Theropod tracks from Lower Cretaceous of Tunisia + Algorachelus (pelomedusoid turtle) shell from Cretaceous of Spain
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Ben Creisler
Jun 6, 2024, 5:02:12 PMJun 6
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Ben Creisler
New papers:
The oldest bothremydid remain in Europe is presented here
The shell was found in shallow marine deposits
It evidences the oldest dispersal of a pelomedusoid turtle from Gondwana to Laurasia
The Albian-early Cenomanian global warming favored the dispersal
The adaptation of the lineage of Algorachelus to marine environments also favored it
Abstract
A turtle carapace, identified as Algorachelus cf. peregrina (Pleurodira, Pelomedusoides, Bothremydidae), is reported here from the shallow marine deposits of the Boundary Marls Unit (Utrillas Group), in Estercuel (Teruel Province, northeastern Spain). These levels are identified as deposited during the Lower to Upper Cretaceous transition (late Albian to earliest Cenomanian). This is the oldest record of a bothremydid turtle in Laurasia, documenting that the first dispersal of pelomedusoid turtles from Gondwana to Laurasia occurred earlier than previously identified, most probably in the Early Cretaceous. Pleurodiran turtles always require warm climatic conditions and are mainly freshwater forms. This dispersal was favored by climate change (global warming) that began in the Albian, as well as by the habitat change of the Algorachelus lineage from freshwater to coastal marine environments.
====
Jihed Dridi, Yassine Houla, Ilyes Salhi & Mohamed Faouzi Zagrarni (2024)
Evidence of theropod dinosaurs in the upper Hauterivian–lower Barremian of Jebel Kebar (central Tunisia): paleobiogeographic implications
Journal of African Earth Sciences 105306
doi: https://doi.org/10.1016/j.jafrearsci.2024.105306
https://www.sciencedirect.com/science/article/abs/pii/S1464343X24001390
Highlights
Here we describe the first vertebrate tracks from the upper Hauterivian–lower Barremian of central Tunisia.
These tracks represent the oldest record of vertebrate traces in central Tunisia so far.
The tracks were made by medium to large-sized non-avian theropods and cannot be classified at the ichnogeneric level due to their poor quality.
These specimens extend the geographic range of non-avian theropods to higher latitudes within Gondwana.
Two biogeographic scenarios regarding the occurrence of theropod tracks in the Lower Cretaceous of central Tunisia are proposed and discussed.
Abstract
The fossil record of Mesozoic dinosaurs in Tunisia has long been thought to be restricted exclusively to the southern part of the country. Although tidal and continental environments have been recognized within Cretaceous formations in central Tunisia based on sedimentological analyses, no skeletal remains ascribable to dinosaurs have been found in these deposits. The hypothesis of a possible land connection between central and southern Tunisia during the Early Cretaceous has not been previously explored due to notable lateral variations in facies, marked by the recurrent occurrence of shallow marine deposits separating these domains. The vertebrate ichnological record in the Central Tunisian Atlas was limited to isolated tridactyl footprints exclusively observed in the Albian Kebar Formation. Here, we report the first dinosaur tracks from the pre-Albian Cretaceous (upper Hauterivian–lower Barremian) of central Tunisia. These tracks consist of large tridactyl footprints left behind by medium to large-sized non-avian theropods. They occur within an extensively fractured dolostone bed and exhibit poor morphological preservation. Besides their dimensions, some tracks show morphological features, including broad digit impressions with some terminating in sharp claw traces, low to moderate mesaxony, and a wide divarication angle of the outer digits, reminiscent of the ichnogenus Megalosauripus. However, due to their poor state of preservation and limited number, we refrain from assigning these tracks to the ichnogeneric level and refer to them as indeterminate eubrontid footprints. The occurrence of theropod tracks in the Lower Cretaceous of central Tunisia confirms the sedimentology-based hypotheses about a temporal emergence of parts of this area, which was probably related to tectonic events. We compile previous biostratigraphic, sedimentological, and paleoichnological data to suggest possible periodic connections between the mainland in the south and the tidal flat environments within the central basins. Additionally, two possible scenarios regarding the biogeographic implications of the Jebel Kebar tracks are discussed. The first scenario suggests that a Gondwanan theropod fauna would have been exploring and residing in newly emerged regions of higher latitudes, whereas the alternative scenario posits the existence of a paleogeographic link between the northern margin of Gondwana and Adria, which would have allowed an interchange of theropod faunas between the two landmasses at least in the early Barremian.
