A New Decapod Trackway from the Upper Cretaceous, James Ross Island, Antarctica

A new trace fossil, Foersterichnus rossensis igen. nov. and isp. nov., is described from the Coniacian Hidden Lake Formation, James Ross Island, Antarctica. The trace fossil is a trackway comprising straight, or slightly curving, paired rows of elongate to tear-shaped impressions, parallel or slightly inclined to the long axis of the trackway. Foersterichnus is interpreted to be the trackway of a brachyuran decapod crustacean. It occurs in transgressive shallow marine deposits formed above the storm wave base in a shelf setting. Preservation of the trackway may have been linked to a rapid deoxygenation event during drowning that led to cessation of bioturbation allowing preservation of mixed layer trackways.     

A Middle Jurassic dinosaur trackway site from Oxfordshire, UK

The Middle Jurassic (Bathonian) Ardley trackway site in Oxfordshire, UK is described in detail. The track site is extensive, containing over 40 more-or-less continuous theropod and sauropod trackways preserved together on a single bedding plane with some trackways up to 180 m in length. The trackways display reasonable preservation, with claw marks discernible. Sauropod trackways are by far the most abundant and are representative of taxa that exhibit both narrow and wide-gauge styles of locomotion. Theropod trackways are represented by large tridactyl prints and claw impressions that display exceptionally low pace angulation values during their walking phase. One theropod trackway is unique in that it reveals a gait transition associated with a temporary increase of speed. These dinosaurs were walking over a lime-mud firmground to hardground that was emergent, or locally very shallowly submerged. GPS (Global Positioning Satellite) data reveal that the tracks, preserved during a short time interval, trend in a north-easterly direction. Multi-herding behaviour is suggested for the sauropods of differing size. The discovery of this site adds significantly to our knowledge of the taxonomic composition of Middle Jurassic ecosystems. Evidence concerning locomotor styles employed by saurischian dinosaurs, footprint identification, potential trackmaker, social interactions and observations concerning estimates of Middle Jurassic faunal diversity, as well as aspects of dinosaur locomotor evolution are discussed.     

Pterosaur tracks and the terrestrial ability of pterosaurs

Unusual tracks of a quadrupedal animal with a three-digit (occasionally four-digit) manus print and four-digit pes print were first interpreted as those of pterosaurs in the 1950s. In the 1980s these tracks were reinterpreted as crocodilian, but new material shows that the original identification was correct. Two features: evidence for elongate penultimate phalanges in digits two to four of the pes, and manus trackways up to three times the width of pes trackways, can only be attributed to pterosaurs. Recent improvements in understanding of pterosaur anatomy and functional morphology explain remaining difficulties regarding the interpretation of ich-nites such as the orientation of the manus digits and the absence of some expected ichnological features. Pteraichnus and Pteraichnus-like tracks show that, when grounded, some, perhaps all, pterosaurs were plantigrade, quadrupedal, and had a semi-erect stance and gait. This is consistent with some functional interpretations of pterosaur anatomy and resolves a long-running debate regarding the terrestrial ability of this group.     

Trackway Ratio: A New Look at Trackway Gauge in the Analysis of Quadrupedal Dinosaur Trackways and its Implications for Ichnotaxonomy

A new parameter, the Trackway Ratio (TR), is proposed to supplement the previously used trackway gauge to describe and quantify the relative width of trackways in dinosaur quadrupedal gaits. It is expressed as the ratio of the width of the tracks relative to the total width of the trackway (both measured perpendicular to the long axis of the trackway). The ratio may be used with either pes (PTR) or manus (MTR) tracks. The PTR range of values for wide-, medium- and narrow-gauge trackways of previous authors are provisionally suggested to be ≤35%, 36–49% and ≥50%, respectively. The application of such a ratio would permit a more consistent ichnotaxonomy to be adopted where both track morphology and trackway parameters are used to define ichnotaxa.

Determination of the TR, as well as other parameters, will be affected by track preservation quality. Recent experiments on track simulation in the laboratory have shed further light on observations made in the field concerning the value of track measurements (in particular track length and width) recorded from below the surface on which the maker was moving. Experimental track simulations in the laboratory have shown that the dimensions of transmitted tracks preserved below the surface on which the foot was impressed may vary from 65% to 135% of the true dimensions of the indenter. Two case studies are presented that quantify the errors that may be made on calculating TR and the size, gait and speed of the maker, from trackways if the preservation of the tracks are not fully understood.

