Site Selectivity of the Pit Oichnus excavatus Donovan and Jagt Infesting Hemipneustes striatoradiatus (Leske) (Echinoidea) in the Type Maastrichtian (Upper Cretaceous,The Netherlands)

Two tests of the holasteroid echinoid Hemipneustes striatoradiatus (Leske) from the type area of the Maastrichtian Stage (Upper Cretaceous) bear a varied infestation of episkeletozoans (oysters, bryozoan colony, and serpulids), borings (probable Caulostrepsis isp., Oichnus simplex Bromley), surface abrasion (Gnathichnus? isp.), and pits (O. excavatus Donovan and Jagt). Only O. excavatus represents a premortem infestation. In one specimen, the four individual pits of this ichnospecies are each associated with a different ambulacrum and pore pairs that, in life, bore respiratory tube feet; the anterior ambulacrum, of different gross morphology, is not infested. In the second test, three out of four of the same ambulacra are infested, although there are also O. excavatus in the interambulacra. The association between O. excavatus and the ambulacra of the echinoid, and thus its tube feet, is open to several plausible explanations, but most likely provided some form of feeding or protective advantage to the pit-forming organism.     

Cretaceous Nonmarine Trace Fossils from the Hasandong and Jinju Formations of the Namhae Area,Kyongsangnamdo, Southeast Korea

Nonmarine strata of the Cretaceous Hasandong and Jinju formations of the Sindong Group of the Namhae area, Kyongsangnamdo, southeast Korea, contain relatively diverse and abundant ichnofaunas including domichnia, fodinichnia, pascichnia, and repichnia. These ichnofaunas are systematically described herein and three ichnocoenoses, namely the Skolithos, Palaeophycus, and Chondrites ichnocoenoses, are defined based on their paleoenvironmental occurrence. The Skolithos ichnocoenose characterizes tabular laminated sandstone facies deposited on fluvial channel levées. It is dominated by infaunally produced ichnotaxa, particularly Skolithos magnus Howell, Planolites montanus Richter and Chondrites isp. type A, with reduced numbers of Skolithos verticalis (Hall) Taenidium barretti (Bradshaw) and rare examples of Circulichnus montanus (Vyalov), Cochlichnus anguineus Hitchcock, Helminthopsis abeli Ksi??kiewicz, Helimthopsis hieroglyphica Wetzel and Bromley, Laevicyclus isp., Planolites beverleyensis (Billings), Skolithos isp., Spirodesmos isp., Thalassinoides suevicus (Rieth), and rhizoliths. The Palaeophycus ichnocoenose characterizes floodplain environments and occurs in purple mudstones and associated massive sandstone facies of crevasse-splay deposits and dark gray to green shale facies of abandoned channels. Palaeophycus tubularis Hall and Planolites montanus Richter are the most characteristic ichnotaxa, while Beaconites coronus (Frey, Pemberton and Fagerstrom), Planolites annularius Walcott, Skolithos magnus Howell, Thalassinoides paradoxicus (Woodward), and sauropod and ornithopod tracks also occur but in reduced numbers. The Chondrites ichnocoenose occurs in dark gray to black mudstones deposited in marginal lacustrine environments. It is dominated by Chondrites isp. type B. with associated Beaconites antarcticus Vyalov, Helminthopsis hieroglyphica, Palaeophycus tubularis, Skolithos magnus, Taenidium barretti, and Torrowangea rosei Webby. The three ichnocoenoses recognized herein cannot be satisfactorily assigned to currently defined nonmarine ichnofacies, suggesting that existing models of such ichnofacies are in need of additional refinement.     

