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THe ichnogenus Conopsoides, established in the Nineteenth Century, was differentiated from other ichnogenera by the presence of mounds of sediment associated with the tracks, but this characteristic is now considered an invalid ichnotaxobase by some invertebrate ichnologists. Consequently, Conopsoides has been compared to other ichnogenera in the Hitchcock collection in order to determine if other characteristics could be used to differentiate it. As a result, the morphologies exhibited by Conopsoides are seen in two other ichnogenera, Acanthichnus and Bifurculapes. Specifically, the morphologies seen in the type species, Conopsoides larvalis, are observed in Acanthichnus cursorius and Acanthichnus saltatorius, and therefore different specimens of Conopsoides larvalis are considered to belong to these two ichnospecies. Similarly, the morphology observed in Conopsoides curtus is observed in Bifurculapes laqueatus, so the former ichnospecies is considered a junior subjective synonym of the latter. On differenciait l'ichnogenre Conopsoides, etabli au cours du 19e siecle, des autres ichnogenres par la presence de monticules de sediments associes aux traces, mais certains ichnologues des invertebres considerent desormais cette caracteristique comme une ichnotaxobase invalide. Les chercheurs ont en consequence compare le Conopsoides a d'autres ichnogenres a l'interieur de la collection de Hitchcock afin de determiner si d'autres caracteristiques pourraient servir a le differencier. Les morphologies que presente le Conopsoides ont ainsi ete observees chez deux autres ichnogenres, l'Acanthichnus et le Bifurculapes. Les morphologies relevees chez l'espece type, le Conopsoides larvalis, sont en particulier presentes chez l'Acanthichnus cursorius et l'Acanthichnus saltatorius, de sorte que differents specimens de Conopsoides larvalis sont consideres comme des membres de ces deux ichnoespeces. Dans le meme ordre d'idees, la morphologie observee chez le Conopsoides curtus est presente chez le Bifurculapes laqueatus, de sorte que l'ancienne ichnoespece est consideree comme un synonyme subjectif plus recent de la seconde. [Traduit par la redaction], INTRODUCTION In order for trace fossil names to be useful, they should communicate specific information about the biogenic structures to which they are applied (Rindsberg 2012). To that end, those [...]

A large open-pit quarry in Plainville, Massachusetts, has yielded fourteen invertebrate ichnotaxa from the Pennsylvanian Rhode Island Formation of the Narragansett Basin. These traces include Cochlichnus anguineus, Diplichnites cuithensis, Diplichnites gouldi, Diplopodichnus biformis, Gordia carickensis, Helminthoidichites tenuis, Lockeia isp., Mitchellichnus cf. ferrydenensis, Planolites montanus, Siskemia elegans, Stiallia pilosa, Stiaria intermedia, Tonganoxichnus buildexensis and Narragansettichnus fortunatus new ichnogenus and ichnospecies. Specimens were collected from talus and the depositional environment has been inferred from sedimentary structures. The sediment -ology of the slabs on which the traces were preserved indicates that the rocks represent lake-margin and shallow lacustrine sedimentary facies. Distinct ichnofacies occur in the different sedimentary environments. The lake-margin traces belong to the Scoyenia ichnofacies and include traces of apterygote insects, arthropleurid myriapods, bivalved arthropods and vermiform animals in association with tracks of temnospondyl amphibians and diapsid reptiles. The lacustrine traces include arthropod trackways, fish trails and a newly named body imprint possibly produced by an aquatic mayfly larva. These shallow lacustrine traces are attributed to the Mermia ichnofacies. Une vaste carriere a ciel ouvert a Plainville, Massachusetts, a mis au jour 14 ichnotaxons invertebres de la formation du Rhode Island de la periode pennsylvanienne dans le bassin de Narragansett. Les traces relevees comprennent Cochlichnus anguineus, Diplichnites cuithensis, Diplichnites gouldi, Diplopodichnus biformis, Gordia carickensis, Helminthoidichites tenuis, Lockeia isp., Mitchellichnus cf. ferrydenensis, Planolites montanus, Siskemia elegans, Stiallia pilosa, Stiaria intermedia et Tonganoxichnus buildexensis, et le nouveau ichnogenre et ichnoespeces Narragansettichnus fortunatus. Les specimens ont ete preleves d'un talus et le milieu de sedimentation a ete deduit a partir de structures sedimentaires. La sedimentologie des plaques sur lesquelles les traces ont ete conservees revele que les roches representent un facies sedimentaire caracteristique des marges lacustres et des eaux lacustres peu profond. Des ichnofacies distincts sont presents dans les differents milieux sedimentaires. Les traces riveraines font partie de l'ichnofacies Scoyenia et comprennent des traces d'insectes apterygotes, de myriapodes arthropleurides, d'arthropodes bivalves et d'animaux vermiformes associees a des pistes d'amphibiens temnospondyles et de reptiles diapsides. Les traces lacustres comprennent des traces d'arthropodes, des pistes de reptation de poissons et une empreinte d'organisme nouvellement baptise possiblement produite par une larve d'ephemere commune aquatique. Ces traces lacustres peu profondes sont rattachees a l'ichnofacies Mermia., [Traduit par la redaction] INTRODUCTION Over a century ago, when Woodworth (1900) described the first vertebrate tracks from the Narragansett Basin, he noted the depauperate state of knowledge of Carboniferous [...]

