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opencc-by-4.0Jul 2012View details →

Fig. 2 in Pleistocene equid brain endocast from Shanxi Province, China

Fig. 2. Fossil equid brain endocast (TNU V44) from Shanxi Province, China (early Pleistocene) and associated bones in left lateral (A) and right lateral (B) views. Photographs (A1, B1) and sketches (A2, B2).

FIGURE 11 in Endocranial morphology of the extinct Antillean shrew Nesophontes (Lipotyphla: Nesophontidae) from natural and digital endocasts of Cuban taxa

FIGURE 11. Brain morphology of selected extinct and extant mammals, including Nesophontes spp. Upper row contains extant placentals and marsupials. Lower row contains extinct taxa and Nesophontes. Olfactory lobes are in red, neocortex is in blue, and hindbrain is in green. Scale bar equals 10 mm. Sources: Monodelphis domestica drawn from Rowe et al. (2011); Solenodon paradoxus from Allen (1910); Tenrec ecuadatus from Stephan and Andy (1982); Eoryctes melanus from Thewissen and Gingerich (1989); Hyopsodus lepidus from Orliac et al. (2012); Vincelestes neuquenianus from Macrini et al. (2007a) Nesophontes taxa reported here, and the remaining from the Comparative Brain Collection at www.brainmuseum.org. A and P stand for anterior and posterior. Scale bar = 1 cm.

FIGURE 8 in Endocranial morphology of the extinct Antillean shrew Nesophontes (Lipotyphla: Nesophontidae) from natural and digital endocasts of Cuban taxa

FIGURE 8. Cribriform and olfactory regions in Nesophontes major (1) and Nesophontes micrus (2). Abbreviations: ar annular ridge; As alisphenoid; cef cribroethmoidal foramen; cg crista galli; ec ectoturbinal foramina; etI ethmoturbinal foramina; fo foramen ovalae; hs horizontal sulcus; Js jugun sphenoidalis; nc nasocribriform foramina; ntf nasoturbinal foramina; of optic foramen for optic nerve; off olfactory fossa; otc orbitotemporal canal; psp parasphenoid plate; sof sphenorbital fossa; sor sphenorbital ridge. A and P stand for anterior and posterior.

FIGURE 7 in Endocranial morphology of the extinct Antillean shrew Nesophontes (Lipotyphla: Nesophontidae) from natural and digital endocasts of Cuban taxa

FIGURE 7. Endocranial casts of Cuban Nesophontes spp. Nesophontes micrus (C437) first column. Endocast volume: 0.580 mL, encephalization quotients (EQ 2 and 3): 0.21 and 0.33. Nesophontes micrus (C436), second column. Endocast volume: 1.231 mL, EQ 2 and 3: 0.33 and 0.52. Nesophontes major (270), third column. Endocast volume: 0.729 mL, EQs: 0.27 and 0.43. Nesophontes major (C133), fourth and last column. Endocast volume: 0.888 mL, EQs: 0.36 and 0.57.

FIGURE 6 in Endocranial morphology of the extinct Antillean shrew Nesophontes (Lipotyphla: Nesophontidae) from natural and digital endocasts of Cuban taxa

FIGURE 6. Volume rendering of Nesophontes major (C133) endocranial space in lateral (1) and oblique (2) views showing possible olfactory nerve fibers (onf), sylvian fissure (S. f.), and rhinal fissure (rhf). A and P stand for anterior and posterior.

FIGURE 5 in Endocranial morphology of the extinct Antillean shrew Nesophontes (Lipotyphla: Nesophontidae) from natural and digital endocasts of Cuban taxa

FIGURE 5. Digital endocranial cast of Nesophontes major (C133) in right lateral (1), anterior (2), and inferior (3) views. Abbreviations: Cb cerebellum; cc possible cast of spinal cord space; cs superior colliculi; fan annular or circular fissure; hy hypophyseal fossa; Iar internal auditory region; lal lateral lobe of cerebellum; las lateral transverse sinus; Ncx neocortex; Ob olfactory lobes; Och. optic chiasm; Ocx olfactory (=piriform) cortex, onf olfactory nerve fiber, otg orbitotemporal groove; Pfl paraflocculus; rhf rhinal fissure; sas sagittal sinus or longitudinal sinus; Sphr sphenorbital region; Sv confluence of the transverse and sagittal sinuses; Vc cerebellar vermis. A and P stand for anterior and posterior.

