DOCSLIB.ORG

Hierarchical Random Walks in Trace Fossils and the Origin of Optimal Search Behavior

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Hierarchical Random Walks in Trace Fossils and the Origin of Optimal Search Behavior Hierarchical random walks in trace fossils and the origin of optimal search behavior David W. Simsa,b,c,1, Andrew M. Reynoldsd, Nicolas E. Humphriesa, Emily J. Southalla, Victoria J. Wearmoutha, Brett Metcalfee, and Richard J. Twitchettf aMarine Biological Association of the United Kingdom, Plymouth PL1 2PB, United Kingdom; bOcean and Earth Science, National Oceanography Centre Southampton, University of Southampton, Waterfront Campus, Southampton SO14 3ZH, United Kingdom; cCentre for Biological Sciences, University of Southampton, Highfield Campus, Southampton SO17 1BJ, United Kingdom; dRothamsted Research, Harpenden, Hertfordshire AL5 2JQ, United Kingdom; eEarth and Climate Cluster, Faculty of Earth and Life Sciences, VU University Amsterdam, 1081 HV, Amsterdam, The Netherlands; and fDepartment of Earth Sciences, The Natural History Museum, London SW7 5BD, United Kingdom Edited by H. Eugene Stanley, Boston University, Boston, MA, and approved June 19, 2014 (received for review April 1, 2014) −μ Efficient searching is crucial for timely location of food and other “walk clusters” with no characteristic scale, such that P(l) ∼ l , resources. Recent studies show that diverse living animals use a with 1 < μ ≤ 3, where l is the move step length between turns and theoretically optimal scale-free random search for sparse resources μ the power-law exponent. Over many iterations, a Lévy walk will known as a Lévy walk, but little is known of the origins and evo- be distributed much further from its starting position than a lution of foraging behavior and the search strategies of extinct Brownian walk of the same length [hence is termed super- organisms. Here, using simulations of self-avoiding trace fossil trails, diffusive (8)], because small-step walk clusters are interspersed we show that randomly introduced strophotaxis (U-turns)—initiated by long “steps” to new locations, with this pattern repeating by obstructions such as self-trail avoidance or innate cueing—leads across all scales. It has been demonstrated that a Lévy walk with to random looping patterns with clustering across increasing scales exponent μ ∼2 is optimal when the search targets are not de- that is consistent with the presence of Lévy walks. This predicts that pleted or rejected once visited but instead may be revisited prof- optimal Lévy searches may emerge from simple behaviors observed itably, either because they replenish overtime or because targets in fossil trails. We then analyzed fossilized trails of benthic marine are distributed patchily (1, 2). Importantly, Lévy searches with ECOLOGY organisms by using a novel path analysis technique and find the first μ ∼2 are optimal for a very broad range of target densities and evidence, to our knowledge, of Lévy-like search strategies in extinct distributions (9). In the very low-density regime, Lévy strategies animals. Our results show that simple search behaviors of extinct remain the optimal solution with the optimal exponent 1 < μopt ≤ 2 animals in heterogeneous environments give rise to hierarchically dependent on specific environmental properties, such as the nested Brownian walk clusters that converge to optimal Lévy pat- degree of spatial landscape heterogeneity or temporal target terns. Primary productivity collapse and large-scale food scarcity revisitability (10, 11). Consequently, optimal Lévy searches result characterizing mass extinctions evident in the fossil record may in more predictable target encounters during foraging in other- have triggered adaptation of optimal Lévy-like searches. The find- wise unpredictable environments (9). Because Lévy walks can SCIENCES ings suggest that Lévy-like behavior has been used by foragers optimize search efficiencies in this way, it is proposed that natural APPLIED PHYSICAL since at least the Eocene but may have a more ancient origin, which selection should have led to adaptations for Lévy walk foraging might explain recent widespread observations of such patterns [the Lévy flight foraging (LFF) hypothesis] (1–3). The apparent among modern taxa. Brownian motion | superdiffusion | scale invariance | climate change Significance How best to search for food in heterogeneous landscapes is he specific pattern of searching movements used by an or- a universal problem facing mobile organisms. Diverse modern ganism to locate food relative to the food’s distribution closely T animals use a random search strategy called a Lévy walk, determines the