Orthosuchus osteohistology + Toarcian climatic effects on marine reptiles + plesiosaur swimming + Squamata and Anura at oldest Deccan Trap in India
40 views
Skip to first unread message
Ben Creisler
Oct 28, 2024, 11:36:29 AMOct 28
to DinosaurMa...@googlegroups.com
Ben Creisler
New papers:
Bailey M. Weiss, Kathleen N. Dollman, Jonah N. Choiniere, Claire Browning & Jennifer Botha (2024)
The osteohistology of Orthosuchus stormbergi using synchrotron radiation microcomputed tomography
Journal of Anatomy (advance online publication)
doi: https://doi.org/10.1111/joa.14166
https://onlinelibrary.wiley.com/doi/10.1111/joa.14166
Free pdf:
https://onlinelibrary.wiley.com/doi/epdf/10.1111/joa.14166
Orthosuchus stormbergi was a small-bodied crocodyliform, representative of a diverse assemblage of Early Jurassic, early branching crocodylomorph taxa from the upper Elliot Formation of South Africa. The life history of these early branching taxa remains poorly understood, with only sparse investigations into their osteohistology, yet species like Orthosuchus have potential to inform about the macroevolution of growth strategies on the stem leading to crown crocodilians. In order to elucidate the growth patterns of Orthosuchus, we used propagation phase contrast X-ray synchrotron micro-computed tomography to virtually image the osteohistology of the postcrania of two specimens, including multiple elements from the type (SAM-PK-K409), and the femur of a referred specimen (BP/1/4242). In total, we scanned nine mid-diaphyseal sections of the humerus, radius, ulna, radiale, femur, tibia, fibula, and a rib. We then compared our results to osteohistological sections of crocodylomorph taxa from the published literature. Our results show that the most predominant bone tissue type in Orthosuchus is lamellar, with a few patches of woven and parallel-fibred bone. The type specimen contains four to five lines of arrested growth and the hindlimb elements present outer circumferential lamellae, whereas the referred specimen contains six to seven. Both specimens grew at similar rates, reaching adult skeletal body size at year four or five. The sectioned bones, most notably the radius and ulna, are comparatively thick walled and compact. Our virtual osteohistological sections are one of the first for an early branching crocodyliform, and the broad sample of skeletal elements makes Orthosuchus a key anchor point for understanding the plesiomorphic life history traits of the clade.
====
Free pdf:
Bailey M. Weiss, Kathleen N. Dollman, Jonah N. Choiniere, Claire Browning & Jennifer Botha (2024)
The osteohistology of Orthosuchus stormbergi using synchrotron radiation microcomputed tomography
Journal of Anatomy (advance online publication)
doi: https://doi.org/10.1111/joa.14166
https://onlinelibrary.wiley.com/doi/10.1111/joa.14166
Free pdf:
https://onlinelibrary.wiley.com/doi/epdf/10.1111/joa.14166
Orthosuchus stormbergi was a small-bodied crocodyliform, representative of a diverse assemblage of Early Jurassic, early branching crocodylomorph taxa from the upper Elliot Formation of South Africa. The life history of these early branching taxa remains poorly understood, with only sparse investigations into their osteohistology, yet species like Orthosuchus have potential to inform about the macroevolution of growth strategies on the stem leading to crown crocodilians. In order to elucidate the growth patterns of Orthosuchus, we used propagation phase contrast X-ray synchrotron micro-computed tomography to virtually image the osteohistology of the postcrania of two specimens, including multiple elements from the type (SAM-PK-K409), and the femur of a referred specimen (BP/1/4242). In total, we scanned nine mid-diaphyseal sections of the humerus, radius, ulna, radiale, femur, tibia, fibula, and a rib. We then compared our results to osteohistological sections of crocodylomorph taxa from the published literature. Our results show that the most predominant bone tissue type in Orthosuchus is lamellar, with a few patches of woven and parallel-fibred bone. The type specimen contains four to five lines of arrested growth and the hindlimb elements present outer circumferential lamellae, whereas the referred specimen contains six to seven. Both specimens grew at similar rates, reaching adult skeletal body size at year four or five. The sectioned bones, most notably the radius and ulna, are comparatively thick walled and compact. Our virtual osteohistological sections are one of the first for an early branching crocodyliform, and the broad sample of skeletal elements makes Orthosuchus a key anchor point for understanding the plesiomorphic life history traits of the clade.
