Bollettino SPI Vol. 56 (2) - OPEN ACCESS!
Ichnia: Ichnology for the 21st Century
This Issue is a collection of articles derived from the Fourth International Congress on Ichnology “Ichnia 2016″ (Portugal, May 2016)
Published in September 2017
- Santos V.F. (2017)
Museu Nacional de História Natural e da Ciência: cento anni di icnologia dei dinosauri in Portogallo
Jacinto Pedro Gomes (1844-1916) was a naturalist at the Mineralogical and Geological Museum of the former Polytechnic School of Lisbon (nowadays National Museum of Natural History and Science - Universidade de Lisboa). His interest in dinosaurs started when he began to study dinosaur tracks from Cabo Mondego (Figueira da Foz) at the end of the 19th century. The Cabo Mondego coalmine administration generously sponsored the campaign to remove the tracks from the outcrop close to the sea and transfer them to the museum in Lisbon. Gomes was a pioneer in studying dinosaur tracks in Portugal and with him the National Museum of Natural History and Science became an important player in the study of Portuguese dinosaur tracksites and their conservation. Indeed, besides the study of the dinosaur footprints from Cabo Mondego, Gomes recognized the importance of rescuing those footprints from ongoing marine erosion. Since Gomes’ pioneer work, many additional dinosaur tracksites were discovered and studied and in the 1990’s five dinosaur tracksites were designated as natural monuments thanks to the efforts of António Marcos Galopim de Carvalho (at the time Director of this Museum). At present, several important tracksites have been protected but they still need a better valorization to further promote the public’s interest for geological and palaeontological heritage. The Avelino tracksite was subject to a museological intervention in 2012, improving its accessibility and allowing autonomous public visits. The Galinha tracksite was protected and made accessible in 1996-1998 but it requires renovation to improve its geoconservation status and to assure the in situ preservation of the dinosaur tracks. Also, it is worth keeping in mind that the Galinha tracksite was the first palaeontological site in Portugal, where a geoconservation strategy and unprecedented musealization was applied.
- Goldstein D.H., Getty P.R. & Bush A.M. (2017)
Hitchcock’s treptichnid trace fossils (Jurassic, Massachusetts, USA): conflicting interpretations in the “Age of Fucoids”
Edward Hitchcock was one of the most influential 19th century ichnologists. In a career that lasted nearly three decades, he established 31 invertebrate ichnogenera for Early Jurassic traces from the Hartford and Deerfield Basins of Connecticut and Massachusetts, some of which are in widespread use today. Upon re-examining some of Hitchcock’s specimens, we have identified a number of fossils that are similar to the well-known ichnogenus Treptichnus. Modern ichnologists generally interpret non-marine occurrences of these burrows as the traces of larval insects. In some instances, Hitchcock ascribed his fossils to the activities of annelids or larval insects, and his descriptions of their mode of formation are similar to those presented in much more recent works. However, he also interpreted some treptichnids as algal/plant fossils. We suspect that his varied interpretations reflect differences in morphology and preservation among specimens. Hitchcock worked in the 19th century, a time known as the “Age of Fucoids”, and his comments also reflect the prevailing uncertainty on trace fossil origins.
- Zhang L.J., Buatois L.A., Mangano M.G., Qi Y.A. & Tai C. (2017)
Middle Cambrian Diplocraterion parallelum from North China: Ethologic significance and facies controls
The middle Cambrian Mantou Formation of the Mianchi section of western Henan Province, North China provides an opportunity to address infaunal colonization during the aftermath of the Cambrian explosion. The trace fossil Diplocraterion is common within intertidal very fine-grained sandstone of the Member II of the Mantou Formation (Stage 5). Diplocraterion consists of perpendicular to bedding plane, lined U-shaped burrows with well-developed marginal tubes, having distinctive, dark and light colored, laminae forming retrusive and protrusive spreiten reflecting the activity of a suspension feeder. No scratches are observed on the wall of the marginal tubes. SEM-EDS mapping detection shows that the dark laminae are dominated by Si, Al and Fe, whereas the light laminae are dominated by Ca and Si. Based on ichnological, stratigraphical and SEM-EDS features, it is suggested that the specimens of Diplocraterion studied here results from the equilibrium behavior and that the delayed appearance of this ichnotaxon in North China is due to lack of appropriate siliciclastic facies.The depositional environment of the facies is part of a carbonate platform top near the fair-weather wave base, within subtidal zone, with development of “algal” mounds and sedimentation of debris from the same buildups. The composition and components distribution of both microfacies fit well with the mounds previously described in other outcrops of the Valdeteja Formation, with the exception of the participation of chaetetids as a main building component in some beds.
