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Trace fossil assemblages and lacustrine sequence stratigraphy: (a) overfilled lakes; (b) balanced-fill lakes; (c) underfilled lakes. Stratal patterns illustrated after Bohacs et al. (2000).
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At present, three continental archetypal ichnofacies are widely accepted: the Scoyenia, Mermia and Coprinisphaera ichnofacies. The last is present in palaeosols, and the first two occur in fluvio-lacustrine environments. Additionally, the Skolithos ichnofacies may be present in relatively high-energy fluvio-lacustrine deposits. The ichnofauna from...
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Context 1
... trace fossils are commonly well developed in overfilled lake basins (Fig. 10a), and are useful to delineate parasequences and parasequence sets. Fluvial discharge into over- filled lakes usually generates density currents that oxygenate lake bottoms, allowing the estab- lishment of epifaunal and infaunal ...
Context 2
... lake basins commonly contain abundant firmground trace fossils, but soft- ground assemblages are usually depauperate (Fig. 10b). During lowstands, shallow balanced-fill lakes are characterised by relatively thin aggradational parasequences due to desicca- tion (Bohacs et al. 2000). Lowstand deposits contain abundant and widespread ichnofaunas of the Scoyenia ichnofacies. Striated trace fossils, such as Scoyenia and Spongeliomorpha, record- ing the firmground ...
Context 3
... Scoyenia ichnofacies is widespread in underfilled lake basins, but the Mermia ichno- facies is commonly suppressed (Fig. 10c). Deposition during lowstands is restricted to eva- porite accumulation in remnant pools developed in the zones of maximum subsidence (Bohacs et al. 2000). Evaporite pools are among the most stressful environments and, with few excep- tions, lack biogenic structures. In the remaining zones, sediments that accumulated during the previous ...
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The Triassic red beds of the Caturrita Formation (Paraná Basin, southern Brazil) contain abundant Skolithos, common Taenidium, and rare Arenicolites in low-angle, trough cross-bedded fine-grained sandstones interpreted as crevasse-splay deposits, forming a Skolithosdominated composite piperock and providing easily mappable horizons. Skolithos cf. s...
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... Facies association 2 is interpreted as aeolian interdune deposits. Convolute structures formed in a subaqueous environment (Figure 9c), as evidenced by the red mudstones laminae, and the occurrence of Scoyenia ichnofacies indicates ephemeral fluvial environments (Figure 9a,b; Buatois & Mángano, 2004;Frey et al., 1984). The aeolian interdunes are interlayered with the aeolian dune deposits of facies association 1 (Figure 4d). ...
... The coarsening-upward successions suggest crevasse splay and the fine deposits interlayered with the sandbodies are interpreted as overbank or floodplain environments (Figure 8c,d;Allen, 1970). The Scoyenia ichnofacies indicate periodical emersion and flooding in an overall fluvial environment (Buatois & Mángano, 2004;Frey et al., 1984). Emersion is further attested by the gypsum layers also indicative of a semi-arid environment. ...
Aridification of Central Asia in the Late Mesozoic led to drastic environmental changes characterized by widespread aeolian deposits. We systematically investigated fluvial‐aeolian deposits in the Middle Jurassic Toutunhe Formation, Upper Jurassic Kalazha Formation, and Lower Cretaceous Tugulu Group in the Junggar Basin to the north of the Tianshan Orogenic Belt via unmanned aerial vehicle‐based photogrammetry, scanning electron microscope, grain‐size analysis, and detrital zircon geochronology. Paludal and deltaic environments transitioned to a fluvial‐aeolian environment from the late Middle Jurassic to the Late Jurassic. Fan delta and incisive braided river deposits accumulated in the earliest Cretaceous and evolved into a lacustrine environment with aeolian deposits in the lakeshore. Aeolian deposits are characterized by moderate‐ to well‐sorted and subangular to subround sandstones with large‐scale, high‐dip cross‐bedding, inversely graded lamination, dominant saltation grains, crescent‐shaped, and dish‐shaped impact structures. Aeolian deposits contain heavy minerals including more ilmenite, zircon, garnet, and, tourmaline and less magnetite and epidote than the fluvial deposits. The preserved aeolian sediments of the Kalazha Formation extend west–east for more than 100 km, suggesting a wide desert area during the latest Jurassic. The detrital zircon age patterns indicate that the provenance of the aeolian deposits was similar to that of coeval fluvial deposits. The cooccurrence of fluvial and aeolian deposits and the similar provenances but orthogonal flow directions indicate that the aeolian deposits were mainly sourced from the nearby fluvial material within the basin. The evolution of the fluvial‐aeolian system responded to a complete base‐level cycle controlled by the aridification and tectonics. Due to decreased sediment supply caused by aridification, the base level rose, leading to the change from braided rivers to meandering rivers, along with the deposition of aeolian sediments. Due to the tectonic reactivation in the Late Jurassic, the base level fell, causing the occurrence of alluvial fans and the expansion of the aeolian sediments. Previous studies revealed that the Tianshan in the Jurassic exhibited low relief. The fluvial‐aeolian system played an important role in maintaining the limited relief in southern Central Asia.
