Skeletal Fossils Research Articles

Pleistocene fauna of the Cape south coast revealed through ichnology at two localities

East of Still Bay on the Cape south coast of South Africa lies a rugged, remote stretch of sea cliffs that expose Late Pleistocene aeolianites. A zone of dense concentration of fossil tracks occurs within this area. Two large rocks, which we call Roberts Rock and Megafauna Rock, were identified ~400 metres apart. These rocks contained a variety of trackways, individual tracks, burrow traces and invertebrate trace fossils on multiple bedding planes. Both rocks were found ex situ, but their context could be determined. Roberts Rock has subsequently slid into the ocean, and Megafauna Rock lies at the base of a coastal cliff. Probable trackmakers include elephant, long-horned buffalo, giant Cape horse, rhinoceros, medium and small artiodactyls, golden mole, birds and invertebrates. Dating studies at an adjacent site, which is comparable to the stratigraphy described here, indicate that both rocks were most likely deposited in Marine Isotope Stage 5e (~128–116 ka). Analysis and description of these tracksites confirms the potential of ichnology to complement the skeletal fossil record and to enhance the understanding of Pleistocene life in southern Africa. The ephemeral nature of such tracksites makes repeated visits to this coastline desirable, both to monitor the fate of known sites and to search for newly exposed trace fossil surfaces.
 Significance:
 
 Roberts Rock and Megafauna Rock are two remarkable fossil tracksites on the Cape south coast, which contain tracks of four members of the Late Pleistocene megafauna. They provide a glimpse of Pleistocene dune life and suggest an area teeming with large mammals.
 These tracks were made on dune surfaces near an interface between the grassland of the Palaeo-Agulhas Plain and the inland Fynbos–Strandveld–Renosterveld. Faunal assemblages from both vegetation zones might therefore be recorded.
 The trace fossil record and body fossil record both have inherent biases, but have the potential to independently provide complementary information on palaeofaunal composition.
 The two rocks have provided the first South African records of fossil elephant tracks (as first described by Dave Roberts and colleagues in 2008), the first rhinoceros track and the first extinct giant Cape horse track, and track evidence of the extinct long-horned buffalo.
 Roberts Rock has slumped into the ocean, and it provides an example of the fate of many exposed tracksites. Conversely, new sites frequently become exposed. This scenario stresses the need for regular ichnological surveys along this track-rich coastline to monitor existing sites and to search for new sites.

Revisiting the world famous Lufeng Formation dinosaur fauna: new approaches to old problems

ABSTRACT The Lufeng area is a key locality for Early and Middle Jurassic Chinese dinosaurs. This region is perhaps best known internationally for the co-occurrence of basal sauropodomorph-eusauropod dinosaurs and has therefore been an important research area since the 1930s. We review on a series of palaeoecological analyses in this paper and assess biomass, in particular, using skeletal fossils from this region and analyses of large living terrestrial vertebrates as well as new sporopollenin and sedimentary information. The results of this analysis suggest a gradual substitution of basal sauropodomorphs (e.g. Lufengosaurus) by eusauropods (e.g. Chuanjiesaurus) between the Early Jurassic and Middle Jurassic in concert with increasing biomass and decreasing overall faunal diversity.

Re-examination and reinterpretation of the stratigraphy of the Matjies River Formation, Cango Caves Group, Neoproterozoic to early Palaeozoic Saldania Belt, South Africa

