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... These swim tracks are most abundant and best preserved in the upper portion of the Torrey Member in central to southern Utah. The paleoenvironmental conditions and substrate properties required for the detailed production and preservation of fossil tracks has been explored (e.g., Scrivner and Bottjer, 1986;Falkingham et al., 2011) and localized occurrences of well-preserved tetrapod swim tracks are known (e.g., McCrea et al., 2004;Milner et al., 2006;Bennett et al., 2014). The widespread distribution of well-preserved swim tracks has thus far only been reported from Lower to Middle Triassic deposits of western North America (Thomson and Lovelace, 2014), suggesting the operation of regional paleoenvironmental controls on their production and preservation. ...
... Random footmarks that do not form recognizable traceways most likely represent bottom-walking behaviors similar to those observed in modern hippopotami where the body weight is supported by water permitting a range of locomotive styles (Coughlin and Fish, 2009). The preservation of subaqueous traceways and footmarks in the fossil record exhibiting these behaviors has recently been recognized in an assemblage of hippopotamus footmarks from Africa (Bennett et al., 2014). ...
... Thus a unique combination of factors in Early Triassic delta systems (delayed ecologic recovery, depositional environments, and tetrapod swimming behavior) resulted in the production and preservation of swim tracks (Fig. 14). Although swim tracks are not uncommon throughout the rest of the Mesozoic (e.g., McAllister, 1989;Milner et al., 2006;Xing et al., 2013) and Cenozoic (e.g., McCrea et al., 2004;Bennett et al., 2014) these occurrences are still localized in contrast to widespread and abundant like swim tracks in the Moenkopi Formation. This suggests that it is not the swimming behavior itself but the prevalence of unbioturbated substrates resulting from the unique combination of ecological and environmental conditions during the Early Triassic that led to the production and preservation of swim tracks in the Moenkopi Formation. ...
Thesis
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Tetrapod swim tracks attributed to reptiles occur abundantly throughout Lower to Middle Triassic deposits across the western United States. In central and southern Utah these swim track localities are stratigraphically restricted to the upper portion of the Torrey Member of the Moenkopi Formation. Here they show detailed features such as longitudinal striae and disc-shaped claw impressions that must have required specific substrate conditions in order to be produced and preserved. A suite of sedimentologic and ichnologic observations at several swim track localities demonstrates the widespread development and persistence of subaqueous firmground substrates buried by crevasse splay deposits in the interdistributary areas of a large lower delta plain. The heterolithic stratigraphy is typical of interdistributary bays and channels and generally consists of decimeter-scale fining-upward cycles of mud- and siltstone beds below the track-bearing horizons and thicker, massive or cross-bedded sandstones above. Siltstone and sandstone beds show low angle accretion sets, vary laterally in thickness, and commonly pinch out so that they cannot be correlated regionally. Common sedimentary structures indicate predominately quiet subaqueous conditions with periodic higher energy events. These include trough cross stratification, climbing ripples, rip-up clasts, and soft sediment deformation. Track surfaces often exhibit localized dewatering structures and load casts in addition to flute casts and current crescents indicating unidirectional current flow. Mudcracks are rare. The low diversity invertebrate ichnoassemblage is comprised of locally high densities of relatively diminutive traces and reflects stressed brackish water faunas. These characteristics are almost certainly augmented by delayed biotic recovery following the end-Permian mass extinction and resulted in extremely low degrees of bioturbation. This lack of biogenic mixing promoted semi-consolidation of dewatered mud substrates resulting in the widespread production and persistence of firmgrounds capable of recording and maintaining detailed swim tracks. The subsequent burial of these firmground surfaces under coarser-grained crevasse splay deposits resulted in sharp heterolithic contacts further facilitating the preservation of detailed track features.
... The buoyant hypothesis is also compatible with the wide range of pedal digit divarication in the Niñu-Mayu tracks, where digits spread at an angle that depends on the distance of the hip from the bottom during buoyancy. In this way, the ankylosaurian locomotion could reflect a gait somewhat similar to that of a hippo in the water, where digits lack a fleshy enclosure and spread out maximizing the supporting surface (McCrea, 2000; Coughlin and Fish, 2009). 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 Moreover, Bennett et al. (2014) studied both modern and fossil subaqueous hippo tracks and describe similar features with those from Niñu-Mayu. On one hand, the tracks produced by an autopodium that pushed backward the sediment generated a digit-only track with a posterior sediment mound and anterior drag marks (Bennett et al., 2014; track type 1 to 3, Fig. 9AeC), as in pes prints from Niñu-Mayu. ...
... In this way, the ankylosaurian locomotion could reflect a gait somewhat similar to that of a hippo in the water, where digits lack a fleshy enclosure and spread out maximizing the supporting surface (McCrea, 2000; Coughlin and Fish, 2009). 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 Moreover, Bennett et al. (2014) studied both modern and fossil subaqueous hippo tracks and describe similar features with those from Niñu-Mayu. On one hand, the tracks produced by an autopodium that pushed backward the sediment generated a digit-only track with a posterior sediment mound and anterior drag marks (Bennett et al., 2014; track type 1 to 3, Fig. 9AeC), as in pes prints from Niñu-Mayu. On the other hand, tracks produced by an autopodium that contact the sediment vertically leaved a track without both a posterior mound and drag marks (Bennett et al., 2014; track type 4, Fig. 9D), as in manus prints from Niñu-Mayu. ...
... On one hand, the tracks produced by an autopodium that pushed backward the sediment generated a digit-only track with a posterior sediment mound and anterior drag marks (Bennett et al., 2014; track type 1 to 3, Fig. 9AeC), as in pes prints from Niñu-Mayu. On the other hand, tracks produced by an autopodium that contact the sediment vertically leaved a track without both a posterior mound and drag marks (Bennett et al., 2014; track type 4, Fig. 9D), as in manus prints from Niñu-Mayu. Because of these trackway features, buoyancy high enough to permit a paddling with the hindfeet and printing of posteriorly directed long drag marks is discounted (McAllister, 1989). ...
Article
Since the second half of the 20th Century, the study of fossil tracks in South America has steadily increased. A large number of tetrapod ichnogenera is currently known mainly from Argentina, Bolivia and Brazil. In this study, we present a new record consisting of several trackways that we refer to cf. Tetrapodosaurus, representing the first explicit mention of the ichnogenus in South America. These tracks come from the lacustrine to transitional El Molino Formation, deposited in Maastrichtian-Danian times, at the locality of Niñu-Mayu, near Sucre, Bolivia. These tracks preserve a quite similar manual morphology to that of Tetrapodosaurus borealis and minor differences in its pedal prints. Tetrapodosaurus is a typical ichnogenus of the northern hemisphere and commonly assigned to an ankylosaurian trackmaker. Tracks assigned to ankylosaurs were already reported from other sites of Bolivia, Brazil and possibly Argentina; the new finding further improves our understanding of the ankylosaurian record from South America. A detailed morphological analysis allows us to make an accurate trackmaker identification and footprints are attributed to a member of the ankylosaurian family, the Nodosauridae. The trackways from Niñu-Mayu also have paleobiological implications. Manus prints are complete, pes prints generally lack the proximal region of the pes, the sole pad, expulsion rims are proximally placed in pes prints and the trackway parameters are highly variable, suggesting registration influenced by certain buoyancy of the trackmakers.
... The footprint dimensions and the foot morphology are largely consistent with those of Middle Pleistocene and modern hippos (Laporte and Behrensmeyer, 1980;Behrensmeyer and Laporte, 1981;Fisher et al., 2007Fisher et al., , 2010Bennett et al., 2014). The attribution to Hippopotamus is the only one coherent with the tracks discovered at Gombore II-2. ...
... Hypothetical or well-documented hippo tracks from the Pleistocene that would allow comparisons are only recorded at Olduvai and Koobi Fora. At Olduvai (Tanzania), a few isolated footprints were discovered in a Plio-Pleistocene clay deposit (Ashley and Liutkus, 2003;Bennett et al., 2014). These footprints are 10-25 cm wide and 15-40 cm deep, but are scarcely detailed and cannot be given any specific attribution. ...