It is shown that in individual trackways the PTR may vary along the length of the trackway; so that part of the trackway may be classified as wide-gauge and other parts medium-gauge. There is a relationship between variation in PTR and that of pace angulation along the length of a single trackway. An analysis of 42 trackways, principally sauropod, shows a temporal distribution that does not agree closely with previous suggestions relating to narrow- and wide-gauge trackways.     

Las cerradicas tracksite (Berriasian,Galve, Spain): Growing evidence for quadrupedal ornithopods

Dinosaur footprints occur in shallow marine sedimentary units of the Berriasian Villar del Arzobispo Formation in the Aliaga basin, NE Spain. Las Cerradicas is a small outcrop (25 m²), near Galve, with four dinosaur trackways. Three tridactyl trackways indicate bipedal animals, and have parallel orientation. A fourth or‐nithopod trackway indicates a quadrupedal animal and is the smallest among any reported in the literature (L = 23 cm, W = 23 cm of pes tracks). It has manus prints that are oval‐shaped impressions. These and other recent discoveries shed much light on the abundance of quadrupedal ornithopods during the early Cretaceous.     

Manus-only titanosaurid trackway from Fumanya (Maastrichtian, Pyrenees): further evidence for an underprint origin

The origin of manus-only and manus dominated sauropod trackways has been a matter of intense debate since two hyphothesis exist: (a) manus-only and manus-dominated trackways result from a 'swimming' sauropod, and (b) they result from a selective underprint phenomenon that only leaves the manus recorded. Several new sauropod trackways are reported in the Fumanya tracksite area (Maastrichtian), in SE Pyrenees, where both tracks and undertracks are found on the same stratigraphic bedding surface. In one of the trackways, footprint morphology together with the trackway pattern displays a clear succession of manus-only impressions attributed to a sauropod dinosaur in a walking gait. The ichnological comparison between the manus-only trackway with the other complete trackway (manus-pes) display an identical distribution of the manus pattern. This fact clearly points towards an underprint phenomenon as the origin for manus-only trackways, since it is rather unlikely that the same pattern would completely match different locomotion behaviours such as walking and swimming. Therefore, we suggest an interpretation based on the differential loading between the hindfoot and the forefoot on an upper stratigraphic track-level, for the studied manus-only trackway. □ Fumanya tracksite, manus-only trackways, titanosaurs, trackway pattern, underprint, Upper Cretaceous.     

A New Pterosaur Tracksite from the Jurassic Summerville Formation,Near Ferron,Utah

Pterosaur tracks (cf. Pteraichnus) from the Summerville Formation of the Ferron area of central Utah add to the growing record of Pteraichnus tracksites in the Late Jurassic Summerville Formation and time-equivalent, or near time-equivalent, deposits. The site is typical in revealing high pterosaur track densities, but low ichnodiversity suggesting congregations or “flocks” of many individuals. Footprint length varies from 2.0 to 7.0 cms. The ratio of well-preserved pes:manus tracks is about 1:3.4. This reflects a bias in favor of preservation of manus tracks due to the greater weight-bearing role of the front limbs, as noted in other pterosaur track assemblages. The sample also reveals a number of well-preserved trackways including one suggestive of pes-only progression that might be associated with take off or landing, and another that shows pronounced lengthening of stride indicating acceleration.

One well-preserved medium-sized theropod trackway (Therangospodus) and other larger theropod track casts (cf. Megalosauripus) are associated with what otherwise appears to be a nearly monospecific pterosaur track assemblage. However, traces of a fifth pes digit suggest some tracks are of rhamphorynchoid rather than pterodactyloid origin, as usually inferred for Pteraichnus. The tracks occur at several horizons in a thin stratigraphic interval of ripple marked sandstones and siltstones. Overall the assemblage is similar to others found in the same time interval in the Western Interior from central and eastern Utah through central and southern Wyoming, Colorado, northeastern Arizona, and western Oklahoma. This vast “Pteraichnus ichnofacies,” with associated saurischian tracks, remains the only ichnological evidence of pre-Cretaceous pterosaurs in North America and sheds important light on the vertebrate ecology of the Summerville Formation and contiguous deposits.     