Abstract The carbonate-siliciclastic rocks of the late Neoproterozoic Matjies River Formation, Cango Caves Group (CCG) in South Africa, form part of the Neoproterozoic to early Palaeozoic Saldania Belt. Re-examination of the Matjies River Formation, consisting of the Nooitgedagt and overlying Kombuis members, led to a revision of the stratigraphy and interpretation of the geology of this formation. The discovery of unconformities, locally associated with palaeovalleys and/or ferruginous sedimentary rocks, makes it possible to subdivide the Matjies River Formation into a number of unconformity-bounded sequences which comprise coarsening upward and to a lesser extent fining upward sedimentary cycles. The unconformities and palaeovalleys are of tectonic and/or possibly glaciogenic origin. The clastic sediments of the Nooitgedagt Member were thought to be supplied from an eastern source area. However, the occurrence of thick very coarse, locally poorly-sorted conglomerates, which occur in a restricted north to south trending zone, also indicates a northern and/or southern provenance for the Nooitgedagt Member. The Nooitgedagt Member has been deformed in north-northeast - south-southwest trending synclines and anticlines during the Neoproterozoic to early Palaeozoic Pan-African Orogeny. East-west trending synclines and anticlines, which formed during the Palaeozoic and early Mesozoic orogenic events, are quite common in the overlying Kansa Group and Cape Supergroup but were not found in the Matjies River Formation. Soft-bodied Ediacaran-type and skeletal fossils were found in the Nooitgedagt and Kombuis members and indicate an Ediacaran age for the Matjies River Formation.

Una biota transicional Ediacárica–Cámbrica en el anticlinal de Abenójar (Macizo Ibérico, España)

Se describe una secuencia conteniendo una biota transicional ediacárica–cámbrica, en el valle del arroyo de las Navezuelas, anticlinal de Abenójar (Grupo Ibor, Zona Centroibérica, España). La secuencia empieza con capas siliciclásticas de grano fino conteniendo Vendotaenia antiqua y moldes de Cloudina cf. hartmannae, uno de los primeros animales con esqueleto mineralizado. Continúa con carbonatos con Cloudina fosfatizadas, coincidiendo en muestra de mano con Vendotaenia antiqua y con protoconodontos semejantes a Protohertzina unguliformis, lo cual sugiere una edad ediacárica terminal o cámbrica basal. Las capas detríticas sobre este nivel contienen pistas fósiles simples de organismos sedimentívoros. Sobre un estrato superior de carbonatos con pequeños vendoténidos se ha hallado un conjunto de pistas fósiles de aspecto cámbrico, incluyendo Treptichnus pedum y madrigueras ornamentadas semejantes a la superficie ventral de Psammichnites. El hallazgo de protoconodontos es nuevo para la transición Ediacárico–Cámbrico en Europa, y esta es la tercera vez a escala mundial que este tipo de fósiles típicamente cámbricos son hallados junto con cloudínidos, típicamente ediacáricos, lo cual sugiere que la transición Ediacárico–Cámbrico fue biológicamente más gradual de lo que se pensaba anteriormente.

Exploring the drivers of early biomineralization.

The first biomineralized hard parts are known from ∼810 Million years ago (Ma), consisting of phosphatic plates of probable protists formed under active biological control. Large skeletons in diverse taxa, probably including total-group poriferans and total-group cnidarians, first appear in the terminal Ediacaran, ∼550 Ma. This is followed by a substantial increase in abundance, diversity and mineralogy during the early Cambrian. The biological relationship of Ediacaran to early Cambrian skeletal biota is unclear, but tubular skeletal fossils such as Cloudina and Anabarites straddle the transition. Many Ediacaran skeletal biota are found exclusively in carbonate settings, and present skeletons whose form infers an organic scaffold which provided the framework for interactions between extracellular matrix and mineral ions. Several taxa have close soft-bodied counterparts hosted in contemporary clastic rocks. This supports the assertion that the calcification was an independent and derived feature that appeared in diverse groups, which was initially acquired with minimal biological control in the highly saturated, high-alkalinity carbonate settings of the Ediacaran, where the carbonate polymorph was further controlled by seawater chemistry. The trigger for Ediacaran-Cambrian biomineralization is far from clear, but may have been either changing seawater Mg/Ca ratios that facilitated widespread aragonite and high-Mg calcite precipitation, and/or increasing or stabilizing oxygen levels. By the Early Cambrian, the diversity of biomineralization styles may have been an escalating defensive response to increasing predation pressure, with skeletal hard parts first appearing in abundance in clastic settings by the Fortunian. This marks full independence from ambient seawater chemistry and significant biological control of biomineralization.