number of successful encounters (1–3). The evo- composed of many small move steps interspersed by rare long lution of optimal search patterns is predicted because natural steps, which theoretically is optimal for locating sparse resour- selection favors individuals that are best able to find resources ces. Here, we find the first evidence, to our knowledge, that critical to survival (4). It is recognized, however, that the natural extinct animals, in this case 50 My-old sea urchins, used a Lévy- environment is too complex for evolution to produce a behavior like search strategy. Our results are important because they pattern that is optimal across all scales and contexts (5). Rather, indicate Lévy walks likely have an ancient origin and may arise simple rules probably will evolve that, on average, perform well from simple behaviors observed in much older fossil trails. This in their natural environment (5). Such rules are exemplified in foraging strategy may have adapted in response to decreased the different movement modes that tend to characterize behav- food availability after productivity collapse associated with past ior across different spatiotemporal scales. For instance, simple climate change and mass extinctions. deterministic foraging searches, such as Archimedean spirals (6) or area-restricted searching (7), that are driven by sensory and Author contributions: D.W.S., A.M.R., and R.J.T. designed research; D.W.S. and A.M.R. cognitive abilities are efficient where food distributions are known, conceived the research independently and brought their results together in the closing easily detected, or predictable. However, these patterns are in- stages of their work; D.W.S. and R.J.T. planned and led the empirical research; D.W.S., efficient when food resources are sparsely or patchily distributed A.M.R., N.E.H., B.M., and R.J.T. performed research; B.M. and R.J.T. undertook field re- and the forager has incomplete information on resource location; search and specimen tracings; D.W.S., N.E.H., E.J.S., and V.J.W. conducted track and sta- tistical analyses; A.M.R. undertook simulations and MLE modeling; N.E.H. wrote the under these conditions, probabilistic searches such as Lévy walks software for track digitization and for MLE and model selection for track analysis; become advantageous (1–3). N.E.H. contributed new reagents/analytic tools; D.W.S., A.M.R., N.E.H., E.J.S., V.J.W., and Theory predicts that Lévy walk search strategies should be R.J.T. analyzed data; and D.W.S. wrote the paper with contributions from all authors. optimal where food is sparse and distributed unpredictably (1), The authors declare no conflict of interest. whereas Brownian walks are sufficiently efficient for locating This article is a PNAS Direct Submission. abundant prey (2). A Lévy walk search pattern comprises dis- 1To whom correspondence should be addressed. Email: [email protected]. placements (move steps) drawn from a probability distribution This article contains supporting information online at www.pnas.org/lookup/suppl/doi:10. with a heavy power-law tail that results in a fractal pattern of 1073/pnas.1405966111/-/DCSupplemental. www.pnas.org/cgi/doi/10.1073/pnas.1405966111 PNAS Early Edition | 1of6 Downloaded by guest on September 27, 2021 ubiquity of Lévy patterns among extant organisms, including Simulation outputs show that before encountering an obstruc- humans (1–3, 12–18), suggests that searches that approximate tion, the model organism spirals outward, forming an Archimedes them have evolved naturally (3). It has been hypothesized that spiral (Fig. 1A) characteristic of some early fossil traces (6). After behavioral adaptations to changes in environmental resources encountering obstructions, random looping patterns appear (Fig. cue the switching between localized Brownian and Lévy ran- 1A). The presence of starting spirals and, in particular, clusters of dom searching (2, 3, 13) or that sensory interactions with localized “walks” are common in meandering trace fossils, such heterogeneous environments may give rise to Lévy movement as in Cosmorhaphe (Fig. 1B). Our simulation shows that initial patterns (an emergent phenomena) (19); however, the origins spiraling becomes less evident as the number of obstructions of such potential mechanisms remain elusive. increases (Fig. 1C). In the presence of sufficiently numerous The fossilized records of animal movements preserved as trails obstructions, model parameter estimation using maximum likeli- and burrows (trace fossils) are the only direct record of extinct hood estimation (MLE) and Akaike information criteria weights organisms’ behavior and may provide a means to understand the (wAIC) for best-fit model selection (Materials and Methods)favors evolution of search strategies in ancient landscapes, including a power-law over an exponential (Brownian) model as being the during dramatic environmental changes (6, 20, 21). At intervals better model of the step-length distribution, i.e., the distribution of throughout evolutionary history, organisms have faced large-scale distances traveled