Vertebrate Ichnopathology: Pathologies Inferred from Dinosaur Tracks and Trackways from the Mesozoic

Literature concerning dinosaur footprints or trackways exhibiting abnormal gait or morphology reflecting pathology (ichnopathology) is rare. We report on a number of Jurassic and Cretaceous occurrences of theropod footprints from western North America with unusual morphologies interpreted herein as examples of inferred pathologies, or ichnopathologies. The majority of ichnopathologies are primarily manifested in the digit impressions and include examples of swelling, extreme curvature, dislocation or fracture, and amputation. A number of occurrences are single tracks on ex situ blocks with substantial deformation (inferred dislocation or fracture), or absence of a single digit impression. Two occurrences are from in situ natural mould trackways, one of which is a lengthy trackway of a presumed allosauroid with no noticeable deformation of the digits or feet but with strong inward rotation of the left footprint toward the midline and a pronounced, waddling limp. The other is a tyrannosaurid trackway consisting of three footprints (one right, two left) with the two left prints exhibiting repetitive ichnopathology of a partially missing Digit II impression.     

Reinterpretation of problematical tracks at Clayton Lake State Park,New Mexico: Not one pterosaur,but several crocodiles

A series of six problematical and controversial footprints at Clayton Lake State Park, New Mexico, described as a supposed pterosaur trackway were reexamined to determine what sort of animal made them and how they were made. Additional footprints and two tail drags were found. These, together with some of the six problematical footprints, form at least three trackways of crocodylomorph animals, probably crocodilians. The trackways were probably formed in shallow water and may record the transition from walking to swimming.     

Trackways of the American Crocodile (Crocodylus acutus) in Northwestern Costa Rica: Implications for Crocodylian Ichnology

We documented trackways of free-living Crocodylus acutus on beaches at the mouths of Tamarindo and Ventanas estuaries, Costa Rica. Our crocodiles had estimated total lengths of 1–3 meters or more. Manus prints have five digits, with digits I–III bearing claw marks. Pes prints have four digits, with claw marks on digits I–III. The pes is plantigrade. Claws generally dig into the substrate. Apart from claw marks, digit I and the heel of the pes are usually the most deeply impressed parts of footprints. Trackways are wide-gauge. Pes prints are usually positioned just behind ipsilateral manus prints of the same set and may overlap them. Manus and pes prints angle slightly outward with respect to the crocodile's direction of movement. Claw-bearing digits of both the manus and pes may create curved, concave-toward-the-midline drag marks as the autopodium is protracted. The tail mark varies in depth and clarity, and in shape from nearly linear to markedly sinuous. Sometimes the tail mark hugs the trackway midline, but sometimes it is closer to, or even cuts across, prints of one side. American crocodile footprints and trackways are similar to those observed in other extant crocodylian species, indicating substantial trackway conservatism across the group.     

辽西早白垩世九佛堂组两种新的翼手龙类化石(英文)

简要报道了辽西热河群上部九佛堂组两件新的翼手龙类化石 ,即夜翼龙科(Nyctosauridae)的张氏朝阳翼龙 (新属、新种 )Chaoyangopteruszhangigen .etsp .nov.和古魔翼龙科 (Anhangueridae)的顾氏辽宁翼龙 (新属、新种 )Liaoningopterusguigen .et.sp .nov.。前者为保存较完整的化石骨架 ,后者为一大型翼龙的头骨和部分头后骨骼化石。朝阳翼龙是夜翼龙科在亚洲大陆的首次确切的化石记录 ,也是层位最低和保存最完整的化石骨架。朝阳翼龙具有4节翼指骨 ,手指爪粗大弯曲 ,这些发现补充和修正了前人认为的夜翼龙科只有 3节翼指骨 ,手指爪退化缺失等一些重要的形态学特征。朝阳翼龙与该科的Nyctosaurusgracilis头后骨骼相比 ,具有许多不同的特征 ,如胫骨特长 ,远长于股骨 ,翼掌骨和第 1翼指骨相对较短 ,肩胛骨短于乌喙骨等。辽宁翼龙是我国已发现的个体最大的翼龙化石 ,发育前上颌骨和齿骨弧形脊突这一古魔翼龙科的重要鉴别特征。与该科的其他成员相比 ,辽宁翼龙上、下颌的牙齿较少 ,仅分布在其前部 ,齿列约占上、下颌长度的 1 / 2。上颌第 1、3齿小 ,第 2、4齿巨大 ,其中第 4齿最大 ,为已知翼龙中最大的牙齿。牙齿具有明显的替换现象。夜翼龙科的成员仅分布于美洲大陆的晚白垩世地层中 ,而古魔翼龙科的成员则是     

An ophiuroid trackway from the Lower Devonian Hunsrück Slate, Germany

A new trace fossil, Arcichnus saltatus , from the Lower Devonian Hunsrück Slate, Germany, is interpreted as the trackway of a protasterid ophiuroid, Taeniaster. The trackway consists of a series of horseshoe-shaped impressions, produced by a pair of arms, a feature characteristic of some ophiuroid trackways. This new trace fossil demonstrates that protasterids lived both infaunally and epifaunally.     