Palaeoecology of giraffe tracks in Late Pleistocene aeolianites on the Cape south coast

Until now there have been no reliable historical or skeletal fossil records for the giraffe (Giraffa camelopardalis) south of the Orange River or northern Namaqualand. The recent discovery of fossil giraffe tracks in coastal aeolianites east of Still Bay, South Africa, significantly increases the geographical range for this species, and has implications for Late Pleistocene climate and vegetation in the southern Cape. Giraffe populations have specialised needs, and require a savanna ecosystem. Marine geophysical and geological evidence suggests that the broad, currently submerged floodplains of the Gouritz and Breede Rivers likely supported a productive savanna of Vachellia karroo during Pleistocene glacial conditions, which would have provided a suitable habitat for this species. We show evidence for the hypothesis that the opening of the submerged shelf during glacial periods acted as a pathway for mammals to migrate along the southern coastal plain.
 Significance: 
 
 The identification of fossil giraffe tracks on the Cape south coast, far from the area in which giraffe have previously been known to occur, is unexpected; conclusions about prehistoric conditions and vegetation can be drawn from this discovery.

Fluorapatite diagenetic differences between Cretaceous skeletal fossils of Mongolia and Korea

The skeletal tissue of modern bones is mostly composed of hydroxyapatite, which contains calcium and phosphate. During diagenesis, calcium, phosphorus and minerals of the hydroxyl group can be exchanged with other elements to form carbonate-fluorapatite. It is well-established that paleoenvironmental evolution and geological events have played a significant role in the compositional changes of fossilized bones. For example, skeletal fossils from the Hasandong Formation (Aptian- early Albian) of the Gyeongsang Basin in Korea are characterized by black and dark colors, whereas dinosaur bones from the Nemegt Formation (early Maastrichtian) of the Nemegt and Altan Uul ranges in Mongolia are light brown and white. This study investigated the mineralogical and geochemical causes for the differences in coloration between these two groups of fossilized bones. Multiple synchrotron-based techniques were utilized, including synchrotron–XRF, –XRD, –X-ray micro-computed tomography (μ-CT), micro-XRF and SEM-EDX data to analyze the elemental composition and mineral phases in dark Korean fossilized bones, which are characterized by the presence of iron, aluminum, magnesium and other trace elements. Chamosite was identified as a secondary mineral at 5% by weight of the total fossil mass, which is primarily composed of carbonate-fluorapatite. However, skeletal fossils from Mongolia are characterized by secondary minerals, such as barite, goethite and calcite, which accumulate in pore spaces. Since different secondary minerals result from different alteration procedures, the presence of chamosite in the Korean fossils suggests alteration by spatial replacement, and the presence of barite in the Mongolian fossils suggests alteration by accumulation. The investigation of these two skeletal groups, analyzed using a suite of synchrotron-based multidisciplinary techniques, revealed contrasting mineralogical and geochemical details and helps to determine the origin of fossil colorization.

Ichnological evidence of semi-aquatic locomotion in early turtles from eastern Iberia during the Carnian Humid Episode (Late Triassic)

Some of the earliest European records of fossil turtle footprints (Late Triassic, Middle Carnian, ~227–237Ma) are interpreted from 46 footprints from three outcrops, Domeño, Quesa and Cortes de Pallas, located in the Iberian Range (eastern Spain). The samples were obtained from Upper Triassic rocks in Keuper Facies. They are characterized in the studied area by two well-defined evaporitic sequences, separated by a detrital stratigraphic interval, constituting the Manuel Sandstones Formation in which the studied fossil footprints were recorded. These fluvial deposits are correlatable with the Carnian Humid Episode. The footprints are tridactyl and tetradactyl, mainly digitigrade, and elongated scratch marks are common. The digit traces present triangular and curved claws. The morphology of these marks suggests they were produced by the autopodium of a tetrapod animal while swimming near the bottom, and they are consistent with the anatomical features of a turtle's manus. Other footprints were produced by turtles walking in wet medium- to coarse-grained sand in a subaerial environment. A short trackway is identified, sharing similarities with both the ichnogenera Emydhipus and Chelonipus. The observed tracks support a freshwater semi-aquatic habit for some stem turtles during the early Late Triassic. These are remarkably ancient turtle tracks, close to the origin of the group, as indicated by skeletal fossils; they confirm that the earliest forms were narrowly related to aquatic (fluvial) environments.