... In only a few instances there are also the typical prints of 4 toes and toenails. The larger footprints are attributed to adult Hippopotamus gorgops, the smaller ones (18-20 cm) to young specimens or to the pygmy Hippopotamus aethiopicus (Behrensmeyer and Laporte, 1981;Bennett et al., 2014). The paleoenvironmental reconstruction suggests shallow waters and random walking over a surface submerged under 10 cm or so of water. ...
... Crocodilian, turtle, amphibian and hippopotamus swim traces are not adequate to estimate the water depth because of the known bottom walking (or punting) and swimming habits of these groups (e.g., Brand, 1979; Bennett et al., 2014; Lockley et al., 2014). Instead, they are very good indicators of subaqueously-deposited substrates, as are fish swim trace fossils. ...
... Late Palaeozoic amphibian swim traces have been mostly assigned to two ichnogenera: Lunichnium Walter, 1983 (Fig. 7) and Serpentichnus Braddy et al., 2003 (e.g., Turek, 1989; Minter and Braddy, 2006). Hippopotamus bottom walking or punting (underwater gait mode consisting in limbs pushing off the substrate producing alternating phases of thrust and glide) traces have been described from the fluvial-lacustrine deposits of the Pliocene-Pleistocene Koobi Fora Formation , Kenya (Bennett et al., 2014). These traces appear on the same surface, although at a distance of tens of meters, where hominin and normal walking hippopotamus tracks occur, confirming footprint formation in a subaqueous substrate as originally interpreted by Behrensmeyer and Laporte (1981). ...
... We find few published records of mammalian swim tracks (Rutherford and Russell, 1928;Russell, 1930;Bennett, Morse, and Falkingham, 2014). Rutherford and Russell (1928) described an unusual trackway from the Paleocene Paskapoo Formation in Alberta as being tracks of creodonts or condylarth mammals, but the trackmaker's identity was regarded as condylarth shortly afterward (Russell, 1930). ...
... These swim tracks were produced by hippopotami that were probably completely submerged in water to produce traces typical of a hippo's bottom-walking or punting. This kind of swimming behavior is well known in modern hippopotami, which register tracks identical in morphology to those from the Koobi Fora Formation (Bennett, Morse, and Falkingham, 2014). ...
... This includes not only body and appendicular morphology and swimming behaviour, but also factors such as water depth, substrate composition and substrate consistency, current direction, subsequent bioturbation, and diagenesis. Swimming traces can vary from almost fully recognisable 'footprints' (e.g., the 'swimming' tracks described by Müller, 1955or McAllister, 1989, to more elongate striations, such as some of the hippopotamus traces described by Bennett et al. (2014). The amount of recognisable morphological information contained in a swimming trace is commonly far less than can be distilled from a detailed, 'elite' walking track, leaving the identification of the trace maker rather challenging. ...
... Swimming traces can differ considerably in appearance dependent on depth and buoyancy of the trace maker, as exemplified in the swimming hippopotamus tracks described in Bennett et al. (2014) -there, the morphology changes from deep, recognisable tracks to long parallel grooves imprinted by the almost fully buoyant animal. Similarly, Diedrich (2002) discussed the changing appearance of Rhynchosauroides tracks from dry to fully waterlogged substrate (Diedrich, 2002: fig 5A). ...
Article
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We describe a tetrapod swimming traceway from the Middle Triassic Vossenveld Formation of the Netherlands. Forty-five individual traces, each consisting of two parallel claw drag marks, were followed over 9 m in a roughly east–west direction. The asymmetry of the traceway geometry indicates the trace maker negotiated a lateral current. The trace maker could not be identified, but the traces described here are markedly different from Dikoposichnus traces attributed to swimming nothosaurs.
... A track is produced by the interplay between the shape/ anatomy of the foot and the pattern of loading, mediated through a compliant substrate that is sufficiently elastic to deform yet rigid enough to retain the impression. The variables at play here are complex and a single trackmaker may produce a range of tracks (e.g., Brand, 1996;Bennett et al., 2014;Milner and Lockley, 2016). In many cases detailed knowledge of a trackmaker's pedal anatomy may be unknown. ...
Article
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We describe late Miocene tetrapod footprints (tracks) from the Trachilos locality in western Crete (Greece), which show hominin-like characteristics. They occur in an emergent horizon within an otherwise marginal marine succession of Messinian age (latest Miocene), dated to approximately 5.7 Ma (million years), just prior to the Messinian Salinity Crisis. The tracks indicate that the trackmaker lacked claws, and was bipedal, plantigrade, pentadactyl and strongly entaxonic. The impression of the large and non-divergent first digit (hallux) has a narrow neck and bulbous asymmetrical distal pad. The lateral digit impressions become progressively smaller so that the digital region as a whole is strongly asymmetrical. A large, rounded ball impression is associated with the hallux. Morphometric analysis shows the footprints to have outlines that are distinct from modern non-hominin primates and resemble those of hominins. The interpretation of these footprints is potentially controversial. The print morphology suggests that the trackmaker was a basal member of the clade Hominini, but as Crete is some distance outside the known geographical range of pre-Pleistocene hominins we must also entertain the possibility that they represent a hitherto unknown late Miocene primate that convergently evolved human-like foot anatomy.
... Inf.). Analogous swim tracks of subrecent hippos have been described by Bennett et al. (2014). ...
Article
The Eifelian dolomites in the Zachełmie Quarry (Holy Cross Mountains, Poland) contain trackways and tracks of tetrapods 390–391 Ma old, and thus the oldest known so far. The environments of the trackway-bearing beds have been investigated using sedimentological, palaeontological, geochemical and palaeomagnetic methods. The reconstructed tetrapod habitats comprised shallow-water lagoons separated from an open marine basin by sparsely vegetated islands and spits. The lagoonal waters were well-aerated and a few metres deep at most, undergoing periodic desiccation. The dolomitic sediments, primarily of microbial origin, formed in tropical waters of slightly modified marine composition. Oxygen isotope data obtained from the dolomicrites suggest water temperatures around 30 °C. The seasonal semi-arid to sub-humid climate, deduced from paleosol characteristics, was probably of a tropical monsoonal type. The degree of restriction of the lagoonal system evolved from relatively open, evaporation-dominated towards increasingly closed, freshwater influenced.
... Fossil footprints and tracks e which can be produced by a number of species e are important in providing snapshot evidence of the evolution of paleolandscapes. They have been discovered at Plio-Pleistocene African sites extending over sizeable areas, as at Laetoli (Leakey, 1987), or occurring repeatedly at various stratigraphic levels, as at Koobi Fora (Bennett et al., 2014) and Gombore II (reported below). ...
Article
Environment, climatic change and human evolution have been debated over the last 50 years giving special attention to the Plio-Pleistocene sites of the Rift Valley. In this paper we discuss the environment and the limits of hominin adaptability based on evidence from Melka Kunture, at 2000 m asl on the Ethiopian highlands, and specifically on the ~850 ka to ~700 ka sequence at sub-site Gombore II. Human fossils and multiple Acheulean occurrences, as well as hippo remains and footprints, combined with palynological analysis, provide a highly detailed chronological resolution of the changing local environmental conditions during the last ~150 ka of the MPT (Mid Pleistocene Transition), including the sequence of events after a volcanic eruption. Layers containing footprints and fossils are evidence of near-continuous occupation by hippos and their recolonization of the area after a disruptive volcanic eruption. Conversely, Acheulean implements and human fossils suggest that peopling by hominins occurred at a different and discontinuous pace even when the flora and fauna were re-established and the environment was rather stable. Most notably, the assembled evidence points to the limits of Homo erectus s.l. adaptability. Apparently, this hominin could no longer live at 2000 m asl when the climate deteriorated during glacial isotopic stage 20, becoming markedly colder than it is today, but re-colonized the area when the climate turned warmer again during isotopic stage 19.
... With the exception of the 1.47 Ma hominin tracks from a similar lake margin setting 45 km to the south at Koobi Fora (Behrensmeyer and Laporte, 1981;Bennett et al., 2014), we currently lack comparable data from other regions needed to address patterns of habitat use among hominins. The ITC evidence shows that H. erectus used a lake margin grassland repeatedly and extensively over a period of 20 ka . ...
