Rusophycus carleyi (James, 1885), Trace Fossils from the Lower Ordovician of Southern Morocco,and the Trilobites that Made Them

Thin-bedded, pyrite-rich, fine sandstones and mudstones of the Floian-Dapingian Upper Fezouata Formation contain abundant trace fossils Rusophycus carleyi in close association with a species of the asaphid trilobite Asaphellus. The sizes and shapes of this trilobite and the traces match closely. Five specimens have even been found where an articulated specimen of Asaphellus appears to be directly located over a specimen of Rusophycus carleyi within a thin bed of sandstone, suggesting that the trilobite animal may have been trapped on top of a trace that it had just made. Such intimate associations between a putative tracemaker and a trace are rare in the fossil record and particularly rare for Trilobita. The number of coxal impressions that form part of R. carleyi, eleven, matches the number expected for an asaphid trilobite (one for each of eight thoracic segments and one for each of three post-oral cephalic appendages). Impressions of the hypostome, thoracic tip impressions, cephalic margin, and pygidial margin in a few of the traces also match those of this asaphid trilobite. R. carleyi has been found in Ordovician strata of other parts of the world in association with asaphid trilobites.     

The trace fossil Cruziana semiplicata and the trilobite that made it

A set of criteria is suggested for associating a trace fossil with a plausible fossil: (1) close association in the field; (2) concurrent stratigraphic range; (3) a minimal choice of candidates available that could have made the trace; (4) consistent size range between trace fossil population and that of the maker; and (5) consistent biogeographic ranges for both. In the Upper Cambrian Andam Formation of Oman, there is a rare, direct association between trilobite body fossils and the trace fossil Cruziana in the same rock succession. An association of the trilobite Maladioidella cf. colcheni with the trace fossil Cruziana semiplicata is supported by the criteria listed. Maladioidella is associated with C. semiplicata over a wide geographical area in western Gondwana. It is therefore likely that some Cruziana species were made by trilobites.     

Name change for the Cambrian trilobite <Emphasis Type="Italic">Turkestanella</Emphasis> Repina, 1975

A replacement name, Irakimaspis nom. nov., is proposed for the mid-Cambrian redlichiide trilobite Turkestanella Repina, 1975. The name was preoccupied by the tentaculite Turkestanella Klishevich, 1969 (Dacrioconarida).     

Lower Jurassic Arthropod Resting Trace from the Hartford Basin of Massachusetts,USA

Cheliceratichnus lockleyi ichnogen. nov. et ichnosp. nov. is a new ichnotaxon of arthropod resting trace (cubichnium) from the Lower Jurassic (Hettangian) East Berlin Formation in Holyoke, Massachusetts, USA. The trace fossil is preserved as showing many of the external anatomical features of the exoskeleton, which resemble those of some chelicerates, notably sun spiders (Solifugae). The resting trace is directly associated with a trackway of the ichnospecies Acanthichnus cursorius Hitchcock. This is the first described fossil resting trace of a solifugan-like arthropod, and the first direct evidence of a trackmaker of A. cursorius.     

Ichnology of deep‐sea fan overbank deposits of the Ganei slates (Eocene,Switzerland)— a classical flysch trace fossil locality studied first by Oswald Heer

Ganei (Switzerland) is a classical locality for trace fossils. At this site, Heer (1877) described a large number of trace fossils, several of which were new taxa. The trace fossils occur in thin‐bedded turbidites in which the basal divisions of the Bouma sequence are typically absent; the turbidites are assigned to the Ganei Slates and are Eocene in age. They are interpreted to have been deposited in an overbank environment within an upper to middle fan area distal to a channel. Two trace‐fossil associations occur: the first (I) is characterized by bulldozing organisms producing biodeformational structures, Scolica, and Nereites irregularis; the second (II) association shows a distinct tiering pattern with near‐surface graphoglyptids and a mixed layer with simple tubes such as cf. Palaeophycus and Planolites, plus patterned tubes such as Nereites cirrinalis, and Chondrites. Deeper turbidite layers were colonized by Chondrites and Gyro‐phyllites. All trace fossils show a normal size spectrum compared to previously studied trace‐fossil associations, so the degree of oxygenation probably did not influence the composition of either trace‐fossil association. Seafloor sediment was probably soft and did not affect the trace‐fossil associations. Sedimentation rate and event frequency did not change and are estimated to have been in a range of 5–10 cm/1000 years and 2–5 events per 1000 years, respectively. The composition of trace‐fossil associations I and II is therefore interpreted to have been controlled by the benthic food content being higher for trace‐fossil association I than for II.     