The sclerobionts of the Bajocian Oolithe ferrugineuse de Bayeux Formation from Calvados (Paris Basin,Normandy, France)

Silicified fossils collected in ploughed fields at Gavrus (Calvados, France), mainly mollusc shells, are Bajocian in age, and come from the Oolithe ferrugineuse de Bayeux Formation. The entire formation is highly condensed and most fossils are reworked. Their silicification allowed treatment with dilute hydrochloric acid. This treatment brought to light numerous encrusting sclerobionts: Porifera (3 taxa), Bryozoa (n), Polychaeta (9), Brachiopoda (n), Bivalvia (5). The borings and bioerosional traces are described using the “categories of architectural design” as defined by Buatois et al. (2017). Among the 28 ichnotaxa described (corresponding to an ichnodisparity of 14), Planavolites wisshaki isp. nov., Kleithrichnus belemnophilus igen. nov., isp. nov. and Foggara foggara igen. nov., isp. nov. are new. Some Gastrochaenolites dijugus Kelly and Bromley, 1984 borings accommodate the shell of the presumed borer Lithophaga fabella J.-A. Eudes-Deslongchamps, 1838. A group of Nododendrina europaea (Fischer, 1875) on a belemnite rostrum provides a good instance of an ichnogenetic series. Encrusting sclerobionts and macroscopic boring and bioerosional trace-makers are dominantly suspension feeders. The ichnofacies is a peculiar Entobia-ichnofacies, found in deeper, lower-energy environments than the “classical” coastal Entobia-ichnofacies, on deep shell-grounds far from the coast, in the deep euphotic zone.     

Oichnus Bromley Borings in the Irregular Echinoid Hemipneustes Agassiz from the Type Maastrichtian (Upper Cretaceous,The Netherlands and Belgium)

Three ichnospecies of Oichnus Bromley occur in tests of the large holasteroid echinoid Hemipneustes striatoradiatus (Leske) in the type area of the Maastrichtian (Upper Cretaceous) in The Netherlands and Belgium; Oichnus simplex Bromley (penetrative), Oichnus paraboloides Bromley (nonpenetrative and showing two distinct morphologies), and Oichnus excavatus isp. nov. (nonpenetrative). The two distinct morphologies of O. paraboloides (both shallow, one with a central boss) are gregarious, but do not occur together on the same specimens, suggesting they were generated by different taxa. Oichnus paraboloides with a central boss occurs on H. striatoradiatus from the upper Nekum Member, Maastricht Formation (Maastrichtian, Upper Cretaceous). Tests of the host echinoid are smaller in the overlying Meerssen Member, Maastricht Formation, where they are infested by O. excavatus, the largest borings considered herein, which have concave walls and a large central boss. Blisters inside tests from the Meerssen Member show that this infestation occurred when the echinoid was alive. It is postulated that producers of these borings in H. striatoradiatus may have been genetically related and increased in size during the Maastrichtian even as the host echinoids showed a size decrease. This size increase in H. striatoradiatus was genetic and cannot be related to increase in size of borings.     

Devonian Trace Fossils of the Horlick Formation,Ohio Range,Antarctica: Systematic Description and Palaeoenvironmental Interpretation

The clastic Horlick Formation contains an ichnofauna of 28 ichnotaxa dominated by burrowers. These are a mixture of simple vertical forms (Skolithos linearis, S. magnus, Bergaueria cf. langi, Rosselia socialis, Monocraterion isp.), U or arc-like forms (Diplocraterion parallelum, Arenicolites types A and B, Catenarichnus antarcticus, C. isp., aff. Lanicoidichna isp.), and complex, vertical spiral structures (Asterosoma isp., Spirophyton isp.). Horizontal burrows include Ancorichnus cf. capronus, Palaeophycus tubularis, and Psammichnites devonicus isp. nov. Surface traces comprise Haplotichnus isp., Cruziana problematica, C. rhenana, Rusophycus aff. carbonarius, R. isp., Protovirgularia rugosa, Lockeia ornata and cubichnia indet., while trackways include Diplichnites gouldi, D. isp., Maculichna? isp. and large imprints. The Horlick Formation (maximum 56 m) records an early Devonian transgression onto a deeply weathered land area that lay in the direction of Marie Byrd Land, spreading from the South Africa sector of Gondwana. Analysis of the trace fossils confirms their formation in near-shore to intertidal environments, with some ichnotaxa living close to the marine/fluvial boundary (e.g., Spirophyton, aff. Lanicoidichna, Cruziana problematica, Rusophycus aff. carbonarius, Maculichna?). The ichnofauna probably comprised a variety of marine suspension and deposit-feeding worms, shallow burrowing molluscs (bivalves and possibly bellerophontids) and several different types of arthropods, including trilobites.     

