264 research outputs found
Pleistocene reptile swim traces confirmed from South Africa’s Cape south coast
Large Pleistocene reptile tracks and traces were described from the Cape south coast of South Africa in 2020, including ‘probable swim traces’. These trace fossils were found on loose slabs and blocks of the Klein Brak Formation. Subsequently, another surface has become exposed on this coastline, also on a loose slab. It exhibits more definitive evidence of swim traces in epirelief, probably made by the Nile crocodile (Crocodylus niloticus) or water monitor (Varanus niloticus), although a chelonian origin cannot be excluded. Length of a possible crocodylian trackmaker was estimated from measurements of interdigital distance in the swim traces. These provide a compelling example of reptile swim traces from Africa.Significance:
Pleistocene reptile swim traces have now been confidently confirmed from the Cape south coast of South Africa.
The findings complement the suite of recently identified large reptile tracks.
Trackmaker size can be estimated from the dimensions of reptile swim traces.
These are the first compelling non-dinosaurian reptile swim traces to be described from Africa
A Diverse Mammal-Dominated, Footprint Assemblage from Wetland Deposits in the Lower Cretaceous of Maryland
A newly discovered assemblage of predominantly small tracks from the Cretaceous Patuxent Formation at NASAs Goddard Space Flight Center, Maryland, reveals one of the highest track densities and diversities ever reported (~70 tracks, representing at least eight morphotypes from an area of only ~2m(exp 2)). The assemblage is dominated by small mammal tracks including the new ichnotxon Sederipes goddardensis, indicating sitting postures. Small crow-sized theropod trackways, the first from this unit, indicate social trackmakers and suggest slow-paced foraging behavior. Tracks of pterosaurs, and other small vertebrates suggest activity on an organic-rich substrate. Large well-preserved sauropod and nodosaurs tracks indicate the presence of large dinosaurs. The Patuxent Formation together with the recently reported Angolan assemblage comprise the worlds two largest Mesozoic mammal footprint assemblages. The high density of footprint registration at the NASA site indicates special preservational and taphonomic conditions. These include early, penecontemporaneous deposition of siderite in organic rich, reducing wetland settings where even the flesh of body fossils can be mummified. Thus, the track-rich ironstone substrates of the Patuxent Formation, appear to preserve a unique vertebrate ichnofacies, with associated, exceptionally-preserved body fossil remains for which there are currently no other similar examples preserved in the fossil record
FIRST REPORT ON DINOSAUR TRACKS FROM THE BURRO CAN YON FORMATION, SAN JUAN COUNTY, UTAH, USA – EVIDENCE OF A DIVERSE, HITHERTO UN KNOWN LOWER CRETACEOUS DINOSAUR FAUNA
The newly discovered White Mesa tracksite in the Burro Canyon Formation represents a snap shot of a diverse, Lower Cretaceous dinosaur fauna from south-eastern Utah. The tracks were found at a construction site where the sand stone had been bull dozed and broken up. All tracks were found as deep, well-preserved natural casts on the under side of the sand stone slabs. Individual theropod tracks are 19–57 cm in length; one peculiar track shows evidence of a possible pathological swelling in the middle of digit III and an apparently didactyl track is tentatively as signed to a dromaeosaurid. Individual sauropod tracks are found with pes lengths of 36–72 cm, and interestingly, three distinct shapes of manus tracks, ranging from wide banana shaped to rounded and hoof-like. Ornithopods are represented with individual tracks 18–37 cm in length; a single track can possibly be attributed to the thyreophoran ichnogenus Deltapodus. Zircon U-Pb dating places the track-bearing layer in the Barremian, contemporary to the lower Yellow Cat Member of the Cedar Mountain Formation, which has a similar faunal composition based on both tracks and body fossils. This new track-fauna demonstrates the existence of a diverse dinosaurian assemblage in the lower part of the Burro Canyon Formation, which hitherto is not known to yield skeletal remains
Hominin tracks in southern Africa: a review and an approach to identification
Three Late Pleistocene hominin tracksites have been reported from coastal aelioanites in South Africa. Two have been dated to 124 ka and 117 ka , and the third is inferred to be 90 ka. There are no other globally reported sites for probable Homo sapiens tracks older than
46 ka. Given this documented record, a search for further hominin tracksites in southern Africa may well yield additional positive results. However, this is a field that demands scientific rigour, as false positive tracksites (pseudotracks) may occur. Criteria have been
developed for the identification of fossil vertebrate tracks and hominin tracks, but these are specific neither to southern Africa nor to aeolianites.An important caveat is that the tracks of shod humans would not fulfil these criteria. Preservation of tracks varies with facies
and is known to be suboptimal in aeolianites. An analysis of the tracks from the three documented South African sites, along with pseudotracks and tracks of questionable provenance, allows for the proposal and development of guidelines for fossil hominin track
identification that are of specific relevance to southern Africa. Such guidelines have broader implications for understanding the constraints that track preservation and substrate have on identifying diagnostic morphological features.Palaeontological Scientific Trust (PAST)JNC201
First report on dinosaur tracks from the Burro Canyon Formation, San Juan County, Utah, USA - Evidence of a diverse, hitherto unknown Lower Cretaceous dinosaur fauna
Possible Pleistocene hominin tracks from South Africa’s west coast
Two probable tracks have been identified on the ceiling of a small overhang in the Pleistocene Langebaan Formation on South Africa’s west coast. They may have been made by a hominin trackmaker. They appear to have been registered at walking speed on a level, sandy dune substrate. Three tracks, attributed to Homo sapiens, were previously identified near Langebaan in 1995, and were popularly labelled ‘Eve’s Footprints’. The new identification of possible hominin tracks near Langebaan is the second from South Africa’s west coast. This discovery adds to the sparse but growing global record of possible hominin tracks preserved in aeolianites.
