The Recognition of Ophiomorpha irregulaire on the Basis of Pellet Morphology: Restudy of Material from the Type Locality

Serial grinding of a specimen of Ophiomorpha irregulaire collected from Coal Creek Canyon in the Book Cliffs of Utah, USA—the type locality of the ichnospecies—allows us to assess the validity of pellet morphology as an ichnotaxobase for species-level identification. The importance of O. irregulaire stems from its abundance in petroliferous shallow marine strata of post-Paleozoic age. Our three-dimensional reconstruction of the burrow wall of O. irregulaire demonstrates for the first time that it is composed of sand-cored pellets. The typically spiky nature of the pellets in cross-section is inferred to result from differential compaction of the sand core and pelletal lining. Rupturing of the thin outer clay coating of the sand pellets is considered to produce the distinctively attenuated, spiky outer surface to the burrow wall of this ichnospecies. This study demonstrates the utility of pellet morphology in species-level classification of Ophiomorpha and lends support to O. irregulaire being a cosmopolitan ichnospecies present in post-Paleozoic strata. It also demonstrates the need to ensure that ichnotaxonomic identifications are based on three-dimensional knowledge of the trace fossil in question.     

The earliest fossil evidence of bone boring by terrestrial invertebrates,examples from China and South Africa

We report the oldest fossil evidence of osteophagia by terrestrial invertebrates on both the Asian and African continents. Bones attributable to the Middle Jurassic dinosaur Chuanjiesaurus (Dinosauria: Sauropoda) were found with post-mortem insect modification in the Chuanjie Formation, Yunnan Province, China. The morphology of the borings closely matches the ichnogenus Cubiculum. Based on the lack of bioglyphs observed in Cubiculum ornatus, a new ichnospecies is proposed here. The new trace fossil, Cubiculum inornatus isp. nov., is interpreted to have been constructed for pupation by an unknown taxon of insect. Additionally, we report even older borings from Early Jurassic dinosaur bones of the Elliott Formation in the Karoo Basin, which represent the second oldest occurrence of insect traces in bone from continental settings. Both trace fossils sites have palaeogeographic implications for the origins and dispersal of osteophagia amongst terrestrial invertebrates during the Mesozoic. These discoveries push back the antiquity of pupation in animal bones by more than 100 million years to the Middle Jurassic, indicating that this behaviour, and osteophagy more generally, originated early in the Mesozoic, roughly comparable with the origination of insect pupation in woody substrates (Late Triassic).     

Taxonomic reassessment ofBolonia Meunier, 1886 (trace fossil) based on new material from the type area in Boulonnais, northern France

The ichnospeciesBolonia lata Meunier, 1886 is a straight, bilobate trace fossil with a somewhat heart-shaped outline in cross-section. It has previously been reported from various localities mainly from the Jurassic by different authors under various names such asGyrochorte, Scolicia, orProtovirgularia. Because none of these previous determinations fully agrees with the trace fossils’ morphology, the ‘forgotten name’ is reintroduced, and due to a lack of type material a neotype from the type area of Boulonnais, France is proposed. The ichnogenus is currently represented only by one ichnospecies,B. lata Meunier, 1886. Diagnostic criteria ofBolonia and morphologically related trace fossils such asScolicia, Gyrochorte, Bichordites, “Taphrhelminthopsis nelsoni”, andProtovirgularia are discussed, the synonymy ofB. lata is provided and finally a discussion on the possible producer ofBolonia is given.      

Bivalve Wood Borings of the Ichnogenus Teredolites Leymerie from the Bohemian Cretaceous Basin (Upper Cretaceous,Czech Republic)

Finds of fossil wood with bivalve wood borings (Teredolites clavatus and T. longissimus) occur in various facies and presumed sedimentary settings of the platform, shallow-marine Bohemian Crectaceous Basin. The basin comprises areas with sandy-dominated sediments, with marl and clay-dominated sediments, areas with predominat sandy-marly rocks, and finally areas dominated by calcareous nearshore sediments. Teredolites clavatus is common in fossil wood of sandstones, originating in beach or deltaic settings; marl and clay-dominated rock frequently bear wood fragments densely bored by Teredolites longissimus. When accompanied by evidence of marine environments as body fossils, glauconite or typical trace fossils, most of the wood fragments are bored. The presence/absence of borings in wood fragments can be considered the most reliable and easily useable criterion of distinction of marine settings in sandy sediments of the margin of the Bohemian Cretaceous Basin.     