Article
The ecological and selective forces that sparked the emergence of Homo's adaptive strategy remain poorly understood. New fossil and archaeological finds call into question previous interpretations of the grade shift that drove our ancestors' evolutionary split from the australopiths. Furthermore, issues of taphonomy and scale have limited reconstructions of the hominin habitats and faunal communities that define the environmental context of these behavioral changes. The multiple ∼1.5 Ma track surfaces from the Okote Member of the Koobi Fora Formation at East Turkana provide unique windows for examining hominin interactions with the paleoenvironment and associated faunas at high spatiotemporal resolution. These surfaces preserve the tracks of many animals, including cf. Homo erectus. Here, we examine the structure of the animal community that inhabited this landscape, considering effects of preservation bias by comparing the composition of the track assemblage to a skeletal assemblage from the same time and place. We find that the track and skeletal assemblages are similar in their representation of the vertebrate paleocommunity, with comparable levels of taxonomic richness and diversity. Evenness (equitability of the number of individuals per taxon) differs between the two assemblages due to the very different circumstances of body fossil versus track preservation. Both samples represent diverse groups of taxa including numerous water-dependent species, consistent with geological interpretations of the track site environments. Comparisons of these assemblages also show a pattern of non-random hominin association with a marginal lacustrine habitat relative to other vertebrates in the track assemblage. This evidence is consistent with behavior that included access to aquatic foods and possibly hunting by H. erectus in lake margins/edaphic grasslands. Such behaviors may signal the emergence of the adaptative strategies that define our genus.
... The only other fossil hippopotamus tracks that have been described are swimming tracks from Koobi Fora in Kenya (Bennett et al., 2014). The probable hippopotamus tracks at Wilderness are therefore the first reported dry-land tracks for this family. ...
Article
Body fossil remains usually provide the main palaeontological resource for palaeoecological studies. Ichnology has the capacity to independently complement such data. Fossil tracksites provide a direct record of animals whose tracks have been preserved, and with regard to the Palaeo-Agulhas Plain they have direct relevance in considering palaeoecology. While biases may be present in ichnological data, they are different from the biases inherent in traditional body fossil studies. A ground survey along a 350 km portion of the Cape south coast, between Arniston in the west and Robberg in the east, identified well over a hundred-and-thirty ichnofossil sites in Late Pleistocene coastal aeolianites and lithified foreshore deposits. Some of these tracks were made by extinct species or subspecies. In other cases these tracksites demonstrate spatial range extensions of extant species, when compared with data available from body fossils or historical records. These sites include the largest and best preserved archive of Late Pleistocene hominin tracks thus far described. The tracksites occur on the margin of the Palaeo-Agulhas Plain, which may allow for palaeoenvironmental conclusions to be drawn regarding Late Pleistocene conditions on this extinct landscape. We summarize the most important sites, discuss the limitations and challenges of ichnological studies, and provide perspectives on future work.
... Where exposed in cross-section, the larger, ve-toed prints display characteristics of footprints made by heavy vertebrates in water-saturated, weakly-consolidated sediment 20,21,22 (Fig. 4). Although poor preservation precludes detailed analysis of print morphology in the cross-sectional examples, evidence for the direction of travel is afforded by the downward rotation of the anterior portion of the foot as the toes press deeper into the substrate during forward propulsion 3 . ...
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Evidence for the earliest invasion of the marine realm by mammals was previously restricted to Eocene (48.6-37.8 Ma) skeletal remains. We report incontrovertible ichnofossil evidence for brackish-water habitat use by at least two mammalian species in southern Wyoming during the late Paleocene (58 Ma). These are the first Paleocene mammal trackways recorded in the United States and only the fourth documented in the world. Multiple tracks preserved in restricted marine deposits represent animals repeatedly walking across submerged to partially emergent tidal flats. Hundreds of tracks are preserved in planform and cross-sectional exposure within five horizons along a 1,032 m tracksite. Four prints exhibit five clear toe imprints, while two others distinctly display four toes. Some tracks penetrate beds populated by dwelling traces of marine bivalves and polychaetes in the upper layers and sea anemones at the base. Candidates for the five-toed tracemakers are pantodonts such as Titanoides , Barylambda , and Coryphodon , which have been recovered from late Paleocene strata throughout western North America. The four-toed tracks provide the earliest evidence of previously-undescribed large artiodactyls and/or tapiroids, mutually supporting recent molecular phylogenetic studies that place the origin of Cetartiodactyla near the Cretaceous-Paleogene boundary (~67.7 Ma). Collectively, these trackways irrefutably demonstrate the utility of ichnological data in reconstructing the evolutionary history and adaptive behaviors of extinct taxa beyond the evidence provided by body fossils alone.
... We are not aware of previous reports of fossil reptile swim traces from Africa, although hippopotamus swim traces have been reported. 34 not aware of reports of fossil non-crocodylian reptile swim traces. However, crocodylian swim traces feature in the global ichnological record. ...
Article
The Cape south coast of South Africa contains a wealth of Pleistocene vertebrate trace fossil sites in aeolianites and cemented foreshore deposits. Published studies have described mammal and avian tracksites identified along this coastline. We report here on a number of Pleistocene palaeosurfaces within the Garden Route National Park that exhibit tracks of large reptiles, including probable swim traces. The tracks were probably made by more than one species, and may include a crocodylian. There are no extant reptiles in this coastal region capable of making such tracks and traces, which probably represent an indication of a previously more extensive range for the Nile crocodile and a monitor lizard. These findings demonstrate the potential for ichnology to complement the traditional body fossil record. Two Middle Stone Age stone artifacts were found embedded in one palaeosurface containing multiple reptile trackways. These discoveries have implications for the understanding of Pleistocene palaeoenvironment and palaeoclimate – in an area which is important in the study of modern human origins. Significance: • Large reptile Pleistocene fossil tracksites have recently been discovered on the Cape south coast of South Africa where there are no previous such records, and no reptiles of this size are currently found in the region. • These sites include the first reported probable reptile swim traces in Africa and one tracksite also contained two Middle Stone Age artifacts. • These discoveries have implications for Pleistocene environments and climate on the Cape south coast.
... Where exposed in cross-section, the larger, five-toed prints display key characteristics of tracks made by heavy vertebrates in water-saturated, weakly-consolidated sediment 16,20,21 (Figs. 2,3,4,5,6). ...
Article
Full-text available
Evidence for the earliest invasion of the marine realm by mammals was previously restricted to Eocene (48.6–37.8 Ma) skeletal remains. We report incontrovertible ichnofossil evidence for brackish-water habitat use by at least two mammalian species in southern Wyoming during the late Paleocene (58 Ma). These are the first Paleocene mammal trackways recorded in the United States and only the fourth documented in the world. Multiple tracks preserved in restricted marine deposits represent animals repeatedly walking across submerged to partially emergent tidal flats. Hundreds of tracks are preserved in planform and cross-sectional exposure within five horizons along a 1032 m tracksite. Four prints exhibit five clear toe imprints, while two others distinctly display four toes. Some tracks penetrate beds populated by dwelling traces of marine bivalves and polychaetes in the upper layers and sea anemones at the base. Candidates for the five-toed tracemakers are pantodonts such as Titanoides , Barylambda , and Coryphodon , which have been recovered from late Paleocene strata throughout western North America. The four-toed tracks provide the earliest evidence of previously-undescribed large artiodactyls and/or tapiroids, mutually supporting recent molecular phylogenetic studies that place the origin of Cetartiodactyla near the Cretaceous-Paleogene boundary (~ 67.7 Ma). Collectively, these trackways irrefutably demonstrate the utility of ichnological data in reconstructing the evolutionary history and adaptive behaviors of extinct taxa beyond the evidence provided by body fossils alone.
Article
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Large animal tracks, unequivocally attributable to terrestrial mammals, are reported for the first time in sediment from uppermost Bed I (Tuff IF; ∼1.803 million years ago) at Olduvai Gorge, Tanzania. One track in particular (attributed to the ichnogenus Pecoripeda) retains an exceptional level of detail, demonstrating the excellent trackway-preserving potential of the volcanic ash fall (tuff) layers at this important hominin archaeological locality. Olduvai Gorge is renowned for its abundant Plio-Pleistocene (zoo)archaeological discoveries and fossiliferous deposits vis-à-vis studies of human evolution. Fossil trackways, and trace fossils more widely, provide an important additional tool for characterizing ancient ecosystems, which remain underexplored at Olduvai. Considered together with fossil hominin remains, information derived from coeval fossil animal tracks provides additional insight into our ancestors’ behaviour and their interactions with the surrounding palaeoenvironment. A range of large herbivore tracks indicates the availability of nearby resources (i.e., freshwater, vegetation preferred by grazers/browsers). These newly-discovered tracks are of archaeological and palaeontological significance because they highlight the potential for future discovery of animal or hominin tracks and trackways preserved in tuff at Olduvai and in other archaeological localities.