... Elements of the Skolithos Ichnofacies can be present not only in the proximal parts of turbiditic systems but also in their distal parts (Buatois et al., 2001) and deep shelf settings (Baucon et al., 2023). High-energy fluvio-lacustrine deposits may also display the Skolithos Ichnofacies (Buatois and Mángano, 2004). Marine Skolithos is usually attributed to phoronids or annelids, whereas non-marine Skolithos is produced by insects or spiders (Schlirf and Uchman, 2005). ...
Volcanic processes create peculiar types of terrestrial and freshwater ecosystems but, surprisingly, very little is known about the infaunal palaeoecology of continental volcanic ecosystems such as caldera lakes and streams. Here, we report an invertebrate trace fossil association from the largest and best-exposed Cisuralian supervolcano in Europe, the Bolzano Supervolcano. The fossil association is dominated by abundant trace fossils that are unusually straight, i.e., their curvature is zero along the entire preserved length. The trace fossils are attributed to Planolites and Palaeophycus and they form a bioturbated texture (ichnofabric) with a characteristically high bioturbation intensity (percent bioturbated>90%). U-shaped (Arenicolites) and concentrically lined (Cylindrichnus) burrows are minor components of the ichnofabric. The characteristics of the trace fossil association suggest substrate colonization by r-strategic organisms during periods of minor volcanic activity. In these periods of stasis, the volcanic rocks were eroded by seasonal streams, which provided suitable softground substrates for the infauna. Insects are regarded as the most plausible tracemakers of the straight burrows. Similar ichnofabrics are found in other continental volcanoclastic sites, suggesting that ichnofabrics dominated by straight burrows may represent an ichnological proxy of brief windows for colonization in volcanically influenced freshwater environments. Generative artificial intelligence has been used to graphically reconstitute the tiering pattern and the palaeoenvironment. As such, this study provides the first application of AI to the graphic representation of a bioturbated palaeoenvironment.
... In this sense, substrate characteristics and the taphonomic processes are critical for trace-fossil description and ichnotaxonomic attribution (Bromley 1996;Bertling et al. 2006;de Barros et al. 2021). This is clearly illustrated by the desiccation and predesiccation suites of continental Scoyenia ichnofacies, wherein some ichnofabrics represent progressive substrate dewatering (Buatois and Mángano 2004;Netto 2007;Sedorko et al. 2020). Another example of substrate control is the production of different trace fossils by the same organism due to contrasting substrate moisture and texture conditions, as observed in Protovirgularia and its several preservational variants (Uchman 1998;Mángano et al. 1998Mángano et al. , 2002Rindsberg 2018). ...
The morphology and architectural design of trace fossils are strongly influenced by substrate characteristics, organism anatomy, and burrowing behavior. In this study, we explore the influence of substrate moisture on preservation variants of mole cricket burrows and discuss its correspondence to previously described ichnogenera. Field observations were conducted on clayey and sandy substrates; burrows were described and photographed in situ, and laboratory analyses were performed on collected samples. Mole cricket burrows consist of branched, straight to sinuous tunnels with circular to semicircular cross sections and exhibit distinctive features on the inner walls that are influenced by substrate moisture and texture. Morphotypes were identified based on substrate characteristics, including well-developed pelletized roofs, subtle scratch traces, collapsed roofs, and lateral fringes. Understanding the impact of substrate moisture changes on the preservation and morphology of mole cricket burrows is essential for interpreting trace fossils in paleoenvironmental reconstructions. Besides providing insights into the modes of preservation and substrate conditions of mole cricket burrows, this study also compares their preservation variants with those of Protovirgularia and Sphaerapus.