Review of Japanese Dinosaur Track Localities: Implications for Ichnotaxonomy,Paleogeography and Stratigraphic Correlation

Nine dinosaur ichnospecies from the Lower Jurassic to Upper Cretaceous of Japan, including two that are new, are described herein. The new ichnotaxa are Asianopodus pulvinicalx ichnogen. et ichnosp. nov. and Schizograllator otariensis ichnosp. nov. The Japanese ichnotaxa are allied to Lower Jurassic ichnospecies in South China, North America, Western Europe and South Africa, and Upper Jurassic to Lower Cretaceous ichnospecies from Southeast and East Asia. This suggests they were part of a global ichnofauna before continental drift began in the Middle Jurassic, leading to the development of a more endemic dinosaur fauna in the Cretaceous. At least two assemblages, an ornithopod-gracile-toed theropod-dominated community, in northeastern Asia, and a robust theropod- and sauropod-dominated community in the southern part of the continent, existed in the Cretaceous. This parallels North American dinosaur distribution patterns in the Cretaceous and seems to be a reflection of paleolatitudinal controls.     

Middle Jurassic trace fossils from the Ridang Formation in Sajia County,South Tibet,and their palaeoenvironmental significance

An ichnofauna consisting of 18 ichnospecies (one of them new) in 14 ichnogenera are described for the first time from the Middle Jurassic Ridang Formation in Sajia County, South Tibet. The ichnofauna can be subdivided into two ichnoassemblages in ascending stratigraphic order: the Palaeophycus–Megagrapton ichnoassemblage in the lower and middle parts of the Ridang Formation, followed by the Cosmorhaphe–Nereites–Paleodictyon ichnoassemblage in the upper Ridang Formation. Overall, the trace fossils occur in a middle–distal turbidite fan sequence, as evidenced by both sedimentological analysis and the composition of the trace fossils. Several subenvironments of the middle–distal fan system have been recognized on the basis of the spatial distribution of the trace fossils. Typically, the channel-fill deposits in the middle part of the turbidite fan lack trace fossils, the interchannel and upper channel-fill (levee) subenvironments of the middle turbidite fan contain abundant facies-crossing trace fossils, in contrast to the distal part of the turbidite fan where deep-water trace fossils are dominant. The ichnofauna is similar to typical flysch ichnofaunas from Europe and North America in characteristics, and is interpreted to represent a typical deep-sea Nereites ichnofacies. The presence of these deep-sea trace fossils therefore would suggest that a continental slope environment existed in southern Tibet during the Middle Jurassic and the study area was located in a slope-abyssal plain setting.     

Diversity variation and tempo-spatial distribution of Otozamites (Bennettitales) in the Mesozoic of China

Otozamites is a representative fossil leaf morphogenus of the extinct Bennettitales, with an extensive distribution during the Mesozoic, especially in China. Understanding the fossil diversity variation and distribution pattern of Otozamites in China will provide information on biodiversity of bennettitalean plants as well as for reconstruction of palaeogeography and palaeoclimate conditions during the Mesozoic. So far, 46 species of this genus have been described in China, excluding unspecified species. The results show that the fossils of Otozamites are extensively recorded in the Late Triassic, and then reach their maximum development in the Early Jurassic, followed by a reduction in diversity in the Middle and Late Jurassic, and finally become extinct at the end of Early Cretaceous. Geographically, they occur in both Northern and Southern Floristic Provinces in the Mesozoic of China, with a relatively higher abundance in the Southern Floristic Province. It implies that the diversity variation and distribution of Otozamites are closely related to the change of the palaeoclimatic conditions. The warm and humid climate prevailed in the Late Triassic and Early Jurassic in South China, propitious to the development of Otozamites. After the Middle Jurassic, dry and hot climate may have caused the lower diversity level and blocked the development of Otozamites; finally at the end of the Early Cretaceous, the frequent arid climate may be a major cause for the extinction of Otozamites.     

<Emphasis Type="Italic">Rosselia socialis</Emphasis> in the Upper Marine Molasse of southwestern Germany

Sediments of the Miocene Upper Marine Molasse in southern Germany (southwestern Bavaria) represent a shallow marine, siliciclastic, and tide-influenced depositional environment. Three sections cutting through these sediments contain a distinct horizon of trace fossils. Preserved in a fine-grained quartz-sandstone are numerous more or less vertical burrows that are usually funnel-shaped, closely spaced, and locally branching. The burrows belong to the ichnospecies Rosselia socialis. The sequence-stratigraphic relevance of the Rosselia-horizons is discussed, and a hypothesis is put forward on the correlation of selected sections of the Upper Marine Molasse based on these layers.     

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.     