Vertebrate Trace Fossils from the Late Pleistocene of Kangaroo Island, South Australia

ABSTRACTIt is rapidly becoming apparent that the Late Pleistocene vertebrate trace fossil record of southern Australia is much more comprehensive than previously understood, and complements the skeletal fossil record with regard to the distribution of taxa in coastal environments and the palaeobiology of both extinct and extant organisms. We surveyed the majority of prospective Bridgewater Formation outcrops on Kangaroo Island in South Australia and discovered a trace fossil site preserving hundreds of individual traces. A minimum of ten different reptile, bird, and mammal taxa, as well as invertebrates, are represented at the site. Single-grain optically stimulated luminescence dating indicates that the dune in which the traces imprinted was deposited at the beginning of Marine Isotope Stage 5e (135.4 ± 5.9 ka). The traces were made by several extinct taxa including large quadrupeds (most probably diprotodontids), short-faced (sthenurine) kangaroos, and thylacines, as well as extant taxa including possums, the Tasmanian Devil, goannas, shorebirds, and a variety of kangaroos. This site demonstrates that, even though vertebrate trace fossil sites do not often allow the same level of taxonomic differentiation as skeletal fossil deposits, they can nevertheless provide important information about taxon distribution and behavior that can be correlated and contrasted with skeletal fossil assemblages.

Identifying remains of extinct kangaroos in Late Pleistocene deposits using collagen fingerprinting

ABSTRACTOur knowledge of past animal populations, including the geographical ranges of extinct species, has largely been derived from morphological analyses of skeletal fossil remains. However, a major barrier to the identification of the remains of extinct megafaunal species in archaeological and palaeontological sites is the highly fragmented nature of the material, which often precludes confident taxonomic identifications based on morphology. Biomolecular techniques are able to go beyond these limitations and are increasingly being used to make such identifications. Protein analysis offers a promising alternative to DNA techniques because they can be much cheaper, more amenable to high‐throughput processing and work on much older specimens. Here we demonstrate the potential of collagen fingerprinting in an Australian context by extracting collagen from 50‐ka kangaroo fossils from two caves in Tasmania, and identify several species including the extinct short‐faced kangaroo Simosthenurus occidentalis. Importantly, of the five fossil bones sampled that had hitherto been ascribed morphology‐based identifications below the family level, three had been incorrectly identified during an initial assessment of photographs taken in the field. Our results highlight the utility of using protein‐based methods for making genus‐level identification of marsupial bone, especially those that may form a basis for broader arguments such as that of late‐surviving megafaunal species.

The oldest Cambrian skeletal fossils of Spain (Cadenas Ibéricas, Aragón)

AbstractDiverse skeletal assemblage has been discovered in the Ediacaran/Cambrian strata of the Codos locality in NE Spain (Aragón, Cadenas Ibéricas). This assemblage includes at least seven genera, only three of which can be ascribed to known taxa. All the fossils are preserved in phosphate but their original microstructures are traceable by both elementary composition and microstructural features that are indicative for primary aragonite and high-magnesium calcite biomineralogies. Already these early skeletal fossils show sophisticated microstructures represented by heterogeneous multilayered composites to satisfy the requirements for better protection against both chemical dissolution and mechanical predator deterioration. The most common and best-preserved fossil, which is tubicolous Codositubulus grioensis gen. et sp. nov., is described here. The composition of the fossil assemblage and its stratigraphic position are indicative for the lowermost Terreneuvian (lower Cambrian) or even pre-Terreneuvian age of this fauna.

