A Tetrapod Ichnoassociation from the Middle Triassic (Anisian,Pelsonian) of Northern Italy

A new Middle Triassic ichnofauna recovered nearby the town of Tisens (Bozen) in the Adige Valley (Trentino, Northern Italy) is described. A relatively large ichnoassociation, in which various ichnogenera can be recognized, comes from the basal inter-supratidal layers of a mixed carbonate siliciclastic unit of Pelsonian (Middle Anisian) age. Most of the isolated footprints and trackways pertain to lizard-like reptiles referable to Rhyncosauroides and, subordinately, to archosaurian reptiles. In particular, the ichnogenera Rotodactylus, Synaptichnium and Chirotherium have been recognized. Many tracks are at present unidentified; among them a lizard-like morphotype (morphotype A). The site also yelded numerous fossil plant horizons and some scattered vertebrate remains referable to Placodontidae (cf. Placodus gigas). The site shows the continuity in the Pelsonian of the “chirothere ichnofauna” and the dominance of Rhynchosauroides in carbonate, tidal flat environments.     

Theropod and Ornithischian Footprints from the Middle Jurassic Yanan Formation of Zizhou County,Shaanxi, China

New tracksites reported from the Zizhou area elucidate the nature of the Early-Middle Jurassic dinosaurian ichnofaunas in Shaanxi Province. The assemblage is composed of footprints and trackways of medium- to large-sized theropods that show similarities with both the ichnogenera Kayentapus and Eubrontes and of small bipedal ornithischians that are referred to AS Anomoepus isp. Additionally tracks of a quadruped are present and assigned to Deltapodus isp. that may be related to a stegosaurian. Anomoepus isp. is similar to the holotype of Shensipus tungchuanensis which is, although apparently lost, re-assigned here and considered to be a subjective junior synonym of Anomoepus. It is therefore placed in new combination as Anomoepus tungchuanensis comb. nov. Identical tracks have been reported from well-preserved trackways both in the Zizhou and Shenmu areas, where they also co-occur with theropod tracks (Kayentapus and Grallator) and tracks of quadrupedal ornithischians (Shenmuichnus and Deltapodus). Thus, it appears that the carbonaceous (coal-bearing) facies of the region reveal ichnofaunas with both relatively abundant saurischian (theropod) and ornithischian tracks. This is in contrast with many areas where the ichnofaunas are heavily or exclusively saurischian (theropod) dominated.     

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.     

Behaviour of Dinosaurian Track-Makers in the Winton Formation (Cretaceous,Albian–Cenomanian) at Lark Quarry,Western Queensland,Australia: Running or Swimming?

A remarkable assemblage of dinosaur trackways in the Winton Formation (Albian–Cenomanian) at Lark Quarry, in western Queensland, Australia, has long been regarded as evidence of a stampede involving small theropods, whose tracks were classified in the ichnogenus Skartopus, and small ornithopods, whose tracks represented a second ichnogenus, Wintonopus. However, one recently-published study has claimed that existing interpretation of Lark Quarry is incorrect: it maintains that all the track-makers were ornithopods, that the ichnogenus Skartopus is a variant form of Wintonopus, and that most of the Lark Quarry track-makers were not running but more probably swimming downstream in a current of water. Those iconoclastic claims are investigated here and shown to be untenable. They derive from overgeneralized interpretation of the Lark Quarry track assemblage and invoke ad hoc auxiliary hypotheses which are either untestable or demonstrably incorrect. Closer inspection of the evidence underpinning those claims corroborates the existing interpretation of Lark Quarry as the site of a dinosaurian stampede and confirms the validity of the original distinction between theropod tracks (Skartopus) and ornithopod tracks (Wintonopus).     