Trace fossils from arenig flysch sediments of eire and their bearing on the early colonisation of the deep seas

A sequence of Lower Ordovician (Arenig) turbidites in Co. Wexford, Eire, has yielded one of the earliest diverse ichnofaunas yet recorded from deep water sediments comprising: Chondrites, Glockerichnus, Gordia, Helminthopsis, Lorenzinia, Neonereites, Palaeophycus, Paleodictyon, Planolites, Sublorenzinia, Taenidium, Taphrhelminthopsis, Teichichnus and Tomaculum. This ichnofauna is critical in any analysis of the colonisation of the deep seas by trace fossil‐producing animals.

A world‐wide review shows that the earliest trace fossils are mainly from Late Precambrian shelf sea environments, but many more evolved during very rapid diversification in the pre‐trilobite Lower Cambrian.

There was little increase in diversity in shallow water after the Lower Cambrian but a progressive colonisation of the deep ocean took place and this accelerated during the Ordovician, when the main lineages of deep sea trace fossils were established there. Rosetted, patterned, meandering and simple spiral forms evolved in shallow water in the Upper Precambrian and pre‐trilobite Lower Cambrian and only later migrated into the deep sea, whereas complex, closely programmed, spiral traces may have evolved there.     

Intrastratal trace fossil zonation,Cretaceous flysch of northern California

Dissection of fine‐grained turbidites within the Franciscan complex at Trinidad Harbor reveals intrastratal zonation of biogenic structures. The pre‐depositional association comprises only three ichnotaxa (preserved in convex hyporelief) and is less diverse than the tiered post‐depositional association (comprised by at least seven ichnotaxa preserved in full relief). The latter association is dominated by Melatercichnus (n. ichnogen.). Post‐depositional trace‐makers exploited abundant plant detritus deposited with the turbidite sand. Temporal alternation of trace fossil associations resulted from the infrequent, but catastrophic, disturbance of pre‐turbidite communities and local replacement by assemblies of opportunistic organisms. Although probably short‐lived at specific sites, the post‐turbidite infauna was tiered, enabling a variety of deposit feeders to harvest phytodetritus of varied size or density simultaneously at different depths within newly deposited turbidite sand layers.     

The cuticle of the enigmatic arthropod Phytophilaspis and biomineralization in Cambrian arthropods

Lin, J.‐P., Ivantsov, A.Y. & Briggs, D.E.G. 2011: The cuticle of the enigmatic arthropod Phytophilaspis and biomineralization in Cambrian arthropods. Lethaia, Vol. 44, pp. 344–349. Many non‐trilobite arthropods occur in Cambrian Burgess Shale‐type (BST) biotas, but most of these are preserved in fine‐grained siliciclastics. Only one important occurrence of Cambrian non‐trilobite arthropods, the Sinsk biota (lower Sinsk Formation, Botomian) from the Siberian Platform, has been discovered in carbonates. The chemical compositions of samples of the enigmatic arthropod Phytophilaspis pergamena Ivantsov, 1999 and the co‐occurring trilobite Jakutus primigenius Ivantsov in Ponomarenko, 2005 from this deposit were analysed. The cuticle of P. pergamena is composed of mainly calcium phosphate and differs from the cuticle of J. primigenius, which contains only calcium carbonate. Phosphatized cuticles are rare among large Cambrian arthropods, except for aglaspidids and a few trilobites. Based on recent phylogenetic studies, phosphatization of arthropod cuticle is likely to have evolved several times. □arthropod cuticle, Burgess Shale‐type preservation, fossil‐diagenesis, phosphatization.     