Chapter
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Animal footprints are preserved in the archaeological record with greater frequency than perhaps previously assumed. This assertion is supported by a rapid increase in the number of discoveries in recent years. The analysis of such trace fossils is now being undertaken with an increasing sophistication, and a methodological revolution is afoot linked to the routine deployment of 3D digital capture. Much of this development has in recent years been driven by palaeontologists, yet archaeologists are just as likely to encounter footprints in excavations. It is therefore timely to review some of the key methodological developments and to focus attention on the inferences that can and, crucially, cannot be justifiably made from fossil footprints with specific reference to human tracks.
Article
Human, and hominin tracks, occur infrequently within the geological record as rare acts of sedimentary preservation.They have the potential, however, to reveal important information about the locomotion of our ancestors, especially when the tracks pertain to different hominin species.The number of known track sites is small and in making inter-species comparisons, one has to work with small track populations that are often from different depositional settings, thereby complicating our interpretations of them.Here we review several key track sites of palaeoanthropological significance across one of the most important evolutionary transitions (Australopithecus to Homo) which involved the development of anatomy and physiology better-suited to endurance running and walking.The sites include the oldest known hominin track site at Laetoli (3.66Ma; Tanzania) and those at Ileret (1.5Ma; Kenya).Tracks from both sites are compared with modern tracks made by habitually unshod individuals using a whole-foot analysis.We conclude that, contrary to some authors, foot function has remained relatively unchanged, perhaps experiencing evolutionary homeostasis, for the last 3.66Ma. These data suggest that the evolutionary development of modern biomechanical locomotion pre-dates the earliest human tracks and also the transition from the genus Australopithecus to Homo.
Article
New ichnological data are available at the prehistoric site of Melka Kunture, Upper Awash Valley in Ethiopia. Excavation of new test pits enabled us to explore the volcanic and fluvio-lacustrine sequence at the Gombore II Open Air Museum archaeological site (ca. 0.85 Ma). This has allowed a detailed reconstruction of the palaeoenvironment and of the fauna present in the time interval between 1.2 and 0.85 Ma. Various-sized mammals, birds, molluscs as well as hominins left tracks throughout the sequence, and document a varied fauna and associated behaviours. Most of the hominin tracks were made by young individuals on the basis of size and are some of the earlier child tracks to be reported. The mollusc traces document the presence and orientation of water streams which, according to the associated vertebrate traces, were visited by hominins, mammals and birds. Most of these traces were found within levels traditionally considered barren for archaeology, yet they all document life activity and are always in situ. This confirms the potential of the ichnological research as an important complementary tool for archaeological investigations. To help you access and share this work, a personalized Share Link provided by Elsevier provides 50 days' free access to the paper. Anyone clicking on this link before October 10, 2020 will be taken directly to the final version of the article on ScienceDirect, which they are welcome to read or download. No sign up, registration or fees are required. Personalized Share Link: https://authors.elsevier.com/a/1bcDb-4PRxn8k
Chapter
Vertebrate ichnology is being revolutionised by the ease with which 3D data can be acquired and there is an increased focus on developing analytical tools and approaches that allow hypothesis driven testing. This revolution is not without its detractors, but is perhaps more advance than the use of 3D data in forensic science. In this chapter we first consider the role of 3D data in the formal classification of tracks and the review some of the challenges associated with demonstrating co-association while interpreting track assemblages. This is followed by four case studies based on the research work of the authors.
Chapter
Human tracks have now been recorded at a number of sites across the globe. Lockley et al. (Ichnos 15:106–125, 2008) provides a definitive review of many of these sites and our aim here is to focus on a few important examples which are either in the authors’ judgement particularly significant or feature within this book. Sites can be grouped on many different criteria such as by: (1) geographical regions; (2) geological facies in which they are preserved; (3) their age and therefore potential species of track-maker; or (4) by their archaeological or palaeoanthropological significance. While there is a natural tendency to focus on the unusual, biggest, or oldest, in reality footprint sites tend to separate into those which pre-date Homo sapiens and those that don’t. Those that do are limited in number but have the potential to offer information about the evolution of gait between hominin species and as such they accord a level of significance far greater than other footprint sites. Such sites are few in number however and while Holocene sites may not have the glamour of older localities, they have the potential to offer important laboratories in which to explore the interaction of a track-maker’s gait with such things as substrate. For ease we have chosen to divide this chapter into those examples that potentially pre-date Homo sapiens (Pliocene to Early/Middle Pleistocene) and those that don’t (Late Pleistocene to Holocene).
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We currently have little archaeological and historical data about mining areas of North Africa that were exploited in pre-Roman times, and even the rare ancient proofs can be mostly dated to Roman period. However, it was the searching for new metals that brought Phoenician to the western expansion: North Africa was one of the richest Mediterranean areas and we believe that such a small amount of information about this region has to be connected to the lack of dedicated studies. Every time that the scientific interest focuses on this important part of the economic and social life in the ancient world (as it was already made in Spain and Sardinia), new data emerges and offers a bigger historical background. Current researches of ‘Researches about Phoenicians in North Africa: archaeology, numismatic and economic history’ aims, first of all, to define historical and technological background of all the metal production cycle, the exploitation, the manipulation techniques and the resources management of mining areas in North Africa, Morocco and Algeria in particular
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The collection and dissemination of vertebrate ichnological data is struggling to keep up with techniques that are becoming commonplace in the wider palaeontological field. A standard protocol is required to ensure that data is recorded, presented and archived in a manner that will be useful both to contemporary researchers, and to future generations. Primarily, our aim is to make the 3D capture of ichnological data standard practice, and to provide guidance on how such 3D data can be communicated effectively (both via the literature and other means) and archived openly and in perpetuity. We recommend capture of 3D data, and the presentation of said data in the form of photographs, false‐colour images, and interpretive drawings. Raw data (3D models of traces) should always be provided in a form usable by other researchers (i.e. in an open format). If adopted by the field as a whole, the result will be a more robust and uniform literature, supplemented by unparalleled availability of datasets for future workers.
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In addition to skeletal remains that record the presence of a diverse vertebrate fauna, the Baynunah Formation also preserves fossil trackways. These are found on deflated surfaces of carbonateCarbonate-rich beds, mainly at sites located inland from the coast. FootprintsFootprint (track), like other trace fossils, may be difficult to assign to particular species, but provide a window onto ancient behavior that is not attainable from skeletal remains alone. Nine sites bearing fossil footprintsFootprint (track) have been identified to date in the Baynunah Formation. These are presented and described here, most for the first time. The large majority of footprints (and the most easily identifiable) were made by proboscideans, but three trackways belong to a large ungulate, probably a giraffidGiraffidae (giraffid), and one print may be that of a hippopotamid. The site of Mleisa 1 is particularly important for its remarkable preservation of the passage of a proboscidean herd intersected by the trackway of a large solitary individual, showing that herding behavior, and possibly also sexual segregation, both hallmarks of modern elephants, were already present in late Miocene proboscideans. Given the large areas across which the carbonatesCarbonate of the Baynunah Formation are exposed inland, many more trackways likely remain to be discovered.
Chapter
This chapter provides a broad overview of tracks and trackways relevant to both vertebrate and forensic footprints and footwear, along with a review of the rationale and contents of this book. Key definitions are introduced and explained and some principles of scientific method are also explored which are important to questions of data interpretation especially in forensic practice which is discussed in later chapters.