Hominid Ichnotaxonomy: An Exploration of a Neglected Discipline

Although more than 60 ancient hominid track sites ranging in age from 3.7 million to less than 500 B. P. are recorded from all continents except Antarctica, no ichnotaxonomic names have ever been formally proposed for hominid tracks. There is no prohibition to the naming of fossil footprints of species that created tracks and trackways similar to those of living species. On the contrary, there is precedent for the naming of ichnotaxa corresponding to the dominant extant vertebrates classes: mammals = Mammalipedia and birds = Avipeda. The hominid track site sample includes only about a dozen sites where footprint preservation is good enough to show details of diagnostic foot morphology and typical trackway morphology. We infer that the Acahualinca Footprint Museum site in Nicaragua represents the most important ancient hominid track site that combines accessibility, a large sample of well-preserved trackways and reliable dating. For this reason, we select the Nicaraguan tracks as the type sample for the new ichnotaxon Hominipes modernus ichnogen., and ichnsp. et ichnosp. nov., which we infer to represent fully modern Homo sapiens. Our preliminary investigations of other track sites suggest that the majority also yield H. modernus. However, at many sites preservation is insufficient to make an ichnotaxonomic designation at the species level or to infer that the trackmaker was H. sapiens. Thus, at many sites including the famous Laetoli site, we apply the more general label of Hominipes isp. indet.     

Dinosaur Footprints from the Lower Cretaceous Sarten Member of the Mojado Formation at Cerro de Cristo Rey,Dona Ana County,New Mexico

Dinosaur tracks and swimming traces have been discovered at three localities in the latest Albian Sarten Member of the Mojado Formation, Bisbee Group (= “Anapra Sandstone”), at Cerro de Cristo Rey in Sunland Park, southernmost Dona Ana County, New Mexico. These localities preserve footprints of ornithopod (Caririchnium) and theropod (Magnoavipes) dinosaurs, ?reptilian swimming traces and possible tracks of an ankylosaurian dinosaur. The Sarten Member is of the latest Albian age, so the Cerro de Cristo Rey tracks are slightly younger than the well-known late Albian tracksites of northeastern New Mexico. At Cerro de Cristo Rey, the dominance of ornithopod tracks and absence of sauropod tracks fit regional patterns of late Albian-early Cenomanian track distribution consistent with North American extirpation of sauropods before the end of Albian time. The deltaic/coastal plain depositional setting of the Sarten Member is also remarkably similar to the track-bearing late Albian-Cenomanian sandstones of NE New Mexico, Oklahoma, Nebraska, and SE Colorado, which also have a tetrapod footprint ichnofacies dominated by ornithopod (Caririchnium) and theropod (Magnoavipes) tracks throughout the so-called “dinosaur freeway.”     

First Occurrence of Tetrapod Footprints from Westphalian Strata of the Sidi Kassem Basin,Central Morocco

The Sidi Kassem Basin is the only limnic basin of Westphalian age in Morocco. It is built up of 1,250 m of alluvio-fluvial to lacustrine deposits that have so far yielded plant fossils and invertebrate remains only. Recent exploration for fossil tetrapod footprints in floodplain-deposits of the basin revealed a moderately diverse vertebrate ichnofauna composed of tracks assigned to cf. Batrachichnus Woodworth, 1900; cf. Hylopus Dawson, 1882; Dimetropus Romer and Price, 1940; and Notalacerta Butts, 1891. The tracks can be referred to temnospondyl, anamniote reptiliomorph, non-therapsid synapsid (pelycosaur), and captorhinomorph trackmakers. The described ichnoassemblage is important in at least three aspects: (1) It suggests an Early to mid-Pennsylvanian age for the footprint-bearing strata of the study area. (2) It is the oldest association of tetrapod footprints from Africa. (3) It is the first evidence of the relatively rare ichnogenera cf. Hylopus and Notalacerta outside of North America and Europe. Judged from the variety of tetrapod tracks and previously collected floral remains, the Sidi Kassem Basin must have represented a well-established continental ecosystem during Pennsylvanian time. Further exploration for trace and body fossils of Palaeozoic vertebrates in this basin may be important for the reconstruction of early tetrapod evolution.     