Euendoliths versus ambient inclusion trails from Early Cambrian Kuanchuanpu Formation, South China

Abundant microstructures have been discovered in small skeletal fossils (SSFs) and embryo-like fossils collected from the Lower Cambrian Kuanchuanpu Formation (ca. 535Ma) in Xixiang County, Shaanxi Province, China. These involve two co-occurring structures: (1) long, unbranched cylindrical filaments, which are comparable to phosphatic casts of microborings constructed by euendolithic cyanobacteria (Endoconchia lata) in morphology and preservation pathway; and (2) meandering micro-tubes or grooves on fossil moulds (and steinkerns) of a wide range of sizes and morphological diversities, perceived as ambient inclusion trails (AITs). Herein, we also report a new occurrence of organic carbon spherules as AIT-propelled material, which is rare in comparable fossils. From direct comparison of endolith fossils and AITs, we propose a mechanism to account for their notably different preservation, and further attempt to offer an explanation for their co-occurrence. Their differential preservation suggests a chronological, taphonomic sequence of their formation. We interpret that E. lata microborings formed prior to phosphate sedimentation, whereas AITs are likely generated in a later phase of (or after) phosphorite precipitation but before calcareous re-cementation. Dissecting the sequence of formation of these structures, in conjunction with detailed morphological observations, assists in distinguishing true biologically produced endoliths from otherwise abiogenically produced microstructures.

Angolan ichnosite in a diamond mine shows the presence of a large terrestrial mammaliamorph, a crocodylomorph, and sauropod dinosaurs in the Early Cretaceous of Africa

We report here new and the first mammaliamorph tracks from the Early Cretaceous of Africa. The tracksite, that also bears crocodylomorph and sauropod dinosaurian tracks, is in the Catoca diamond mine, Lunda Sul Province, Angola. The mammaliamorph tracks have a unique morphology, attributed to Catocapes angolanus ichnogen. et ichnosp. nov. and present an anterolateral projection of digit I and V. The tracks with an average length of 2.7cm and width of 3.2cm are the largest mammaliamorph tracks known from the Early Cretaceous unmatched in size in the skeletal fossil record. The crocodylomorph trackways and tracks are attributed to Angolaichnus adamanticus ichnogen. et ichnosp. nov. (‘ichnofamily’ Batrachopodidae) and present a functionally pentadactyl pes, an extremely outwardly rotated handprint, and an unusual tetradactyl and plantigrade manus. One medium-sized sauropod dinosaur trackway preserved skin impressions of a trackmaker with stride length of 1.6m; a second is that of a small-sized sauropod trackmaker with a pace length of 75cm.

ACloudina-like fossil with evidence of asexual reproduction from the lowest Cambrian, South China

AbstractThe earliest fossil record of animal biomineralization occurs in the latest Ediacaran Period (c. 550 Ma).CloudinaandSinotubulitesare two important tubular taxa among these earliest skeletal fossils. The evolutionary fate ofCloudina-type fossils across the Ediacaran–Cambrian transition, however, remains poorly understood. Here we report a multi-layered tubular microfossilFeiyanella manicagen. et sp. nov. from a phosphorite interval of the lowest Cambrian Kuanchuanpu Formation, southern Shaanxi Province, South China. This newly discovered fossil is a conical tube with a ‘funnel-in-funnel’ construction, showing profound morphological similarities toCloudinaandConotubus. On the other hand, the outer few layers, and particularly the outermost layer, ofFeiyanellatubes are regularly to irregularly corrugated, a feature strikingly similar to the variably folded/wrinkled tube walls ofSinotubulites. TheFeiyanellatubes additionally exhibit two orders of dichotomous branching, similar to branching structures reported occasionally inCloudinaand possibly indicative of asexual reproduction. Owing to broad similarities in tube morphology, tube wall construction and features presumably indicative of asexual reproduction,Cloudina, Conotubus, Sinotubulitesand the here describedFeiyanellamay thus constitute a monophyletic group traversing the Ediacaran–Cambrian boundary. The tube construction and palaeoecological strategy ofFeiyanellaputatively indicate evolutionary continuity in morphology and palaeoecology of benthic metazoan communities across the Ediacaran–Cambrian transition.