Insights on the Behavior of Late Paleozoic Aquatic Crustaceans (Pygocephalomorpha?): Compound Trace Fossils from Western Argentina

We describe intergradations between the arthropod repichnial trace fossils Diplichnites gouldi (Gevers et al., 1971), Dendroidichnites Demathieu et al., 1992, and Monomorphichnus Crimes, 1970 with two distinct cubichnial traces, Gluckstadtella cooperi Savage, 1971 and Huilmuichnus santracruzensis new ichnogenus and ichnospecies. These compound ichnofossils are part of high ichnodiversity arthropod-dominated trace fossil associations from the Late Carboniferous Agua Escondida Formation of the San Rafael Basin (Argentina). The complex ichnotaxonomy of Diplichnites and the ichnospecies D. gouldi are discussed and some possible working solutions are proposed. The most likely producer of the compound trace fossils are the Pygocephalomorpha, a group of Late Paleozoic crustaceans that are recorded in nearby basins from Uruguay and Brazil. The compound trace fossils are used to infer a number of complex behaviors of pygocephalomorphs in a subaqueous setting, including caridoid (tail flip) or more primitive escape reactions, landing followed by resting and transient resting during normal walking. In addition, different gaits can be inferred from well-preserved D. gouldi, which can be correlated with contrasting trackway morphology.     

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.     

Atoposaurid crocodyliforms from the Khorat Group of Thailand: first record of <Emphasis Type="Italic">Theriosuchus</Emphasis> from Southeast Asia

We describe a partial crocodilian skull from the Mesozoic non-marine sediments of the Khorat Plateau Sao Khua Formation (Berriasian-Barremian) in northeastern Thailand and assign it to Theriosuchus grandinaris sp. nov. An isolated dentary from the Phu Kradung Formation (latest Jurassic–Early Cretaceous) is also tentatively assigned to the genus Theriosuchus, and an isolated tooth from the Khok Kruat Formation (Aptian-Albian) may belong to this genus. The Thai fossils represent the first unambiguous evidence of presence of Theriosuchus outside Europe. Its occurrence in Thailand increases the known diversity of neosuchian crocodyliforms from Southeast Asia and suggests that Atoposauridae had a wide geographical distribution from the Late Jurassic to the Early Cretaceous.     

Trace fossils of the arthropod Camptophyllia from the Westphalian (Carboniferous) rocks of Lancashire, UK and their palaeoenvironmental context

Two arthropod trace fossils are described and analysed from the Carboniferous Lower Westphalian (C. communis and basal A. modiolaris chronozones) coal-bearing strata of Lancashire. The biserial trackway Diplichnites triassicus consists of five overlapping en echelon sets of 7–9 tracks preserved as epichnia and hypichnia in lacustrine siltstones. The trackway suggests subaqueous in-phase walking by a multi-segmented producer with a body length of 35–40 mm, width 17–22 mm, and 7–9 appendages. Curved, clustered, or laterally repeated, hypichnial lobes with transverse striations on the base of ripple cross-laminated sandstone are identified as Rusophycus versans. This trace fossil is interpreted as shallow resting or furrowing burrows of a homopodous arthropod, 30–60 mm long, 15–30 mm wide, and probably the same kind of arthropod as produced D. triassicus.A review of contemporary arthropod body fossils from Lagerstätten in Lancashire favours the onisciform, or Arthropleura like arthropod Camptophyllia as a potential producer of both of these trace fossils in a lacustrine palaeoenvironment.This study integrates the analysis of sediments, trace fossils and body fossils for reconstructing the arthropod biota and ecology in Westphalian lacustrine and crevasse splay fluvial palaeoenvironments.     

Parataenidium,a new taenidium‐like ichnogenus from the carboniferous of Ireland

The new ichnogenus Parataenidium is erected for backfilled tubular trace fossils that can appear superficially similar to Taenidium, but are divided horizontally into two distinct levels. Two ichnospecies are recognised: Parataenidium mullaghmorensis isp. nov. and Parataenidium moniliformis (Tate 1859). The latter ichnospecies is transferred from Eione Tate 1859, which is a junior homonym of Eione Rafinesque 1814, and therefore unavailable for Tate's ichnotaxon. The ichnogenus is an important component of late Paleozoic shallow‐water siliciclastic sediments, and can be considered as a “guide”; indicator for the Carboniferous.     

