The Reverend Henry Duncan (1774–1846) and the Discovery of the First Fossil Footprints

The Reverend Henry Duncan (1774–1846), clergyman, philosopher, writer, politician, archeologist, poet, educator, social reformer, and the founder of savings banks, was indeed a “Man for All Seasons.” In 1824, while Minister of the Church of Scotland at Ruthwell, Dumfriesshire, Scotland, he was presented with a slab of red sandstone from the Corncockle Muir quarry in Annandale, exhibiting a set of footprints. Although Duncan felt from the start that he was dealing with the tracks of an animal, he wrote to the Reverend William Buckland, Reader in Mineralogy and Geology at the University of Oxford, to solicit his opinion on the origin of these curious markings. Buckland was at first skeptical but, after receiving casts of the markings from Duncan, he became convinced that they did in fact represent footprints, urging Duncan to study and publish on what he considered to be a very important paleontological find. On January 7, 1828 Duncan described the Corncockle Muir footprints to the Royal Society of Edinburgh and quoted Buckland's findings. Duncan's paper was not published by the Society until 1831, but it aroused considerable interest and was reported in several newspapers. This represents the first scientific report of a fossil track.     

History of Ichnology: The Reverend William Buckland (1784–1856) and the Fugitive Poets

William Buckland not only was an eccentric scientist liked by virtually all his peers, but in the early 1800s he was also one of the foremost authorities on geology. Buckland's vivid sense of humor and the fact that he enjoyed working on rather strange subjects, such as coprolites, rain drop impressions, cave paleontology, and fossil footsteps, provoked a great deal of light-hearted jesting from both his friends and his students. A collection of humorous poems and caricatures were produced to pay homage to the “Geologic Wizard.” Among these fugitive poets and artists were Buckland's good friends Phillip Duncan, Philip Shuttleworth, Henry De la Beche, Richard Whately, William Conybeare, and Thomas Sopwith. Buckland was still the subject of humorous verse well into the 1950s by the contemporary South African poet William Plomer.     

Formation and Taphonomy of Human Footprints in Microbial Mats of Present-Day Tidal-flat Environments: Implications for the Study of Fossil Footprints

This study concerns the formation, taphonomy, and preservation of human footprints in microbial mats of present-day tidal-flat environments. Due to differences in water content and nature of the microbial mats and the underlying sediment, a wide range of footprint morphologies was produced by the same trackmaker. Most true tracks are subjected to modification due to taphonomic processes, leading to modified true tracks. In addition to formation of biolaminites, microbial mats play a major role in the preservation of footprints on tidal flats. A footprint may be consolidated by desiccation or lithification of the mat, or by ongoing growth of the mat. The latter process may lead to the formation of overtracks. Among consolidated or (partially) lithified footprints found on present-day tidal flats, poorly defined true tracks, modified true tracks, and overtracks were most frequently encountered while unmodified and well-defined true tracks are rather rare. We suggest that modified true tracks and overtracks make up an important percentage of fossil footprints and that they may be as common as undertracks. However, making unambiguous distinctions between poorly defined true tracks, modified true tracks, undertracks, and overtracks in the fossil record will remain a difficult task, which necessitates systematic excavation of footprints combined with careful analysis of the encasing sediment.     

Footprints of Giant Birds from the Upper Eocene of the Paris Basin: An Ichnological Enigma

In 1859 the French geologist Jules Desnoyers reported the discovery of vertebrate footprints in the Late Eocene gypsum of the Paris region. Although they attracted some attention at the time, those footprints were never illustrated or described in detail, and the present whereabouts of the specimens seem to be unknown. Several types of footprints were referable to animals known by skeletal elements from the gypsum, but some were not. Among the latter were tridactyl footprints of very large birds, which Desnoyers tentatively attributed to the giant ground bird Gastornis, which had been discovered in the Lower Eocene of the Paris region a few years earlier. Gastornithids are now known from the Paleocene to the Middle Eocene, but no skeletal remains of giant birds have yet been found in the Upper Eocene of Europe. The tracks of giant birds from the gypsum of the Paris region are thus an example of fossil footprints without known osteological counterparts, and the identity of the trackmakers remains an enigma.     