... Therefore, the observed increase in track abundance and anatomical fidelity upstratigraphy, which we have linked to fine and veryfine sandy substrates with microbes, might have been ultimately controlled by the dominant sedimentary processes in palaeoenvironments that changed through time (Fig. 7). This is similar to the concept of 'facies control' in ichnology, where sedimentation significantly influences the formation, preservation, and distribution of trace fossils (e.g., Bromley and Ekdale, 1984;Buatois and M angano, 2004;Taral et al., 2022;Zouheir et al., 2023) across space, in the contemporaneous sub-environments of the same depositional system (i.e., in facies equivalents). However, in this case, the facies control is demonstrated across time through a continental depositional interval of >35 Ma in the main Karoo Basin from the Late Triassic to the Early Jurassic. ...
Our paper is open access, but for now, we can only share its journal pre-proof (in press) version:
https://www.sciencedirect.com/science/article/pii/S2095383624000014
Tracks registration is influenced by the dynamic interplay between the pedal anatomy of the trackmaker, its behaviour, and the substrate conditions it interacts with. Differences in substrate conditions, especially those linked to grain size and moisture content, often result in the most dramatic variations in track morphology. In the upper Stormberg Group, main Karoo Basin of southern Africa, diverse trace fossils, primarily comprising Late Triassic–Early Jurassic dinosaur tracks, are preserved. Numerous studies have extensively documented individual ichnosites, investigating variations between sites over time, with recent studies suggesting that track abundance and anatomical fidelity increase up-stratigraphy. Despite the well-established link between substrate and track morphology, past studies have not specifically focused on substrate conditions, often emphasizing macro-sedimentary features instead. Here, we examine the micro-sedimentary features of track-bearing units in the upper Stormberg Group using petrographic techniques to better understand the palaeosubstrate and its effect on fossil track registration and preservation. The analysis revealed that very fine-grained sandstones and substrates modified by microbial activity tend to preserve tracks with greater abundance and / or higher anatomical fidelity. Furthermore, the prevalence of very fine-grained and microbially modified strata, and their associated track trends increases in younger stratigraphic units. Across the Triassic – Jurassic boundary in southern Africa, a boom in dinosaur track abundances is observed and credited to the proliferation of dinosaur populations during the Early Jurassic. Our findings, however, suggest that the observed local increase in track abundance (and anatomical fidelity) up-stratigraphy may be linked to substrate composition differences, which were ultimately controlled by large-scale changes in the palaeoenvironment from high-energy meandering fluvial to lower-energy aeolian-lacustrine settings in the Late Triassic and Early Jurassic, respectively. These findings have implications for global macroevolutionary patterns, palaeo-geographical reconstructions, and biostratigraphic correlations in the early Mesozoic.
... Suite 3 hosts dwelling and reproduction structures along with deposit-feeding and locomotion traces of hygrophilic and terraphilic taxa in a firmground substrate. Recognition of these assemblages and the quality of burrow preservation and their crosscutting relations enables more detailed characterization of depositional conditions and recognition of subdivisions of the main facies (Buatois and Mángano 2004). ...
The Santa Clara Abajo and Santa Clara Arriba formations host a diverse assemblage of trace fossils that record a wide range of behaviors and a broad array of ecological niches during the Middle Triassic, a critical period in the evolution of continental fauna with the diversification of both synapsids (cynodont and dicynodont) and archosauromorphs (dinosaurs, pterosaurs, and crocodilians) that represent post-Permian faunal recovery. The Santa Clara formations are part of the continental infill of the Cuyana rift Basin in Argentina and represent a lacustrine system with fluvial input and delta development. Sedimentological characteristics of these units as well as their stacking patterns characterize a “fluctuating profundal” facies association typical of a balanced-fill lake basin. The lacustrine and associated terrestrial environments preserve a rich record of invertebrate traces with 26 ichnogenera from ethological classes of fodichnia, domichnia, repichnia, pascichnia, and cubichnia occupying all co ntinental tiers (subaerial and subaqueous, surficial/very shallow, shallow, mid, and deeper) and ecological niches (epiterraphilic, terraphilic, hygrophilic, and hydrophilic). In association with the invertebrate traces, two taphonomic modes of tetrapod footprints have been found: a moderate fidelity mode and a high fidelity mode. Physical sedimentary features, burrows, trails, and tracks, and their stratigraphic positions are integrated to interpret the main factors involved in footprint preservation in these subsettings. The most significant and variable preservational factor found is water-table fluctuations controlled by the paleohydrology of a balanced-fill lake system. These data show that in balanced-fill lake systems, diverse trace assemblages occur in the lake and associated subsettings such as delta plains, and lake-margin settings whereas trace fossils can be totally absent in coeval lake-center strata, particularly if anoxic lake bottom conditions occur, as probably occurred in the meromictic Santa Clara lake system.