Jihed Dridi, Yassine Houla, Ilyes Salhi & Mohamed Faouzi Zagrarni (2024)
Evidence of theropod dinosaurs in the upper Hauterivian–lower Barremian of Jebel Kebar (central Tunisia): paleobiogeographic implications
Journal of African Earth Sciences 105306
doi: https://doi.org/10.1016/j.jafrearsci.2024.105306
https://www.sciencedirect.com/science/article/abs/pii/S1464343X24001390
Highlights
Here we describe the first vertebrate tracks from the upper Hauterivian–lower Barremian of central Tunisia.
These tracks represent the oldest record of vertebrate traces in central Tunisia so far.
The tracks were made by medium to large-sized non-avian theropods and cannot be classified at the ichnogeneric level due to their poor quality.
These specimens extend the geographic range of non-avian theropods to higher latitudes within Gondwana.
Two biogeographic scenarios regarding the occurrence of theropod tracks in the Lower Cretaceous of central Tunisia are proposed and discussed.
Abstract
The fossil record of Mesozoic dinosaurs in Tunisia has long been thought to be restricted exclusively to the southern part of the country. Although tidal and continental environments have been recognized within Cretaceous formations in central Tunisia based on sedimentological analyses, no skeletal remains ascribable to dinosaurs have been found in these deposits. The hypothesis of a possible land connection between central and southern Tunisia during the Early Cretaceous has not been previously explored due to notable lateral variations in facies, marked by the recurrent occurrence of shallow marine deposits separating these domains. The vertebrate ichnological record in the Central Tunisian Atlas was limited to isolated tridactyl footprints exclusively observed in the Albian Kebar Formation. Here, we report the first dinosaur tracks from the pre-Albian Cretaceous (upper Hauterivian–lower Barremian) of central Tunisia. These tracks consist of large tridactyl footprints left behind by medium to large-sized non-avian theropods. They occur within an extensively fractured dolostone bed and exhibit poor morphological preservation. Besides their dimensions, some tracks show morphological features, including broad digit impressions with some terminating in sharp claw traces, low to moderate mesaxony, and a wide divarication angle of the outer digits, reminiscent of the ichnogenus Megalosauripus. However, due to their poor state of preservation and limited number, we refrain from assigning these tracks to the ichnogeneric level and refer to them as indeterminate eubrontid footprints. The occurrence of theropod tracks in the Lower Cretaceous of central Tunisia confirms the sedimentology-based hypotheses about a temporal emergence of parts of this area, which was probably related to tectonic events. We compile previous biostratigraphic, sedimentological, and paleoichnological data to suggest possible periodic connections between the mainland in the south and the tidal flat environments within the central basins. Additionally, two possible scenarios regarding the biogeographic implications of the Jebel Kebar tracks are discussed. The first scenario suggests that a Gondwanan theropod fauna would have been exploring and residing in newly emerged regions of higher latitudes, whereas the alternative scenario posits the existence of a paleogeographic link between the northern margin of Gondwana and Adria, which would have allowed an interchange of theropod faunas between the two landmasses at least in the early Barremian.