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.     

History of Ichnology: The Misconceived Footprints of Rhynchosaurs

In 1842 Richard Owen described a Triassic reptile from Grinshill, Shropshire, which he named Rhynchosaurus articeps. He suggested that footprints found in the same beds were those of this fossil. However, the footprints were characterised by a backward-pointing toe and so were of the type now known as Rotodactylus. Huxley (1877), Woodward (1907), and Benton (1990) have subsequently shown that the five digits of Rhynchosaurus point forward and so could not have left these footprints. In 1896 Beasley classified the Triassic footprints found in Cheshire, his type D prints being those earlier assigned to rhynchosaurs. His D1 prints were named Rhynchosauroides articeps by Maidwell (1911). However, these D1 prints, which come from a lower horizon in the Anisian, are consistently too small to match Owen's fossil. Beasley's D3 form, now named Synaptichnium pseudosuchoides Nopcsa, is more likely to represent the footprints of Rhynchosaurus articeps, although further research and study of more complete trackways will be necessary to clarify whether these are the footprints of Archosauromorphs, such as rhynchosaurs or possibly those of Archosauriformes, for example, erythrosuchids or proterosuchids. Maidwell's Rhynchosauroides rectipes and Rhynchosauroides membranipes, originally believed to be distinct ichnospecies, are more likely to be synonyms, their apparent differences reflecting variations in the substrate traversed.     

Enigmatic didactyl tracks from the Jurassic of Iran

Didactyl tracks of theropod affinity are reported in this study based on a small sample of footprints in sandstones within the Middle Jurassic (Aalenian-Bajocian) Dansirit Formation in the Baladeh area, Alborz Mountains, Iran. These tracks superficially resemble footprints attributed to small deinonychosaurian dinosaurs known mainly from the Cretaceous of Asia. The relative length of the traces of digits III and IV is atypical for deinonychosaurids, especially dromaeosaurids, but could potentially be attributed to a troodontid-like trackmaker. The possibility of small Middle Jurassic deinonychosaurian trackmakers cannot be ruled out on the basis of the age of these traces. However, reports of pre-Cretaceous tracks of deinonychosaurian or deinoychosaur-like affinity remain rare and problematic. To date previous reports of pre-Cretaceous didactyl tracks pertain to a variable range of footprint morphologies, some of which predate known deinonychosaurian body fossil occurrences.     

From footprint morphometrics to the stature of fossil hominins: A common but uncertain estimate

Hominin footprints are a particular remain in paleoanthropology representing brief moments of life of extinct individuals. Footprints not only provide information on the locomotor behavior of fossil taxa but also on their body characteristics such as their stature. This stature is usually estimated from the length of the footprints based on the well-known foot length to stature ratio. However, footprint length does not result only from the foot length but of a combination of factors. Therefore, it is necessary to investigate the relationships between footprint length and stature of individuals using experimental approaches. Secondly, recent discoveries of fossil footprints have led to the estimation of statures from isolated footprints. However, such estimates may be biased because of the intraindividual morphometric variation of the footprints. Moreover, footprints may also be incomplete making it impossible to measure the length and therefore the estimation of a stature. The search for relationships between stature and other morphometric variables is therefore necessary to have the most accurate picture possible of the individuals who left these tracks. In this context, this article reports the results of an experimental study that aims to determine the relationships between the stature of individuals and different morphometric variables and to quantify the intraindividual variation of each variable. Thus, 21 morphometric variables were measured on a total of 175 experimental footprints left by 20 individuals in an experimental area composed of loose sand. Statistical analyses show that footprint lengths are not only the variables most correlated with stature but also those with the least intraindividual variation. However, estimation of stature from footprints left by fossil hominins is subject to three types of uncertainties: residuals from linear regression, intraindividual variation that can be particularly large in soft substrates, and the application of relationships defined on modern populations to fossil taxa.     