- Bayet-Goll A. & Neto De Carvalho C. (2017)
Sedimentological and ichnological characteristics of deltaic and non-deltaic successions of the Lower Ordovician of Shahmirzad area, Alborz Mountains of northern Iran
The integration of sedimentological and ichnological characteristics from deltaic and non-deltaic siliciclastics of the Lower Ordovician Lashkerak Formation in the Alborz Mountains of northern Iran has led to more reliable determinations of the relative degree of influence imposed by river influx, waves, and storms on the coastal and shallow marine regimes. The trace fossil distribution and composition of ichnological assemblages is strongly linked with inferred degree of stability and temporal persistence of physico-chemical conditions. Ichnology combined with sedimentological evidence determined the relationship between the organism behaviors and environmental stresses, such as variations in oxygenation, salinity, water turbidity, substrate consistency, and sedimentation rates. Using facies characteristics and stratal geometries, the siliciclastic successions are divided into two facies associations, FA1 (the wave-dominated shoreface-offshore complex), and FA2 (mixed river- and wave-influenced delta). Seven ichnocoenoses are differentiated in the studied section, according to the composition and distribution of the ichnofossils, colonization styles, trophic types and ethologic groups, degree of bioturbation and the consistency of the substrate. High diversity, high bioturbation intensity and the occurrence of diverse and robust trace fossil suites characteristic of ichnocoenoses of open marine facies association (FA1) correspond to the archetypal Cruziana and Skolithos ichnofacies in wave-dominated shoreface complex reflecting homogeneous distribution of food, normal salinity, and oxygenated waters. In deltaic successions of FA2, hypopycnal and hyperpycnal flows created several stress factors, such as increasing sedimentation rate, and salinity fluctuations, and water turbidity that had large impact on the benthic faunas. The resulting ichnological suites are characterized by lower ichnodiversities, low degrees of bioturbation, and sporadic distribution of ichnofossils throughout the deposits, as compared to non-deltaic shoreline successions of FA1. The increase in environmental fluctuations and thus physico-chemical stresses on infaunal communities in the prodelta to delta-front deposits is reflected by the dominance of current-generated structures, normal and inversely graded beds, soft-sediment deformation, and syneresis cracks. The classification method used here has the potential to improve the use of trace fossils and ichnofacies in palaeoenvironmental analysis for recognition and differentiation of deltaic from non-deltaic shoreline successions of the Early Palaeozoic.
- Rozhnov S. (2017)
Cyanobacterial origin and morphology of the Volkhov hardgrounds (Dapingian, Middle Ordovician) of the St. Petersburg region (Russia)
- Gutiérrez C., Pazos P.J. & Fernández D.E. (2017)
Analysis of the ichnogenus Herradurichnus in quartzites of the Balcarce Formation (lower Silurian) from the Tandilia System of Argentina
Herradurichnus Poiré & del Valle, 1996 from the Balcarce Formation (lower Paleozoic of the Tandilia System, Argentina) is an enigmatic ichnogenus previously considered as problematic. In this paper, Herradurichnus is revised and key material from collections is redescribed together with other specimens documented in situ from outcrops and quarries. The diagnosis is emended to include its morphological variability. The revised Herradurichnus includes negative, epichnial, U-shaped, V-shaped and parabolic depressions. The specimens are horizontal, subhorizontal or oblique with respect to the bedding plane, and are recorded in fine-grained to very coarse-grained sandstones. Other characteristics are also described in detail. The holotype of Herradurichnus scagliai (Borrello, 1967) has been recovered. Material previously included in Crescentichnus Romano & Whyte, 2015 is now reassigned to Herradurichnus. Xiphosurans and trilobites are disregarded as possible tracemakers of Herradurichnus. The producers were able to construct structures oriented with the convex side of the arch in an opposite sense to the main paleocurrents. This ichnogenus is now reappraised and found to range from the Cambrian to the lower Silurian of Gondwana.
