An ecomorphological approach to the relationship between craniomandibular morphology and diet in sigmodontine rodents from central-eastern Argentina

Barbero, Sofía; Teta, Pablo; Cassini, Guillermo Hernán

doi:10.1016/j.zool.2022.126066

Cited by 6 publications

(1 citation statement)

References 68 publications

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“…By contrast, the specialised grass-feeding broad-toothed rat Mastacomys and granivore rabbit-rat Conilurus penicillatus score low on both the residual PC1 and 2, reflecting curved anterior rostra and relatively smaller cranial vaults. This is consistent with findings of the wider skulls and dorsally shifted temporalis muscles that increase the muscle mass for masticating fibrous foods, which has evolved in specialist folivores across several rodent families (Samuels, 2009) and leads to more robust cranial dimensions in this species (Breed & Ford, 2007) and other folivores (Barbero et al, 2023). Similarly, cranial morphology is expected to be strongly influenced by the most challenging foods encountered by a species (Figueirido et al, 2014;Mitchell, 2019;Strait et al, 2009;Van Valkenburgh, 1989), so that frequent consumption of hard seeds and insects by the desert-living hopping generalists Notomys and Conilurus (Murray et al, 1999) might explain their more robust crania relative to braincase than expected for their size.…”

Section: Sssupporting

confidence: 90%

Beyond CREA: Evolutionary patterns of non‐allometric shape variation and divergence in a highly allometric clade of murine rodents

Marcy,

Mitchell,

Guillerme

et al. 2024

Ecology and Evolution

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The shared functions of the skull are thought to result in common evolutionary patterns in mammalian cranial shape. Craniofacial evolutionary allometry (CREA) is a particularly prominent pattern where larger species display proportionally elongate facial skeletons and smaller braincases. It was recently proposed that CREA arises from biomechanical effects of cranial scaling when diets are similar. Thus, deviations from CREA should occur with changes in cranial biomechanics, for example due to dietary change. Here, we test this using 3D geometric morphometric analysis in a dataset of Australian murine crania, which are highly allometric. We contrast allometric and non‐allometric variation in the cranium by comparing evolutionary mode, allometry, ordinations, as well as allometry, integration, and modularity in functional modules. We found evidence of stabilising selection in allometry‐containing and size‐free shape, and substantial non‐allometric variation aligned with dietary specialisation in parallel with CREA. Integration among cranial modules was higher, and modularity lower, with size included, but integration between rostrum and cranial vault, which are involved in the CREA pattern, dropped dramatically after size removal. Our results thus support the hypothesis that CREA is a composite arising from selection on cranial function, with substantial non‐allometric shape variation occurring alongside CREA where dietary specialisation impacts selection on gnawing function. This emphasises the need to research mammalian cranial evolution in the context of allometric and non‐allometric selection on biomechanical function.

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