===
Free pdf:
A. Pérez-García & C. Rubio (2024)
A turtle from northeastern Spain reveals that the dispersal of Pelomedusoides from Gondwana to Laurasia probably occurred in the Early Cretaceous
Cretaceous Research 105938
doi: https://doi.org/10.1016/j.cretres.2024.105938
https://www.sciencedirect.com/science/article/pii/S0195667124001113
Highlights
A. Pérez-García & C. Rubio (2024)
A turtle from northeastern Spain reveals that the dispersal of Pelomedusoides from Gondwana to Laurasia probably occurred in the Early Cretaceous
Cretaceous Research 105938
doi: https://doi.org/10.1016/j.cretres.2024.105938
https://www.sciencedirect.com/science/article/pii/S0195667124001113
Highlights
The oldest bothremydid remain in Europe is presented here
The shell was found in shallow marine deposits
It evidences the oldest dispersal of a pelomedusoid turtle from Gondwana to Laurasia
The Albian-early Cenomanian global warming favored the dispersal
The adaptation of the lineage of Algorachelus to marine environments also favored it
Abstract
A turtle carapace, identified as Algorachelus cf. peregrina (Pleurodira, Pelomedusoides, Bothremydidae), is reported here from the shallow marine deposits of the Boundary Marls Unit (Utrillas Group), in Estercuel (Teruel Province, northeastern Spain). These levels are identified as deposited during the Lower to Upper Cretaceous transition (late Albian to earliest Cenomanian). This is the oldest record of a bothremydid turtle in Laurasia, documenting that the first dispersal of pelomedusoid turtles from Gondwana to Laurasia occurred earlier than previously identified, most probably in the Early Cretaceous. Pleurodiran turtles always require warm climatic conditions and are mainly freshwater forms. This dispersal was favored by climate change (global warming) that began in the Albian, as well as by the habitat change of the Algorachelus lineage from freshwater to coastal marine environments.
Gregory Paul
Jun 7, 2024, 1:16:07 PMJun 7
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Richard Ellis is gone at 86 https://tetzoo.com/blog/2024/6/6/in-memory-of-richard-ellis
(there are NYTimes and WashPost obits behind paywalls)
Richard mainly researched and illustrated modern marine life -- I did not realize he designed the full scale blue whale at the American Museum, which was done just before it was fully realized how shallow the heads of rorquals are when not feeding (https://www.biorxiv.org/content/10.1101/2022.08.28.505602v1).
But he did the book Sea Dragons, Predators of the Prehistoric Oceans in 03. He also did a key paleoillustration. Back in the early 70s there was this Baker guy (that was how most thought the name was pronounced) going on about dinosaurs being warm-blooded, and running about including in packs and herds and small ones with feathers and sauropods being terrestrial and all that silly nonsense. I went into the Northern Virginia Community Community College library one of my favorite places and there on the magazine display shelves back when they had those was the latest April 75 issue of Scientific American with an eye grabbing color illustration a branch crawling green thingy with a spectacular dorsal display array called Longisquama and below that the headline Dinosaur Renaissance and I immediately realized it must be an article by Bakker as I snatched the issue from the shelf (it includes the first artistic rendering of a feathered dinosaur by Sarah Landry of a Syntarsus chasing a gliding lizard down the slope of a dune)!!!!! That cover was by Ellis.
I never met Richard, we communicated some via email. Lost touch awhile back and now I have a better idea of why.
GSPaul
mkir...@gmail.com
Jun 7, 2024, 4:41:20 PMJun 7
to Dinosaur Mailing Group
I remember Richard Ellis when he was on the DML in 1999 to the early 2000s.
Gregory Paul
Jun 9, 2024, 3:49:38 PMJun 9
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Had forgotten that. Was when he was researching his marine sea herp book.
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mkir...@gmail.com
Jun 9, 2024, 4:45:22 PMJun 9
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"Sea Dragons, Predators of the Prehistoric Oceans," 2003? I was surprised to see that the entire book is available on-line (and can also be downloaded as a pdf) at:
Gregory Paul
Jun 9, 2024, 5:55:39 PMJun 9
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