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The Baynunah Formation has produced a diverse assemblage of plant, invertebrateInvertebrate, and vertebrate fossils that provides the only window onto the terrestrial late Miocene record of the Arabian Peninsula. This chapter reviews and revises the age, biogeography, environments, and ecology of the Baynunah fauna. Biochronological estimates indicate an age of between 8 and 6 Ma, with several indicators favoring the older end of this range. Paleomagnetostratigraphic correlation more precisely favors an age between ~7.7 and 7.0 Ma, and a maximum duration of less than 720 kyr. Rough estimates of sedimentationSedimentation rate based on assumptions of precessional control of carbonateCarbonate formation in the upper parts of the Baynunah Formation here tentatively suggest a duration of ~250 kyr. The most common body fossils found are remains of fishFish(catfishCatfish (see also Siluriformes)and cichlidsCichlidae (cichlid)), turtlesTestudines (turtle), and crocodiles, indicating the presence of a large but shallow and slow-moving river. A diverse community of mammalian herbivoresHerbivore subsisted along the banks of the Baynunah RiverBaynunah River, ranging from rodentsRodentia (rodent) to proboscideans, and carnivoresCarnivore included a mustelid, hyaenids, and a saber-toothed felidSaber-toothed felid. The fauna, in conjunction with stable isotope data, indicates the presence of a highly seasonal semi-arid environment, characterized by open habitats with C4 grasslands and trees. The most common large mammals are equids, bovids, hippopotamids, and proboscideans. The high abundance of equids in the Baynunah Formation is unlike African late Miocene assemblages and more like those from the eastern MediterraneanMediterranean, but the underlying ecological reasons for this are not clear. Baynunah species indicate dominantly African biogeographic influences combined with Eurasian elements. Genus-level comparisons indicate that the Baynunah fauna was part of the widespread Old World Savanna PaleobiomeOld World Savanna Paleobiome (OWSP) that covered much of Africa and Eurasia during the late Miocene. Food webFood web (trophic network) analyses of the large mammals indicate a highly connected community similar to that of the modern Serengeti. Among the largest Baynunah herbivoresHerbivore (giraffids, proboscideans), only juveniles would have been vulnerable to predation, even under scenarios of cooperative hunting. In contrast to the fluvial Baynunah sediments, the underlying Shuwaihat FormationShuwaihat Formation indicates arid conditions, and provides some of the oldest evidence for desertification in the Saharo-Arabian desert belt.
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The impact of large vertebrates on the sedimentary record in an East African groundwater-fed wetland in Ngorongoro Crater, Tanzania, is used as a modern analog to interpret an ancient (Plio-Pleistocene) wetland record in Olduvai Gorge, Tanzania. The 3 km2 wetland at Olduvai is characterized by massive silty claystones produced by intense vertebrate trampling, as well as trails by vertebrates frequenting the wetlands and isolated footprints that represent a "snapshot in time." Based on modern analogs, a paleo hippo trail (1.2 m wide and 0.6 m deep) in the Plio-Pleistocene wetlands is interpreted as a frequently used corridor between hippo pools (days) and grazing meadows (nights). Groundwater-fed wetlands are low energy environments where the physical record appears to be dominated by plant and animal activity. The bioturbation record reflects a number of interacting factors such as substrate texture, moisture content, sedimentation rate, frequency of flooding, type of animals present, trampling rate, and post-depositional changes (compaction). Lithofacies in both the modern and ancient wetlands include muddy sandstone (drainage channels) and silty claystone (vegetated and nonvegetated mud flats). Organic-rich sediments eventually oxidize, eliminating most evidence of the habitat. Modern wetlands have organic-rich mud and peat, whereas the ancient analog has siliceous earthy claystones that contains plant remains, bone fragments, pollen, phytoliths, and localized beds of diatomite. Thus, the physical record of vertebrate bioturbation in conjunction with paleontological and lithological records provides crucial information on the ecology of ancient wetland environments.
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Although tracks of dinosaurs are well known from Upper Jurassic sediments, tracks of non-dinosaurian vertebrates are fairly rare. The Upper Jurassic Lastres Formations of Asturias in northern Spain contain many vertebrate tracksites that include footprints and trackways of non-dinosaurian tetrapods. Several of these tracks are natural casts of pentadactyl to tridactyl footprints with digits connected by arched structures. The digits are short with deep scratch marks oriented anteriorly. The Asturian tracks show a high degree of morphological similarity to other specimens previously described as possible turtle tracks. Observations from extant turtle trackways show some surprising similarities with the fossil material. The tracks are here interpreted as having been made by turtles partially buoyed by water or by turtles walking in a slightly wet subaerial environment.
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A fundamental question remaining unanswered in dinosaur behavior is whether they had the ability to swim. We report the discovery of an exceptional swimming dinosaur trackway, with 12 consecutive footprints, in lacustrine nearshore sediment from the Early Cretaceous Cameros Basin, La Rioja, Spain. The singular morphology of these footprints strongly suggests a floating animal clawing the sediment as it swam. Diagnostic traits of theropod dinosaur footprints are identifiable in these peculiar elongated S-shaped ichnites. Paleoenvironmental reconstruction indicates an upper shoreface setting with a maximum water depth of ˜3 m, substantiating the swimming hypothesis. Ichnological analysis of the trackway shows that this theropod used a pelvic paddle motion, similar to that of modern bipeds, and swam with amplified asymmetrical walking movements to maintain direction into a leftward water current. After recent hints of swimming dinosaurs, this new evidence persuasively demonstrates that some non-avian theropod dinosaurs were swimmers.
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Footprints and trackways from 12 species of extant crocodylians are compared to give an overview of the morphological variation found among the tracks of modern crocodylians. Crocodylians often overprint the manus prints and drag their hindfeet along the sediment surface. The extent of tail and belly dragging varies significantly with gait, age and progression speed of the animal. The dragmark from the tail is not always situated in the middle of the trackway, but can be offset toward one side of the trackway. The divarication angle between pedal digits I-IV is higher among Alligatoridae, averaging 74°, than among Crocodylidae, which have an average angle of 42°. Fresh feces from crocodylians are typically cylindrical to tapering and composed of concavo-convex units. They often have one or two bends of approximately 140°, a feature also observed in putative crocodylian coprolites.
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The trackway of a swimming theropod (ichnogenus Characichnos) is reported from the Lower Cretaceous Feitianshan Formation of Sichuan, China. These swim tracks help confirm that non-avian theropods were capable of forging moderately deep bodies of water. The trackway occurs on the same surface as a typical walking trackway of a sauropod (ichnogenus Brontopodus). Both occurrences are the first reported from the Cretaceous of Sichuan, and the swim tracks are the first well-preserved example of a Characichnos trackway from China. Additionally, a theropod walking trackway and several ornithopod walking trackways (similar to the ichnogenus Caririchnium) occur in the same horizon. The ornithopod trackways show a parallel orientation, suggesting gregarious behavior of the trackmakers, which may have been iguanodontiforms and/or hadrosauriforms. The co-occurrence of theropod swim tracks and theropod walking tracks suggests a fluctuation of water depth within a distinct time span.
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Recalibration of the Pliocene and early Pleistocene geomagnetic time scale using the K-Ar dated fluvial sequence of the Turkana Basin in East Africa agrees with calibrations based on astronomical calculations. Ages estimated here are: Olduvai Subchron, 1.78-1.96 Ma; Reunion Subchrons, 2.11-2.15 Ma and 2.19-2.27 Ma; Matuyama-Gauss boundary, 2.60 Ma; Kaena Subchron 3.02-3.09 Ma; Mammoth Subchron, 3.21-3.29 Ma; Gauss-Gilbert boundary, 3.57 Ma.
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Use of the aquatic environment by hippopotami (Hippopotamus amphibius) allows locomotive styles impossible to achieve on land by such heavy animals. Videos of the underwater locomotion of 2 hippopotami were analyzed frame by frame. Average horizontal velocity underwater was 0.47 m/s. Hippopotami used a gait underwater that was similar to a gallop with extended unsupported intervals. Ground contact time decreased with increasing horizontal velocity, vertical displacement during the unsupported intervals increased with an increase in ground contact time, and time between consecutive footfalls decreased with an increase in horizontal velocity. Hippopotami use an unstable gait underwater, which is facilitated by the increased buoyancy of water. Despite restrictions to movement on land due to its massive weight, locomotion of the hippopotamus underwater is analogous to movement in a microgravity environment.