A sauropod dinosaur megatracksite from the Late Jurassic of northern Switzerland

The largest known sauropod trackway site from the Upper Jurassic in Europe has been found in the northern Jura Mountains of Switzerland. Since the initial discovery of the site in 1988, detailed ichno‐facies mapping of the sites has been undertaken and completed. Six separate sites (from 5 to 45km apart) have been located to date; the largest one, displaying 345 single imprints, extends over a surface of 7000 m². As all of the reported sites occur within the same bed, these vertebrate prints form a megatracksite covering an area of more than 360 km². All localities are stratigraphically within the Reuchenette Formation. Two biostratigraphically diagnostic ammonites have been found within the sequence (Aulacostephanus; Gravesia), indicating an Upper Kimmeridgian age (sensu gallico). In the easternmost sites, imprints occur on mud‐cracked tidal pond deposits, whereas the western tracksites are found in supratidal algal marsh deposits. The track‐bearing horizon is immediately below a trans‐gressive event at all the sites, suggesting that the ichnofaunas represent dinosaur activity during a relative sea‐level low‐stand. Footprint size and morphology, as well as trackway dimensions, suggest that the track producers belong to the largest sauropods yet recorded in the European Jurassic, closely resembling the Breviparopus tracks from the Middle Jurassic of Morocco.     

Vertebrate Tracksites in the Middle Jurassic-Upper Cretaceous of South Tunisia

Four vertebrate tracksites from the Middle Jurassic and Upper Cretaceous in the Tataouine basin of southern Tunisia are described. Approximately 130 tridactyl footprints distributed over an area of 200 square meters, preserved on Callovian beds exposed at the Beni Ghedir site, represent the oldest evidence of a dinosaur fauna in Tunisia. In addition, three tracksites—Chenini, Ksar Ayaat, and Jebel Boulouha—have been discovered in the Cretaceous beds of the upper Continental Intercalaire, previously considered as a strictly marine depositional sequence. In addition to dinosaur tracks, the Chenini tracksite (late Albian) includes poorly preserved crocodilian tracks, and footprints assigned to a pleurodiran turtle have been recovered at the Ksar Ayaat locality (early Cenomanian). The Jebel Boulouha tracksite is dominated by well-preserved tridactyl tracks referred to small-sized theropods. Depositional settings of each tracksite have been defined on stratigraphic and sedimentologic data, and tracks were ascribed to different ichnocoenoses in relation to their paleoenvironments. This new and differentiated track record gives important information on how the fossil vertebrate fauna changed in southern Tunisia during mid-Jurassic to mid-Cretaceous times. These data provide a unique and useful census of tetrapod associations along the southern margin of the peri-Mediterranean area.     

Use of soil transfer for reforestation on abandoned mined lands in Alaska

Soil transfers from an intermediate successional site and a mature forest site were applied to Populus balsamifera L. cuttings and Alnus crispa (Ait.) Pursh seedlings placed on an abandoned mined site in south central Alaska to improve plant establishment. Mycorrhizal fungi in the soil transfers from the two successional stages were hypothesized to have different effects on plant species that colonize disturbed sites at different times or on different substrates. The site consisted of coarse, dry, low-nutrient spoils and was naturally colonized by scattered P. balsamifera but not A. crispa, although seed sources for both were adjacent to the site. Physical dimensions of the transplanted seedlings and cuttings were measured at the beginning and end of each growing season. Selected plants were harvested at the end of the 2-year study and examined for mycorrhizal formation, current growth, and leaf tissue nutrient concentrations. Both plant species were taller when treated with the soil transfers from the mature forest than with soils from the intermediate site although the increase for A. crispa was greater. Physical dimensions, current growth, and nutrient concentrations were greater when A. crispa was treated with the mature soil transfer compared with the intermediate soil transfer. Mycorrhizae which infected Alnus were predominantly a brown woody type, while other types accounted for greater relative mycorrhizal infection percentage on Populus. Insufficient quantities of mycorrhizal inoculum of suitable species, as well as low moisture and low nutrient conditions, may be factors limiting A. crispa colonization on primary disturbed sites in south central Alaska.     