- Mikuláš R., Rindsberg A.K., Santos A. & Pavela M. (2017)
A Carboniferous chiton (Mollusca, Polyplacophora) at the end of its trail: a unique find from the Czech Republic
An exceptional find of a chiton preserved at the end of its locomotion trace comes from the Culm facies, that is, from a succession of turbidity-controlled dark shales, greywackes and sandstones. The chiton trace is a smooth, rather indistinct, 7-8 mm wide bilobate ridge (convex epirelief), forming an incompletely preserved loop of estimated extent 50 x 80 mm. At its end is preserved a completely articulated chiton Proleptochiton sp., 4.0 mm wide and 11.5 mm long, oriented congruently with the trace. The neighbouring strata provide relatively common ichnofossils, including Chondrites isp., Planolites isp., Dictyodora liebeana (Geinitz) and Diplocraterion isp. The chiton’s trace fossil corresponds to ichnotaxa that have historically been compared to modern gastropod trails. The gastropods are well-known for two different monotaxic locomotion techniques, one for hard substrates such as glass, and another for soft substrates, where the animals move through muscular waves of much higher amplitude than observed on glass. Thereby, adhesion useable for movement on the hard surface is functionally replaced with friction. Loosening of the sediment by rapid movements of foot muscles is the cause of the structure’s convexity, that is, increasing volume. Similar behaviour is documented for the first time in chitons. The studied specimen is the first locomotion trace fossil attributed to polyplacophorans. The find documents the burrowing technique of chitons in deep-marine, turbidity-influenced soft substrate during the Viséan (330 Ma). It demonstrates the similarity of chiton and some gastropod traces in soft substrates, and adds to the lengthening list of animals that were fossilized within their traces.
- Bordy E.M., Abrahams M. & Sciscio L. (2017)
The Subeng vertebrate tracks: stratigraphy, sedimentology and a digital archive of a historic Upper Triassic palaeosurface (lower Elliot Formation), Leribe, Lesotho (southern Africa)
Dinosaur vertebrate body and ichnofossils are relatively abundant in the Upper Triassic-Lower Jurassic Elliot Formation (Stormberg Group, Karoo Supergroup) in the main Karoo Basin in southern Africa. Herein we present the results of our sedimentological, stratigraphical and ichnological investigations at a historic ichnosite in NE Lesotho that is among the first documented vertebrate track-bearing palaeosurfaces in southern Gondwana. After decades of neglect, the Subeng ichnosite is restudied in this paper in light of the advances in ichnological methods and the formalised stratigraphy of the Stormberg Group. Documentation of this ichnosite was conducted using a mix of field-based sedimentological and ichnological methods and photogrammetry, which collectively allowed us to place the site within the lowermost Elliot Formation (Upper Triassic). Our detailed palaeoenvironmental reconstruction, based on palaeocurrent measurements and sedimentary facies analysis of the host rocks, suggests that this diverse Upper Triassic assemblage of vertebrate ichnofossils, which is an integral part of the history of life on land just before the end-Triassic mass extinction event, formed near a shallow oxbow lake or drying up watering hole on the floodplain of a meandering river system. This water source attracted numerous bipedal and quadrupedal animals as attested by the presence of tridactyl, tetradactyl and pentadactyl tracks on the palaeosurface. We have also produced a photogrammetric digital 3D model (available online) of the Subeng ichnosite to serve as a digital replica and archive for further ichnological study. This digital documentation is important not only for the preservation of this rapidly eroding palaeosurface (situated in an active streambed), but also for the provision of a visually stimulating tool for community outreach and science education in rural African communities.