Three New Ichnogenera of Biting and Gnawing Traces on Reptilian and Mammalian Bones: A Case Study from the Miocene of the Czech Republic

The Ahníkov (Miocene, Czech Republic) site represents a concentration of vertebrate skeletal remains in a swamp setting. Autochthonous bone deposits were strongly altered by sedimentary processes and early diagenesis. Biting and gnawing traces recognized on hard animal tissues (bones, teeth, antlers, turtle thoraces) represent seven recurring morphotypes. The following ichnotaxa are erected: Nihilichnus nihilicus n. igen. et n. isp., Nihilichnus mortalis n. isp., Machichnus regularis n. igen. et n. isp., Machichnus multilineatus n. isp., Machichnus bohemicus n. isp., and Brutalichnus brutalis n. igen. et n. isp. Each kind of bones or similar substrates bears a specific proportion of various bite traces but no observed morphotype is specific for a single substrate. Ethologically, traces of sharpening of teeth are principally different from predation traces. The beavers Steneofiber eseri and Steneofiber depereti, the carnivore Amphicyon sp. and the crocodiles are presumed as the tracemakers.     

Early cretaceous bird-dominated and dinosaur footprint assemblages from the northwestern margin of the Junggar Basin, Xinjiang, China

Here we describe a number of mostly isolated bird and non-avian dinosaur footprints from the Huangyangquan track site in the Lower Cretaceous Lower Layer of the Tugulu Group near Huangyangquan Reservoir in the Wuerhe District, Karamay, Xinjiang Uyghur Autonomous Region, China. Bird footprints at the site pertain to Koreanaornis dodsoni n. ichnosp., Goseongornipes isp., Aquatilavipes isp., and Moguiornipes robusta n. ichnogen. n. ichnosp. Moguiornipes tracks may be the products of a bird with lobed feet. These shorebird-morph tracks are the first solid evidence of birds in the Tugulu Group, and greatly enrich the known faunal diversity of the Lower Layer of the Tugulu Group. The Huangyangquan avian ichnofauna is comparable to those of the Jindong Formation, Korea and the Dakota Formation, USA. Non-avian dinosaur footprints at the site pertain to cf. Jialingpus isp., Asianopodus isp., and Kayentapus isp. This is the first report of Jialingpus from Lower Cretaceous strata. The discoveries of Asianopodus isp. and Kayentapus isp. increase the known ranges of these two ichnogenera.     

An Updated Review of the Avian Footprint Record from the Yacoraite Formation (Maastrichtian-Danian), Northwestern Argentina

Abstract

The Yacoraite Formation (Maastrichtian–Danian; Balbuena Subgroup; Salta Group), from Northwestern Argentina, represents a shallow epeiric unit which is the result of transgressions in the Andean basin of South America. Herein, we study the avian footprints from the Maimará locality, Jujuy province, and Quebrada del Tapón ichnosite, Salta province. The avian footprints from the Maimará locality is less diverse, made up: cf. Alaripeda isp., Avipeda isp., cf. Gruipeda filiportatis, and cf. Gruipeda isp. The avian track record from the Quebrada del Tapón ichnosite is composed of: cf. Alaripeda isp., Ardeipeda cf. egretta., Gruipeda filiportatis (=Yacoraitichnus avis) and others Gruipeda or compared to this ichnogenus, cf. Uhangrichnus isp., and several indetermined avian footprints. Both ichnological assemblages have tracks assigned to shorebirds or Charadriiformes. The facies distribution of trace fossils reinforces the overall model of a shorebird tracks dominance in moderate to low energy settings. This distribution can be divided into three sub-environments: (1) a moderate to high energy shoreline under wave action, (2) a supratidal body of ephemeral ponds, far away from direct wave influence and (3) a landward position, beyond the ephemeral ponds system. We have included all the ichnoassemblages within the shorebird ichnosubfacies as a subset of the Scoyenia Ichnofacies.     