Load more

Recommended publications
  • Planispiral Burrows from a Recent Lacustrine Beach, Gander Lake, Newfoundland
    Planispiral Burrows from a Recent Lacustrine Beach, Gander Lake, Newfoundland ROBERT B. M AC NAUGHTON Geological Survey of Canada, 3303 – 33 Street NW, Calgary, Alberta T2L 2A7 Canada; e-mail: [email protected] MacNaughton, Robert B. 2003. Planispiral burrows from a Recent lacustrine beach, Gander Lake Newfoundland. Canadian Field-Naturalist 117(4): 577-581. Simple horizontal, planispiral burrows occur in Recent beach sediments on the south shore of Gander Lake, Newfoundland. The burrows apparently represent deposit feeding, possibly by an arthropod. This occurrence extends the known environ- mental range of such traces into lacustrine settings and illustrates that such behaviour is not exclusive to marine settings. Key Words: ichnology, lacustrine, Recent, palaeoecology, Newfoundland. Ichnology is the study of the physical records of The beach on which the burrows were observed is behaviour, including, for example, tracks, trails, bur- approximately 90 m east of the mouth of Fifteen Mile rows, and borings (Bromley 1990). Studies are under- Brook (Figure 1). At the time of study, the beach was taken both in fossil and Recent contexts (palichnol- approximately 3 m wide by 24 m long. It passed on ogy and neoichnology, respectively). Fossilised traces the landward side into forest-covered glacio-fluvial are referred to as “trace fossils” or “ichnofossils” and sand and gravel (Figure 1), from which it was prob- are classified using Linnean binominal nomenclature. ably, in part, derived (cf., Batterson and Vatcher 1991). Although much ichnological research is focused on the Small driftwood logs were scattered over the beach. fossil record, neoichnology can provide crucial data The beach surface consisted of damp to wet (but not when interpreting ancient behaviours (e.g., Schäfer water-saturated), muddy to silty, fine- to medium- 1972; Chamberlain 1975; Ratcliffe and Fagerstrom grained sand containing local concentrations of finely 1980; Metz 1987).
    [Show full text]
  • The Discovery of a Paleodictyon-Like Trace Fossil from the Late Cambrian Machinchang Formation in Pulau Jemuruk, Langkawi, Malaysia
    Geological Society of Malaysia, Bulletin 46 May 2003; pp. 421-424 The discovery of a Paleodictyon-like trace fossil from the Late Cambrian Machinchang Formation in Pulau Jemuruk, Langkawi, Malaysia MOHD SHAFEEA LEMAN School of Environmental Sciences and Natural Resources, Faculty of Science and Technology Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor Abstract: Closely spaced polygonal Paleodictyon-like trace fossil was recently discovered in Late Cambrian Machinchang Formation at Pulau Jemuruk, Langkawi. Each polygon is bounded by six segments of ridges forming unique hexagonal framework. The Jemuruk fossil has an epi-relief origin, contrary to the hypo-relief burrow Paleodictyon. The Jemuruk trace fossils formed in relatively shallower marine environment compared with other known Paleodictyon. This study shows that the Kinneyia structure found in the same layer originated from these Paleodictyon-like trace fossils. Abstrak: Surihan berbentuk poligon menyerupai Paleodictyon telah ditemui dalam batuan Kambria Akhir Formasi Machinchang di Pulau Jemuruk, Langkawi. Setiap ruang fosil surih ini disempadani enam segmen permatang membentuk kerangka heksagon yang menarik. Fosil Jemuruk berasalan epi-jasatimbul manakala Paleodictyon adalah sejenis korekan hipo-jasatimbul. Fosil surih Jemuruk terbentuk pada sekitaran laut lebih cetek berbanding dengan Paleodictyon yang diketahui. Kajian juga menunjukkan bahawa struktur Kinneyia yang ditemui dalam lapisan yang sarna adalah berasal daripada fosil surih seakan Paleodictyon ini. INTRODUCTION the Tarutao Formation described (later) by Teroaka et al. (1982) from Ko Tarutao in southern Thailand. The later The Machinchang Formation is perhaps the best has a comparatively similar lithological sequence with the described Cambrian rock formation in Malaysia. Despite Machinchang Formation and is a northern extension of the being one of the oldest rock formation in the country, most Machinchang Formation beyond the Malaysia-Thailand of its rocks are neither strongly deformed nor highly border.