FIGURE 4 in Endocranial morphology of the extinct Antillean shrew Nesophontes (Lipotyphla: Nesophontidae) from natural and digital endocasts of Cuban taxa

FIGURE 4. Natural endocranial casts extracted from Nesophontes spp. skulls. (4.1) Nesophontes major hindbrain fragment; (4.2) N. major olfactory lobes; (4.3-4.4) Nesophontes micrus superior (4.3) and left lateral (4.5) views of a partial hindbrain. Cb cerebellum; cs superior colliculi; lal lateral lobe of cerebellum; Ob olfactory lobes; op olfactory peduncle; Pfl paraflocculus; Ts transverse sinus canal; Ts-c confluence of the transverse and sagittal sinuses. A and P stand for anterior and posterior.

FIGURE 3 in Endocranial morphology of the extinct Antillean shrew Nesophontes (Lipotyphla: Nesophontidae) from natural and digital endocasts of Cuban taxa

FIGURE 3. Anatomical terminology of Nesophontes endocranial casts. 1, superior and lateral views of Nesophontes major endocranial cast (C181). 2, superior and lateral views of Nesophontes micrus (C145) specimen. 3, single view of partial endocranial cast extracted from an uncataloged N. micrus skull. Abbreviations of anatomical terminology: Cb cerebellum; cs superior colliculi; fan annular or circular fissure; Iar internal auditory region; lal lateral lobe of cerebellum; las lateral transverse sinus; Ncx neocortex; Ob olfactory lobes; otg orbitotemporal groove; Ocx olfactory (=piriform) cortex; Pfl paraflocculus; rhf rhinal fissure; sas sagittal sinus or longitudinal sinus; Sphr sphenorbital region; Sv confluence of the transverse and sagittal sinuses; Vc cerebellar vermis. A and P stand for anterior and posterior.

FIGURE 1 in Endocranial morphology of the extinct Antillean shrew Nesophontes (Lipotyphla: Nesophontidae) from natural and digital endocasts of Cuban taxa

FIGURE 1. Natural (1), digital (2), and radiographic images (3) of Nesophontes spp. crania used in this study. 1, these skulls were the source of natural endocasts for Nesophontes micrus (C145) and Nesophontes major (C181) shown in Figures 1 and 2. 2, Digital rendering of N. major skull (C133) from which the digital endocast in Figure 5 was reconstructed. 3, are negative and positive lateral radiographs of Nesophontes spp. endocranial morphology and space.

FIGURE 2 in Endocranial morphology of the extinct Antillean shrew Nesophontes (Lipotyphla: Nesophontidae) from natural and digital endocasts of Cuban taxa

FIGURE 2. Natural endocranial casts of Cuban Nesophontes spp. 1, superior, and right lateral view of Nesophontes major (specimen number C181) endocasts. 2-3, superior and right lateral views of Nesophontes micrus endocasts. 2, Nesophontes micrus (C145); 3-4, are not cataloged.

FIGURE 12 in Endocranial morphology of the extinct Antillean shrew Nesophontes (Lipotyphla: Nesophontidae) from natural and digital endocasts of Cuban taxa

FIGURE 12. Idealized brain reconstruction of Nesophontes major compared to other insectivoran-mammals, plus the Norway rat Rattus norvegicus. Sorex, Blarina, Condylura, Scalopus, and Rattus specimens were redrawn and modified from specimens in the Comparative Brain Collection at www.brainmuseum.org and Sarko et al. (2009). Erinaceous, Tenrec, and Solenodon were drawn from Stephen and Andy (1982). A and P stand for anterior and posterior. Scale bar = 1 cm.

FIGURE 9 in Endocranial morphology of the extinct Antillean shrew Nesophontes (Lipotyphla: Nesophontidae) from natural and digital endocasts of Cuban taxa

FIGURE 9. Endocranial morphology of Nesophontes micrus and Nesophontes major calotte showing slight differences in tectum and transverse sinus. Top arrows point to the confluence of the transverse sinus and the colliculi fossae. A and P stand for anterior and posterior.

FIGURE 10 in Endocranial morphology of the extinct Antillean shrew Nesophontes (Lipotyphla: Nesophontidae) from natural and digital endocasts of Cuban taxa

FIGURE 10. Idealized brain reconstruction of Nesophontes spp (1), and Solenodon paradoxus (2) in superior and lateral views. The brain of Nesophontes is a composite reconstruction based on natural and digital casts. Solenodon paradoxus was drawn from photographs of Stephen and Andy (1982:541, figures 20-22). Lines and labels on the lateral views indicate similar morphologic features. Olfactory lobes are in red, neocortex is in blue, and posterior brain (part of midbrain and cerebellum) is in green. Specimens are not to same scale. Abbreviations: Cb cerebellum; cs superior colliculi; Fan annular or circular fissure; Iar internal auditory region; lal lateral lobe of cerebellum; las lateral transverse sinus; Ncx neocortex; Ob olfactory lobes; Och optic chiasm; Ocx olfactory (=piriform) cortex; onf olfactory nerve fiber; otg orbitotemporal groove; Pfl paraflocculus; Pof post-orbital fissure; rhf rhinal fissure; sas sagittal sinus or longitudinal sinus; Sphr sphenorbital region; Sv confluence of the transverse and sagittal sinuses; T tectum; Vc cerebellar vermis. A and P stand for anterior and posterior.