Ichnosystematics of the Lower Permian Invertebrate Traces from the Collio and Mt. Luco Basins (North Italy)

The Lower Permian ichnofauna in the Collio Formation (Artinskian) in the Val Trompia (Brescian Prealps, North Italy) has been studied for a long time, but the studies have focused mainly on vertebrate prints. In this study, the invertebrate ichnofauna of the Collio Formation, and in the epiclastites of the Monte Luco Formation (Artinskian) cropping out in the Monte Luco area (Trentino Alto Adige region), is systematically analyzed for the first time. This ichnocoenosis consists of: Permichnium isp., Paleohelcura tridactyla, Diplichnites gouldi (Types A and B), Diplopodichnus biformis, Circulichnis montanus, Helminthopsis hieroglyphica, Gordia marina, Acripes cf. multiformis, Cruziana cf. problematica, Cochlichnus anguineus, Palaeophycus tubularis, Planolites isp. and ?Scoyenia isp. The ichnoassociation from the Collio Formation belongs to the Scoyenia ichnofacies, while that from the Mt. Luco Formation belongs to the Mermia ichnofacies. The latter, because of the lack of complete data, can be linked only to one of several submersion phases of the intravolcanic basin and is not referred to the complete continental Permian sequence in this zone. The composition of the ichnoassociation here analysed is similar to those of other European (especially France and Germany) and extra-European areas (especially North America and Argentina).     

A New Ichnospecies of Gastrochaenolites Leymerie from the Pleistocene Port Morant Formation of Southeast Jamaica and the Taphonomy of Calcareous Linings in Clavate Borings

The ichnospecies Gastrochaenolites pickerilli isp. nov. is based on ten borings found in a shell of the gastropod Strombus gigas Linné from the Pleistocene (Sangamonian) Port Morant Formation of southeast Jamaica. These borings bear morphological similarities to Gastrochaenolites torpedo Kelly and Bromley but differ from all other Gastrochaenolites ispp. in having prominent and numerous calcareous meniscate structures arrayed adjacent to one side of the boring. These menisci are concave towards the center of the boring and are the remnants of calcareous tubes that lined earlier boreholes, that the boring bivalve treated as part of the lithified substrate when relocating. They are thus evidence of the former positions of borings that, unusually, were breached as the bivalve migrated sideways. Although this was a common behavior for Gastrochaenolites-producing bivalves within this substrate, the reason for it occurring is uncertain.     

Two modes of mitochondrial dysfunction lead independently to lifespan extension in Caenorhabditis elegans

In Caenorhabditis elegans, longevity is increased by a partial loss‐of‐function mutation in the mitochondrial complex III subunit gene isp‐1. Longevity is also increased by RNAi against the expression of a variety of mitochondrial respiratory chain genes, including isp‐1, but it is unknown whether the isp‐1(qm150) mutation and the RNAi treatments trigger the same underlying mechanisms of longevity. We have identified nuo‐6(qm200), a mutation in a conserved subunit of mitochondrial complex I (NUDFB4). The mutation reduces the function of complex I and, like isp‐1(qm150), results in low oxygen consumption, slow growth, slow behavior, and increased lifespan. We have compared the phenotypes of nuo‐6(qm200) to those of nuo‐6(RNAi) and found them to be distinct in crucial ways, including patterns of growth and fertility, behavioral rates, oxygen consumption, ATP levels, autophagy, and resistance to paraquat, as well as expression of superoxide dismutases, mitochondrial heat‐shock proteins, and other gene expression markers. RNAi treatments appear to generate a stress and autophagy response, while the genomic mutation alters electron transport and reactive oxygen species metabolism. For many phenotypes, we also compared isp‐1(qm150) to isp‐1(RNAi) and found the same pattern of differences. Most importantly, we found that, while the lifespan of nuo‐6, isp‐1 double mutants is not greater than that of the single mutants, the lifespan increase induced by nuo‐6(RNAi) is fully additive to that induced by isp‐1(qm150), and the increase induced by isp‐1(RNAi) is fully additive to that induced by nuo‐6(qm200). Our results demonstrate that distinct and separable aspects of mitochondrial biology affect lifespan independently.     

