Groups keyboard shortcuts have been updated
Dismiss
See shortcuts
Paralligator neurocranial anatomy + Borealosuchus from Paleocene of Colorado + Triassic capitosauromorph parasphenoids
40 views
Skip to first unread message
Ben Creisler
Jan 9, 2025, 2:19:25 PMJan 9
to DinosaurMa...@googlegroups.com
Ben Creisler
Recent tetrapod papers:
B. I. Morkovin (2024)
Structural Features of the Muscular Crests of the Parasphenoid in Early Triassic Capitosauromorphs (Amphibia: Capitosauromorpha) of the East European Platform as a Reflection of Adaptive Differences
Paleontological Journal 58(11): 1291–1300
doi: https://doi.org/10.1134/S0031030124601130
https://link.springer.com/article/10.1134/S0031030124601130
Free pdf:
https://www.researchgate.net/publication/387851775_Structural_Features_of_the_Muscular_Crests_of_the_Parasphenoid_in_Early_Triassic_Capitosauromorphs_Amphibia_Capitosauromorpha_of_the_East_European_Platform_as_a_Reflection_of_Adaptive_Differences
This paper describes variations in the shape of the muscular crests of the parasphenoid body in Early Triassic capitosauromorphs from the East European Platform and estimates their frequency in individual age samples in a number of species. These structures have been compared with their counterparts in modern tailed and tailless amphibians. The resulting data suggest possible functional and adaptive differences in the studied fossil forms.
===
Ivan T Kuzmin, Ekaterina A Sichinava, Evgeniia V Mazur, Victor A Gombolevskiy, Andrey G Sennikov & Pavel P Skutschas (2025)
Neurocranial anatomy of Paralligator (Neosuchia: Paralligatoridae) from the Upper Cretaceous of Mongolia
Zoological Journal of the Linnean Society 203(1): zlae177
doi: https://doi.org/10.1093/zoolinnean/zlae177
https://academic.oup.com/zoolinnean/article-abstract/203/1/zlae177/7950486
Neurocranial features appear to be phylogenetically informative and key in assessing the still contentious relationships within Crocodylomorpha. However, the braincases of many non-crocodylian taxa are incompletely studied precluding the assessment of evolutionary modifications at the base of Crocodylia. Here, we describe the braincase osteology and neuroanatomy of the paralligatorid crocodylomorph Paralligator from the Upper Cretaceous of Mongolia based on computed tomography (CT)-scanning, segmentation, and 3D modelling of several specimens. The anatomy of the brain endocast, nerves, and the paratympanic pneumatic cavities of Paralligator is consistent with its phylogenetic position close to or at the base of Eusuchia. Paralligator shares a suit of neuroanatomical features with basal eusuchians and crocodylians reflecting the plesiomorphic condition for Crocodylia. In addition, differences in the brain endocasts between the larger-sized individuals of Paralligator and Kansajsuchus and the smaller Shamosuchus are consistent with ontogenetic changes in extant crocodylians. This suggests that members of the more basal clade Paralligatoridae and the crown-group Crocodylia share similar brain modifications during ontogeny. We also review the distribution of the mesethmoid in Crocodylomorpha and show its presence in several clades including Paralligatoridae and Dyrosauridae.
======
Neurocranial anatomy of Paralligator (Neosuchia: Paralligatoridae) from the Upper Cretaceous of Mongolia
Zoological Journal of the Linnean Society 203(1): zlae177
doi: https://doi.org/10.1093/zoolinnean/zlae177
https://academic.oup.com/zoolinnean/article-abstract/203/1/zlae177/7950486
Neurocranial features appear to be phylogenetically informative and key in assessing the still contentious relationships within Crocodylomorpha. However, the braincases of many non-crocodylian taxa are incompletely studied precluding the assessment of evolutionary modifications at the base of Crocodylia. Here, we describe the braincase osteology and neuroanatomy of the paralligatorid crocodylomorph Paralligator from the Upper Cretaceous of Mongolia based on computed tomography (CT)-scanning, segmentation, and 3D modelling of several specimens. The anatomy of the brain endocast, nerves, and the paratympanic pneumatic cavities of Paralligator is consistent with its phylogenetic position close to or at the base of Eusuchia. Paralligator shares a suit of neuroanatomical features with basal eusuchians and crocodylians reflecting the plesiomorphic condition for Crocodylia. In addition, differences in the brain endocasts between the larger-sized individuals of Paralligator and Kansajsuchus and the smaller Shamosuchus are consistent with ontogenetic changes in extant crocodylians. This suggests that members of the more basal clade Paralligatoridae and the crown-group Crocodylia share similar brain modifications during ontogeny. We also review the distribution of the mesethmoid in Crocodylomorpha and show its presence in several clades including Paralligatoridae and Dyrosauridae.
