The primate semicircular canal system and locomotion

Spoor, Fred; Garland, Theodore; Krovitz, Gail E.; Ryan, Timothy M.; Silcox, Mary; Walker, Alan

doi:10.1073/pnas.0704250104

Cited by 330 publications

(666 citation statements)

References 43 publications

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“…It was compared quantitatively on the basis of arc shape and size of the semicircular canals, using features known to distinguish hominids, hylobatids, and other catarrhines 25,26,43,44 . Data are provided in Supplementary Table 1.…”

Section: Semicircular Canals Of the Inner Earmentioning

confidence: 99%

“…In the case of extant hominoids, this concerned a model representing the mean shape and size of the sample. Data were also obtained for additional anthropoid species 43,44 , for use in the phylogenetic analyses. The mean radius of curvature of the semicircular canals was scaled against body mass (Extended Data comparisons, but in a few cases published species averages were used to include key taxa.…”

Section: Semicircular Canals Of the Inner Earmentioning

confidence: 99%

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New infant cranium from the African Miocene sheds light on ape evolution

Nengo

Tafforeau

Gilbert

et al. 2017

Nature

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and dental development, it possesses no definitive hylobatid synapomorphies. The combined evidence suggests that nyanzapithecines were stem hominoids close to the origin of extant apes, and that hylobatid-like facial features evolved multiple times during catarrhine evolution.Hominoids underwent a major evolutionary radiation during the Miocene epoch, with over 40 widely recognized species in at least 30 genera 1 . Despite this multitude of taxa, only about one-third are known from any cranial remains, and no more than half a dozen preserve any significant portion beyond the face and palate 2 . Thus, much about hominoid cranial evolution remains poorly understood, especially with respect to the ancestral morphology that gave rise to the clade containing extant apes and humans. Importantly, the African fossil record lacks any reasonably complete hominoid crania between 17 and 7 million years (Myr) ago, and no cranial specimens are known at all from between 14 and 10 Myr (refs 3-6), greatly hampering the analysis of hominoid evolution. The KNM-NP 59050 cranium reported here was recovered from Napudet (South Turkana, Kenya) and dated to 13 Myr; it thus falls within this critical yet poorly represented period. The infant specimen is nearly complete, but is missing the deciduous dental crowns (Fig. 1a-d and Extended Data Fig. 1a-f). The unerupted adult dentition, brain endocast, and bony labyrinths were visualized using propagation phase-contrast X-ray synchrotron microtomography (PPC-SR-CT; Fig. 1e-h Locality and horizon. Napudet (2° 57′ N, 35° 52′ E), Turkana Basin, Kenya, Emunyan Beds, Brown Bedded Tuffs (Extended Data Fig. 2a).Geological age. 13 Myr. Diagnosis.A large species of Nyanzapithecus, with M 1 significantly larger than in N. pickfordi (P < 0.05), N. harrisoni (P < 0.01), and probably N. vancouveringorum ( Fig. 3a and Extended Data Table 1a; Cranial morphologyKNM-NP 59050 is a nearly complete but somewhat distorted cranium of an infant primate (Fig. 1). The cranium is slightly crushed bilaterally and the posterior portion of the basicranium is both broken and distorted. All the deciduous tooth crowns are broken off, but their roots are preserved. The permanent teeth are unerupted, with the right I 1 being visible in its crypt.The overall dimensions of KNM-NP 59050 are similar to those of Symphalangus crania of equivalent dental age, except for the maxillo-alveolar size, which is similar to Hoolock (Extended Data Table 1b). Relative to overall cranial size, the snout is small as in juvenile hylobatids, and smaller than in extant juvenile hominids . This difference between hylobatids and hominids persists into adulthood (Extended Data Fig. 4b, d), and assuming that N. alesi followed the same pattern, its snout would have been relatively small as an adult, unlike that of Afropithecus and Saadanius.The orbits appear large, but are well within the expected range for an extant juvenile hominoid of its size (Extended Data Fig. 4e). The orbits are slightly taller than wide, which may reflect the bilateral dist...

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Section: Semicircular Canals Of the Inner Earmentioning

confidence: 99%

Section: Semicircular Canals Of the Inner Earmentioning

confidence: 99%

New infant cranium from the African Miocene sheds light on ape evolution

Nengo

Tafforeau

Gilbert

et al. 2017

Nature

Self Cite

View full text Add to dashboard Cite

show abstract

“…width)/2, according to Schmelzle et al (2007). In order to obtain suitable data for comparison with the data set of Spoor et al (2007), i.e., the height and width as maximum distance from the vestibule to the center of the canal, we calculated the mean of the inner and outer curvature of the canals. The number of cochlear turns was calculated according to West (1985) by using a projection line from the inflection point of the fenestra cochleae to the apex of the cochlear canal.…”

Section: Methodsmentioning

confidence: 99%

“…The radius of curvature of the semicircular canals of the investigated specimens was compared to body mass following Spoor et al (2007) and Silcox et al (2009), a correlation that allows estimation of the degree of locomotor agility. For this purpose, we used the following estimates of body mass of the investigated species.…”

Section: Methodsmentioning

confidence: 99%

“…Besides postcranial anatomy, the shape and proportions of vestibular labyrinth structures also record configurations related to locomotion and posture, which in turn can be used as a reliable proxy to characterise locomotor behaviour and agility in extant, and, by extrapolation, extinct mammals (e.g., Spoor et al 2007;Walker et al 2008;Silcox et al 2009;David et al 2010;Macrini et al 2010;Malinzak et al 2012;Ryan et al 2012;Berlin et al 2013). To date, nothing is known about this pattern in Leptictida.…”

Section: Introductionmentioning

confidence: 99%

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