Walking on ashes: insect trace fossils from Laetoli indicate poor grass cover associated with early hominin environments

More than 4000 insect trace fossils collected in recent years from Pliocene deposits at Laetoli in northern Tanzania provide new insights on early hominin palaeoenvironments. These trace fossils include: Fictovichnus gobiensis, Coprinisphaera murguiai, C. kheprii, Coprinisphaera ispp., Quirogaichnus isp., Teisseirei linguatus isp. nov., Celliforma ritchiei isp. nov., C. spirifer, C. germanica, C. cfr. curvata, Celliforma ispp., Rosellichnus isp., Vondrichnus planoglobus, Laetolichnus kwekai igen. et isp. nov. and Krausichnidae indet. They reveal that at least one species of moth, three dung beetles and five other coleopterans, nine taxa of solitary bees, and an indeterminate number of taxa of termites inhabited the Lower Laetolil environments. The Upper Laetolil environments, which have yielded a rich diversity of vertebrate fossils, including the early hominin Australopithecus afarensis and its putative footprints, supported several taxa of termites, one dung beetle, five other coleopterans, and eleven taxa of bees. The Upper Ndolanya environments, which have yielded the hominin Paranthropus aethiopicus, record four taxa of dung beetles, four other coleopterans, and two taxa of bees. The record of larval mortality and lack of intruder activity, revealed by the absence of emergence and intruder traces, may be associated with the anoxic/hypoxic conditions caused by the instantaneous burial of soils under thick volcanic ashes. The record of the Celliforma Ichnofacies in the Upper Laetolil environments indicates the dominance of shrubland to woodland with limited grass cover. This is supported also by the absence of Coprinisphaera, which suggests a scarcity of fresh grasses and a low abundance of large mammal grazers.     

The Tommotian phase of the Early Cambrian Agronomic Revolution in the carbonate mud environment of central Siberia

The profound ecological change of the marine benthos that eventually led to the almost complete destruction of the Precambrian matgrounds by benthic grazers and bioturbators (the agronomic revolution) was largely completed in the Tommotian. At that time, burrows produced by bottom‐dwelling animals as shelters against predators were supplemented by burrowing for food by predators and sediment feeders. The limy mud ichnofauna of that age in Siberia was very different from the roughly coeval sand bottom faunas of Baltica. Although the exact zoological identity of the animals forming the infaunal Tommotian traces remains unknown, they probably mostly represent various kinds of early nemathelminthes. No apparent locomotion traces of mollusc origin have been encountered in the Early Cambrian, despite the abundant occurrence of skeletal fossils attributed to molluscs. Possibly the standard muscular foot, typical of modern molluscs, had not yet developed. Ichnotaxa represented are Teichichnus isp., Rhizocorallium isp., Chondrites isp., possibly the Buren ichnocomplex and others.     