A dinosaur ichnocoenosis from the middle jurassic of Yorkshire,UK

An assemblage of dinosaur tracks from the undersurface of a sandstone bed in the Saltwick Formation (Middle Jurassic) of Yorkshire shows a range of morphological types, preservational variants and behavioral styles. The tracks are combinations of transmitted prints and underprints and include three distinct trackways. One trackway was made by an animal walking on exposed damp sand, another was left by an animal swimming diagonally across a current and being swept down current, while the third may have been made by an animal either running or pushing off with its feet as it drifted down current. Environmental conditions that existed during the formation of the trackways varied between crevasse splay floods and exposed damp sand. The morphology of the swimming tracks is sufficiently distinctive to warrant the erection of a new ichnogenus and ichnospecies—Characichnos tridactylus. Previously described material from Kansas, Wyoming and New Mexico can be attributed to this new ichnogenus, while specimens from Germany and Utah are only provisionally referred to it. This indicates a known range from Triassic to Cretaceous.     

Thunder lizard handstands: Manus-only sauropod trackways from the Glen Rose Formation (Lower Cretaceous,Kendall County,Texas)

Abstract

Three parallel, manus-only sauropod trackways from the Coffee Hollow A-Male tracksite (Glen Rose Formation, Kendall County, Texas) were studied separately by researchers from the Heritage Museum of the Texas Hill Country and the Houston Museum of Natural Sciences. Footprint and trackway measurements generally show good agreement between the two groups’ data sets. Footprints appear to be shallowly impressed true tracks rather than undertracks. One of the Coffee Hollow trackways shows marked asymmetry in the lengths of paces that begin with the left as opposed to the right forefoot, and two of the Coffee Hollow trackways are unusually broad. The Coffee Hollow trackways differ enough from the manus portions of other Glen Rose Formation sauropod trackways to suggest that they were made by a different kind of sauropod. Greater differential pressure exerted on the substrate by the forefeet than the hindfeet probably explains the Coffee Hollow trackways, like other manus-only sauropod trackways, but the possibility that they indicate unusual locomotion cannot at present be ruled out.     

The matrix affects trackway corridor suitability for an arenicolous specialist beetle

In conserving regional insect diversity dispersal corridors are advocated to counteract fragmentation and for resilience to climate change. However, influences of corridor design and management on their function are poorly understood. Effects of contrasting matrix structure on the suitability and function of trackways as corridors for dispersal of an arenicolous carabid beetle, Harpalus rufipalpis (Sturm), was studied within a plantation landscape using mark-release-recapture. A total of 1,120 marked H. rufipalpis were released into four trackways: two “open” trackways surrounded by pine plantations aged 13–16 years and two “shaded” trackways surrounded by plantations aged 26–37 years. Dispersal was monitored by a grid of pitfall transects placed across trackways at intervals of four meters, extending 44 m north and south of the release point. Numbers of resident and marked recaptured H. rufipalpis, their average daily movement rates and numbers of recaptures in the north and south direction were compared between open and shaded trackways using 238 recaptures. The surrounding matrix affected trackway suitability with greater abundance of resident beetles found in open trackways; however H. rufipalpis was also naturally present in shaded trackways. H. rufipalpis were more active in low quality shaded corridors as inferred from the greater number of recaptures and from greater daily movement rates. Corridor edge permeability differed between trackway types, with more individuals leaving the corridor to enter the matrix in the less suitable shaded trackways. Thus matrix type affected the potential habitat suitability and conduit function of trackway corridors.     