Pliocene Animal Trackways at Laetoli: Research and Conservation Potential

Laetoli, a paleoanthropological site in Northern Tanzania, is perhaps best known for its famous fossil hominid footprints that were discovered by Mary Leakey and her co-workers in 1978. The site not only preserves the hominid footprints but also trackways, which provide a snapshot of Pliocene faunal communities from East Africa and their inferred environments. Unlike the hominid footprints at site G, which have received tremendous attention, the animal trackways, especially at Localities 7, 8 and 10 have been neglected and are fast disappearing. In this paper, we discuss animal tracks at a newly discovered exposure and provide preliminary data on the tracks at this exposure and other sites. We also discuss the importance of the animal trackways as ecological indicators, which we have investigated as part of ongoing research and conservation efforts initiated by the Tanzania Field School in Paleoanthropology and the Associated Colleges of the Midwest (ACM) Tanzania Semester Abroad programs.     

Mammal and Bird Tracks from the Eocene Puget Group,Northwest Washington,USA

In 1997, coal extraction at the John Henry Mine in western King County, Washington, USA, exposed bedding planes in Eocene sandstone that contained numerous bird and mammal tracks. By the time scientists arrived at the site several months later, the track-bearing surfaces had mostly been obliterated by landslides. Several track specimens were collected but not curated, described, or studied. In 2011, the specimens were found in a storage room at the University of Washington Burke Museum of History and Culture, triggering an investigation that yielded many photographs of the fossil site taken at the time of the 1997 discovery. Perissodactyl mammal tracks are named herein as Oplidcatylapes eocenica ichnogenus and ichnospecies nov. Photographs also show a trackway containing eight footprints that have prominent claw impressions. These tracks are inferred to have been made by a creodont, but because of the absence of specimens or track casts to serve as holotypes, ichnotaxonomic names have not been assigned.     

Diverse Dinosaur-Dominated Ichnofaunas from the Potomac Group (Lower Cretaceous) Maryland

Until recently fossil footprints were virtually unknown from the Cretaceous of the eastern United States. The discovery of about 300 footprints in iron-rich siliciclastic facies of the Patuxent Formation (Potomac Group) of Aptian age is undoubtedly one of the most significant Early Cretaceous track discoveries since the Paluxy track discoveries in Texas in the 1930s. The Patuxent tracks include theropod, sauropod, ankylosaur and ornithopod dinosaur footprints, pterosaur tracks, and miscellaneous mammal and other vertebrate ichnites that collectively suggest a diversity of about 14 morphotypes. This is about twice the previous maximum estimate for any known Early Cretaceous vertebrate ichnofauna. Among the more distinctive forms are excellent examples of hypsilophodontid tracks and a surprisingly large mammal footprint. A remarkable feature of the Patuxent track assemblage is the high proportion of small tracks indicative of hatchlings, independently verified by the discovery of a hatchling-sized dinosaur. Such evidence suggests the proximity of nest sites. The preservation of such small tracks is very rare in the Cretaceous track record, and indeed throughout most of the Mesozoic.

This unusual preservation not only provides us with a window into a diverse Early Cretaceous ecosystem, but it also suggests the potential of such facies to provide ichnological bonanzas. A remarkable feature of the assemblage is that it consists largely of reworked nodules and clasts that may have previously been reworked within the Patuxent Formation. Such unusual contexts of preservation should provide intriguing research opportunities for sedimentologists interested in the diagenesis and taphonomy of a unique track-bearing facies.     

Constructing and testing hypotheses of dinosaur foot motions from fossil tracks using digitization and simulation

Whilst bones present a static view of extinct animals, fossil footprints are a direct record of the activity and motion of the track maker. Deep footprints are a particularly good record of foot motion. Such footprints rarely look like the feet that made them; the sediment being heavily disturbed by the foot motion. Because of this, such tracks are often overlooked or dismissed in preference for more foot-like impressions. However, the deeper the foot penetrates the substrate, the more motion is captured in the sediment volume. We have used deep, penetrative, Jurassic dinosaur tracks which have been naturally split into layers, to reconstruct foot motions of animals living over 200 million years ago. We consider these reconstructions to be hypotheses of motion. To test these hypotheses, we use the Discrete Element Method, in which individual particles of substrate are simulated in response to a penetrating foot model. Simulations that produce virtual tracks morphologically similar to the fossils lend support to the motion being plausible, while simulations that result in very different final tracks serve to reject the hypothesis of motion and help generate a new hypothesis.     