======
Emily J. Lessner, Holger Petermann & Tyler R. Lyson (2025)
First record of Borealosuchus sternbergii from the lower Paleocene Denver Formation (lower Danian), Colorado (Denver Basin)
Journal of Vertebrate Paleontology e2434214
doi: https://doi.org/10.1080/02724634.2024.2434214
https://www.tandfonline.com/doi/full/10.1080/02724634.2024.2434214
The Late Cretaceous through Paleogene fossil record for North American eusuchians is remarkable in that it indicates high levels of survivorship across the Cretaceous–Paleogene (K–Pg) boundary, as well as an increase in diversity through the early Eocene. Despite the clade’s continued existence, gaps remain in its fossil record, particularly near the K–Pg boundary and in Colorado. A eusuchian from the lower Paleocene Denver Formation of Corral Bluffs is represented by specimens identified as Borealosuchus sternbergii. Here, we provide anatomical descriptions and comparisons supported by micro-CT scan data of three partial crania. We conduct a phylogenetic analysis, the results of which are influenced by the potential sub-adult ontogenetic stage of the specimens and species-level assignment is preliminary. The specimens fill both geographic and temporal gaps in the record of the Borealosuchus species complex as the first specimens from the earliest Paleocene of Colorado. These additions highlight the uncertainty in phylogenetic relationships among the Borealosuchus species complex, the importance of taking ontogenetic stage into account when assessing such relationships, and help constrain biogeographic dispersal patterns and ecological niche occupation of the clade.
===
First record of Borealosuchus sternbergii from the lower Paleocene Denver Formation (lower Danian), Colorado (Denver Basin)
Journal of Vertebrate Paleontology e2434214
doi: https://doi.org/10.1080/02724634.2024.2434214
https://www.tandfonline.com/doi/full/10.1080/02724634.2024.2434214
The Late Cretaceous through Paleogene fossil record for North American eusuchians is remarkable in that it indicates high levels of survivorship across the Cretaceous–Paleogene (K–Pg) boundary, as well as an increase in diversity through the early Eocene. Despite the clade’s continued existence, gaps remain in its fossil record, particularly near the K–Pg boundary and in Colorado. A eusuchian from the lower Paleocene Denver Formation of Corral Bluffs is represented by specimens identified as Borealosuchus sternbergii. Here, we provide anatomical descriptions and comparisons supported by micro-CT scan data of three partial crania. We conduct a phylogenetic analysis, the results of which are influenced by the potential sub-adult ontogenetic stage of the specimens and species-level assignment is preliminary. The specimens fill both geographic and temporal gaps in the record of the Borealosuchus species complex as the first specimens from the earliest Paleocene of Colorado. These additions highlight the uncertainty in phylogenetic relationships among the Borealosuchus species complex, the importance of taking ontogenetic stage into account when assessing such relationships, and help constrain biogeographic dispersal patterns and ecological niche occupation of the clade.
===
===
Free pdf:
B. I. Morkovin (2024)
Structural Features of the Muscular Crests of the Parasphenoid in Early Triassic Capitosauromorphs (Amphibia: Capitosauromorpha) of the East European Platform as a Reflection of Adaptive Differences
Paleontological Journal 58(11): 1291–1300
doi: https://doi.org/10.1134/S0031030124601130
https://link.springer.com/article/10.1134/S0031030124601130
Free pdf:
https://www.researchgate.net/publication/387851775_Structural_Features_of_the_Muscular_Crests_of_the_Parasphenoid_in_Early_Triassic_Capitosauromorphs_Amphibia_Capitosauromorpha_of_the_East_European_Platform_as_a_Reflection_of_Adaptive_Differences
This paper describes variations in the shape of the muscular crests of the parasphenoid body in Early Triassic capitosauromorphs from the East European Platform and estimates their frequency in individual age samples in a number of species. These structures have been compared with their counterparts in modern tailed and tailless amphibians. The resulting data suggest possible functional and adaptive differences in the studied fossil forms.
===
Reply all
Reply to author
Forward
0 new messages