Shell composition of Terreneuvian tubular fossils from north‐east Sichuan, China

AbstractIdentification of the primary constituents of small shelly fossil (SSF) shells is important for explaining the evolution of SSF faunas. The characteristics and constituents of Terreneuvian tubular SSFs found in north‐east Sichuan, China, are revealed using light microscopy, scanning electron microscopy and energy dispersive X‐ray spectroscopy. Petrographic thin sections indicate that the chemical composition of the shells is mainly calcium carbonate with smaller amounts of phosphorus, silica and pyrite. Most of the tubular shells composed of calcium carbonate have a distinct layered structure. Evidence of replacement of the original shell by phosphatization, pyritization and silicification, and recrystallization of calcium carbonate have been found, all of which destroyed the shell's original layered structure. Most fossils treated with acetic acid are phosphatic casts or steinkerns, with some preserving organic textures of the shell as phosphatic casts. We conclude that the Terreneuvian tubular SSFs from north‐east Sichuan were originally composed mainly of calcium carbonate; indeed, most Terreneuvian small skeletal fossils appear to have had an originally calcareous composition. The fossil casts or internal core fossils are composed of phosphate, which is related to local taphonomic processes.

The Precambrian–Phanerozoic and Ediacaran–Cambrian boundaries: a historical approach to a dilemma

Abstract The Cambrian was originally defined as a rock interval with a trilobite-dominated fauna that overlay a presumed biologically barren Precambrian epoch. Work to formally define the Cambrian base arose after the discovery of Precambrian macrofossils in South Australia. The Working Group on the Precambrian–Cambrian Boundary (set up in 1972) promoted an emphasis on an extended pre-trilobitic interval with mineralized skeletal elements (small shelly fossils or early skeletal fossils). The study of early skeletal fossils made the Ulakhan-Sulugur (Siberia) and Meishucun (South China) sections candidates for the basal Cambrian Global Stratotype Section and Point (GSSP), but difficulties in correlation and the taxonomy of early skeletal fossils did not allow the selection of a reliably correlative horizon. Bilaterian ichnofaunas below the first diverse early skeletal fossils suggested the definition of a Cambrian base GSSP below the early skeletal fossils. Work on the thick, stratigraphically continuous and fairly unifacial sections in the Burin Peninsula, southeastern Newfoundland led in 1992 to an ichnofossil-defined GSSP at Fortune Head. Despite arguments for a revision and redefinition of the lower boundary of the Cambrian System, the best definition of the basal Cambrian GSSP is at Fortune Head and does not rely on the Treptichnus/Trichophycus pedum (abbreviated below as T. pedum ) first appearance datum, but rather on the base of the T. pedum Assemblage Zone at the highest occurrence of Ediacaran taxa and in the lower range of T. pedum .

Transitional Ediacaran–Cambrian small skeletal fossil assemblages from South China and Kazakhstan: Implications for chronostratigraphy and metazoan evolution

The Ediacaran–Cambrian transition records distinct evolutionary changes of metazoans. The Ediacaran fossils (i.e., Ediacara-type biota and tubular fossils) are contrasting with the diverse small skeletal fossils (SSFs) from the early Cambrian. The apparent dissimilarities hindered studies deciphering their evolutionary relationships. This also led to a popular assumption that there exists a mass extinction of the Ediacara biota and cloudinids at the Precambrian–Cambrian (Pc–C) boundary. Here we report for the first time a transitional fauna which consists of typical elements of Ediacaran, i.e. cloudinids and related tubicolous organisms, together with Cambrian SSFs including protoconodonts, anabaritids and siphogonuchitids from South China and Maly Karatau (Kazakhstan). The sediments yielding the transitional fauna are characterized by siliceous rocks in both regions and were previously considered to be unfossiliferous. Their chronostratigraphic assignment in South China has been debated for years. Based on the new fossil assemblage, the siliceous strata of the Daibu Member (Northeast Yunnan, South China) and the basal Kuanchuanpu Formation (South Shaanxi, South China) can be assigned to the earliest Cambrian SSF biozone (Anabarites trisulcatus–Protohertzina anabarica Assemblage Zone) and thus can be considered of early Cambrian in age. A new subzone of the earliest SSF zone in eastern Yunnan (South China) is proposed herein defined as Ganloudina symmetrica–Rugatotheca typica Interval Subzone. The new fauna demonstrates that the cloudinids, originally confined to the late Ediacaran, persisted into the Cambrian Fortunian, and no major extinction event occurred at the Pc–C transition.