- Belvedere M., Franceschi M., Sauro F. & Mietto P. (2017)
Dinosaur footprints from the top of Mt. Pelmo: new data for Early Jurassic palaeogeography of the Dolomites (NE Italy)
Dinosaur footprints from the Lower Jurassic of northeastern Italy are well known and, since the first discoveries in the early 1990s, many sites have been described. Tracks are mostly found in the peritidal limestones of the Calcari Grigi Group, deposited on the Trento carbonate platform, now cropping out in the Southern Alps. In 2011, a group of speleologists discovered a new tracksite in the Lower Jurassic Calcari Grigi Group exposed almost at the top of Mt. Pelmo (Dolomites), 3037 m above sea level. Footprints are generally poorly preserved, but it proved possible to recognise some tridactyl footprints with theropodian features (i.e., elongated digit III and narrow interdigital angle) and some possible quadruped tracks whose con guration resembles that of a sauropodomorph trackmaker. Careful examination of the depressions excludes their inorganic origin (chemical weathering). Despite the poor quality of the traces, the Pelmo site is significant because it is the most easterly site ever found on the Trento Platform and the only one which is located north of the Valsugana Fault. This fault system is a major alpine tectonic lineament that separates the classical successions of the Calcari Grigi Group in the Italian Prealps from those located in the Dolomites. Moreover, the discovery of the Pelmo tracks considerably expands the documented area of movement of Early Jurassic terrestrial vertebrates in the northern part of the Trento Platform, extending the size of the Early Jurassic megatracksites of the Southern Alps.
- Gierlinski G., Lagnaoui A., Klein H., Saber H., Oukassou M. & Charriere A. (2017)
Bird-like tracks from the Imilchil Formation (Middle Jurassic, Bajocian-Bathonian) of the Central High Atlas, Morocco, in comparison with similar Mesozoic tridactylous ichnotaxa)
Small bird-like tracks have recently been discovered at three outcrops of the Imilchil Formation (Middle Jurassic, Bajocian- Bathonian) in the Central High Atlas of Morocco. The track-bearing strata are part of a marine-continental transitional succession, the studied surfaces being sandy marls and limestones of a brackish depositional environment. The footprints strongly resemble the ichnogenus Trisauropodiscus Ellenberger, 1970, from the Lower Elliot Formation (latest Triassic) of Lesotho, southern Africa and are assigned to Trisauropodiscus isp. These are functionally tridactyl, widely divaricated pes tracks with digit III being longest and a trace of the reverted digit I (hallux) being occasionally imprinted. In contrast to some former studies suggesting Trisauropodiscus as a junior synonym and extramorphological variation of the ornithischian ichnogenus Anomoepus, this ichnotaxon is considered here as a distinctive morphotype among similar theropod tracks found in Jurassic-Cretaceous ichnoassemblages. An amended diagnosis is proposed focusing on the features that are here discussed and considered as key characters of this ichnotaxon. An avian interpretation of the trackmaker is problematical, especially against the background of the stratigraphic range of Trisauropodiscus back to the Late Triassic. Presently, theropods with very bird-like feet are the more likely producers. Future analyses and comparison of Trisauropodiscus with pes skeletons of avian and non-avian theropods might enlighten this.
- Figueiredo S., Dinis P., Belo J., Rosina P. & Bachtsevanidou Strantzali I. (2017)
A new record of a possible ornithopod footprint from the Lower Cretaceous of Cabo Espichel (Sesimbra, Portugal)
We present a new dinosaur footprint from Praia do Guincho, Portugal. Praia do Guincho is a seaside locality, situated 2 km north of Cabo Espichel. A loose cast of a tridactyl dinosaur footprint was discovered during fieldwork in 2011. The cliff where the footprint was found is composed of limestones, marls, sandstones and conglomerates that were deposited in shallow marine, lagoon and estuarine environments. The succession belongs to the Papo-Seco Formation (Lower Cretaceous-Barremian). The remains of several groups of vertebrates, including dinosaurs, have been reported in this formation. This paper provides a trackmaker study consisting of a visual analysis under different light angles and photogrammetric 3D modelling. The specimen has a digit III longer than II and IV. However, a substantial part of the shape of digit III is sediment, giving a flawed impression that it belongs to the footprint itself. The photogrammetric modelling revealed that digit III is shorter and more rounded than it appeared to be in the first place and the morphology of the cast (large plantar surface, similar length and width rounded heel, with elongate, narrow digits) matches with the features of the pes of ornithopods and with the characteristics described as belonging to ornithopod dinosaurs.