Satellite tracking of gulls and genomic characterization of faecal bacteria reveals environmentally mediated acquisition and dispersal of antimicrobial‐resistant Escherichia coli on the Kenai Peninsula,Alaska

Gulls (Larus spp.) have frequently been reported to carry Escherichia coli exhibiting antimicrobial resistance (AMR E. coli); however, the pathways governing the acquisition and dispersal of such bacteria are not well described. We equipped 17 landfill‐foraging gulls with satellite transmitters and collected gull faecal samples longitudinally from four locations on the Kenai Peninsula, Alaska to assess: (a) gull attendance and transitions between sites, (b) spatiotemporal prevalence of faecally shed AMR E. coli, and (c) genomic relatedness of AMR E. coli isolates among sites. We also sampled Pacific salmon (Oncorhynchus spp.) harvested as part of personal‐use dipnet fisheries at two sites to assess potential contamination with AMR E. coli. Among our study sites, marked gulls most commonly occupied the lower Kenai River (61% of site locations) followed by the Soldotna landfill (11%), lower Kasilof River (5%) and upper Kenai River (<1%). Gulls primarily moved between the Soldotna landfill and the lower Kenai River (94% of transitions among sites), which were also the two locations with the highest prevalence of AMR E. coli. There was relatively high spatial and temporal variability in AMR E. coli prevalence in gull faeces and there was no evidence of contamination on salmon harvested in personal‐use fisheries. We identified E. coli sequence types and AMR genes of clinical importance, with some isolates possessing genes associated with resistance to as many as eight antibiotic classes. Our findings suggest that gulls acquire AMR E. coli at habitats with anthropogenic inputs and subsequent movements may represent pathways through which AMR is dispersed.     

Late Jurassic footprints reveal walking kinematics of theropod dinosaurs

Avanzini, M., Piñuela, L. & García‐Ramos, J.C. 2011: Late Jurassic footprints reveal walking kinematics of theropod dinosaurs. Lethaia, Vol. 45, pp. 238–252. This study describes a set of theropod footprints collected from the Late Jurassic Lastres Formation (Asturias, N Spain). The footprints are natural casts (tracks and undertracks) grouped into three morphotypes, which are characterized by different size frequency, L/W relationship and divarication angles: ‘Grallatorid’ morphotype, ‘Kayentapus–Magnoavipes’ morphotype, ‘Hispanosauropus’ morphotype. The tracks were produced in firm, stiff and soft sediments. The infills of deep tracks, which are typically formed in soft mud, lack fine anatomical details, but they can reveal the walk kinematics of the trackmaker through the morphology of internal track fills and sinking traces. In all footprints, a horizontal outwardly directed translation movement and rotation are recognizable. The amount and geometry of digit penetration in the ground also show a pronounced difference. It can be inferred from the described sample that different theropoda‐related ichnogenera share common kinematics. □Asturias, dinosaur footprint, late jurassic, theropods, walking kinematics.     

Thinopus and a Critical Review of Devonian Tetrapod Footprints

Devonian tetrapod tracks and trackways can be recognized by three criteria: morphology of the manus and pes impressions that matches known Devonian tetrapod skeletal morphology, manus smaller than pes, and the alternating trackway pattern that results from lateral sequence walking in quadrupedal tetrapod locomotion. The first reported Devonian tetrapod track, named Thinopus antiquus, from Pennsylvania, is not a tetrapod track and is likely an impression of a fish coprolite(s). A critical review of the published Devonian track record indicates only three can be verified as produced by a tetrapod trackmaker—Genoa River, Australia; Easter Ross, Scotland; and Valentia Island, Ireland. The supposed tetrapod tracks from the Middle Devonian of the Zache?mie quarry, Poland, fail the criteria for identification as Devonian tetrapod tracks. Indeed, no convincing case has been made that the Zache?mie structures are tetrapod tracks. Instead, they are reinterpreted as fish nests/feeding traces (ichnogenus Piscichnus). The oldest Devonian tetrapod trackway is Givetian and this is the oldest record of a tetrapod, but the sparse record of Devonian tetrapod tracks is of no other biostratigraphic and little paleobiogeographic significance. Bona fide Devonian tetrapod tracks are from nonmarine facies, so they do not support a marginal marine origin of tetrapods. They indicate lateral sequence walking and pelvic-limb-propelled, fully terrestrial (subaerial) locomotion in freshwater environments by at least some Devonian tetrapods.     