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It is commonly held that the major functional features of the human foot (e.g. a functional longitudinal medial arch, lateral to medial force transfer and hallucal (big-toe) push-off) appear only in the last 2 Myr, but functional interpretations of footbones and footprints of early human ancestors (hominins) prior to 2 million years ago (Mya) remain contradictory. Pixel-wise topographical statistical analysis of Laetoli footprint morphology, compared with results from experimental studies of footprint formation; foot-pressure measurements in bipedalism of humans and non-human great apes; and computer simulation techniques, indicate that most of these functional features were already present, albeit less strongly expressed than in ourselves, in the maker of the Laetoli G-1 footprint trail, 3.66 Mya. This finding provides strong support to those previous studies which have interpreted the G-1 prints as generally modern in aspect.
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The occurrence of sauropod manus-only trackways in the fossil record is poorly understood, limiting their potential for understanding locomotor mechanics and behaviour. To elucidate possible causative mechanisms for these traces, finite-element analyses were conducted to model the indentation of substrate by the feet of Diplodocus and Brachiosaurus. Loading was accomplished by applying mass, centre of mass and foot surface area predictions to a range of substrates to model track formation. Experimental results show that when pressure differs between manus and pes, as determined by the distribution of weight and size of respective autopodia, there is a range of substrate shear strengths for which only the manus (or pes) produce enough pressure to deform the substrate, generating a track. If existing reconstructions of sauropod feet and mass distributions are correct, then different taxa will produce either manus- or pes-only trackways in specific substrates. As a result of this work, it is predicted that the occurrence of manus- or pes-only trackways may show geo-temporal correlation with the occurrence of body fossils of specific taxa.
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This paper describes a sequence of tuffs between the KBS and the Chari Tuff of Omo Group formations in Kenya and Ethiopia. These tuffs have recently been shown to be 1.87 ± 0.02 Ma and 1.38 ± 0.03 Ma in age, respectively. The sequence of tuffis that is derived is consistent with 40Ar/39Ar ages reported separately, and provides the stratigraphic framework for interpreting those ages. Further, new correlations are established to the Konso Formation in southern Ethiopia. As drainage from the Ethiopian Rift to the Omo-Turkana Basin developed after deposition of the Konso Formation, pumice clasts in tuffs of the Omo-Turkana Basin probably were transported there by the Omo River. The tuffs are divided into five groups on the basis of their stratigraphic position in relation to extensive ash layers. The sequence of tuffs has import for the placement and age of archaeological sites in the Koobi Fora Formation, and for ages of mammalian faunas (including hominids). Many tuffs were deposited during a 90 ka interval during which Mediterranean sapropels are lacking, suggesting that Nile flow was reduced, and that the level of a lake that occupied the Omo-Turkana Basin at the time was low. Thus the record of climatic influence on deposition in the Omo-Turkana Basin, previously shown for the Kibish Formation (≤200 ka), extends at least to early Pleistocene time.
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Hominin footprints offer evidence about gait and foot shape, but their scarcity, combined with an inadequate hominin fossil record, hampers research on the evolution of the human gait. Here, we report hominin footprints in two sedimentary layers dated at 1.51 to 1.53 million years ago (Ma) at Ileret, Kenya, providing the oldest evidence of an essentially modern human–like foot anatomy, with a relatively adducted hallux, medial longitudinal arch, and medial weight transfer before push-off. The size of the Ileret footprints is consistent with stature and body mass estimates for Homo ergaster/erectus, and these prints are also morphologically distinct from the 3.75-million-year-old footprints at Laetoli, Tanzania. The Ileret prints show that by 1.5 Ma, hominins had evolved an essentially modern human foot function and style of bipedal locomotion.
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Sites in eastern Africa have shed light on the emergence and early evolution of the genus Homo. The best known early hominin species, H. habilis and H. erectus, have often been interpreted as time-successive segments of a single anagenetic evolutionary lineage. The case for this was strengthened by the discovery of small early Pleistocene hominin crania from Dmanisi in Georgia that apparently provide evidence of morphological continuity between the two taxa. Here we describe two new cranial fossils from the Koobi Fora Formation, east of Lake Turkana in Kenya, that have bearing on the relationship between species of early Homo. A partial maxilla assigned to H. habilis reliably demonstrates that this species survived until later than previously recognized, making an anagenetic relationship with H. erectus unlikely. The discovery of a particularly small calvaria of H. erectus indicates that this taxon overlapped in size with H. habilis, and may have shown marked sexual dimorphism. The new fossils confirm the distinctiveness of H. habilis and H. erectus, independently of overall cranial size, and suggest that these two early taxa were living broadly sympatrically in the same lake basin for almost half a million years.
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Small beach bars, spits, and barriers, composed predominantly of coarse sand, granules, and pebbles, are present along much of the modern shoreline of Lake Bogoria, a perennial saline, alkaline lake in the Kenya Rift Valley. Study of their distribution and composition indicates that most of the sediments are derived from peripheral fan-deltas, including material brought down in flood, and that derived by erosion of older exposed fan-delta sediments. Much of the sediment is redistributed by longshore currents, induced by winds funnelled along the axis of the lake. Surrounding the lake, a series of regressive littoral terraces, composed of angular gravels, record shoreline sedimentation associated with former higher lake levels during the Holocene. During terrace formation, many fan-delta platforms were drowned and shoaling effects reduced, thereby increasing wave energy around much of the shoreline. The terraces record a complex history of Holocene lake-level fluctuations. -from Authors
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Four trackways consisting mainly of sauropod manus prints were discovered from the Middle Jurassic of the central High Atlas Mountains, Morocco. This supports R.T.Bird's theory of sauropod swimming ability. -Author
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Fossil tracks represent a direct window onto the lives of extinct organisms, being formed and preserved in situ. Because track morphology is determined by limb motion, foot anatomy and substrate consistency, studies of fossil tracks can provide insight into producer, behaviour and palaeoenvironment. However, each determining factor is subject to variation, either continuous or discrete, and this variation may be co-dependent, making it difficult to correctly interpret a track. In addition to variance from the track-forming variables, tracks and tracksites are subject to further obfuscation because of time averaging, even before the effects of weathering, erosion and exposure are accounted for. This paper presents a dis-cussion of the factors that may confound interpretation of fossil tracks, trackways and tracksites, and reviews experimental studies that have attempted to elucidate and eliminate these sources of confusion.
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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
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A recently discovered series of mollusc faunas from the late Cenozoic of the eastern Turkana Basin constitutes one of the best documented metazoan fossil sequences. Evolutionary patterns in all lineages conform to the `punctuated equilibrium' model; no `gradualistic' morphological trends occur. These faunas provide the first fine-scaled palaeontological resolution of events during speciation: fundamental phenotypic transformation of both sexual and asexual taxa occurs rapidly, in comparatively large populations, and is accompanied by a significant elevation of phenotypic variance. This increase in variance reflects extreme developmental instability in the transitional populations.
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We investigated the use of the pelvic fins for locomotion along the bottom in the little skate, Leucoraja erinacea by video recording locomotor behavior of skates both in the field and in captivity and by examining various anatomical preparations of their pelvic fins. An external notch or concavity in the lateral margin of the pelvic fins partially separates each fin into anterior and posterior lobes. The skeletal elements and musculature of the anterior lobe are highly modified and comprise a functionally distinct appendage (the crus) that possesses three flexible joints. Locomotion of skates along the bottom is almost always due to the exclusive activity of the crura of the pelvic fins pushing off the substrate synchronously to generate thrust. The skate then glides through the water a short distance as the crura are repositioned for the next thrust phase. This type of thrust and glide locomotion is called punting. We conclude that punting is a significant form of locomotion suited to the benthic lifestyle of skates.
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A redefinition of the lithostratigraphy will be useful in studying the Turkana basin. The Koobi Fora formation is <560 m thick, 4.3-0.6 m.y. old and has eight members, delineated by volcanic ash horizons and so resolving the earlier biostratigraphic zonation conflicts. This sequence has now been correlated with other deposits in the Turkana basin and with those at Hadar and in the Gulf of Aden.-R.E.S.