Upper Triassic (Keuper) non-marine trace fossils from the Haßberge area (Franconia, south-eastern Germany)

Various trace fossils from the Hassberge Formation and the Löwenstein Formation (Middle Keuper, Upper Triassic) of the Haßberge region are described. Twenty-three different forms have been identified, 17 of which are named, includingCruziana pascens n. isp.,Lockeia cunctator n. isp., andRusophycus versans n. isp.Lockeia siliquaria James, 1879,L. amygdaloides (Seilacher, 1953),L. triangulichnus Kim, 1994, andL. elongata (Yang, 1984) are revised and synonymized under the oldest available name,L. siliquaria James, 1879.Rusophycus eutendorfensis (Linck, 1942) andR. carbonarius Dawson, 1864 are revised. The diagnosis ofPolykladichnus Fürsich, 1981 is emended, and a diagnosis forHelminthoidichnites Fitch, 1850 is given for the first time. Among the described ichnotaxa,Skolithos ispp.,Rusophycus carbonarius, andTaenidium barretti are the most common forms. The trace fossil association is typical of theScoyenia ichnofacies, which indicates non-marine, periodically or completely inundated environments, such as floodplains and lake margins. Two palaeoichnocoenoses are identified. One ichnocoenosis, dominated byCruziana problematica, cf.Polykladichnus isp., andSkolithos isp. B characterizes margins of trough cross-bedded sandstones. Another ichnocoenosis, dominated byRusophycus versans n. isp.,Taenidium barretti,Scoyenia gracilis andSkolithos isp. A is related to ephemeral lake deposits. Taxonomic recommendations for the use of hitherto described and figured invertebrate Keuper trace fossils from Germany are given.     

Revision of Late Permian tetrapod tracks from the Dolomites (Trentino-Alto Adige,Italy)

The Val Gardena Formation of the Dolomites region in northern Italy preserves the most significant assemblage of Late Permian tetrapod footprints in the world. More than 120 years of collecting resulted in about 900 publicly accessible specimens from the study area. This huge amount of data is comprehensively revised in the light of recent advances in the study of Late Palaeozoic – Early Mesozoic tetrapod ichnofossils. According to our analyses, the Val Gardena Sandstone Formation includes tracks that can be assigned to cf. Batrachichnus isp. (temnospondyl amphibian), Capitosauroides isp. (amphibian), Dicynodontipus isp. (cynodont therapsid), Dolomitipes accordii n. igen. n. comb. (dicynodont therapsid), cf. Dromopus isp. (neodiapsid), Pachypes dolomiticus (pareiasaurian parareptile), Paradoxichnium problematicum (archosauromorph neodiapsid), Procolophonichnium tirolensis n. comb. (procolophonoid parareptile), cf. Protochirotherium isp. (archosauriform neodiapsid) and Rhynchosauroides pallinii (neodiapsid). The ichnoassociation is dominated by tracks of neodiapsid and parareptilian tetrapods, whereas synapsid and anamniote tracks are rather minor components. It includes 10 out of 12 tetrapod ichnogenera known from Lopingian deposits and thus it constitutes a reference for the Paradoxichnium biochron. It shows striking similarities with other low-latitude non-aeolian contemporaneous ichnoassociations of Europe and North Africa, differences may be linked to the palaeoenvironment. Moreover, it shows a clear Triassic affinity.

The new ichnogenus Dolomitipes was registered in Zoobank.org. urn:lsid:zoobank.org:act:5B4D871C-D16A-4E93-8211-CEE08019BA60     

The Trace Fossil Diplopodichnus from the Lower Jurassic Lacustrine Sediments of Central China and the Isopod Armadillidium vulgare (Pillbug) Lebensspuren as its Recent Analogue

The trace fossil Diplopodichnus isp. was identified in lacustrine siliciclastics of the Lower Jurassic Anyao Formation in the Henan Province, central China. This is the youngest occurrence of this ichnogenus. It is similar to some variants of recent surface traces of the isopod Armadillidium vulgare (pillbug) crawling on soft mud in temporal puddles. Therefore, isopods are suggested to be producers of the described Diplopodichnus isp. It seems that isopods should be taken into account as important component of deep lacustrine ecosystems by the Early Jurassic.     