    [Show full text]
  • Cambrian Substrate Revolution
    Vol. 10, No. 9 September 2000 INSIDE • Research Grants, p. 12 • Section Meetings Northeastern, p. 16 GSA TODAY Southeastern, p. 18 A Publication of the Geological Society of America • Happy Birthday, NSF, p. 22 The Cambrian Substrate Revolution David J. Bottjer, Department of Earth Sciences, University of Southern California, Los Angeles, CA 90089-0740, [email protected] James W. Hagadorn, Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125, [email protected] Stephen Q. Dornbos, Department of Earth Sciences, University of Southern California, Los Angeles, CA 90089-0740, [email protected] ABSTRACT The broad marine ecological settings prevalent during the late Neo- proterozoic–early Phanerozoic (600–500 Ma) interval of early metazoan body plan origination strongly impacted the subsequent evolution and development of benthic metazoans. Recent work demonstrates that late Neoproterozoic seafloor sediment had well-developed microbial mats and poorly developed, vertically oriented bioturbation, thus producing fairly stable, relatively low water content substrates and a sharp water-sediment interface. Later in the Cambrian, seafloors with microbial mats became increasingly scarce in shallow-marine environments, largely due to the evolution of burrowing organisms with an increasing vertically oriented component to their bioturba- tion. The evolutionary and ecological effects of these substrate changes on Figure 1. Looping and meandering trace fossil Taphrhelminthopsis, made by a large Early Cambrian benthic metazoans, referred to as the bioturbator, on a bedding plane from Lower Cambrian Poleta Formation, White-Inyo Mountains, California. Such traces, consisting of a central trough between lateral ridges, occur in sandstones Cambrian substrate revolution, are deposited in shallow-marine environments.
    [Show full text]
  • 10 Ekdale & Gibert.Indd
    SPANISH JOURNAL OF PALAEONTOLOGY Late Miocene deep-sea trace fossil associations in the Vera Basin, Almería, Southeastern Spain Allan A. EKDALE1* & Jordi M. de GIBERT2 1 Department of Geology and Geophysics, University of Utah, FASB 383, 115 South 1460 East, Salt Lake City, UT 84112- 0102, U.S.A.; [email protected] 2 Deceased (September 23, 2012) * Corresponding author Ekdale, A. & Gibert, J.M. 2014. Late Miocene deep-sea trace fossil associations in the Vera Basin, Almería, Southeastern Spain. [Asociaciones de trazas fósiles marinas profundas del Mioceno superior de la cuenca de Vera, Almería, Sureste de España]. Spanish Journal of Palaeontology, 29 (1), 95-104. Manuscript received 02 May 2013 © Sociedad Española de Paleontología ISSN 2255-0550 Manuscript accepted 12 September 2013 ABSTRACT RESUMEN The Vera Basin in southeastern Spain was a small, tectonically La Cuenca de Vera, en el sureste español, fue un pequeño active depocenter throughout the Miocene. In the early depocentro tectónicamente activo durante todo el Mioceno. Messinian, approximately 7.2 to 6.0 million years ago, A principios del Messiniense, hace aproximadamente 7,2- the basin received hemipelagic marl deposits that were 6,0 millones de años, la cuenca recibió depósitos margosos punctuated by turbidite events. Soles of thin, turbidite sand hemipelágicos, interrumpidos por episodios turbidíticos. beds preserve an abundance of pre-depositional graphoglyptid En la base de los niveles de arenas turbidíticas se conserva (agrichnial) burrows that represent diverse deep-sea una gran cantidad de grafoglíptidos pre-deposicionales ichnocoenoses, including Paleodictyon, Urohelminthoida (agrichnia) que representan diversas icnocenosis de aguas and Helminthorhaphe. Post-depositional feeding burrows, profundas, incluyendo Paleodictyon, Urohelminthoida including Ophiomorpha (created by crustaceans) and y Helminthorhaphe.