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Only two vertebrate trackways are known from the Paleocene of western Canada and are among the few Paleocene vertebrate trackways known worldwide.A natural cast trackway consisting of five prints (three pes, two manus) on a fallen block was found along the Red Deer River, near the town of Red Deer, Alberta, in 1927. The discoverers, Ralph Rutherford and Loris Russell, identified the strata the track block had fallen from as belonging to the Paskapoo Formation (upper Paleocene: middle Tiffanian). The trackway was attributed to a mammalian track-maker in two subsequent publications. However, the prints are more characteristic of a reptilian (crocodylian) track-maker.A natural cast track-bearing block was discovered on Signal Hill in the city of Calgary during the preparation of a new residential subdivision in 1990. The large track-bearing block was found in a rock pile but is suspected to have originated from strata belonging to the Porcupine Hills Formation (Upper Paleocene: late Torrejonian), which was being excavated at the time. This large slab contains twelve prints (six pes, six manus) and is associated with extensive mud cracks. The mammalian affinity of the trackmaker was recognized by researchers from the Royal Tyrrell Museum of Palaeontology.
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This report summarizes the stratigraphical relationships of the Plio-Pleistocene sediments at East Rudolf and formalizes the Stratigraphical nomenclature.
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Reevaluation of published information and discussion reveals serious shortcomings in the swimming‐sauropod interpretation proposed by Roland Bird in 1944. The most plausible alternative interpretation is that the tracks are underprint expressions of brontosaur trackways made during terrestrial progression. This circumstance indicates that thin beds of sediment ‘buoy up’ or support animals above underlayers just as effectively as several meters of water. Evidence supporting the underprint interpretation includes footprint depth and completeness, differential manus‐pes size (heteropody) in sauropods, trackway configurations, and the relationship between tracks and sedimentary structures, none of which has been considered in sufficient detail in previous studies. The underprint interpretation also lends support to the theory that brontosaurs were terrestrial and not aquatic in their adaptations, and shows how important it is to interpret footprint evidence with caution.
Article
We report here that in 1978, while studying Koobi Fora Formation sedimentary environments and fossils in northern Kenya, we discovered single footprints and trails of large vertebrates in a number of different strata. One of these trails is that of a bipedal hominid, the second known record of early hominid tracks in Africa, the other being that reported at Laetoli, Tanzania1.
Article
Since the discovery1 of late Cenozoic hominid-bearing deposits in the Koobi Fora area, north Kenya, a variety of studies2–9 have been undertaken to provide a chronostratigraphical and palaeoenvironmental context for the important palaeoanthropological and early archaeological discoveries1,10. Unfortunately, although the exposures are areally extensive (>1,000 km2), they are broken up into subareas (Fig. 2); these local sections are often difficult to correlate with one another due to intervening bush cover and faulting. Here I summarize a molluscan biostratigraphical analysis which demonstrates serious stratigraphical miscorrelations between certain local sections, including some previously indicated by vertebrate evidence. These miscorrelations require substantial revisions to current stratigraphical interpretation of the Koobi Fora deposits. In particular, both the Suregei and Tulu Bor tuff horizons actually represent different levels. Although the Tulu Bor is considered to overlie the Suregei, some exposures currently attributed to the Tulu Bor are actually older than some units previously mapped as the Suregei. Fortunately, the stratigraphical miscorrelations reported here do not significantly affect the relative placement of the mollusc faunas reported in a previous evolutionary analysis15; superpositional relationships in the areas from which these faunas were collected (mainly collecting areas 102, 103, 110, 123, 202 and 203) are unaffected by the miscorrelations reported here.
Article
Based on morphological traits, hippos have traditionally been classified with pigs and peccaries in the suborder Suiformes. However, molecular data indicate that hippos and cetaceans are sister taxa. This study analyses muscle characters of the common hippo hind limb in order to clarify the phylogenetic relationships and functional anatomy of hippos. Several muscles responsible for propelling the body through water are robust and display extensive fusions, including mm. semimembranosus, semitendinosus, biceps femoris and gluteus superficialis. In addition, common hippos retain long flexor and extensor tendons for each digit, reflecting the fact that all four toes are weight-bearing. These flexor tendons, together with the well-developed intrinsic muscles of the pes, serve to adduct the digits, preventing splaying of the toes when walking on soft terrain. Lastly, common hippos retain a number of primitive features, including the presence of m. articularis coxae, a well-developed m. obturator internus, superficialis and profundus tendons to all digits, mm. flexor digitorum brevis, abductor digiti V, lumbricalis IV, adductores digitorum II and V, and two mm. interossei per digit. Pygmy hippos share these features. Thus, hippopotamids retain muscles that have been lost in the majority of artiodactyls, including other suiforms. These and previously reported findings for the forelimb support the molecular data in indicating an early divergence of the Hippopotamidae from the rest of the Artiodactyla.© 2010 The Linnean Society of London, Zoological Journal of the Linnean Society, 2010, 158, 661–682.
Article
The diet of African hippopotamids can be documented through δ13C analyses of enamel and other tissues. Analysis of a 10-million-year sequence of hippopotamids in and near the Lake Turkana Basin of northern Kenya shows that hippos have included a substantial fraction of C3 vegetation in their diets since the late Miocene when C4 vegetation first appears in hippo diet as a measurable fraction. The C4 component of vegetation becomes dominant (>50%) by Upper Burgi time (c. 2 million years ago) but does not reach 100% for all individuals. It is therefore not unexpected that the δ13C values of modern hippopotamids show a higher fraction of dietary C3 biomass than has been estimated from traditional observations. Analysis of δ18O of hippos from different stratigraphic levels shows no systematic trend over time; the average value for fossil hippos over the last 10 million years is similar to that of modern hippos from the Omo River system.
Article
Zoological institutions provide naturalistic exhibits for their animals in order to offer a more appealing look for visitors and give the animal the opportunity to engage in more natural behaviors. Examining space use of the animals in the naturalistic exhibit may aid in the management of these animals and inform future naturalistic exhibit design. The hippopotamus is an amphibious ungulate that spends much of its days in the wild in the water but may be found along the banks of the rivers basking in the sun. Our objective was to determine how captive female hippos utilize their exhibit by examining whether hippos selected for certain areas of a naturalistic exhibit. Scan sample data were collected on a group of nine captive female hippos housed at Disney's Animal Kingdom®. Using ArcView, the data were analyzed to determine distribution of hippos in the exhibit and their utilization of depth categories while in the water. Hippos were found to aggregate in preferred areas of the exhibit, mostly water, and selected most for water depths of 0.6-1.0 m. These results will aid in the understanding of hippopotamus space use and may aid zoological institutions in the design of naturalistic exhibits for hippos.
Article
Generalized sedimentation models have been developed from a review of more than sixty recent papers on modern and ancient braided-stream deposits. Braided rivers consist of a series of broad, shallow channels and bars, with elevated areas active only during floods, and dry islands. There are three main bar types; longitudinal, comprising crudely bedded gravel sheets; transverse to linguoid, consisting of sand or gravel and formed by downstream avalanche-face progradation; and point or side bars, formed by bedform coalescence and chute and swale development in areas of low energy. Important sediment-forming processes include bar formation, channel-floor dune migration, low-water accretion and overbank sedimentation.
Article
A sequence of fossil stromatolites from Lake Turkana in Kenya was examined for δ18O and δ13C content. These stromatolites, ranging in age from Holocene (∼10,000 yrsB.P.) to Middle Pliocene (≈3 m.y.) showed a variety of growth forms from oncolitic, columnar layered to bulbous heads. The stromatolites used in our study contain filamentous blue-green algae of one morphological type and rare coccoids; thus the stromatolites are considered biogenic. The stable isotope ratios for oxygen and carbon indicate changing climatic conditions, ranging from a cool, wet climate prior to ca. 1.9 m.y. to much drier, warmer conditions around 1.4 m.y., followed in turn by a somewhat cooler and wetter climate at the end of the Pleistocene.
Article
The Plio-Pleistocene Koobi Fora Formation, about 560 m thick, crops out east of Lake Turkana and is part of the much larger depositional system of the Omo-Turkana Basin. The upper half of the Koobi Fora Formation from just below the KBS Tuff to above the Chari Tuff is particularly notable for its wealth of hominid fossils and archaeological sites. Silicic tuffaceous horizons have provided the basis for stratigraphic subdivision and correlation. Pumice clasts within the tuffs contain anorthoclase phenocrysts, ideal for 40Ar/39Ar single-crystal dating. Feldspars from pumice clasts in about 15 tephra within the stratigraphic interval from the KBS Tuff to the Silbo Tuff have yielded precise ages that allow much finer definition of the numerical time framework for the sedimentary sequence between the KBS Tuff (1.869 ± 0.021 Ma) and the Chari Tuff (1.383 ± 0.028 Ma) and to yet higher in the sequence to the Silbo Tuff (0.751 ± 0.022 Ma). These results provide a precise and accurate time scale for the upper part of the sequence in the whole of the Omo-Turkana Basin. A number of these tuffs are recognized elsewhere in East Africa; thus ages determined at Koobi Fora also apply to the wider region.