opencc-by-4.0Aug 2017View details →

Text-fig. 6. Fossil endocasts of large mammals from Gánovce-Hrádok Neanderthal site. a) Equidae gen. et sp. indet. (NM-Rv 21008); b) Equidae gen. et sp. indet. (NM-Rv 21007); c) Equidae gen. et sp. indet. (NM-Rv 21006); d) Bovidae gen. et sp. indet. (NM-Rv 21009); e) Ursus ex gr. spelaeus (NM R-604); f) Ursus ex gr. spelaeus (NM-Rv 21010); lateral and dorsal (except for f: ventral) views; lateral view for d and f are inverted. in Revised Floral And Faunal Assemblages From Late Pleistocene Deposits Of The Gánovce-Hrádok Neanderthal Site -Biostratigraphic And Palaeoecological Implications

Text-fig. 6. Fossil endocasts of large mammals from Gánovce-Hrádok Neanderthal site. a) Equidae gen. et sp. indet. (NM-Rv 21008); b) Equidae gen. et sp. indet. (NM-Rv 21007); c) Equidae gen. et sp. indet. (NM-Rv 21006); d) Bovidae gen. et sp. indet. (NM-Rv 21009); e) Ursus ex gr. spelaeus (NM R-604); f) Ursus ex gr. spelaeus (NM-Rv 21010); lateral and dorsal (except for f: ventral) views; lateral view for d and f are inverted.

opencc-zeroJun 2020View details →

Cranial endocast of the stem lagomorph Megalagus and brain structure of basal Euarchontoglires

Early lagomorphs are central to our understanding of how the brain evolved in Glires (rodents, lagomorphs and their kin) from basal members of Euarchontoglires (Glires + Euarchonta, the latter grouping primates, treeshrews, and colugos). Here we report the first virtual endocast of the fossil lagomorph Megalagus turgidus, from the Orella Member of the Brule Formation, early Oligocene, Nebraska, USA. The specimen represents one of the oldest nearly complete lagomorph skulls known. Primitive aspects of the endocranial morphology in Megalagus include large olfactory bulbs, exposure of the midbrain, a small neocortex, and a relatively low encephalization quotient. Overall, this suggest a brain morphology closer to that of other basal members of Euarchontoglires (e.g., plesiadapiforms and ischyromyid rodents) than to that of living lagomorphs. However, the well-developed petrosal lobules in Megalagus, comparable to the condition in modern lagomorphs, suggest early specialization in that order for the stabilization of eye movements necessary for accurate visual tracking. Our study sheds new light on the reconstructed morphology of the ancestral brain in Euarchontoglires and fills a critical gap in the understanding of palaeoneuroanatomy of this major group of placental mammals.

opencc-zeroAug 2022View details →

Morphometric analysis of lungfish endocasts elucidates early dipnoan palaeoneurological evolution

Lungfish (Dipnoi) are lobe-finned fish (Sarcopterygii) that have persisted for over 400 million years from the Devonian Period to present day. They are the extant sister group to tetrapods and thus have the ability to provide unique insight into the condition of the earliest tetrapods as well as their own evolutionary history. The evolution of their dermal skull and dentition is relatively well understood, but this is not the case for the central nervous system. While the brain itself has very poor preservation potential and is not currently known in any fossil lungfish, substantial indirect information about it and associated structures such as the inner ears can be obtained from the cranial endocast. However, before the recent development of X-ray tomography as a palaeontological tool, these endocasts could not be studied non-destructively, and few detailed studies were undertaken. Here we describe and illustrate the endocasts of six Palaeozoic lungfish (Iowad ipterus halli, Gogodipterus paddyensis, Pillararhynchus longi, Griphognathus whitei, Orlovichthys limnatis, and Rhinodipterus ulrichi) from tomographic scans. We combine these with six previously described digital lungfish endocasts (4 fossil and 2 recent taxa) into a 12-taxon data set for multivariate morphometric analysis using 17 variables. We find that the olfactory region appears to be more highly plastic than the hindbrain, and undergoes significant elongation in several taxa. Further, while the semicircular canals covary as an integrated module, the utriculus and sacculus of the inner ear instead vary independently of each other. Functional interpretation suggests that olfaction has remained a dominant sense throughout lungfish evolution, and that changes seen in the labyrinth system may potentially reflect a change from a nektonic niche in older marine lungfish to more near-shore environments over time. Phylogenetic implications propose that endocranial form fails to support the monophyly of the 'chirodipterids'. Those with elongated crania similarly fail to form a distinct clade, suggesting that these are two paraphyletic groups that have converged either towards head elongation or truncation driven by constraints other than phylogeny.

