples of possible durophagous injuries on Cambrian trilobites and agnostoids.

*Information about the possible predator or other reason for the injury taken from the original publication when mentioned.

 

 

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.

Biological Reviews, 93(2):754-784  PDF LINK