Scolicia and its producer in shallow-marine deposits of the Miocene Chenque Formation (Patagonia,Argentina): functional morphology and implications for understanding burrowing behavior

Abstract

Scolicia is one of the most conspicuous trace fossils in lower shoreface deposits of the Miocene Chenque Formation of Patagonia, Argentina. This ichnotaxon consists of horizontal, sinuous or meandering trace fossils with a laminated backfill and two parallel strings located at the base. Abundant body fossils attributed to Brisaster iheringi occur in close association to these trace fossils. The echinoids are very well preserved, and most of the specimens have some areas with their spines attached in life position. In particular, preservation of the subanal tufts of spines, associated to isopores (which are interpreted as being associated to funnel building tube feet), supports the interpretation that these organisms are the producers of Scolicia isp. A shaft connecting the burrow with the sediment-water interface was not observed in vertical sections of the excavations, although on bedding plane surfaces, some small circular tube outlets are recognized. However, the great diversity and abundance of ichnofossils co-occurring in these deposits may preclude adequate identification of vertical structures. These deposits provide an excellent opportunity to integrate trace fossil data, body fossil information and observations from modern analogues in order to perform a morpho-functional analysis of Scolicia.     

Lunulichnus Tuberosus Ichnogen. and Ichnosp. Nov. from the Early Eocene Wasatch Formation,Fossil Butte National Monument,Wyoming: An Arthropod-Constructed Trace Fossil Associated with Alluvial Firmgrounds

A new trace fossil, Lunulichnus tuberosus, is described from fluvial deposits of the Wasatch Formation (early Eocene) at Fossil Butte National Monument, southwestern Wyoming, USA. L. tuberosus are straight, vertical to obliquely oriented, unlined cylindrical burrows with pronounced crescent-shaped wall sculptings. In situ examples of these trace fossils are most commonly preserved as sand-filled casts emanating from the erosional bases of fluvial channel sandstone bodies into underlying floodplain mudstone/siltstone beds. L. tuberosus is interpreted as the dwelling trace of a stream-dwelling decapod crustacean. Excellent preservation of fine detail, particularly their diagnostic crescent-shaped wall sculptings, support the hypothesis that L. tuberosus were excavated in firm substrata subjacent to fluvial erosional surfaces. As such, they are interpreted as constituents of alluvial Glossifungites trace fossil assemblages.     

Balanoglossites Mägdefrau, 1932 from the middle triassic of Germany: part of a complex trace fossil probably produced by burrowing and boring polychaetes

The ichnogenusBalanoglossites Mägdefrau, 1932 is re-described from its type area and is interpreted as part of a complex trace fossil comprising both burrow and boring components. The type ichnospecies,B. triadicus, consists of predominantly deep U- or Y-shaped tunnel elements, whereasB. ramosus n. isp. encompasses irregularly ramified galleries. Both ichnospecies occur frequently in firmground and hardground substrates with sporadic epikarst features. In the underlying softground, they may integrate intoLabyrintichnus terrerensis Uchman &; Álvaro, 2000, a network of irregular galleries and communicating shafts. On the omission surface, the tunnels are linked to elongated or winding grooves in hard or firm substrates. Further elements of the complex trace fossil include lobate burrows similar toZoophycos andRhizocorallium, mainly occurring in firmground and softground, shallow to deep U-shaped pouches and winding tunnels (Maeandropolydora sulcans Voigt, 1965) in hard and firm substrates. Finally, some tunnel portions and well preserved top surfaces of the ichnofabrics are scattered with the faecal pelletsCoprulus oblongus Mayer, 1952.C. oblongus has a rounded shape and a homogeneous structure and belongs to the Coprulidae n. ichnofam. Based on the numerous fingerprints preserved in the complex trace fossil, polychaete worms are identified as possible tracemakers. This is in accordance with the close combination of borings and burrows, a tunnel system highly variable in shape and size, blind ending side-branches and tunnel terminations, association with scolecodonts and exceptionally preserved polychaete remains. In addition, different commensals may have contributed to the modification of the complex trace fossil.     

