Darting towards Storm Shelter: A minute dinosaur trackway from southern Africa
Theropod dinosaurs are considered the main terrestrial carnivores in the Jurassic and Cretaceous. Their rise to dominance has been linked to, among others, body size changes in their early history, especially across the Triassic–Jurassic boundary. However, to qualitatively assess such temporal trend...
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| Format: | Article |
| Language: | English |
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Academy of Science of South Africa
2021-05-01
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| Series: | South African Journal of Science |
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| Online Access: | https://sajs.co.za/article/view/9145 |
| _version_ | 1818981601818705920 |
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| author | Emese M. Bordy |
| author_facet | Emese M. Bordy |
| author_sort | Emese M. Bordy |
| collection | DOAJ |
| description | Theropod dinosaurs are considered the main terrestrial carnivores in the Jurassic and Cretaceous. Their rise to dominance has been linked to, among others, body size changes in their early history, especially across the Triassic–Jurassic boundary. However, to qualitatively assess such temporal trends, robust skeletal and trace fossil data sets are needed globally. The richly fossiliferous southern African continental rock record in the main Karoo Basin offers an unparalleled perspective for such investigations. Herein, by documenting a newly discovered Early Jurassic trackway of very small, functionally tridactyl tracks near Storm Shelter (Eastern Cape) in South Africa, the track record can be expanded. Based on ichnological measurements at the ichnosite and digital 3D models, the footprint dimensions (length, width, splay), locomotor parameters (step length, stride, speed), and body size estimates of the trackmaker are presented. In comparison to other similar tracks, these footprints are not only the smallest Grallator-like tracks in the Clarens Formation, but also the most elongated dinosaur footprints in southern Africa to date. The tracks also show that the small-bodied bipedal trackmaker dashed across the wet sediment surface at an estimated running speed of ~12.5 km/h. During the dash, either as a predator or as a prey, the trackmaker’s small feet sunk hallux-deep into the sediment. The tracking surface is overgrown by fossilised microbial mats, which likely enhanced the footprint preservation. Based on track morphometrics and the regional dinosaur skeletal record, the trackmakers are attributed to Megapnosaurus rhodesiensis (formerly Syntarsus rhodesiensis), a small-to-medium-sized, early theropod common in southern Africa.
Significance:
• A newly discovered Early Jurassic theropod trackway in South Africa contains not only the smallest tracks in the Clarens Formation, but also the most elongated dinosaur footprints in southern Africa to date.
• The tracks show that the small bipedal trackmaker dashed across the wet sediment surface at an estimated running speed of ~12.5 km per hour.
• During the run, the trackmaker’s feet sunk so deeply into the sediment that even the forwards-directed halluces were impressed.
Open data set: https://doi.org/10.6084/m9.figshare.13007240.v1 |
| first_indexed | 2024-12-20T17:33:55Z |
| format | Article |
| id | doaj.art-44e5680a4a90439c92121b676b80f44d |
| institution | Directory Open Access Journal |
| issn | 1996-7489 |
| language | English |
| last_indexed | 2024-12-20T17:33:55Z |
| publishDate | 2021-05-01 |
| publisher | Academy of Science of South Africa |
| record_format | Article |
| series | South African Journal of Science |
| spelling | doaj.art-44e5680a4a90439c92121b676b80f44d2022-12-21T19:31:16ZengAcademy of Science of South AfricaSouth African Journal of Science1996-74892021-05-011175/610.17159/sajs.2021/9145Darting towards Storm Shelter: A minute dinosaur trackway from southern AfricaEmese M. Bordy0Department of Geological Sciences, University of Cape Town, Cape Town, South AfricaTheropod dinosaurs are considered the main terrestrial carnivores in the Jurassic and Cretaceous. Their rise to dominance has been linked to, among others, body size changes in their early history, especially across the Triassic–Jurassic boundary. However, to qualitatively assess such temporal trends, robust skeletal and trace fossil data sets are needed globally. The richly fossiliferous southern African continental rock record in the main Karoo Basin offers an unparalleled perspective for such investigations. Herein, by documenting a newly discovered Early Jurassic trackway of very small, functionally tridactyl tracks near Storm Shelter (Eastern Cape) in South Africa, the track record can be expanded. Based on ichnological measurements at the ichnosite and digital 3D models, the footprint dimensions (length, width, splay), locomotor parameters (step length, stride, speed), and body size estimates of the trackmaker are presented. In comparison to other similar tracks, these footprints are not only the smallest Grallator-like tracks in the Clarens Formation, but also the most elongated dinosaur footprints in southern Africa to date. The tracks also show that the small-bodied bipedal trackmaker dashed across the wet sediment surface at an estimated running speed of ~12.5 km/h. During the dash, either as a predator or as a prey, the trackmaker’s small feet sunk hallux-deep into the sediment. The tracking surface is overgrown by fossilised microbial mats, which likely enhanced the footprint preservation. Based on track morphometrics and the regional dinosaur skeletal record, the trackmakers are attributed to Megapnosaurus rhodesiensis (formerly Syntarsus rhodesiensis), a small-to-medium-sized, early theropod common in southern Africa. Significance: • A newly discovered Early Jurassic theropod trackway in South Africa contains not only the smallest tracks in the Clarens Formation, but also the most elongated dinosaur footprints in southern Africa to date. • The tracks show that the small bipedal trackmaker dashed across the wet sediment surface at an estimated running speed of ~12.5 km per hour. • During the run, the trackmaker’s feet sunk so deeply into the sediment that even the forwards-directed halluces were impressed. Open data set: https://doi.org/10.6084/m9.figshare.13007240.v1https://sajs.co.za/article/view/9145tridactyl footprintsGrallator-like trackssmall theropodssouthern GondwanaJurassic Clarens Formation |
| spellingShingle | Emese M. Bordy Darting towards Storm Shelter: A minute dinosaur trackway from southern Africa South African Journal of Science tridactyl footprints Grallator-like tracks small theropods southern Gondwana Jurassic Clarens Formation |
| title | Darting towards Storm Shelter: A minute dinosaur trackway from southern Africa |
| title_full | Darting towards Storm Shelter: A minute dinosaur trackway from southern Africa |
| title_fullStr | Darting towards Storm Shelter: A minute dinosaur trackway from southern Africa |
| title_full_unstemmed | Darting towards Storm Shelter: A minute dinosaur trackway from southern Africa |
| title_short | Darting towards Storm Shelter: A minute dinosaur trackway from southern Africa |
| title_sort | darting towards storm shelter a minute dinosaur trackway from southern africa |
| topic | tridactyl footprints Grallator-like tracks small theropods southern Gondwana Jurassic Clarens Formation |
| url | https://sajs.co.za/article/view/9145 |
| work_keys_str_mv | AT emesembordy dartingtowardsstormshelteraminutedinosaurtrackwayfromsouthernafrica |