The type and only specimen of the ichnospecies Megapezia longipes, from the Pennsylvanian Rhode Island Formation of Plainville, Massachusetts, consists of two poorly defined tracks, one made by a manus and the other by a pes, rather than a single pedal imprint. Whereas the type species of Megapezia, Megapezia pineoi, has tetradactyl pedal imprints, the pes imprint of Megapezia longipes is pentadactyl, a feature that precludes assignment to this ichnogenus. Rather, the tracks share two characteristics with the ichnogenus Matthewichnus, namely elongate digits II and III on the manus, and a pes imprint oriented anterolaterally to the manus imprint, and are thus tentatively reassigned to that ichnogenus. Cf. Matthewichnus longipes is retained as a separate ichnospecies pending the collection of additional material that can be compared with other species within the ichnogenus. With the tentative reassignment of the Plainville tracks to Matthewichnus, Megapezia becomes monospecific and is no longer recorded in New England. The tracks are the first known occurrence of Matthewichnus from this region. Ce type et seul specimen de 1'ichnoespece Megapezia longipes, de la formation pennsylvanienne du Rhode Island a Plainville, au Massachusetts, est compose de deux pistes mal definies, l'une provenant d'un membre anterieur et l'autre, d'un membre posterieur, plutot que dune empreinte de patte unique. Alors que lespece type Megapezia, Megapezia pineoi a des empreintes de partes tetradactyles, lempreinte de membre posterieur de Megapezia longipes est pentadactyle, une caracteristique qui exclut lattribution a cet ichnogenre. Les pistes partagent plutot deux caracteristiques avec l'ichnogenre Matthewichnus, a savoir des doigts II et III allonges au membre anterieur, et une empreinte de membre posterieur orientee de facon anterolaterale par rapport a lempreinte de membre anterieur, ce qui amene a les reaffecter provisoirement a cet ichnogenre. Cf. Matthewichnus longipes demeure une ichnoespece distincte dans 1 attende de la collecte d'elements supplementaires, que Ton pourra comparer a d autres especes appartenant a cet ichnogenre. Compte tenu de la reaffectation provisoire des pistes de Plainville a Matthewichnus, Megapezia devient monospecifique et nest plus recensee en Nouvelle-Angleterre. Les pistes constituent la premiere occurrence connue de Matthewichnus dans cette region. [Traduit par la redaction], INTRODUCTION Matthew (1903) established the ichnogenus Megapezia for tracks from the Mississippian Horton Group of Parrsboro, Nova Scotia, Canada. Later, Willard and Cleaves (1930) erected a new ichnospecies, Megapezia longipes, [...]

ABSTRACT Jurassic sandstones of the Hartford Basin are well known for their dinosaur trackways, but few studies have characterized their invertebrate ichnofaunas. A notable Portland Formation exposure in this area [...]