Locomotor kinetics on sloped arboreal and terrestrial substrates in a small quadrupedal mammal

Small animals must be capable of moving on a wide variety of surfaces; thus, examining the mechanics of locomotion on a wide variety of substrates is necessary to understand how the animal can utilize its habitat. Therefore, locomotor kinetics are examined on arboreal and terrestrial sloped substrates in the marsupial Monodelphis domestica (gray short-tailed opossum). Substrate reaction forces were measured as opossums moved across four trackways: 30 degrees upslope and 30 degrees downslope trackways, which were flat ("terrestrial") or cylindrical ("arboreal"). Regardless of substrate slope, medial limb forces were measured on arboreal trackways and usually lateral limb forces on terrestrial trackways. Otherwise the general patterns of vertical and craniocaudal forces and impulses were similar between same-sloped terrestrial and arboreal trackways. Some significant modifications to these gross patterns occurred: on the arboreal upslope trackway, hindlimbs supported more body weight than on the terrestrial uphill, possibly because hindlimbs were more stably positioned on the upslope arboreal trackway than forelimbs. Furthermore, the difference between fore- and hindlimbs with respect to craniocaudal impulses was less on the arboreal sloped trackways. In conclusion, kinetic patterns can usually be explained by body weight support roles and by the placement of the limbs on the arboreal trackway.     

Skimming the surface with Burgess Shale arthropod locomotion

The first arthropod trackways are described from the Middle Cambrian Burgess Shale Formation of Canada. Trace fossils, including trackways, provide a rich source of biological and ecological information, including direct evidence of behaviour not commonly available from body fossils alone. The discovery of large arthropod trackways is unique for Burgess Shale-type deposits. Trackway dimensions and the requisite number of limbs are matched with the body plan of a tegopeltid arthropod. Tegopelte, one of the rarest Burgess Shale animals, is over twice the size of all other benthic arthropods known from this locality, and only its sister taxon, Saperion, from the Lower Cambrian Chengjiang biota of China, approaches a similar size. Biomechanical trackway analysis demonstrates that tegopeltids were capable of rapidly skimming across the seafloor and, in conjunction with the identification of gut diverticulae in Tegopelte, supports previous hypotheses on the locomotory capabilities and carnivorous mode of life of such arthropods. The trackways occur in the oldest part (Kicking Horse Shale Member) of the Burgess Shale Formation, which is also known for its scarce assemblage of soft-bodied organisms, and indicate at least intermittent oxygenated bottom waters and low sedimentation rates.     

Sauropod Trackway Reflecting an Unusual Walking Pattern from the Early Cretaceous of Shandong Province,China

The trackway of a quadrupedal dinosaur from the Early Cretaceous (Albian) Qingquan tracksite (Tancheng, Shandong Province) is redescribed, and the trackmaker is identified as a sauropod. The trackway makes a slight turn towards the northwest and is characterized by an extremely narrow gauge pattern and an unusual configuration, i.e., a conspicuous difference between the position of the left and right manus tracks with respect to the position of the preceding pes track. Left manus tracks are located on the inside of the trackway, very close (and sometimes even in connection) to the opposite right pes tracks. So far, the Qingquan trackway is possibly the only extremely narrow-gauge sauropod trackway known from China. However, it is not clear to what extent this extremely narrow gauge pattern is related to the turning or a special behavior, or even linked to an injury (“limping trackway”). We tentatively attribute the Qingquan trackway to cf. Parabrontopodus, even though it has a rather low heteropody that is significantly lower than in Parabrontopodus and not typical for narrow-gauge sauropod trackways, but occurs in the wide-gauge ichnotaxon Brontopodus. Because of this discrepancy, the Qingquan trackway cannot readily be attributed to a more basal sauropod, which is generally considered the producer of narrow-gauge trackways. Therefore, the identification of a distinct sauropod group is not possible presently. The only skeletal remains of sauropods from the Lower Cretaceous of Shandong Province belong to the large titanosauriform, Euhelopus zdanskyi.     

Early Cretaceous pterosaur tracks from a “buried” dinosaur tracksite in Shandong Province,China

Here we describe the pterosaur and tridactyl dinosaur footprint assemblage from a new tracksite in the Early Cretaceous Qugezhuang Formation near the Wenxiyuan Community in Jimo County-level City, Qingdao City, Shandong Province, East China. The construction of a community building has, since the discovery, covered the majority of tracks, but a few specimens on abandoned building stones constitute the first pterosaur track record in eastern China. The pterosaur tracks are assigned to Pteraichnus isp. and were probably made by a small to medium-sized pterodactyloid. The new pterosaur trackway contributes to the growing database of pterosaurian ichnites in Asia. The Wenxiyuan tridactyl dinosaur tracks are morphologically similar to those of theropods, but they are too poorly preserved to be referred to any particular ichnotaxon.