... Comments. Despite being common in shallow-water marine environments, Arenicolites have also been recorded in both deep-water and non-marine environments (Buatois & Mángano, 2004). In non-marine environments, it occurs in Scoyenia and Mermia ichnofacies (Buatois & Mángano, 1995). ...
Many previous studies identified depositional systems for the Resende Basin using sedimentological and petrographic techniques. However, the lack of ichnological research leaves a gap in our understanding of paleoenvironment and paleoecology of this basin. Therefore, this study reports the first occurrence of trace fossils in the Floriano Formation (Miocene) and suggests more refined paleoenvironmental interpretations for this unit. We only observed ichnofossils in an outcrop on the RJ-161 road in Resende municipality, Rio de Janeiro State. The deposit represents a floodplain overlayed by a crevasse splay, both sedimented in a meandering fluvial context. Trace fossils of terraphilic organisms-represented by Taenidium isp., Planolites isp. and Arenicolites isp.-were found in the fine-grained sediments of the outcrop. This ichnocoenosis is composed of feeding (fodinichnia), locomotion (repichnia) and/or habitation (domichinia) structures produced by worm-like invertebrates. The ichnotaxonomic assemblage consists of the first record of Scoyenia ichnofacies for a typical meandering fluvial system in Brazil.
... Given the depositional setting, Skolithos most likely represents dwelling or deposit feeding (Buatois & Mángano, 2004. In continental environments, Skolithos are usually associated with active channels and sandbar deposits (Buatois & Mángano, 2004Hembree & Blair, 2016). ...
... Given the depositional setting, Skolithos most likely represents dwelling or deposit feeding (Buatois & Mángano, 2004. In continental environments, Skolithos are usually associated with active channels and sandbar deposits (Buatois & Mángano, 2004Hembree & Blair, 2016). Fluvial channels are high-energy environments with rapid fluctuations in sedimentation and erosion rates, resulting in very stressful and unstable conditions (Buatois & Mángano, 2004. ...
... In continental environments, Skolithos are usually associated with active channels and sandbar deposits (Buatois & Mángano, 2004Hembree & Blair, 2016). Fluvial channels are high-energy environments with rapid fluctuations in sedimentation and erosion rates, resulting in very stressful and unstable conditions (Buatois & Mángano, 2004. As a result, Skolithos typically occur in low diversity assemblages and tracemakers were likely opportunistic generalists that rapidly colonized exposed surfaces (Buatois & Mángano, 2004;Miller & Collinson, 1994). ...
The long-term response of riparian communities to shifting climatic conditions can be addressed by the ichnofossil record, because organism behavior is typically altered in response to changes in environmental factors. During the late Paleozoic, the Appalachian Basin experienced a shift from an ever-wet to wet–dry climate. Changes in the abundance, diversity, density, and composition of ichnofossil assemblages were investigated in fluvial point bar sandstones from five roadside outcrops of the Middle Pennsylvanian-to-early Permian Allegheny, Conemaugh, Monongahela, and Dunkard groups located in southeast Ohio and northwest West Virginia. Ichnofossil data were collected using a 0.5 × 0.5-m grid placed on bedding plane surfaces and from vertically oriented thin sections. Abundance, density, diversity, and burrow widths increased through the study interval. Behaviors changed from stationary- to mobile-deposit feeding, while community composition shifted toward more established, permanent generalists. These changes in ichnofossil assemblages suggest that the shift to a drier, more pronounced seasonal climate made short- to long-term occupation of the point bar sands more advantageous as surface conditions were more unfavorable and resources limited. This study helps us understand how terrestrial community composition and ecosystem dynamics shift over long time intervals in response to environmental perturbations. By assessing these changes, we can better predict what future impacts climatic shifts will have on continental ecosystems and terrestrial communities.