A Large Trace Fossil in Nodular Limestones (Lower Devonian,Czech Republic): Sedimentological Consequences,Ethology and Taphonomy

Large star-like trace fossil was found on the upper bedding plane of nodular limestone of the Praha Formation (Pragian, Devonian) at Praha, Czech Republic. It was tentatively placed to the ichnogenus Capodistria. It is interpreted as a feeding trace that originated on the seafloor surface. The structure consists of 10–11 radial rays and its longer axis is 60 cm. The rays are preserved as concave epireliefs, up to 10 mm deep and 25 mm wide. The trace fossil partly intersects nodules that cover surfaces of most bedding planes of the Praha Formation, demonstrating that the nodules formed during the earliest stages of diagenesis.     

Associations between trilobite intraspecific moulting variability and body proportions: Estaingia bilobata from the Cambrian Emu Bay Shale,Australia

Trilobites were notably flexible in the moulting behaviours they employed, producing a variety of moult configurations preserved in the fossil record. Investigations seeking to explain this moulting variability and its potential impacts are few, despite abundant material being available for study. We present the first quantitative study on moulting in a single trilobite species using a dataset of almost 500 moult specimens of Estaingia bilobata from the Cambrian (Series 2, Stage 4) Emu Bay Shale, South Australia. Specimens were categorized by moulting mode (Salter's or Sutural Gape) and their associated configurations, and their body proportions measured from both a museum collection (including a bycatch sample) and a randomly-collected field sample. This enabled analysis of the proportion of E. bilobata specimens displaying the Sutural Gape and Salter's modes of moulting and their different configurations, and tests for association between moulting behaviour and body proportions. The results show a wide range of E. bilobata moulting configurations in all samples, suggesting that configurations represent definable instances in a largely continuous spectrum of variation. Analyses comparing body proportions of specimens showing the two modes of moulting were non-significant, suggesting there is no true association between moulting behaviour and body proportion, except for a single significant result for body length. All results were relatively consistent between the museum and field samples. However, removing accessioned specimens from the museum sample brought results even further in line with the field sample, supporting the need for consideration of museum collection bias in palaeontological analyses.     

First Report: Trace Fossil Assemblage Ptychoplasma (P. excelsum,P. vagans), Dendroidichnites (D. irregulare), Ctenopholeus (?C. kutcheri) and Bergaueria (B. hemispherica) in the Cretaceous Rocks of Bagh Formation,Mainland Gujarat,India

Abstract

This report documents the discovery of repichnia trace fossils Ptychoplasma (P. excelsum and P. vagans) and Dendroidichnites (D. irregulare); the fodichnia traces ?Ctenopholeus (?C. kutcheri) and cubichnia traces Bergaueria (B. hemishperica) from silty limestones of the Cretaceous Bagh Formation. These trace fossils have significant implications for the depositional facies and the paleo-environmental interpretations of the Bagh Formation, which have long been debated. Previously identified traces of Protovirgularia were also found in association with the newly discovered trace fossils, indicating the coexistence of both wedge and cleft-foot bivalves. The western area of the mainland Gujarat is known for its abundance and diversity of trace fossils. The trace fossil bearing Cretaceous rocks in the region occur as thin irregular detached patches and linear outcrops. Previous studies documenting trace fossil assemblages from the Bagh Formation characterised them as a combination of dwelling, feeding and locomotion forms, with the stratigraphic unit becoming less fossiliferous westward. Trace fossils in this formation have been studied and described by many workers in the surrounding areas; however, ichnofossils described in this study are new to the Bagh Formation in this area. These trace fossils were observed on recently exposed outcrops along road cuts associated with new road construction from Khasra to Mogra village around Kadipani in Mainland Gujarat.     

A fossil aphid gall from the middle Pleistocene sediment in Hyogo Prefecture,western Japan

We described the external morphology of a fossil insect gall collected from the middle Pleistocene sediment in the Osaka Group of Nishinomiya City, Hyogo Prefecture, western Japan. The fossil was well preserved without major compression and was identified as a gall induced by an aphid species of the genus Nipponaphis (Nipponaphidini: Hormaphidinae: Aphididae), based on its external morphology. This is the first reliable fossil record of an Aphididae gall. This fossil provides evidence that the intimate aphid–plant association can be traced back to the middle Pleistocene, approximately 0.4 million years ago.     