opencc-zeroMay 2024View details →

Data from: Endocranial morphology of three early-diverging ceratopsians and implications for the behavior and the evolution of the endocast in ceratopsians

Ceratopsians underwent great changes including the shift of the locomotion mode, enlarged horns and frills, and increased body size. These changes are along with the changes in endocranial morphology and ecology such as the decrease of the flocculus, the hearing range, the olfactory ratio, and the Reptile Encephalization Quotient. However, the endocranial structures and associated ecology of the earliest ceratopsians are still unknown. Here, we reconstructed the endocasts of three early-diverging ceratopsians including the Late Jurassic Yinlong, and the Early Cretaceous Liaoceratops and Psittacosaurus. These ceratopsians display prominent flocculus, large and separate olfactory bulbs, long and high anterior semicircular canal, and long endosseous cochlear duct. Unlike Liaoceratops and Psittacosaurus, Yinlong exhibits relatively stocky semicircular canals and small flocculus. In Ceratopsia, the evolutional patterns of the endocast include the merging and narrowing of the olfactory bulbs, the disappearing flocculus, the reduction of the anterior semicircular canal, the increasing of the angle between two vertical semicircular canals, and the shortening of the cochlear duct. The endocranial structures suggest early-diverging ceratopsians had a high olfactory acuity and were adapted to hearing high frequencies, unlike the condition of late-diverging ceratopsians with lower olfactory acuity and hearing frequency. Reptile Encephalization Quotient suggests that Yinlong and Psittacosaurus were more encephalized than most extant reptiles and late-diverging ceratopsians. The angle of the lateral semicircular canal suggests that heads in ceratopsians display a transition from an upward posture to a downward posture. The relatively upward head posture indicates that early-diverging ceratopsians could feed more selectively such as to eat some leaves.

opencc-zeroNov 2022View details →

Data from: The endocast of Euparkeria sheds light on the ancestral archosaur nervous system

Understanding the evolution of the tetrapod brain is essential to trace the history of ecomorphological diversification of modern clades. While previous studies focused on the morphological transformation of the nervous system along the dinosaur-bird transition, little is known about the brain anatomy of archosauriformes and early archosaurs. Here, we describe the endocast of Euparkeria capensis, a small-bodied, terrestrial archosauriform closely related to Archosauria, with the goal of resolving the current uncertainties surrounding the ancestral condition of the archosaurian nervous system. The endocast of Euparkeria is sigmoidal, with large olfactory bulbs, an expanded cerebral hemisphere and an elongated flocculus. We suggest that this pivotal taxon was an active predator with a remarkable olfactory acuity. Overall, the endocast of Euparkeria resembles the ones observed in phytosaurs, crocodilians and early dinosaurs, implying that modern crocodilians retain an archosaurian plesiomorphic brain morphology.

opencc-zeroApr 2023View details →

Data from: Cranial endocast of Anagale gobiensis (Anagalidae) and its implications for early brain evolution in Euarchontoglires

Anagalids are an extinct group of primitive mammals from the Asian Palaeogene thought to be possible basal members of Glires. Anagalid material is rare, with only a handful of crania known. Here we describe the first virtual endocast of an anagalid, based on the holotype of Anagale gobiensis (AMNH 26079; late Eocene, China), which allows for comparison with published endocasts from fossil members of modern euarchontogliran lineages (i.e. primates, rodents, lagomorphs). The endocast displays traits often observed in fossorial mammals, such as relatively small petrosal lobules and a low neocortical ratio, which would be consistent with previous inferences about use of subterranean food sources based on heavy dental wear. In fact, Anagale gobiensis has the lowest neocortical ratio yet recorded for a euarchontogliran. This species was olfaction-driven, based on the relatively large olfactory bulbs and laterally expansive palaeocortex. The endocast supports previous inferences that relatively large olfactory bulbs, partial midbrain exposure and low encephalization quotient are ancestral for Euarchontoglires, although the likely fossorial adaptations of Anagale gobiensis may also partly explain these traits. While Anagale gobiensis is a primitive mammal in many aspects, some of its derived endocranial traits point towards a new, different trajectory of brain evolution within Euarchontoglires.