Changes in lifestyle and habitat of Zoophycos‐producing animals related to evolution of phytoplankton during the Late Mesozoic: geological evidence for the ‘benthic‐pelagic coupling model’

The trace fossil Zoophycos characterized by complex, three‐dimensional morphology with systematic internal structures occurs throughout the Phanerozoic marine sediments. The specimens of Zoophycos examined herein consist of a downward and helical spreite and are a product of the excretory behaviour of endobenthic detritus feeders. They are divided into two basic types: pre‐Jurassic and post‐Cretaceous types on the basis of whorls of spreiten in a single specimen. The pre‐Jurassic type has fewer than four whorls. In contrast, most of the post‐Cretaceous specimens exhibit spreite with multiple coils more than ten whorls. The abrupt increase in whorl number during the Cretaceous suggests that the sedentary lifestyle of the producer should change from a short‐term stay to long‐term or permanent occupation of the same burrow. Timing of the lifestyle change the Zoophycos producers seems to be closely related to the deep‐seaward migration of their habitats. The change in lifestyle and migration of Zoophycos‐producing animals during the Cretaceous might be attributable to the establishment of eutrophic bottom conditions in the deep sea. These changes seem to be associated with the flux of large amounts of phytodetrital food produced by phytoplankton, which experienced an explosive increase in species diversity during the Late Jurassic to the Late Cretaceous. The series of changes in lifestyle and habitat of the Zoophycos animals during the Late Mesozoic can serve as one piece of geological evidence for the ‘benthic‐pelagic coupling model’.     

Bioerosive structures from Miocene marine mobile‐substrate communities in southern Spain,and description of a new sponge boring

Abstract: Neogene palaeoshore sediments are abundantly represented along the Mediterranean coast of Iberia. An outcrop north of the Sierra Tejeda, named La Resinera, exposes concentrations of pebbles and boulders of marble, comprising an upper Miocene marine beach deposit. The high diversity of bioerosion trace fossils present in these boulders includes structures produced by polychaete annelids, demosponges, echinoids and endolithic bivalves, which indicate a shallow shoreface environment. The ichnotaxa represented are Maeandropolydora sulcans, Caulostrepsis taeniola, Entobia geometrica, Entobia ovula, Circolites kotoncensis, Gastrochaenolites torpedo, Gastrochaenolites lapidicus, Gastrochaenolites ornatus and Gastrochaenolites turbinatus. The borings are Tortonian (late Miocene) in age. Also present, and particularly abundant, are large sponge borings that have a single chamber from which radiating canals emerge. This trace fossil is designated as Entobia resinensis isp. nov.     

Trace and soft body fossils from the Pedroche Formation (Ovetian, Lower Cambrian of the Sierra de Córdoba, S Spain) and their relation to the Pedroche event

The low Lower Cambrian rocks from the Sierra de Córdoba contain one of the best successions in Europe, which consists of well exposed mixed facies with abundant fossil assemblages showing long stratigraphical ranges throughout the Pedroche Formation. These assemblages include diverse Ovetian archaeocyaths, trilobites, small shelly fossils, calcimicrobes, trace fossils and stromatolites. Trace fossils are still poorly known, and thus they are the main objective of this work. Ichnological data are obtained from the Arroyo de Pedroche 1, Arroyo de Pedroche 2 and Puente de Hierro sections. Trace fossils include the ichnogenera Bergaueria, aff. Bilinichnus, Cochlichnus, aff. Cosmorhaphe?, Cylindrichnus, Dactyloidites, Dimorphichnus, Diplichnites, Monocraterion, Palaeophycus, aff. Phycodes, Planolites, Psammichnites, Rusophycus, Skolithos, Torrowangea and Treptichnus, as well as faecal pellets, meniscate trace fossils and others. They are abundant in shales and sandstones, and indicate important changes in the benthic conditions with respect to the underlying Torreárboles Formation. Changes in fossil assemblages within Member I of the Pedroche Formation indicate palaeoecological disruptions, which led to the disappearance of numerous archaeocyath species and the decrease of stromatolite biodiversity. This was followed by dominance of trilobite and brachiopod assemblages, accompanied by trace fossils of the Psammichnites ichnosp. A ichnoassociation. This biotic turnover (Pedroche event) occurred at the lower part of the archaeocyath Zone III, within the Bigotina bivallata biozone. The diagnoses of the ichnospecies Cochlichnus anguineus and Dactyloidites cabanasi are emended.     

Mesozoic Araucariaceae: Morphology and systematic relationships

The Southern Hemisphere conifer family Araucariaceae has a very restricted present day distribution, but was more widespread in the past. The genusAraucaria is represented by good fossil material in both hemispheres as early as the Jurassic, whileAgathis is only known from the Southern Hemisphere beginning in the Cretaceous. Cuticle studies of extant araucarians have enabled accurate comparisons of fossil leaves to living taxa.Araucaria SectionBunya is represented by cones of several types in the Jurassic. In addition to these remains, a suite of araucarian cones showing affinities to several sections of the genusAraucaria have been described from England, Japan and North America. Evidence that fossil araucarian cones may have produced seeds with hypogeal germination is discussed in light of recent work on germination of extant bunya seedlings and the discovery of new fossil shoots from the Jurassic Morrison Formation of Utah.