- Schnick H.H. (2017)
Exceptional preservation of the endolithic trace fossil Dendrina belemniticola Mägdefrau, 1937 in the Upper Maastrichtian greensand of Nasiłów (central Poland)
The rosette-shaped endolithic trace fossil Dendrina belemniticola Mägdefrau, 1937 is common in biogenic substrates in the Upper Cretaceous chalk facies of Europe but badly preserved. Chalk specimens are affected by an intensive calcite cementation. Basically all parts of borings are secondarily sealed if their internal diameter is less than the size of the cement crystals and application of castingembedding techniques fails to document the morphology of such borings. Therefore, up to now only the macro-morphology of Dendrina-borings could be detected in specimens of the chalk facies. In contrast, biogenic calcitic substrates found in the Upper Maastrichtian greensand of Nasiłów in central Poland remained almost unaltered diagenetically. In these specimens calcite cementation did not occur and endolithic traces can be studied at an exceptional highresolution. Accordingly, new morphological features of the ichnospecies D. belemniticola can be described. Casts of the Dendrina-boring systems show a cover of unbranched hair-like extensions. Those extensions spread into the substrate from all surfaces of the boring and give the Dendrina-casts a hairy or furry appearance. Most likely they had an exploratory function in limited substrates, i.e. locating the boundaries of the substrate and investigating cavities within it. The proof of hair-like extensions that could have enabled sensory functions can explain the stenomorphic reactions of the Dendrina-producer for the first time. Some casts of the hair-like extensions exhibit bulbous swellings. Most probably these structures represent the second phase of the boring process, followed by further expansion and fusion that constitute the typically verrucose Dendrina-rosette. The endolithic trace D. belemniticola can functionally be compared with a foraminiferan test, and a test-less foraminiferan species is considered to be the trace-making organism.
- Monaco P., Rodríguez-Tovar F.J. & Uchman A. (2017)
The ichnocoenosis of the bottom nepheloid layer (BNL) deposits: a case study from the Scaglia Toscana Formation (Paleogene, central Italy)
- Demircan H. & Uchman A. (2017)
Short distance variability of trace fossils in submarine slope and proximal basin plain deposits: a case study from the Ceylan Formation (upper Eocene), Gelibolu Peninsula, NW Turkey
The Ceylan Formation (upper Eocene) from the Thrace Basin (Gelibolu Peninsula, NW Turkey), is composed of pelagic shales, marls, clayey limestones, turbiditic sandstone-shale beds and local conglomerates, debris flow mixtites, slumped deposits and silicified tuffites. These deposits, which are about 1000 m thick, generally shallow upwards, show vertical and lateral changes according to their accumulation on different parts of a submarine slope, with a transition to the proximal basin plain. The variability is also expressed in the trace fossil content (33 ichnotaxa, 26 ichnogenera). The fine-grained background sediments are totally bioturbated and they show an ichnofabric with Trichichnus, Chondrites, Planolites and small Thalassinoides. Generally, abundance and diversity of trace fossils increase with frequency of sandstone intercalations, probably because of higher and more variable food content and higher preservational potential. Turbiditic sandstones of the proximal basin plain contain abundant graphoglyptids (Paleodictyon, Helminthorhaphe, Urohelminthoida, Desmograpton, Belorhaphe, Helicolithus). Continuous reworking of background sediments points to a good or moderate oxygenation of pore waters. The trace fossil assemblage of fine-grained pelagic sediments with isolated sandstone beds can be ascribed to the Zoophycos ichnofacies sensu lato, but some ichnotaxa typical of turbiditic sediments (e.g., Ophiomorpha annulata) can be present in isolated sandstone beds. Series of turbiditic sandstones with abundant graphoglyptids are typical of the Paleodictyon ichnosubfacies of the Nereites ichnofacies. Turbiditic series in the upper slope setting contain much fewer graphoglyptids. The absence of graphoglyptids in isolated sandstone beds shows that their occurrence is not only a matter of taphonomy (scouring and casting) but also is related to the presence of more frequent turbidites modifying the substrate.