===
Free pdf:
Matías Reolid, Wolfgang Ruebsam, Jesús Reolid & Michael J. Benton (2024)
Impact of early Toarcian climatic changes on marine reptiles: Extinction and recovery
Earth-Science Reviews 104965
doi: https://doi.org/10.1016/j.earscirev.2024.104965
https://www.sciencedirect.com/science/article/pii/S0012825224002939
Environmental changes governed the diversity of marine ecosystems and the evolution of marine reptiles during the Jurassic. Abrupt climatic changes, mainly cooling, produced crises in marine ecosystems including marine reptiles, but global warming events at the Pliensbachian/Toarcian boundary and the early Toarcian Jenkyns Event led to a second order mass extinction. The Jenkyns Event coincides with exceptional preservation of marine reptiles in black shales, so widespread extinctions are masked to some extent by increases in specimens and diversity in the Lagerstätten. Marine reptile diversity responded to this biotic crisis; in the early Toarcian, stenopterygid ichthyosaurs and marine crocodylomorphs (thalattosuchians) diversified whereas some groups that survived the Jenkyns Event disappeared during the hyperthermal conditions of the middle and late Toarcian, including ichthyosaurs (leptonectids, temnodontosaurids, baso-parvipelvians), and sauropterygians (plesiosaurids, microcleidids).
After the crisis, Aalenian climates were cold and the sea-level low with a poor record of marine reptiles. The diversity of marine ecosystems increased from the early Bajocian with a turnover in ichthyosaurs (early Jurassic ichthyosaurs were replaced by ophthalmosaurids), sauropterygians diversified and increased in size (mainly pliosaurids and cryptocleidids), and pelagosaurid thalattosuchians disappeared at the same time that machimosaurids diversified and the Metriorhynchidae appeared. Marine reptiles reached a new maximum of diversity during the Callovian, but the Callovian/Oxfordian transition was a time of climatic cooling and sea-level fall that negatively impacted on marine ecosystems, including the extinction of rhomaleosaurids. From the middle Oxfordian, the development of large epeiric platforms and increase of temperature favoured the diversification of marine ecosystems, included marine reptiles. During the Late Jurassic, ophthalmosaurids, pliosaurids, cryptocleidids, and metriorhynchids dominated, and marine turtles diversified in coastal environments (eurysternids) and open carbonate platforms (plesiochelyids and thalassemydids).
Matías Reolid, Wolfgang Ruebsam, Jesús Reolid & Michael J. Benton (2024)
Impact of early Toarcian climatic changes on marine reptiles: Extinction and recovery
Earth-Science Reviews 104965
doi: https://doi.org/10.1016/j.earscirev.2024.104965
https://www.sciencedirect.com/science/article/pii/S0012825224002939
Environmental changes governed the diversity of marine ecosystems and the evolution of marine reptiles during the Jurassic. Abrupt climatic changes, mainly cooling, produced crises in marine ecosystems including marine reptiles, but global warming events at the Pliensbachian/Toarcian boundary and the early Toarcian Jenkyns Event led to a second order mass extinction. The Jenkyns Event coincides with exceptional preservation of marine reptiles in black shales, so widespread extinctions are masked to some extent by increases in specimens and diversity in the Lagerstätten. Marine reptile diversity responded to this biotic crisis; in the early Toarcian, stenopterygid ichthyosaurs and marine crocodylomorphs (thalattosuchians) diversified whereas some groups that survived the Jenkyns Event disappeared during the hyperthermal conditions of the middle and late Toarcian, including ichthyosaurs (leptonectids, temnodontosaurids, baso-parvipelvians), and sauropterygians (plesiosaurids, microcleidids).