Significance:• Two probable fossil tracks have been identified on the ceiling of an overhang near Langebaan.• The tracks may have been made by a human walking on a level dune surface during the Pleistocene.• This discovery is the second of its kind on the west coast, and complements the 1995 identification near Langebaan of Pleistocene fossil tracks attributed to humans
Late Pleistocene vertebrate trace fossils in the Goukamma Nature Reserve, Cape South Coast, South Africa
More than 100 Late Pleistocene trace fossil sites have been identified in aeolianites along a 275 kilometer stretch of the Cape south coast. A zone of concentration of such sites exists within the Goukamma Nature Reserve, both along the coast and along the Goukamma River. These sites provide insight into the Pleistocene fauna along the Cape south coast. Features include lion trackways, multiple elephant tracksites, a long trackway most likely attributable to Long-horned Buffalo, medium-sized carnivore tracks, avian tracks, equid tracks attributable to the giant Cape horse, numerous artiodactyl tracks, and burrow traces. The ephemeral nature of the tracksites makes regular surveys of these areas desirable, along with site documentation and trackway replication and preservation initiatives. The protected status of the area offers opportunities for geoheritage appreciation.JN
A Redescription of the Ichnospecies Koreanaornis Anhuiensis (Aves) from the Lower Cretaceous Qiuzhuang Formation at Mingguang City, Anhui Province, China
The Cretaceous bird trackway originally labeled Aquatilavipes anhuiensis, in 1994, had previously been examined, photographed and replicated, but never described or illustrated in detail. However, it has been part of a widening discussion about the distribution of Aquatilavipes and Koreanaornis in China (and Korea). Here we illustrate and formally describe the holotype in detail and assign it to Koreanaornis (Koreanaornis anhuiensis) as informally proposed by previous authors. We also demonstrate that most authenticated reports of Koreanaornis, including the Anhui occurrence, are from the Lower Cretaceous, not from the Upper Cretaceous as previously reported
Sistem Pengendali Kecepatan Motor Dc Pada Lift Barang Menggunakan Kontroler Pid Berbasis Atmega 2560
Lift barang adalah angkutan transportasi vertikal digunakan untuk memindahkan barang. Lift ini sangat khusus fungsinya untuk barang saja, lift ini hampir sama dengan lift penumpang namun ada sedikit perbedaan dalam sistem keamanannya. Lift barang yang sekarang memang sudah otomatis tetapi hanya pada gedung bertingkat tinggi. Untuk minimarket atau home industry yang memiliki struktur bangunan 2 lantai, banyak dijumpai masih menggunakan pengkatrolan secara manual oleh tenaga manusia untuk memindahkan barang. Hal ini cukup tidak efisien. Pada penelitian ini telah dirancang sistem pengaturan kecepatan motor DC pada lift barang menggunakan kontoler PID dengan kontruksi sistem yang sederhana. Digunakan Kontroler PID untuk mengurangi kesalahan, sehingga putaran motor dapat sesuai dengan kecepatan yang diinginkan. Dengan bantuan kontroler PID maka lift barang mampu bergerak dengan aman dan halus. Pada skripsi ini digunakan metode Ziegler-Nichols tunning 2. Dalam pembuatannya digunakan Arduino Mega 2560, rotary encoder Autonic E40H8 500-6-L-5, limit switch, dan motor DC. Berdasarkan data respons sistem yang diperoleh dari pengujian dengan menggunakan metode kedua Ziegler-Nichols, maka parameter kontroler PID dapat ditentukan dengan gain Kp = 7.71, Ki = 7.035 dan Kd = 2.113.Kata Kunci— Lift barang, Pengendalian Kecepatan, PID, Arduino Mega 2560
Theropod courtship: large scale physical evidence of display arenas and avian-like scrape ceremony behaviour by Cretaceous dinosaurs
Relationships between non-avian theropod dinosaurs and extant and fossil birds are a major focus of current paleobiological research. Despite extensive phylogenetic and morphological support, behavioural evidence is mostly ambiguous and does not usually fossilize. Thus, inferences that dinosaurs, especially theropods displayed behaviour analogous to modern birds are intriguing but speculative. Here we present extensive and geographically widespread physical evidence of substrate scraping behavior by large theropods considered as compelling evidence of "display arenas" or leks, and consistent with "nest scrape display" behaviour among many extant ground-nesting birds. Large scrapes, up to 2 m in diameter, occur abundantly at several Cretaceous sites in Colorado. They constitute a previously unknown category of large dinosaurian trace fossil, inferred to fill gaps in our understanding of early phases in the breeding cycle of theropods. The trace makers were probably lekking species that were seasonally active at large display arena sites. Such scrapes indicate stereotypical avian behaviour hitherto unknown among Cretaceous theropods, and most likely associated with terrirorial activity in the breeding season. The scrapes most probably occur near nesting colonies, as yet unknown or no longer preserved in the immediate study areas. Thus, they provide clues to paleoenvironments where such nesting sites occurred
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