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Abstract Size and shape are often considered important variables that lead to variation in performance. In studies of feeding, size‐corrected metrics of the skull are often used as proxies of biting performance; however, few studies have examined the relationship between cranial shape in its entirety and estimated bite force across species and how dietary ecologies may affect these variables differently. Here, we used geometric morphometric and phylogenetic comparative approaches to examine relationships between cranial morphology and estimated bite force in the carnivoran clade Musteloidea. We found a strong relationship between cranial size and estimated bite force but did not find a significant relationship between cranial shape and size‐corrected estimated bite force. Many‐to‐one mapping of form to function may explain this pattern because a variety of evolutionary shape changes rather than a single shape change may have contributed to an increase in relative biting ability. We also found that dietary ecologies influenced cranial shape evolution but did not influence cranial size nor size‐corrected bite force evolution. Although musteloids with different diets exhibit variation in cranial shapes, they have similar estimated bite forces suggesting that other feeding performance metrics and potentially nonfeeding traits are also important contributors to cranial evolution. We postulate that axial and appendicular adaptations and the interesting feeding behaviours reported for species within this group also facilitate different dietary ecologies between species. Future work integrating cranial, axial and appendicular form and function with behavioural observations will reveal further insights into the evolution of dietary ecologies and other ecological variables.
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Cranial anatomy of the Triassic rhynchosaur Mesosuchus browni based on computed tomography, with a discussion of the vomeronasal system and its deep history in Reptilia
Abstract The stem lineage of Archosauria is populated by a diverse fossil record that remains notably understudied relative to the crown clade. Prominent among these specimens is a beautifully preserved skull of the early mid-Triassic rhynchosaur Mesosuchus browni [Iziko South African Museum (SAM) 6536], whose phylogenetic position has considerable influence on patterns of pan-archosaurian cranial evolution. We used high-resolution, micro-computed tomography to re-examine the anatomy of this specimen, building on previous studies that were either limited to external observations or restricted to the braincase. A digital segmentation of the cranial elements and primary neurovascular canals of SAM-PK-6536 allows for expanded character scoring and constitutes a foundation for future comparative insights. Our data support the phylogenetically oldest instance of a pneumatized maxilla in a pan-archosaur, bringing the record of antorbital pneumatization into closer alignment with that of the neurocranium. The nasal cavity and primary palate of Mesosuchus includes a complex septomaxilla, a novel element anterior to the vomer, and is likely to have supported a well-developed vomeronasal system. The evolution of this system is discussed in terms of both phylogenetic pattern and how the skeletal architecture of Mesosuchus and other fossils could inform the signalling dynamics that pattern the vomeronasal system during development.
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- PAR ID:
- 10532258
- Publisher / Repository:
- Oxford University Press
- Date Published:
- Journal Name:
- Zoological Journal of the Linnean Society
- Volume:
- 201
- Issue:
- 4
- ISSN:
- 0024-4082
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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