... Elements of the Skolithos Ichnofacies can be present not only in the proximal parts of turbiditic systems, but also in their distal parts (Buatois et al., 2001). High-energy fluvio-lacustrine deposits may also display the Skolithos Ichnofacies (Buatois and Mángano, 2004). These occurrences are explained by the fact that ichnofacies are not intended to be absolute paleobathymetric indicators, but archetypical facies models (Ekdale, 1988;Frey et al., 1990). ...
Dense associations of vertical trace fossils are typically used as a proxy for nearshore palaeoenvironments. Here we challenge this assumption by reporting dense associations of vertical tubes occupying vast areas of the deep shelf off Liguria (Italy) at depths ranging from 56 to 85 m. The tubes, produced by the suspension-feeding sabellid Bispira riccardi, are J-shaped and extend for ~5–10 cm above the seafloor. Optical microscopy, SEM imagery and elemental maps evidence that the tubes consist of (1) an outer agglutinated layer consisting of clay- and silt-sized particles, (2) an intermediate mineral layer enriched in manganese, and (3) an inner, sulfur-rich organic layer. The tubes serve to obtain shelter and resuspend food particles, representing a modern reference for understanding palaeoethology of morphologically similar trace fossils. The Ligurian ichnoassociation is comparable to the Skolithos Ichnofacies, but it departs from the typical nearshore environment of the Ichnofacies. The characteristics of the studied ichnoassociation are explained by the significant turbidity of the Ligurian shelf, which favours domichnial, suspension-feeding strategies that are typical of the Skolithos Ichnofacies. As such, the sabellid tubes from the Ligurian Sea are palaeontologically important to identify similar current-swept, high-turbidity settings in the fossil record.
... The identification and delimitation of mm-to m-scale elementary cycles, in terms of stacking pattern of sedimentary facies, and m-scale small-scale cycles, in terms of facies associations, are bounded by key surfaces, such as flooding surfaces (Spence and Tucker, 2007;Catuneanu et al., 2009). In this paper, we apply the facies model and ichnofacies model associated with cyclostratigraphy and sequence stratigraphy to define the lacustrine basin type and the evolution of the lacustrine system (Carroll and Bohacs, 1999;Bohacs et al., 2000;Buatois and Mángano, 2004, 2009Scott and Smith, 2015). ...
... The association between Mm, Lm and Sw facies represents the lowenergy shoreline dominated by fall-out driven sedimentation, oscillatory flows, chemical precipitation, and subsequent periodic subaerial exposure (Talbot and Allen, 1996;Buatois and Mángano, 2004;Nichols, 2009;Renaut and Gierlowski-Kordesch, 2010). The ichnological assemblage indicates the development of a relatively well-diverse Scoyenia ichnofacies (Buatois and Mángano, 1998. ...
... The lack of biogenic structures and the exceptional preservation of fish fossils (+organic matter) characterize a reducing environment in an anoxic lake water column (Cardoso et al., 2019(Cardoso et al., , 2020. These chemical conditions are biologically stressful, hindering the establishment of epifaunal and infaunal benthic communities (e.g., Buatois and Mángano, 2004, 2009McIlroy, 2004;Scott et al., 2012). ...