Article
As an animal moves from air to water, its effective weight is substantially reduced by buoyancy while the fluid-dynamic forces (e. g. lift and drag) are increased 800-fold. The changes in the magnitude of these forces are likely to have substantial consequences for locomotion as well as for resistance to being overturned. We began our investigation of aquatic pedestrian locomotion by quantifying the kinematics of crabs at slow speeds where buoyant forces are more important relative to fluid-dynamic forces. At these slow speeds, we used reduced-gravity models of terrestrial locomotion to predict trends in the kinematics of aquatic pedestrian locomotion. Using these models, we expected animals in water to use running gaits even at slow speeds. We hypothesized that aquatic pedestrians would (1) use lower duty factors and longer periods with no ground contact, (2) demonstrate more variable kinematics and (3) adopt wider stances for increased horizontal stability against fluid-dynamic forces than animals moving at the same speed on land. We tested these predictions by measuring the three-dimensional kinematics of intertidal rock crabs (Grapsus tenuicrustatus) locomoting through water and air at the same velocity (9 cm s-1) over a flat substratum. As predicted from reduced-gravity models of running, crabs moving under water showed decreased leg contact times and duty factors relative to locomotion on land. In water, the legs cycled intermittently, fewer legs were in contact with the substratum and leg kinematics were much more variable than on land. The width of the crab's stance was 19 % greater in water than in air, thereby increasing stability against overturning by hydrodynamic forces. Rather than an alternating tetrapod or metachronal wave gait, crabs in water used a novel gait we termed 'underwater punting', characterized by alternating phases of generating thrust against the substratum and gliding through the water.
Article
New stable carbon isotope measurements, coupled with paleoprecipitation estimates, both from Plio-Pleistocene paleosols of the Turkana Basin, Kenya, provide a high-resolution record of aridification and increasing C4 biomass during the past 4.3 Ma. This aridification trend is marked by several punctuations at 3.58-3.35, 2.52-2, and 1.81-1.58 Ma, during which the running mean and variance of delta13C and paleoaridity estimates increase, suggesting that the proportion of C4 biomass increases in savanna mosaics during periods of heightened aridity. Increase in C4 biomass during these aridification events not only increases the proportion of open habitats, but increases the spatial neg-entropy, or heterogeneity of the ecosystem. The aridification events identified correspond to intervals of increased turnover, but more importantly, increased diversity of bovids. Although the record of hominins from the Turkana Basin lacks the temporal resolution and diversity of the bovid record, the aridification intervals identified are marked by similar increases in the diversity and turnover of hominins. These results support the hypothesis that hominins evolved in savanna mosaics that changed through time, and suggest that the evolution of bovids and hominins was driven by shifts in climatic instability and habitat variability, both diachronic and synchronic.
Article
The investigation of the Plio-Pleistocene sediments in the East Rudolf area was continued in the summer of 1970. This article places the important hominid sites in their geological context.
Article
Based on morphological analyses, hippos have traditionally been classified as Suiformes, along with pigs and peccaries. However, molecular data indicate hippos and cetaceans are sister taxa (see review in Uhen, 2007, this issue). This study analyzes soft tissue characters of the pygmy hippo forelimb to elucidate the functional anatomy and evolutionary relationships of hippos within Artiodactyla. Two specimens from the National Zoological Park in Washington, D.C. were dissected, revealing several adaptations to an aquatic lifestyle. However, these adaptations differ functionally from most aquatic mammals as hippos walk along river or lake bottoms, rather than swim. Several findings highlight a robust mechanism for propelling the trunk forward through the water. For example, mm. pectoralis superficialis and profundus demonstrate broad sites of origin, while the long flexor tendons serve each of the digits, reflecting the fact that all toes are weight-bearing. Pygmy hippos also have eight mm. interossei and a well-developed m. lumbricalis IV. Retention of intrinsic adductors functions to prevent splaying of the toes, an advantageous arrangement in an animal walking on muddy substrates. Published descriptions indicate common hippos share all of these features. Hippo and ruminant forelimbs share several traits; however, hippos are unique among artiodactyls in retaining several primitive muscles (e.g., mm. palmaris longus and flexor digitorum brevis). These findings are consistent with the hypothesis that hippos diverged from other Artiodactyla early in the history of this group. Additional analyses of hindlimb and axial muscles may help determine whether this trajectory was closely allied to that of Cetacea.
Article
Dinosaur tracks from Lower Jurassic rocks at Rocky Hill, Connecticut, were apparently made by a floating or half-submerged animal that was pushing along the bottom with the tips of its toes. These tracks were probably made by large carnivorous dinosaurs (Theropoda) and are apparently the first evidence of swimming by such animals.
Article
Climate change is hypothesized as a cause of major events of Plio-Pleistocene East African hominin evolution, but the vertically discontinuous and laterally confined nature of the relevant geological records has led to difficulties with assessing probable links between the two. High-resolution sedimentary sequences from lacustrine settings can provide comprehensive data of environmental changes and detailed correlations with well-established orbital and marine records of climate. Hominin-bearing deposits from Koobi Fora Ridge localities in the northeast Turkana Basin of Kenya are an archive of Plio-Pleistocene lake-margin sedimentation though significant developmental junctures of northern African climates, East African environments, and hominin evolution. This study examines alluvial channel and floodplain, nearshore lacustrine, and offshore lacustrine facies environments for the approximately 136-m-thick KBS Member (Koobi Fora Formation) exposed at the Koobi Fora Ridge. Aspects of the facies environments record information on the changing hydrosedimentary dynamics of the lake margin and give insights into potential climatic controls. Seasonal/yearly climate changes are represented by the varve-like laminations in offshore mudstones and the slickensides, dish-shaped fractures, and other paleosol features overprinted on floodplain strata. Vertical shifts between facies environments, however, are interpreted to indicate lake-level fluctuations deriving from longer-term, dry-wet periods in monsoonal rainfall. Recurrence periods for the inferred lake-level changes range from about 10,000 to 50,000 years, and several are consistent with the average estimated timescales of orbital precession ( approximately 20,000 years) and obliquity ( approximately 40,000 years). KBS Member facies environments from the Koobi Fora Ridge document the development of lake-margin hominin habitats in the northeast Turkana Basin. Environmental changes in these habitats may be a result of monsoonal rainfall variations that derive from orbital insolation and/or glacial forcing.
Stratigraphy, depositional environments and palaeogeography of the Koobi Fora Formation. 3, Koobi Fora research project
  • F H Brown
  • C S Feibel
Brown, F.H., Feibel, C.S., 1991. Stratigraphy, depositional environments and palaeogeography of the Koobi Fora Formation. 3, Koobi Fora research project pp. 1-30.
The quadrupedal gaits of vertebrates: the timing of leg movements relates to balance, body shape, agility, speed, and energy expenditure
  • Hildebrand
Hildebrand, M., 1989. The quadrupedal gaits of vertebrates: the timing of leg movements relates to balance, body shape, agility, speed, and energy expenditure. Bioscience 39, 766-775.
Selected photographs of two Nile Hippopotamus amphibius through the side wall of their tank at the Adventure Aquarium Philadelphia in 2008 showing an anatomy of a right front foot (A) and various styles of punting behaviour (B-D)
  • Fig
Fig. 12. Selected photographs of two Nile Hippopotamus amphibius through the side wall of their tank at the Adventure Aquarium Philadelphia in 2008 showing an anatomy of a right front foot (A) and various styles of punting behaviour (B-D). See the text for detailed description.
  • F Spoor
  • M G Leakey
  • P N Gathogo
  • F H Brown
  • S C Antón
  • I Mcdougall
  • L N Leakey
Spoor, F., Leakey, M.G., Gathogo, P.N., Brown, F.H., Antón, S.C., McDougall, I., Leakey, L.N., 2007. Implications of new early Homo fossils from Ileret, east of Lake Turkana, Kenya. Nature 448, 688-691.