HISTORY OF ICHNOLOGY—Ichnological Eccentrics: The Curious Case of Dr. Joseph Barratt of Middletown,Connecticut

Joseph Barratt was a British-born and educated physician who settled in the United States in 1819. He had a great interest in natural history, collecting both plants and insects and studying geology, mycology, ornithology, chemistry, meteorology, Native Americans, and local history. He was apparently a man of great energy and ambition but one who could not focus to see a project to completion. Barratt was active in the early history of the discovery of vertebrate footprints in the Newark Supergroup in the eastern United States but latter developed some very strange theories regarding the age and significance of these deposits. In his latter years, Barratt's mental state deteriorated and he became even more obsessed with trying to publicize his outlandish theories. Dr. Joseph Barratt is remembered in ichnology for basically two things; he sold Edward Hitchcock a superb specimen of vertebrate tracks; and he may have the most elaborate ichnological tombstone ever constructed.     

Traces of Floating Archosaurs: An Interpretation of the Enigmatic Trace Fossils from the Triassic of the Tabular Cover of Southern Spain

Twenty-six enigmatic footprints composed of three elongated parallel depressions (two lateral ones and a shorter central one located forward with respect to the others) are described from Middle Triassic red beds of the Tabular Cover in southern Spain. The purpose of this work is the interpretation of these enigmatic tracks. The footprints range from 28 to 48 cm in length and 23 to 44 cm in width. Limestones on top of the footprint-bearing sandstone contain invertebrate traces such as Planolites, Thalassinoides, and Rhizocorallium, and bivalves (Pleuromya, Trigonodus, and Unionites), typical of marine and brackish environments. They indicate that these footprints developed in a coastal or nearly coastal environment. Whereas the enigmatic trace fossils correspond to tridactyl footprints, the digital marks are parallel and do not show any divarication as in typical walking footprints of archosauria. These traces were left when the trackmaker was swimming in a waterbody deep enough for floating only occasionally touching the ground with the digit tips. The tracks formed as a result of the backward sweeping of the tips when the digits came in contact with the bottom while the animal was buoyed by water. They differ from typical swim traces of other archosaurs (such as theropods) that show three longitudinal scratches because in studied tracks the axial digit (III) of the bipedal tridactyl archosaur sinks in the sediment and gives a short and deep scratch. The other digit scratches (from digits II and IV) would correspond to the upper surface of the toes. The studied tracks correspond to Characichnos ichnofacies (swimming tracks composed by parallel scratch marks) and they were made by a bipedal tridactil archosaur or some functionally tridactyl, chirothere tracemaker.     

A phylostratigraphy approach to uncover the genomic history of major adaptations in metazoan lineages

Macroevolutionary trends traditionally are studied by fossil analysis, comparative morphology or evo-devo approaches. With the availability of genome sequences and associated data from an increasing diversity of taxa, it is now possible to add an additional level of analysis: genomic phylostratigraphy. As an example of this approach, we use a phylogenetic framework and embryo expression data from Drosophila to show that grouping genes by their phylogenetic origin can uncover footprints of important adaptive events in evolution.     

Human Tracks from Quaternary Tufa Deposits,Cuatro Cienegas,Coahuila, Mexico

In 1961, two human footprints were excavated from the Cuatro Cienegas region of Coahuila, Mexico, but for decades were not studied scientifically or deposited in any museum. Consequently, knowledge of the locality where they were found was lost. Once the two tracks were relocated they found their way to the Museo del Desierto, Saltillo (Coahuila) where they were placed on display with a tentative label suggesting an early Holocene age (10,000 B.C.). This inference was based only on the known antiquity of humans in the region determined from previous archaeological work and two dated sediment cores close to the footprint site. It was not until 2006 that the presumed footprint discovery site was rediscovered, revealing more than 20 additional well-preserved prints, in at least four trackways representing several different individuals with foot lengths ranging from about 23–27 cm. The tracks include one well-preserved trackway providing step and stride measurements. A poorly preserved cervid trackway and a possible duck footprint have also been identified. The footprints are preserved in hard tufa. Geochemical evidence suggests the tracks were made during periods of increased aridity.     