    [Show full text]
  • Deep-Sea Trace Fossils in the West Crocker Formation, Sabah (Malaysia), and Their Palaeoenvironmental Significance Mazlan Madon
    Bulletin of the Geological Society of Malaysia, Volume 71, May 2021, pp. 23 - 46 DOI: https://doi.org/10.7186/bgsm71202103 Deep-sea trace fossils in the West Crocker Formation, Sabah (Malaysia), and their palaeoenvironmental significance Mazlan Madon Malaysian Continental Shelf Project, National Security Council, Kuala Lumpur, Malaysia Author email address: [email protected] Abstract: In the “flysch” series of the West Crocker Formation (Eocene–Oligocene), Kota Kinabalu, Sabah, trace fossils are fairly common although not ubiquitous. The trace fossils commonly occur as hypichnial semi- or full-reliefs on the sole of thin turbiditic sandstone beds (mainly Bouma Tc division) in the thinly bedded heterolithic sandstone-mudstone facies interpreted as submarine fan lobe deposits. Their presence in mainly the thinly bedded facies of the fan system suggests preferential production and preservation in the fine-grained “distal” parts of the Crocker submarine fan system. Trace fossil assemblages characteristic of the Nereites ichnofacies indicate sedimentary environments mainly in bathyal to abyssal water depths (>2000 m). This ichnofacies is dominated by horizontal grazing, farming and feeding traces, ranging from solitary to branching tubular burrows (Ophiomorpha, Palaeophycus and Planolites) to meandering trails and tunnels (Nereites, Cosmorhaphe, Helminthopsis), as well as the spiriform burrows Spirophycus. Graphoglyptids are the most diagnostic of the Nereites ichnofacies, produced by sediment grazers and farmers (agrichnia) and often displaying intricate networks of mainly horizontal tunnels preserved as hypichnial semi-reliefs. They include the delicate spiral traces of Spirorhaphe, as well as the enigmatic hexagonal network burrow Paleodictyon. Other ichnogenera include Planolites, Thalassinoides and Ophiomorpha which are facies-crossing and not environment specific.
    [Show full text]
  • A Mixed Assemblage of Deep-Sea and Shelf Trace Fossils from the Lower Cretaceous (Valanginian) Kamchia Formation in the Troyan Region, Central Fore-Balkan, Bulgaria
    Annales Societatis Geologorum Poloniae (2003), vol. 73: 27-34. A MIXED ASSEMBLAGE OF DEEP-SEA AND SHELF TRACE FOSSILS FROM THE LOWER CRETACEOUS (VALANGINIAN) KAMCHIA FORMATION IN THE TROYAN REGION, CENTRAL FORE-BALKAN, BULGARIA Alfred UCHMAJV1 & Platon TCHOUMATCHENCO2, 1 Institute o f Geological Sciences, Jagiellonian University, Oleandry 2a, 30-063 Kraków, Poland, e-mail: fred@ing. uj. edu.pl 2 Geological Institute, Bulgarian Academy o f Sciences, Acad. G. Boncev Str., Bl. 24, 1113 Sofia, Bulgaria, e-mail: platon@lark. vmei. acad. bg Uchman, A. & Tchoumatchenco, P., 2003. A mixed assemblage of deep-sea and shelf trace fossils from the Lower Cretaceous (Valanginian) Kamchia Formation in the Troyan region, central Fore-Balkan, Bulgaria. Annales Societatis Geologorum Poloniae, 73: 27-34. Abstract: Trace fossils collected from the best outcrop of the Kamchia Formation have been analysed. There are thirteen ichnotaxa (Curvolithus simplex, Gyrochorte isp., IHelminthoidichnites tenuis, Multina minima [second occurrence], Palaeophycus tubularis, ?Palaeophycus isp., Phycodes bilix, Phycosiphon incertum, Planolites cf. reinecki, Spongeliomorpha Ichevronensis, Squamodictyon tectiforme, Thalassinoides suevicus, Zoophycos isp.) representing different ethologic, toponomic and preservational types, and produced at different depths in the sediment. The ichnoassemblage contains a mixture of forms typical of flysch (Squamodictyon) and shelf deposits (Cun'olithus, Gyrochorte). Probably, sediments of the Kamchia Formation were deposited in an offshore or deeper basin with storm deposition of sand beds and background marly sedimentation. It is possible that storm currents transported trace makers of the shelf trace fossils to the deeper sea. It is not excluded that the trace maker of Gyrochorte migrated to the deep-sea after the Jurassic.