- Panarello A., Santello L., Belvedere M. & Mietto P. (2017)
Anthropic artifacts and donkey horseshoe traces looking like fossil human footprints: a case study from the Roccamonfina volcano (central Italy) with implication for human ichnology)
Fossil footprints of Middle Pleistocene hominids, locally known as “Ciampate del Diavolo”, were discovered in 2001 on the North-Eastern slope of the Roccamonfina volcano (central Italy, municipality of Tora and Piccilli, Caserta). The imprints occur on a surface of Brown Leucitic Tuff (BLT), dated to 349 ± 3 ka. After this discovery, e this tuffaceous formation was investigated in more detail on the North-Eastern, Eastern and South-Eastern side of the Roccamonfina volcano, with the aim of locating other fossil footprints. In 2003 another succession of nine hollows fully compatible with human fossil footprints for stratigraphic position, pattern and dimensional range was found on the same ridge but at a higher level. This second site, known locally as Cantarelle di Carangi, is positioned at a distance of about 1.8 km from the first fossiliferous area (municipality of Marzano Appio, middle-central Italy, Caserta province). Further surveys and archaeological excavations were carried out in the Cantarelle di Carangi site during 2008 to better understand, contextualize and confirm the potential ichnological value of the findings of 2003. Ichnological and stratigraphical analyses, combined with findings during the excavations and historical data, however, tell a different story. What was supposed to be a new ichnosite with Pleistocene fossil footprints, is very likely the result of anthropic digging, erosion made by animals, and weathering. In any case, the discovery shows how careful researchers have to be in interpreting possible fossil footprints, especially in conditions of poorly preserved traces.
- Kopcznski K., Buynevich I., Allen Curran H., Caris J. & Nyquist J. (2017)
Imaging bioturbation in supratidal carbonates: non-invasive field techniques enhance neoichnological and zoogeomorphological research, San Salvador, The Bahamas
A case study in unconsolidated carbonates on San Salvador Island, The Bahamas, utilized high-frequency (800 MHz) georadar imaging to augment existing methodologies (burrow counts and measurements, casting) in brachyuran bioturbation research (Ocypode quadrata and Gecarcinus lateralis), and as part of a new dataset characterizing blue land crab (Cardisoma guanhumi) burrows. Non-invasive techniques such as ground-penetrating radar (GPR) can complement traditional field surveys aimed at quantifying mesoscale bioturbation in modern settings. These methods can establish diagnostic features for tracemaker identification and refine existing ichnofacies models. Drone-mounted aerial coverage provided the first high-resolution images of the micro-topography and large burrow openings of Cardisoma in supratidal muddy sands. Measurements of 20 burrows (minimum length, entrance diameter, and spoil mound size) were complemented by endoscopic camera observations (burrow fill, large bioglyphs, and occupants). Extensive 2D transects and quasi-3D georadar grids not only reveal characteristic subsurface interfaces (open vs. filled burrow, water table, saltwater), but also serve as an archive of bulk in situ sedimentary characteristics of the bioturbated substrate. Signal resolution in dry carbonate sand (~4 cm) was sufficient to differentiate and measure known burrow structures. Our study demonstrates that co-located and georeferenced aerial, geophysical, and ground-based databases will allow rapid and effective assessment of the spatial distribution and gross geometry of comparable biogenic structures in a variety of environments and substrates.