Alexander von Humboldt and the hand-beast: A contribution to palaeontology from the last universal scholar

Despite a certain interest in the discipline, Alexander von Humboldt did not personally contribute much to the progress of palaeozoology. His most remarkable input derived from a communication about hand-like archosaur footprints from the Buntsandstein at the very acme of the important controversy that the discovery of these fossils generated (1835). Humboldt thought that the tracks were probably from a possum-like marsupial, but he did not discount that they could be from a primate. This study is characterized by its superficiality: both the anatomical comparisons and the considerations of the functional morphology of locomotion are very poor. Its effect on the scientific community proved about nil, in both the short and the long run, and Humboldt may himself have doubted his initial conclusions in later years. Nevertheless, in contrast with some contemporaneous renowned geognosts, he had no hesitation from the beginning that the footprints were genuine. He also did not hesitate to weaken the belief of the time on the timing of the succession of organised beings in geological ages, naturally without lapsing into “antiprogressionism”.     

Technical note: A volumetric method for measuring the longitudinal arch of human tracks and feet

Fossil footprints (i.e., tracks) were believed to document arch anatomical evolution, although our recent work has shown that track arches record foot kinematics instead. Analyses of track arches can thereby inform the evolution of human locomotion, although quantifying this 3-D aspect of track morphology is difficult. Here, we present a volumetric method for measuring the arches of 3-D models of human tracks and feet, using both Autodesk Maya and Blender software. The method involves generation of a 3-D object that represents the space beneath the longitudinal arch, and measurement of that arch object's geometry and spatial orientation. We provide relevant tools and guidance for users to apply this technique to their own data. We present three case studies to demonstrate potential applications. These include, (1) measuring the arches of static and dynamic human feet, (2) comparing the arches of human tracks with the arches of the feet that made them, and (3) direct comparisons of human track and foot arch morphology throughout simulated track formation. The volumetric measurement tool proved robust for measuring 3-D models of human tracks and feet, in static and dynamic contexts. This tool enables researchers to quantitatively compare arches of fossil hominin tracks, in order to derive biomechanical interpretations from them, and/or offers a different approach for quantifying foot morphology in living humans.     

伊朗新发现的中新世哺乳动物足迹的亲缘关系及其意义

伊朗晚中新世的几个地点新近发现了哺乳动物足迹化石。足迹化石在伊朗中北部分布在一套被称为上红组的厚层、混杂的泻湖-陆相地层序列的数个层位中;在伊朗北部的里海地区南部,则位于一套陆相沉积序列中。产自上红组的足迹以偶蹄动物类型为主,由于个体很小,可归入几种像羚羊一样大小的种;其他足迹则分别归入小型、中型和大型的鼬科和猫科食肉动物。产自伊朗北部的足迹化石主要为长鼻类,有些可能是犀牛,少数为偶蹄类足迹。根据上红组中发现的猫科动物(剑齿虎)足迹,可认为产足迹的地层年代为晚中新世,而产于伊朗北部古地中海边缘区沉积中的长鼻类足迹显示,地层的最大年龄为中新世最早期。这些足迹化石的发现填补了这一重要地区新近纪哺乳动物化石记录的空白。     

Bipedalism and quadrupedalism in Megatheriurn: an attempt at biomechanical reconstruction

Biomechanical reconstruction is increasingly being applied to the study of the mode of life of fossil animals. Different footprints from the fossil mammal Megatherium sp., the giant ground sloth, seem to indicate that it was able to use either bipedal or quadrupedal locomotion. By means of the estimation of the body mass of the type of the species Megatherium americanum , and using the published tracks, different mechanical parameters, such as speed, Froude number, indicators of athletic ability and bending and resistance moments of the vertebral column were calculated in both bipedal and quadrupedal conditions. Results on leg parameters are not conclusive as to the kind of locomotion to which Megatherium sp. was better adapted, but the calculations on the moments of resistance of the vertebral column and on the bending moment at breaking of the femur seem to indicate that Megatherium sp. presented adaptations to bipedalism. MEGATHERIUM, mammals, legs, vertebral column, locomotion, biomechanics, reconstruction .