    [Show full text]
  • Shallow Marine Paleodictyon from the Upper Ordovician Georgian Bay Formation of Southern Ontario
    ATLAN11c GEOLOGY 115 Shallow marine Paleodictyon from the Upper Ordovician Georgian Bay Formation of southern Ontario D.C.A. Stanley and R.K. Pickerill Departmento/Geology, University of New Brunswick, Fredericton, New Brunswick E3B 5A3, Canada Date Received March 1, 1993 Date Accepted April 26, 1993 Two specimens, and a possible third, of the ichnotaxon Paleodictyon are documented from shallow-water marine strata of the Upper Ordovician Georgian Bay Formation of southern Ontario. Its occurrence indicates that previous suggestions of a post-Early Cambrian palaeoenvironmental retreat of Paleodictyon into deeper water require some modification. Instead, the operative migratory process, at least to the Late Ordovician and possibly even longer, was one of expansion and not of retreat. Deux specimens, et possiblement un troisieme, de la trace fossile Paliodictyon sont reconnus dans des strates marines peu profondes de la Formation de Georgian Bay de l'Ordovicien superieur du sud de }'Ontario. Sa presence indique que les suggestions precedentes d'une retraite paleo-environnementale post-Cambrien precoce dePaliodictyon en eaux plus profondes necessitent quelques modifications. A la place, le processus migratoire operatif, au moins jusqu'a l'Ordovicien tardif et possiblement encore plus longtemps, en etait un d'expansion et non de retraite. [Traduit par la redaction] INTRODUCTION but also we demonstrate that its occurrence there suggests Several recent studies in ichnology have demonstrated or that the environmental 'retreat' intimated by Crimes and suggested an environmental shift in the distribution of certain Crossley (199l)and Crimes et al. (1992) is not so straightfor­ marine ichnotaxa throughout their known stratigraphic range. ward as they suggested.
    [Show full text]
  • Sea-Level Dynamics and Palaeoecological Factors Affecting Trace Fossil Distribution in Eocene Turbiditic Deposits (Gorrondatxe Section, N Spain)
    Palaeogeography, Palaeoclimatology, Palaeoecology 285 (2010) 50–65 Contents lists available at ScienceDirect Palaeogeography, Palaeoclimatology, Palaeoecology journal homepage: www.elsevier.com/locate/palaeo Sea-level dynamics and palaeoecological factors affecting trace fossil distribution in Eocene turbiditic deposits (Gorrondatxe section, N Spain) Francisco J. Rodríguez-Tovar a,⁎, Alfred Uchman b, Aitor Payros c, Xabier Orue-Etxebarria c, Estibaliz Apellaniz c, Eustoquio Molina d a Departamento de Estratigrafía y Paleontología, Facultad de Ciencias, Universidad de Granada, 18002 Granada, Spain b Jagiellonian University, Institute of Geological Sciences, Oleandry Str. 2a, PL-30-063 Kraków, Poland c Departamento de Estratigrafía y Paleontología, Facultad de Ciencia y Tecnología, Universidad del País Vasco, E-48080 Bilbao, Spain d Departamento de Ciencias de la Tierra, Universidad de Zaragoza, E-50009 Zaragoza, Spain article info abstract Article history: Ichnological analysis of the upper Ypresian–lower Lutetian interval at the Gorrondatxe section (W Pyrenees, Received 5 January 2009 N Spain), reveals a relationship between sea-level dynamics and the eco-sedimentary factors influencing Received in revised form 8 October 2009 trace fossil assemblages. The 600 m thick section of deep-sea turbiditic deposits contains 41 ichnospecies Accepted 19 October 2009 belonging to 28 ichnogenera, which are typical of the Nereites ichnofacies, and mostly of the Paleodictyon Available online 25 October 2009 ichnosubfacies, suggesting deposition in a basin plain to fan-fringe setting. The trace fossil diversity and abundance fluctuate, irrespective of turbidite frequency. These ichnological features are strongly affected by Keywords: Eocene trophic level changes related partly to sea-level dynamics according to the sequence stratigraphic Turbidites interpretations for the studied section.