Identifying Differences in Carbon Exchange among Arctic Ecosystem Types

Our objective was to determine how varied is the response of C cycling to temperature and irradiance in tundra vegetation. We used a large chamber to measure C exchange at 23 locations within a small arctic catchment in Alaska during summer 2003 and 2004. At each location, we determined light response curves of C exchange using shade cloths, twice during a growing season. We used data to fit a simple photosynthesis-irradiance, respiration-temperature model, with four parameters. We used a maximum likelihood technique to determine the acceptable parameter space for each light curve, given measurement uncertainty. We then explored which sites and time periods had parameter sets in common—an indication of functional similarity. We found that seven distinct parameter sets were required to explain observed C flux responses to temperature and light variation at all sites and time periods. The variation in estimated maximum photosynthetic rate (P_max) was strongly correlated with measurements of site leaf area index (LAI). The behavior of tussock tundra sites, the dominant vegetation of arctic tundra, could largely be described with a single parameter set, with a P_max of 9.7 μmol m⁻² s⁻¹. Tussock tundra sites had, correspondingly, similar LAI (mean = 0.66). Non-tussock sites (for example, sedge and shrub tundras) had larger spatial and temporal variations in both C dynamic parameters (P_max varying from 9.7–25.7 μmol m⁻² s⁻¹) and LAI (0.6–2.0). There were no clear relationships between dominant non-tussock vegetation types and a particular parameter set. Our results suggest that C dynamics of the acidic tussock tundra slopes and hilltops in northern Alaska are relatively simply described during the peak growing season. However, the foot-slopes and water tracks have more variable patterns of LAI and C exchange, not simply related to the dominant vegetation type.     

Saxifraga rivularis L. on Beinn Eighe

Summary

A new locality for Saxifraga rivularis is described from Beinn Eighe, Wester Ross. Species lists from the site and from two nearby sites are compared in relation to soil analyses.     

Disparate data streams together yield novel survival estimates of Alaska-breeding Whimbrels

Survival estimates are critical components of avian ecology. In well-intentioned efforts to maximize the utility of one's research, survival estimates often derive from data that were not originally collected for survival assessments, and such post hoc analyses may include unintentional biases. We estimated the survival of Whimbrels captured and marked at two breeding sites in Alaska using divergent data streams that in isolation were subject to methodological biases. Although both capture sites were chosen to study the migration ecology of Alaska-breeding Whimbrels, maximizing the conservation value of the data we collected was obviously desirable. We used multi-year telemetry information to infer survival from one site (Colville River) and mark–resight techniques to estimate survival from a second site (Kanuti River). At Colville River, we could not feasibly include a control group of birds to assess potential survival effects of externally mounted transmitters, and at Kanuti River we were unable to account accurately for potential emigration events because we used resightings alone. We integrated these datasets in a Bayesian hierarchical framework, an approach that permitted insights across sites that moderated methodological biases within sites. Using telemetry enabled us to detect permanent emigration events from breeding sites in two of 10 birds, results that informed estimates for birds without tracking devices. These datasets yielded point estimates of true survival of Whimbrels from Colville River equipped with solar-powered satellite transmitters that were higher (0.83) than true survival estimates of Whimbrels from Kanuti River marked with leg flags alone (0.74) or equipped with surgically implanted satellite transmitters (0.50), but the 95% credible intervals on these estimates overlapped across groups. For species such as Whimbrels that are difficult and costly to study, combining information from disparate data streams allowed us to derive novel demographic estimates, an approach with clear application to other similar studies.     

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