Brain Evolution in Fossil Rodents: A Starting Point

Bertrand, Ornella; Silcox, Mary

doi:10.1007/978-3-031-13983-3_16

Cited by 3 publications

(3 citation statements)

References 114 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The proportion of different brain regions can be compared by studying the relationship between the volume of these regions and overall brain volume. The olfactory bulbs are relatively smaller in squirrels than in ischyromyids, but their size relative to body mass appears to be equivalent in the two groups, suggesting that other parts of the brain, such as the neocortex and the petrosal lobules, were expanded in fossil squirrels compared with Ischyromyidae (Bertrand & Silcox 2023). This suggests that olfaction might have remained constant through time in squirrels (and not decreased).…”

Section: Discussionmentioning

confidence: 99%

“…2012) and bat Palaeophyllophora (Maugoust & Orliac 2021), as well as the rodents Reithroparamys and Ischyromys (Bertrand & Silcox 2016; Bertrand et al . 2019; Bertrand & Silcox 2023). Extensive midbrain exposure with visible caudal colliculi has been viewed as potentially being a derived characteristic that could be linked to enhanced auditory acuity (Edinger 1964).…”

Section: Discussionmentioning

confidence: 99%

“…Some extinct mammals have a more complex midbrain morphology with exposed caudal colliculi (= inferior colliculi) that are related to acoustic reflexes (Christensen & Evans 1979), including but not limited to the Eocene 'condylarth' Hyopsodus ) and bat Palaeophyllophora (Maugoust & Orliac 2021), as well as the rodents Reithroparamys and Ischyromys (Bertrand & Silcox 2016;Bertrand et al 2019;Bertrand & Silcox 2023). Extensive midbrain exposure with visible caudal colliculi has been viewed as potentially being a derived characteristic that could be linked to enhanced auditory acuity (Edinger 1964).…”

Section: Midbrain Exposure and Enhanced Auditory Acuitymentioning

confidence: 99%

See 2 more Smart Citations

The virtual brain endocast of Incamys bolivianus: insight from the neurosensory system into the adaptive radiation of South American rodents

Bertrand,

Lang,

Ferreira

et al. 2024

Papers in Palaeontology

Self Cite

View full text Add to dashboard Cite

Caviomorph rodents are endemic to South America and are one of the most adaptively diverse radiations of rodents today. Although their origin and diversification have been intensively studied, questions still remain about many of the details of where, when and how the group radiated. One area of continuing debate relates to the evolution of their neurosensory system. Modern caviomorphs exhibit a rich brain shape and size diversity. So far the oldest species for which endocranial data are known is dated to the Early Miocene. Here, we describe the virtual brain endocast of the late Oligocene stem chinchillid Incamys bolivianus from Bolivia and provide new hypotheses regarding the ancestral brain of Chinchillidae and Caviomorpha more broadly. Caviomorph rodents, independent from other rodent clades, acquired an expanded neocortex and their common ancestor was probably lissencephalic or had few sulci. Incamys uniquely combines extended neocortical temporal lobes and exposed caudal colliculi, which have roles in audition and vocalization processing. We interpret this morphology as evidence for enhanced auditory acuity, vocalization processing and potentially group‐living in Incamys, which is known in modern members of the Chinchillidae family. No temporal effect was found on relative brain size in South American mammals; however, our sample is limited to available brain endocasts and as such remains small and unevenly distributed taxonomically and temporally. Incamys provides crucial insight into the evolution of the caviomorph brain and shows that we still have much to explore regarding how these small mammals achieved one the most impressive adaptive radiations of the Cenozoic.

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Midbrain Exposure and Enhanced Auditory Acuitymentioning

confidence: 99%

See 1 more Smart Citation

The virtual brain endocast of Incamys bolivianus: insight from the neurosensory system into the adaptive radiation of South American rodents

Bertrand,

Lang,

Ferreira

et al. 2024

Papers in Palaeontology

Self Cite

View full text Add to dashboard Cite

show abstract

Unveiling the neuroanatomy of Josephoartigasia monesi and the evolution of encephalization in caviomorph rodents

Ferreira,

Rinderknecht,

de Moura Bubadué

et al. 2024

Brain Struct Funct

View full text Add to dashboard Cite

Adaptation in brain structure and respiratory and olfactory structures across environmental gradients in African and North American muroid rodents

TAYLOR,

NENGOVHELA,

DENYS

et al. 2023

Integr. Zool.

View full text Add to dashboard Cite

Morphometric studies of 3D micro CT‐scanned images can provide insights into the evolution of the brain and sensory structures but such data are still scarce for the most diverse mammalian order of rodents. From reviewed and new data, we tested for convergence to extreme aridity and high elevation in the sensory and brain morphology of rodents, from morphometric data from micro‐CT X‐ray scans of 174 crania of 16 species of three distantly related African murid (soft‐furred mice, Praomyini, laminate‐toothed rats, Otomyini, and gerbils, Gerbillinae) clades and one North American cricetid (deer mice and white‐footed mice, Peromyscus) clade. Recent studies demonstrated convergent evolution acting on the oval window area of the cochlea (enlarged in extremely arid‐adapted species of Otomyini and Gerbillinae) and on endocranial volume (reduced in high elevation taxa of Otomyini and Peromyscus). However, contrary to our predictions, we did not find evidence of convergence in brain structure to aridity, or in the olfactory/respiratory system (turbinate bones) to high elevation. Brain structure differed, particularly in the petrosal lobules of the cerebellum and the olfactory bulbs, between Otomyini and Gerbillinae, with extreme arid‐adapted species in each clade being highly divergent (not convergent) from other species in the same clade. We observed greater “packing” of the maxillary turbinate bones, which have important respiratory functions, in Peromyscus mice from high and low elevations compared to the high‐elevation African Praomyini, but more complex patterns within Peromyscus, probably related to trade‐offs in respiratory physiology and heat exchange in the nasal epithelium associated with high‐elevation adaptation.

show abstract

Brain Evolution in Fossil Rodents: A Starting Point

Cited by 3 publications

References 114 publications

The virtual brain endocast of Incamys bolivianus: insight from the neurosensory system into the adaptive radiation of South American rodents

The virtual brain endocast of Incamys bolivianus: insight from the neurosensory system into the adaptive radiation of South American rodents

Unveiling the neuroanatomy of Josephoartigasia monesi and the evolution of encephalization in caviomorph rodents

Adaptation in brain structure and respiratory and olfactory structures across environmental gradients in African and North American muroid rodents

Contact Info

Product

Resources

About