Three trackways attributable to the ichnospecies Bifurculapes laqueatus Hitchcock, 1858 found in Lower Jurassic rocks of the Newark Supergroup in northeastern North America are preserved in association with current lineations. Each trackway takes turns so that parts of the trackway parallel the current lineations. This parallelism is interpreted as evidence that the trackmakers were entrained in flowing water and had to change course due to the current. If this interpretation is correct, then morphological differences between B. laqueatus and terrestrial insect trackways could be explained by the trackmaker moving subaqueously. Further, B. laqueatus would constitute only the second insect trackway from this region to be recognized as being made subaqueously. From an ecological standpoint, the aquatic insects that made B. laqueatus were probably near the base of the local food chain, the apex predators of which were piscivorous theropod dinosaurs. [ABSTRACT FROM AUTHOR]

The type specimens of the ichnospeciesHaplotichnus indianensisandTreptichnus bifurcuswere compared under low-angle light.H. indianensiswas found to exhibit segments with projections, which are morphological characteristics ofT. bifurcus. Consequently,H. indianensisis reinterpreted here as a shallow, subsurface burrow and is considered to be a subjective junior synonym ofT. bifurcus. Traces assigned toH. indianensis, other than the type, should be reassigned to other ichnotaxa. Looping surface trails, for example, should be calledGordiaisp. [ABSTRACT FROM PUBLISHER]

Eubrontes giganteus is a common ichnospecies of large dinosaur track in the Early Jurassic rocks of the Hartford and Deerfield basins in Connecticut and Massachusetts, USA. It has been proposed that the trackmaker was gregarious based on parallel trackways at a site in Massachusetts known as Dinosaur Footprint Reservation (DFR). The gregariousness hypothesis is not without its problems, however, since parallelism can be caused by barriers that direct animal travel. We tested the gregariousness hypothesis by examining the orientations of trackways at five sites representing permanent and ephemeral lacustrine environments. Parallelism is only prominent in permanent lacustrine rocks at DFR, where trackways show a bimodal orientation distribution that approximates the paleoshoreline. By contrast, parallel trackways are uncommon in ephemeral lacustrine facies, even at sites with large numbers of trackways, and those that do occur exhibit differences in morphology, suggesting that they were made at different times. Overall, the evidence presented herein suggests that parallelism seen in Hartford Basin Eubrontes giganteus is better explained as a response to the lake acting as a physical barrier rather than to gregariousness. Consequently, these parallel trackways should not be used as evidence to support the hypothesis that the trackmaker was a basal sauropodomorph unless other evidence can substantiate the gregariousness hypothesis. [ABSTRACT FROM AUTHOR]

Trace fossils such as Climactichnites offer rare insights into the palaeobiology of Cambrian soft-bodied animals, especially those that inhabited emergent sand flats and are not known from body fossils. Analysis of field and museum Climactichnites, together with experiments on the preservation of similar modern trails, indicates that the tracemaker was an elongate, bilaterally symmetrical, dorsoventrally flattened, soft-bodied animal with a muscular foot. These characteristics are consistent with the tracemaker being a primitive mollusc or mollusc-like animal. Unlike most Neoproterozoic and Cambrian molluscs, the tracemaker could reach considerable size; at up to c. 69 cm long, it was one of the largest Cambrian animals of its time. When moving on the sediment surface, locomotion resulted from muscular waves generated along the sole of its flexible foot; the foot was extended and then clamped onto the substrate. Contraction of pedal muscles then pulled the body forward. Sedimentary structures associated with Climactichnites  wilsoni, such as polygonal desiccation cracks, raindrop impressions, adhesion structures and gas escape structures demonstrate that the animal inhabited intermittently subaerially exposed environments. The tracemaker’s method of locomotion is similar to that employed by modern intertidal gastropods, which make Climactichnites-like trails on exposed sand flats. However, these modern trails are not preserved because of erosion by wind, waves, tides and subsequent bioturbation. Abundant microbial sedimentary structures are associated with C. wilsoni, and together with low levels of vertical bioturbation, intimate that microbial binding may have mediated the preservation of these early mollusc trails. [ABSTRACT FROM AUTHOR]