ArticleProceedings. Biological sciences2016
Virtual endocasts of Eocene Paramys (Paramyinae): oldest endocranial record for Rodentia and early brain evolution in Euarchontoglires.
Article in Proceedings. Biological sciences, 2016. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 14 papers.
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14 citing papers in PubMed.
- But how does it smell? An investigation of olfactory bulb size among living and fossil primates and other euarchontoglirans.Anatomical record (Hoboken, N.J. : 2007) · 2026Article
- The Internal Otic Region of Oromerycids (Artiodactyla, Oromerycidae), Early Camelids (Artiodactyla, Camelidae), and the Vicuña (Artiodactyla, Camelidae), Including Notes on Intraspecific and Subadult Ontogenetic Variation.Integrative organismal biology (Oxford, England) · 2025Article
- The allometry of brain size in Euarchontoglires: clade-specific patterns and their impact on encephalization quotients.Journal of mammalogy · 2024Article
- The virtual brain endocast of Trogosus (Mammalia, Tillodontia) and its relevance in understanding the extinction of archaic placental mammals.Journal of anatomy · 2024Article
- Evolution of cortical geometry and its link to function, behaviour and ecology.Nature communications · 2023Article
- Counter-gradient variation and the expensive tissue hypothesis explain parallel brain size reductions at high elevation in cricetid and murid rodents.Scientific reports · 2023Article
- The earliest dipodomyine heteromyid in North America and the phylogenetic relationships of geomorph rodents.PeerJ · 2023Article
- The impact of locomotion on the brain evolution of squirrels and close relatives.Communications biology · 2021Article
- Orientation Preference Maps in Microcebus murinus Reveal Size-Invariant Design Principles in Primate Visual Cortex.Current biology : CB · 2021Article
- Cranial endocast of the stem lagomorphProceedings. Biological sciences · 2020Article
- Virtual endocranial and inner ear endocasts of the Paleocene 'condylarth' Chriacus: new insight into the neurosensory system and evolution of early placental mammals.Journal of anatomy · 2020Article
- Functional tests of the competitive exclusion hypothesis for multituberculate extinction.Royal Society open science · 2019Article
- A Digital Endocranial Cast of the Early Paleocene (Puercan) 'Archaic' MammalJournal of mammalian evolution · 2018Article
- Virtual endocast of the early Oligocene Cedromus wilsoni (Cedromurinae) and brain evolution in squirrels.Journal of anatomy · 2017Article
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3 authors.
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Abstract
Understanding the pattern of brain evolution in early rodents is central to reconstructing the ancestral condition for Glires, and for other members of Euarchontoglires including Primates. We describe the oldest virtual endocasts known for fossil rodents, which pertain to Paramys copei (Early Eocene) and Paramys delicatus (Middle Eocene). Both specimens of Paramys have larger olfactory bulbs and smaller paraflocculi relative to total endocranial volume than later occurring rodents, which may be primitive traits for Rodentia. The encephalization quotients (EQs) of Pa. copei and Pa. delicatus are higher than that of later occurring (Oligocene) Ischyromys typus, which contradicts the hypothesis that EQ increases through time in all mammalian orders. However, both species of Paramys have a lower relative neocortical surface area than later rodents, suggesting neocorticalization occurred through time in this Order, although to a lesser degree than in Primates. Paramys has a higher EQ but a lower neocortical ratio than any stem primate. This result contrasts with the idea that primates were always exceptional in their degree of overall encephalization and shows that relative brain size and neocortical surface area do not necessarily covary through time. As such, these data contradict assumptions made about the pattern of brain evolution in Euarchontoglires.
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