Chemical preservation of tail feathers from Anchiornis huxleyi,a theropod dinosaur from the Tiaojishan Formation (Upper Jurassic,China)

A panel of geochemical techniques is used here to investigate the taphonomy of fossil feathers preserved in association with the skeleton of the Jurassic theropod Anchiornis huxleyi. Extant feathers were analysed in parallel to test whether the soft tissues morphologically preserved in the fossil also exhibit a high degree of chemical preservation. Scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) indicate that clays and iron oxide pseudomorphs occur in the surrounding sediment and also reveal the preservation of melanosome-like microbodies in the fossil. Carbon gradient along a depth profile and co-occurrence of carbon and sulphur are shown in the fossil by elastic backscattering (EBS) and particle-induced x-ray emission (PIXE), which are promising techniques for the elemental analysis of fossil soft tissues. The molecular composition of modern and fossil soft tissues was assessed from micro-attenuated total reflectance fourier transform infrared spectroscopy (micro-ATR FTIR), solid-state ¹³C nuclear magnetic resonance (CP-MAS ¹³C NMR) and pyrolysis gas chromatography mass spectrometry in the presence of TMAH (TMAH-Py-GC-MS). Results indicate that the proteinaceous material that comprises the modern feathers is not present in the fossil feathers. The fossil feathers and the embedding sediment exhibit a highly aliphatic character. However, substantial differences exist between these samples, revealing that the organic matter of the fossil feathers is, at least partially, derived from original constituents of the feathers. Our results suggest that, despite the morphological preservation of Anchiornis feathers, original proteins, that is keratin, were probably not preserved in the 160-myr-old feathers.     

Fossil remains of an unknown Alona species (Chydoridae, Aloninae) from a high arctic lake in Nordaustlandet (Svalbard) in relation to glaciation and Holocene environmental history

We analyzed a lacustrine sediment core covering the Holocene from Lake Einstaken, Nordaustlandet, for its fossil Cladocera (Crustacea) with an aim to reconstruct past aquatic communities in this environmentally extreme and unexplored region. In the analysis, we encountered remains (carapaces, ephippia, headshields, and postabdomens) of an unknown chydorid (Chydoridae, Aloninae) species during two separate periods in the early Holocene. The remains had some comparable morphological characters with the European Alona guttata s.str. Sars, 1862 and with the glacial relict Alona werestschagini Sinev, 1999, but they differed clearly from the previous species; the headshield had broadly rounded rostrum and narrow fornices, the ephippium was heavily pigmented and reticulated, and the postabdomen had convex dorsal and ventral margins. The postabdomen had evidently similar morphology with Alona bergi R?en, 1992, which has been described, although inadequately, from arctic Canada and northern Greenland. We conclude, based on the morphology of the postabdomen, that the unknown remains belong to species closely resembling A. bergi, named here Alona cf. bergi, and assume that the species, whether the true A. bergi or some other cryptic species of the A. guttata group, is a postglacial relict of the high arctic adapted to cold climate. Herewith, we emphasize the need for extensive biogeographical investigations into both fossil and intact specimens of chydorids in the arctic.     

Ichnologic note

The brittle star Taeniaster bohemicus was found in association with the trace fossil Asteriacites lumbricalis in the Upper Ordovi‐cian of central Bohemia. Morphological features of the trace, coupled with spatial interrelationships between trace and body fossils, provide evidence that the brittle star represents the trace‐maker of this Asteriacites. The cubichnial burrows probably represent negative phototaxis among the ophiuroids.     

A New Ichnogenus for Crustacean Trace Fossils from the Upper Miocene Camacho Formation of Uruguay

Maiakarichnus currani ichnogen. et isp. nov. is a crustacean trace fossil from the Upper Miocene Camacho Formation of Uruguay. This trace fossil is a subspherical chamber preserved in full relief, with numerous thin shafts radiating in a stratigraphically upward direction mainly from its upper part and from the sides. In the Camacho Formation it can be found intergrading with Ophiomorpha and Thalassinoides . Previous (unnamed) findings of similar material are only from the Pamlico Morphostratigraphic Unit (Pleistocene) of North Carolina; these have been interpreted as callianassid brood structures. In this paper we also interpret Maiakarichnus as a brood structure of callianassid origin based on its association with Thalassinoides and Ophiomorpha .