Skeletal fossils and microfacies analysis of the lowermost Cambrian in the southwestern margin of the North China Platform

The Xinji and Zhushadong formations are the oldest record of Cambrian deposits in the southwestern margin of the North China Platform. The two lithostratigraphic units are carbonate-dominated in lithology and are Cambrian Series 2 in age. The basal unit, the Xinji Formation yields diverse skeletal fossils, including sponge spicules, chancelloriid sclerites, hyoliths, micromolluscs, trilobites, echinoderm ossicles, cambroclaves, tianzhushanellids, protoconodonts and other small shelly fossils. The fossil assemblage, as the earliest fauna of the Cambrian in North China, provides an important window to investigate the Cambrian explosion in the region and contains fossil elements with biostratigraphical significance. Seven microfacies types of the Xinji and Zhushadong formations are recognized: (1) phosphorized and selectively dolomitized bioclastic grainstone, (2) dolomitized ooid grainstone, (3) dolomitized peloid wackstone, (4) lime mudstone preserved as dolomitic microsparite, (5) siliciclastic wackstone, (6) calcareous siltstone, and (7) breccia. The different microfacies are traced to three successive depositional environments, beginning with a bioclastic shoal, then a mixed-depositional back-shoal and finally an oolitic shoal. The system of the shoal and back-shoal is interpreted as representing the mixed siliciclastic-carbonate deposition during the initial transgression of the North China Platform as well as the early development of an epeiric environment.

Pleistocene footprints show intensive use of lake margin habitats by Homo erectus groups

Reconstructing hominin paleoecology is critical for understanding our ancestors’ diets, social organizations and interactions with other animals. Most paleoecological models lack fine-scale resolution due to fossil hominin scarcity and the time-averaged accumulation of faunal assemblages. Here we present data from 481 fossil tracks from northwestern Kenya, including 97 hominin footprints attributed to Homo erectus. These tracks are found in multiple sedimentary layers spanning approximately 20 thousand years. Taphonomic experiments show that each of these trackways represents minutes to no more than a few days in the lives of the individuals moving across these paleolandscapes. The geology and associated vertebrate fauna place these tracks in a deltaic setting, near a lakeshore bordered by open grasslands. Hominin footprints are disproportionately abundant in this lake margin environment, relative to hominin skeletal fossil frequency in the same deposits. Accounting for preservation bias, this abundance of hominin footprints indicates repeated use of lakeshore habitats by Homo erectus. Clusters of very large prints moving in the same direction further suggest these hominins traversed this lakeshore in multi-male groups. Such reliance on near water environments, and possibly aquatic-linked foods, may have influenced hominin foraging behavior and migratory routes across and out of Africa.

Skeletal anatomy of the early morid fish Eophycis (Gadiformes, Moridae) from an Oligocene deposit in Poland

The family Moridae (Gadiformes) is diagnosed by an otophysic connection, a horizontal gas bladder septum, unique otoliths and a specific architecture of the caudal skeleton. Their skeletal fossil record is rather scarce and uncertain: the oldest proven representatives (from Oligocene sites of the Paratethys area) are classified in the genus Eophycis. Newly collected specimens from the Hermanowa locality (Poland) allow the description of and commentary on previously unknown characters. The species Eophycis jamnensis was a typical morid fish with an elongated body, a triangular head, and single dorsal and anal fins that are not coalesced with the caudal fin. This species was most similar to the Recent species Guttigadus nana that differs from it (as from other Eophycis species) in meristic features, having two dorsal fins but lacking a vomer. A brief review of the fossil skeletal record of morid fish is presented.