Taphonomic signatures on modern molluscs and corals from Red Sea coast,southern Saudi Arabia

Bioeroded gastropod, bivalve and coral specimens (n = 570) were collected from the Jazan area, Saudi Red Sea coast, from which 22 ichnospecies of 8 ichnogenera were identified and illustrated. These traces were produced by clionid sponges (Entobia geometrica, E. ovula, E. cf. goniodes, E. cretacea, E. laquea, E. cf. paradoxa and E. isp.), duraphagous drillers (Oichnus ovalis, O. paraboloides, O. simplex and O. isp.), endolithic bivalves (Gastrochaenolites cf. dijugus, G. lapidicus, G. torpedo and G. isp.), polychaete annelids (Caulostrepsis taeniola, C. isp., Maeandropolydora sulcans, M. isp. and ?Trypanites isp.), acorn barnacles (Rogerella isp.), and vermetid gastropods (Renichnus isp.). The seashells act as hard substrate for colonization by serpulid worm, bivalves, bryozoans, and barnacles. Ichnogenus Entobia was most abundant (56.1%), followed by Gastrochaenolites (25.4%), Caulostrepsis (5.3%), Trypanites (4.2%), Maeandropolydora (3.2%), Oichnus (2.8%), Renichnus (1.9%), and Rogerella (1.0%). Oichnus occurred on the thin-shelled and smooth molluscs, while most Gastrochaenolites borings were found in the larger and thicker seashells as a suitable substrate for the settlement of polychaetes, lithophages, naticids, mytilids, and vermetids. Presence of annelid traces among radial ribs and at the siphonal areas of bivalves is indicative of nutrient capturing from water flow during the lifetime of these bivalves, within a shallow, high energy marine environment, where disarticulation, fragmentation, and abrasion of the seashells were abundantly observed.     

Avian diversity and behavior in an Eocene coastal plain,Svalbard: the ichnological evidence

Abstract

This study presents an ichnotaxonomical assessment of bird footprints from a coastal plain setting in the Eocene lower to middle Aspelintoppen Formation in Brongniartfjellet and Storvola, Svalbard. These footprints are unique evidence for Paleogene birds from Svalbard and the second evidence of Paleogene avifauna of the Arctic (along with scarce fossil remains from Ellesmere Island). The analyzed footprints are assigned to six ichnotaxa belonging to three ichnofamilies: Aquatilavipes isp., avian footprint morphotype A and B (ichnofamily Avipedidae); Gruipeda cf. G. abeli, Gruipeda cf. G. dominguensis (ichnofamily Gruipedidae); and Gyeongsangornipes isp. (ichnofamily unknown). Associated invertebrate ichnofossils include Helminthoidichnites tenuis, Cochlichnus anguineus, and Helminthopsis isp. The avian footprints reflect small, medium-sized and rare large birds that can be morphologically compared to those of modern relatives including crane, heron, plover, moorhen, gallinule, oystercatcher and curlew. It is also proposed that in situ sets of shorebird footprints showing a preferred orientation, not composing trackways and showing overprinting, can be used as an indicator of the position and orientation of the shoreline.     

Lacertoid Footprints of the Upper Permian Arenaria di Val Gardena Formation (Northern Italy)

Lacertoid footprints are the largest component of the Upper Permian Arenaria di Val Gardena Formation ichnofauna that contains hundreds of specimens mostly referred to the ichnogenus Rhynchosauroides Maidwell 1911. In this paper, we analyzed unpublished material and re-examined the Rhynchosauroides footprints of that ichnofauna, in particular the figured specimens. Analysis of Rhynchosauroides and its type ichnospecies R. rectipes Maidwell 1911 was first necessary. This preliminary investigation highlighted several problems, including ichnospecies named on the basis of poorly preserved material and in some cases significantly different from the type ichnospecies.

The study allowed for recognition of three ichnotaxa referred to Rhynchosauroides: Rhynchosauroides pallinii Conti et al., 1977, Rhynchosauroides isp.1 and Rhynchosauroides isp.2 and Ganasauripus ladinus igen. et isp. nov. Other material previously referred to Rhynchosauroides is herein regarded as unclassifiable, in the light of present ichnological knowledge and procedures.