    [Show full text]
  • Benkovac Stone (Eocene, Croatia): a Deep-Sea Plattenkalk?
    Swiss J Geosci (2011) 104 (Suppl 1):S159–S166 DOI 10.1007/s00015-011-0051-7 Benkovac Stone (Eocene, Croatia): a deep-sea Plattenkalk? Adolf Seilacher • Erwin Mrinjek Received: 16 January 2010 / Accepted: 9 January 2011 / Published online: 11 February 2011 Ó Swiss Geological Society 2011 Abstract In contrast to Solnhofen-type conservation Institutional abbreviations Lagersta¨tten, the platy limestones of the Benkovac Stone of the Eocene of Croatia contains a variety of trace fossils. GPIT Collection of the Institut fu¨r Geologie und They belong to the Nereites ichnofacies, characterized by a Pala¨ontologie, University of Tu¨bingen (Germany) suite of highly specialized ichnogenera, turbiditic preser- YPM Yale Peabody Museum’s collection, Peabody vation, and distinctive pre-event versus post-event Museum of Natural History, Yale University, communities. In siliciclastic rocks, this ichnofacies stands New Haven (CT, USA) for turbiditic deep-sea sediments. Also unusual is the lack of body fossils. The only exceptions are occasional plant debris and Bencovacina concentrica. n. gen., n. sp., which is affiliated with xenophyophorian Foraminifera. These Introduction giant protozoans survive on present deep-sea bottoms, but they were also common on the shallow-marine biomats in Platy (and partly lithographic) limestones of the Solnhofen Ediacaran times. These findings contradict the current type range among the most famous conservation Lagers- shallow-marine interpretation, which is based on the ta¨tten. Historically, their environmental interpretation has regional geologic setting and sedimentary structures typical changed from tropical beaches to quiet waters below storm for tempestites. Thus, the Benkovac Stone would be an wave base. Today, most experts agree that they formed in ideal place to test the reliability of ichnological versus small basins, which received most sediment from sur- sedimentological depth criteria in an entirely calcareous rounding reefs or carbonate platforms in the form of sequence.
    [Show full text]
  • Deep-Sea Trace Fossils of the Oligocene-Miocene Numidian
    Palaeogeography, Palaeoclimatology, Palaeoecology 414 (2014) 155–177 Contents lists available at ScienceDirect Palaeogeography, Palaeoclimatology, Palaeoecology journal homepage: www.elsevier.com/locate/palaeo Deep-sea trace fossils of the Oligocene–Miocene Numidian Formation, northern Tunisia Sami Riahi a,⁎, Alfred Uchman c, Dorrik Stow b,MohamedSoussia, Kmar Ben Ismail Lattrache a a Université de Tunis El Manar, Faculté des Sciences de Tunis, 11 ES 15, Département de Géologie, 2092, Tunis, Tunisia b Institute of Petroleum Engineering, Heriot-Watt University, Edinburgh EH14 4 AS, Scotland, UK c Institute of Geological Sciences, Jagiellonian University, Oleandry 2a, 30-063 Kraków, Poland article info abstract Article history: Twenty-two ichnogenera and thirty-one ichnospecies have been recorded in the Oligocene–Miocene Numidian Received 19 December 2013 Formation of northern Tunisia. Heterolithic successions of thin-bedded turbidite sandstones and interchannel Received in revised form 5 August 2014 mudstones contain the most diverse trace fossil assemblages. Thick- to very thick-bedded structureless sand- Accepted 9 August 2014 stones and conglomerates representing the fill of channel complexes contain a low-diversity trace fossil assem- Available online 17 August 2014 blage. The ichnoassemblage in the lower part of the formation (Oligocene), which includes Paleodictyon isp., Scolicia strozzii, Spirorhaphe isp., ?Cosmorhaphe isp. and Halopoa isp., can be ascribed to the Paleodictyon Keywords: Ichnofacies ichnosubfacies of the Nereites ichnofacies. The ichnoassemblage in the upper part of the formation (Miocene: Numidian Flysch Aquitanian), including Diplocraterion cf. habichi, Scolicia vertebralis and Ophiomorpha isp., is interpreted as the Deep-water turbidites shallower part of the Ophiomorpha rudis ichnosubfacies of the Nereites ichnofacies. The notable switch in Oligocene–Miocene ichnofauna between the Oligocene and lower Miocene reflects variation in environmental and depositional con- Tunisia ditions.