The lateral and vertical distribution of sedimentary facies and ichnofacies in lacustrine systems records sensitive climatic variations and rates of subsidence. The Upper Jurassic–Lower Cretaceous lacustrine system of the Pastos Bons Formation in the Parnaíba Basin, northeastern Brazil, is an excellent opportunity to evaluate the depositional history of the post-CAMP thermal subsidence. This subsidence event succeeded the voluminous emplacement of mafic magma linked to the Central Atlantic magmatic province (CAMP), ~201 Ma, forming a large subsiding area in West Gondwana. In this sense, this paper developed outcrop-based facies and ichnofacies analysis, allowing the interpretation of two depositional phases and four facies associations (FA): 1) The lower depositional phase comprises lacustrine deposits showing an aggradational stacking pattern. FA1 - central lake record fibrous gypsum interbedded with fossiliferous shale beds, forming shallowing-upward cycles. 2) The upper depositional phase reveals a fluvio-lacustrine succession, forming a progradational stacking pattern. Central lake (FA1) central lake comprises laminated mudstone and sandstone beds hosting a suite representative of Mermia ichnofacies, forming coarsening-upward cycles. Lakeshore (FA2) comprising mudstone beds, limestone lenses, and sandstone beds hosting a suite representative of Scoyenia ichnofacies, forming shallowing-upward cycles; and conglomerate lenses overlaid by sandstone beds hosting a suite representative of Skolithos ichnofacies, forming fining-upward cycles. Braided fluvial (FA3) comprising conglomerates and sandstone beds, forming fining-upward cycles. Delta front (FA4) comprises mudstone lenses and sandstone beds hosting a suite representative of Skolithos ichnofacies, organized in coarsening-upward cycles. The fluvial discharge and wave activity oxygenated the water lake in the progradational phase, creating chemical and biological conditions that allowed the establishment of the epifaunal and infaunal benthic communities, represented by the well-preserved ichnological record. The rates of the post-CAMP thermal subsidence (accommodation) balanced with the increase of the wet periods to the top of the succession (sedimentary supply) indicate a depositional evolution from underfilled to overfilled lake basin, during Upper Jurassic-Lower Cretaceous, in West Gondwana.
... Taenidium barretti is a common ichnotaxon in the Scoyenia ichnofacies, chiefly in moist to wet substrate of fluvial settings, forming composite ichnofabrics including Skolithos, Arenicolites, Camborygma, and Beaconites (Savrda et al., 2000;Buatois and M angano, 2004;Melchor et al., 2006Melchor et al., , 2012Buatois et al., , 2020Netto, 2007;Krapovickas et al., 2009;Mancuso et al., 2020;Sciscio et al., 2021). However, the density and prevalence of T. barretti in the studied paleosols hardly allow the recognition of any other burrows (if they existed), resulting in a monotypic ichnofabric. ...
... However, the density and prevalence of T. barretti in the studied paleosols hardly allow the recognition of any other burrows (if they existed), resulting in a monotypic ichnofabric. It also constrains the development of palimpsest surfaces as a product of progressive substrate desiccation (Buatois and M angano, 2004;Melchor et al., 2006;Netto, 2007;Krapovickas et al., 2009;Buatois et al., 2020). Thus, in fluvial systems with high discharge variations in semi-arid to arid environments, the boundaries between the "pre-desiccation suite" and "desiccation suite" of Scoyenia ichnofacies can be diffuse without the common cross-cutting relationships. ...
... The frequency of flooding events and the lowered water table were first-order factors controlling the monotypic Taenidium barretti ichnofabric. The high energy of channel belts in perennial streams prevents opening of the colonization, resulting in Skolithosdominated ichnofabric or non-bioturbated channel deposits (Buatois and M angano, 2004;Buatois et al., , 2020. ...
The present work analyzes the monotypic Taenidium barretti ichnofabric developed in abandoned channels and floodplains to understand its paleoecological significance in highly seasonal fluvial systems. The data come from the Cretaceous paleosols of the Marília Formation (Bauru Basin, SE Brazil), in which the T. barretti ichnofabric and rhizoliths represent the biotic record. Beetle larvae are considered to be the most likely T. barretti tracemakers in these paleosols. The intensity and recurrence of bioturbation suggest that the windows of opportunity for beetle population growth were very short and controlled by the progressive substrate desiccation after flood cessation. The characteristics of the trace fossil assemblage suggest soil colonization by r-strategic organisms triggered by flooding events that provided the resource inputs necessary for their living during rainy seasons. The results also show that in fluvial systems with high discharge variations, the boundaries between a "pre-desiccation suite" and a "desiccation suite" in the Scoyenia ichnofacies can be diffuse due to the short duration of colonization windows and progressive terrestrialization of floodplains and channels. Therefore, the frequency of flooding events, the lowered water table, and the rapidity of substrate desiccation constrained colonization by other burrowers and may be considered as first-order factors controlling the generation of a monotypic T. barretti ichnofabric. Thus, the monotypic Taenidium ichnofabric in the Scoyenia ichnofacies context is an ichnomarker of brief windows for colonization in highly seasonal environments.