After the crisis, Aalenian climates were cold and the sea-level low with a poor record of marine reptiles. The diversity of marine ecosystems increased from the early Bajocian with a turnover in ichthyosaurs (early Jurassic ichthyosaurs were replaced by ophthalmosaurids), sauropterygians diversified and increased in size (mainly pliosaurids and cryptocleidids), and pelagosaurid thalattosuchians disappeared at the same time that machimosaurids diversified and the Metriorhynchidae appeared. Marine reptiles reached a new maximum of diversity during the Callovian, but the Callovian/Oxfordian transition was a time of climatic cooling and sea-level fall that negatively impacted on marine ecosystems, including the extinction of rhomaleosaurids. From the middle Oxfordian, the development of large epeiric platforms and increase of temperature favoured the diversification of marine ecosystems, included marine reptiles. During the Late Jurassic, ophthalmosaurids, pliosaurids, cryptocleidids, and metriorhynchids dominated, and marine turtles diversified in coastal environments (eurysternids) and open carbonate platforms (plesiochelyids and thalassemydids).
===
Free pdf:
Akira Fukuhara, Mitsutoshi Sato, Hisayuki Ogawa, Tamaki Sato, William Sellers & Akio Ishiguro (2024)
Rethinking the four-wing problem in plesiosaur swimming using bio-inspired decentralized control
Scientific Reports 14: 25333
doi: https://doi.org/10.1038/s41598-024-55805-z
https://www.nature.com/articles/s41598-024-55805-z
A locomotor system that can function across different environmental conditions and produce a range of performances is one of the most critical abilities needed for extant and extinct animals in order to survive and maximise their competitive fitness. Recent engineering-inspired paleontological studies have reconstructed feasible locomotor patterns in extinct animals. However, it is still challenging to describe how extinct animals successfully adjust their locomotor patterns to new situations (e.g., changes in locomotor speed and morphology). In this study, we develop a novel reconstruction method based on a bio-inspired control system. We focus on plesiosaurs, an extinct aquatic reptile group which has two pairs of flipper-shaped limbs, and demonstrate that a highly optimised, flexible locomotor pattern for all four flippers can be reconstructed based on a decentralized control scheme formulated from extant animals’ locomotion. The results of our robotic experiments show that a simple, local sensory feedback mechanism allows the plesiosaur-like robot to exploit the fluid flow between the flippers and generate efficient swimming patterns in response to changes in locomotor conditions. Our new method provides further evidence how decentralized control systems can produce a pathway between extinct and extant animals in order to understand the how extinct animals moved and how these movement patterns may have evolved.
Akira Fukuhara, Mitsutoshi Sato, Hisayuki Ogawa, Tamaki Sato, William Sellers & Akio Ishiguro (2024)
Rethinking the four-wing problem in plesiosaur swimming using bio-inspired decentralized control
Scientific Reports 14: 25333
doi: https://doi.org/10.1038/s41598-024-55805-z
https://www.nature.com/articles/s41598-024-55805-z
A locomotor system that can function across different environmental conditions and produce a range of performances is one of the most critical abilities needed for extant and extinct animals in order to survive and maximise their competitive fitness. Recent engineering-inspired paleontological studies have reconstructed feasible locomotor patterns in extinct animals. However, it is still challenging to describe how extinct animals successfully adjust their locomotor patterns to new situations (e.g., changes in locomotor speed and morphology). In this study, we develop a novel reconstruction method based on a bio-inspired control system. We focus on plesiosaurs, an extinct aquatic reptile group which has two pairs of flipper-shaped limbs, and demonstrate that a highly optimised, flexible locomotor pattern for all four flippers can be reconstructed based on a decentralized control scheme formulated from extant animals’ locomotion. The results of our robotic experiments show that a simple, local sensory feedback mechanism allows the plesiosaur-like robot to exploit the fluid flow between the flippers and generate efficient swimming patterns in response to changes in locomotor conditions. Our new method provides further evidence how decentralized control systems can produce a pathway between extinct and extant animals in order to understand the how extinct animals moved and how these movement patterns may have evolved.
