Cranial evolutionary allometry (CREA) is a scientific theory regarding trends in the shape of mammalian skulls during the course of evolution in accordance with body size (i.e., allometry). Specifically, the theory posits that there is a propensity among closely related mammalian groups for the skulls of the smaller species to be short and those of the larger species to be long. This propensity appears to hold true for placental as well as non-placental mammals, and is highly robust. Examples of groups which exhibit this characteristic include antelopes, fruit bats, mongooses, squirrels and kangaroos[1][2][3] as well as felids.[4]

It is believed that the reason for this trend has to do with size-related constraints on the formation and development of the mammalian skull. Facial length is one of the best known examples of heterochrony.[5]

References

  1. ^ Marta Linde-Medina (September 2016). "Testing the cranial evolutionary allometric 'rule' in Galliformes". Journal of Evolutionary Biology. 9 (29): 1873–1878. doi:10.1111/jeb.12918. PMC 5021629. PMID 27306761.
  2. ^ Andrea Cardini (2016). "96th Annual Meeting of the American Society of Mammalogists" (PDF). p. 53.
  3. ^ Cardini, A., Polly, D., Dawson, R., Milne, N., 2015. Why the Long Face? Kangaroos and Wallabies Follow the Same ‘Rule’ of Cranial Evolutionary Allometry (CREA) as Placentals. Evol Biol 42, 169–176. https://doi.org/10.1007/s11692-015-9308-9
  4. ^ Tamagnini, D., Meloro, C., Cardini, A., 2017. Anyone with a Long-Face? Craniofacial Evolutionary Allometry (CREA) in a Family of Short-Faced Mammals, the Felidae. Evol Biol 44, 476–495. https://doi.org/10.1007/s11692-017-9421-z
  5. ^ Cardini, A., Polly, P.D., 2013. Larger mammals have longer faces because of size-related constraints on skull form. Nat Commun 4. https://doi.org/10.1038/ncomms3458
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