    [Show full text]
  • Teacher's Guide
    TEACHER’S GUIDE NSIDE PALEONTOLOGY I 20 Chapter 4 Unsolved Mysteries 3 Dear Educator of the Deep RA N 21 Activity 4.1 Creating a Deep Sea Paleodictyon 4 Chapter 1 EXPLO TIO 22 Activity 4.2 Telling Real Life Stories Discover the Mystery of Trace Fossils of the Deep Dark Sea 5 Activity 1.1 The Deep Ocean: A Black Box O MUN CATI N 6 Activity 1.2 Searching for Vents C M I O 7 Activity 1.3 Defing the Deep 23 Chapter 5 8 Student Activity Sheet Get the Scoop on the Deepest Story Ever L GY 24 Activity 5.1 Dr. Lucidus and Dr. Numbus GEO O Activity 5.2 Finding the ‘Write’ Words 8 Chapter 2 Activity 5.3 Drawing the Deep 9 Get the Drift on the 25 Dr. Nimbus and Dr. Lucidus Scripts Mid-Ocean Rift 26 Student Activity Sheet 10 Resource Page 11 Activity 2.1 Puzzling Plates Activity 2.2 Finding the Global Zipper TECHNOLOGY 12 Student Activity Sheet 27 Chapter 6 13 Geology Map Flip the Switch and See What You’ve Been Missing B L GY 28 Activity 6.1 ‘Lights, Camera, Action’ IO O Activity 6.2 Simulate, Calculate, Create… 14 Chapter 3 A New Improved Alvin Who’s Who in the 29 Student Activity Sheet Sunless Deep? 15 Resource Page 30 Writing Prompts 16 Activity 3.1 Cast of Characters: Critter Cards 31 Glossary Activity 3.2 Where to Rent on a Vent 32 National Education Standards 17 Critter Cards 18 Data Cards 19 Rent on a Vent sheet DEAR EDUCATOR Have you ever wondered if there is anything on Earth scientists haven’t explored? The answer sits just two miles beneath the ocean surface: a sunless world that has evolved in ways we never dreamed possi- ble.
    [Show full text]
  • An Updated Classification of Animal Behaviour Preserved in Substrates
    Geodinamica Acta, 2016 Vol. 28, Nos. 1–2, 5–20, http://dx.doi.org/10.1080/09853111.2015.1065306 An updated classification of animal behaviour preserved in substrates Lothar Herbert Vallona* , Andrew Kinney Rindsbergb and Richard Granville Bromleyc aGeomuseum Faxe (Østsjællands Museum), Østervej 2, DK-4640 Faxe, Denmark; bDepartment of Biological & Environmental Sciences, University of West Alabama, Livingston, AL 35470, USA; cRønnevej 97, DK-3720 Aakirkeby, Denmark (Received 9 February 2015; accepted 19 June 2015) During the last few decades, many new ethological categories for trace fossils have been proposed in addition to the original five given by Seilacher. In this article, we review these new groups and present a version of the scheme of fossil animal behaviour originally published by Bromley updated with regard to modern ethological concepts, especially those of Tinbergen. Because some behaviours are more common in certain environments than others, they are useful in palaeoecological reconstructions, forming the original basis of the ichnofacies concept. To simplify, we summarise some ethological categories as previously done by others. However, the tracemaker’s behaviour in some cases is so distinctive that subcategories should be employed, especially in ecological interpretations of certain environments where a special behaviour may be dominant. Keywords: trace fossils; ethological categories; animal behaviour; palaeoecology; ichnology 1. Introduction regard to four aspects: (1) toponomically, according to The classification of fossil animal behaviour is necessary the relationship that the structures have with contrasting to its utilisation in palaeoecology and stratigraphy but substrate materials; (2) biologically, according to their also presents procedural challenges not faced by relationship to their makers; (3) ethologically, according researchers on modern organisms.
    [Show full text]