====
Anup Dhobale, Dhananjay M. Mohabey, Bandana Samant, Satish J. Sangode & Deepesh Kumar (2024)
Fossil Squamata and Anura from sediments associated with oldest lava piles of Deccan Trap Supergroup (Upper Cretaceous-lower Paleocene), India
Historical Biology (advance online publication)
doi: https://doi.org/10.1080/08912963.2024.2418914
https://www.tandfonline.com/doi/full/10.1080/08912963.2024.2418914
Indian fossil Squamata and Anura are known from the Upper Cretaceous-lower Paleocene Deccan Trap associated sediments for over last one century. However, current knowledge on their taxonomy and stratigraphic implications is poor for their scarce and fragmentary nature and lack of any stratigraphic constraints. We report newly found fossil Squamata and Anura from the new intertrappean locality Bharudpura in Malwa Plateau and describe (i) Scincomorpha (Scincoidea) lizards based on taxonomic study of dentary, maxilla and osteoderms, (ii) Anguimorpha (Anguidae) lizards based on osteoderms, (iii) Squamata indeterminate based on a vertebrae and (iv) Anura (Ranidae, Ranoidea and Anuran indeterminate) based on a ilium, a sacral vertebrae and single dentary. Currently, it is not possible to ascertain if the different fossil specimens belong to a single or more taxa. The lowermost lava pile of Mandleshwar and Kalisindh formations, associated with multiple intertrappean beds including the new Bharudpura fossil locality, have yielded40Ar/39Ar plateau ages from 66.834 Ma, the oldest Deccan Trap flow dated so far in India to 66.352 Ma. The present study records their earliest occurrence in India, from intertrappean associated with oldest Deccan Trap lava pile that erupted during magnetochron C30n of Maastrichtian in the Malwa Plateau.
Fossil Squamata and Anura from sediments associated with oldest lava piles of Deccan Trap Supergroup (Upper Cretaceous-lower Paleocene), India
Historical Biology (advance online publication)
doi: https://doi.org/10.1080/08912963.2024.2418914
https://www.tandfonline.com/doi/full/10.1080/08912963.2024.2418914
Indian fossil Squamata and Anura are known from the Upper Cretaceous-lower Paleocene Deccan Trap associated sediments for over last one century. However, current knowledge on their taxonomy and stratigraphic implications is poor for their scarce and fragmentary nature and lack of any stratigraphic constraints. We report newly found fossil Squamata and Anura from the new intertrappean locality Bharudpura in Malwa Plateau and describe (i) Scincomorpha (Scincoidea) lizards based on taxonomic study of dentary, maxilla and osteoderms, (ii) Anguimorpha (Anguidae) lizards based on osteoderms, (iii) Squamata indeterminate based on a vertebrae and (iv) Anura (Ranidae, Ranoidea and Anuran indeterminate) based on a ilium, a sacral vertebrae and single dentary. Currently, it is not possible to ascertain if the different fossil specimens belong to a single or more taxa. The lowermost lava pile of Mandleshwar and Kalisindh formations, associated with multiple intertrappean beds including the new Bharudpura fossil locality, have yielded40Ar/39Ar plateau ages from 66.834 Ma, the oldest Deccan Trap flow dated so far in India to 66.352 Ma. The present study records their earliest occurrence in India, from intertrappean associated with oldest Deccan Trap lava pile that erupted during magnetochron C30n of Maastrichtian in the Malwa Plateau.
Reply all
Reply to author
Forward
0 new messages