Interspecific analysis of covariance structure in the masticatory apparatus of galagos

Vinyard, Christopher J.

doi:10.1002/ajp.20326

Cited by 48 publications

(10 citation statements)

References 38 publications

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“…These findings correspond closely to similar ontogenetic comparisons within pottos, slow lorises, indriids and lemurids, where much of the variation in adult cranial form is due to the differential extension or truncation of shared growth trajectories [Ravosa, 1992[Ravosa, , 1998[Ravosa, , 2007Ravosa and Daniel, 2010]. Such findings are likewise consistent with recent interspecific analyses of craniofacial covariance patterns across adult galagos, which emphasized the influence of changing body size on the evolution of the masticatory system [Vinyard, 2007]. Although the selective factors underlying body size differentiation in galagos remain to be more fully explored, the presence of pervasive ontogenetic scaling of facial dimensions suggests that galago cranial variation may have resulted in part from selection for size differentiation among sister taxa.…”

Section: Discussionsupporting

confidence: 79%

“…In sum, our comparisons represent the first comprehensive study of the ontogenetic underpinnings of craniomandibular variation across galagids and thus contribute to an understanding of the diversity and evolution of this strepsirhine clade. Indeed, these analyses have the potential to complement a recent study of covariance structure in the galago skull, where it was noted that changing body size may have been a significant factor in the evolution of the masticatory apparatus [Vinyard, 2007].…”

Section: Introductionmentioning

confidence: 99%

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Allometry and Evolution in the Galago Skull

Ravosa¹,

Daniel²,

Costley³

2010

IJFP

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To probe the ontogenetic bases of morphological diversity across galagos, we performed the first clade-wide analyses of growth allometries in 564 adult and non-adult crania from 12 galagid taxa. In addition to evaluating if variation in galago skull form results from the differential extension/truncation of common ontogenetic patterns, scaling trajectories were employed as a criterion of subtraction to identify putative morphological adaptations in the feeding complex. A pervasive pattern of ontogenetic scaling is observed for facial dimensions across galagids, with 2 genera also sharing relative growth trajectories for masticatory proportions (Galago, Galagoides). As the facial growth series and adult data are largely coincidental, interspecific variation may result from character displacement and consequent selection for size differentiation among sister taxa. Derived configurations of the jaw joint and jaw muscle mechanical advantage in Otolemur and Euoticus appear to facilitate increased gape during scraping behaviors. Differences in aspects of masticatory growth and form characterizing these 2 genera highlight selection to uncouple shared ontogenetic patterns, which occurred via transpositions that retained ancestral scaling patterns. Due to the lack of increased robusticity of load-resisting mandibular elements in Otolemur and Euoticus, there is little evidence to suggest that exudativory in galagos results in correspondingly higher masticatory stresses.

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Section: Discussionsupporting

confidence: 79%

Section: Introductionmentioning

confidence: 99%

Allometry and Evolution in the Galago Skull

Ravosa¹,

Daniel²,

Costley³

2010

IJFP

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“…Vinyard [58] found no association between dietary type expressed as percentages of foods consumed and covariation structure of the mandible of galagos. Despite the varied diet of galagos, it was argued that the ability to obtain and digest gum might be the fundamental adaptation of this group [58]–[64].…”

Section: Introductionmentioning

confidence: 94%

“…Despite the varied diet of galagos, it was argued that the ability to obtain and digest gum might be the fundamental adaptation of this group [58]–[64]. If this is the case, the lack of association between diet and covariation structure might not be as surprising.…”

Section: Introductionmentioning

confidence: 99%

The Effect of Dietary Adaption on Cranial Morphological Integration in Capuchins (Order Primates, Genus Cebus)

2012

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A fundamental challenge of morphology is to identify the underlying evolutionary and developmental mechanisms leading to correlated phenotypic characters. Patterns and magnitudes of morphological integration and their association with environmental variables are essential for understanding the evolution of complex phenotypes, yet the nature of the relevant selective pressures remains poorly understood. In this study, the adaptive significance of morphological integration was evaluated through the association between feeding mechanics, ingestive behavior and craniofacial variation. Five capuchin species were examined, Cebus apella sensu stricto, Cebus libidinosus, Cebus nigritus, Cebus olivaceus and Cebus albifrons. Twenty three-dimensional landmarks were chosen to sample facial regions experiencing high strains during feeding, characteristics affecting muscular mechanical advantage and basicranial regions. Integration structure and magnitude between and within the oral and zygomatic subunits, between and within blocks maximizing modularity and within the face, the basicranium and the cranium were examined using partial-least squares, eigenvalue variance, integration indices compared inter-specifically at a common level of sampled population variance and cluster analyses. Results are consistent with previous findings reporting a relative constancy of facial and cranial correlation patterns across mammals, while covariance magnitudes vary. Results further suggest that food material properties structure integration among functionally-linked facial elements and possibly integration between the face and the basicranium. Hard-object-feeding capuchins, especially C.apella s.s., whose faces experience particularly high biomechanical loads are characterized by higher facial and cranial integration especially compared to C.albifrons, likely because morphotypes compromising feeding performance are selected against in species relying on obdurate fallback foods. This is the first study to report a link between food material properties and facial and cranial integration. Furthermore, results do not identify the consistent presence of cranial modules yielding support to suggestions that despite the distinct embryological imprints of its elements the cranium of placental mammals is not characterized by a modular architecture.

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“…9;Mork et al, Chap. 10;Dumont 1997;Williams et al 2002;Vinyard et al 2003;Viguier 2004;Smith 2005, 2007;Vinyard 2007).…”

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Searching for Dental Signals of Exudativory in Galagos

Burrows

Nash²

2010

The Evolution of Exudativory in Primates

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Consumption of exudates requires acquiring exudates. Exudate-feeding marmosets possess a distinct dental signal consisting of the "short-tusked" anterior dentition, which they use to gouge tree bark and elicit exudate flow. Observations of exudate-feeding galagos have indicated that these animals use the toothcomb in some fashion to acquire exudates, but behavioral observations of galago exudate acquisition are incomplete. The present study was designed to assess dental morphometrics of galagos in an effort to search for a more complete dental signal of exudate-feeding in this group. Cleaned and dried skulls from 137 galago specimens were selected representing seven species with varying proportions of exudates in their diets. Two-dimensional measurements were taken from the toothcomb, maxillary canine, mandibular and maxillary first premolars, and the last mandibular molar.

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Interspecific analysis of covariance structure in the masticatory apparatus of galagos

Cited by 48 publications

References 38 publications

Allometry and Evolution in the Galago Skull

Allometry and Evolution in the Galago Skull

The Effect of Dietary Adaption on Cranial Morphological Integration in Capuchins (Order Primates, Genus Cebus)

Searching for Dental Signals of Exudativory in Galagos

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