Head morphological variation in Podarcis muralis and Podarcis sicula: a landmark-based approach

Bruner, Emiliano

doi:10.1163/156853807782152525

Cited by 21 publications

(8 citation statements)

References 12 publications

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“…Despite numerous studies on morphometric variation in lacertid lizards (Bruner & Constantini, 2007;Herrel, Spithoven, Van Damme, & De Vree, 1999;Hipsley, Miles, & Müller, 2014;Hipsley & Müller, 2017;Kaliontzopoulou, Carretero, & Llorente, 2008;Lazić, Carretero, Crnobrnja-Isailović, & Kaliontzopoulou, 2016;Lazić et al, 2015;Ljubisavljević, Urošević, Aleksić, & Ivanović, 2010;Urošević, Ljubisavljević, & Ivanović, 2013), a phylogenetically based comparative approach is greatly hampered by the fact that the phylogeny of the lacertids is still, after multiple efforts, largely unresolved. Recently, Pyron, Burbrink, and Wiens (2013) offered a seemingly resolved phylogeny of a clade included in the "megaphylogeny" of the squamates which contained thousands of species and multiple genes.…”

Section: Introductionmentioning

confidence: 99%

Multilevel assessment of the Lacertid lizard cranial modularity

Urošević

Ljubisavljević

Ivanović

2018

J Zool Syst Evol Res

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Different factors and processes that produce phenotypic variation at the individual, population, or interspecific level can influence or alter the covariance structure among morphological traits. Therefore, studies of the patterns of integration and modularity at multiple levels—static, ontogenetic, and evolutionary, can provide invaluable data on underlying factors and processes that structured morphological variation, directed, or constrained evolutionary changes. Our dataset, consisting of cranium shape data for 14 lizard species from the family Lacertidae, with substantial samples of hatchlings and adults along with their inferred evolutionary relationships, enabled us to assess modularity and morphological integration at all three levels. Five, not mutually exclusive modularity hypotheses of lizard cranium, were tested, and the effects of allometry on intensity and the pattern of integration and modularity were estimated. We used geometric morphometrics to extract symmetric and asymmetric, as well as allometric and nonallometric, components of shape variation. At the static level, firm confirmation of cranial modularity was found for hypotheses which separate anterior and posterior functional compartments of the skull. At the ontogenetic level, two alternative hypotheses (the “anteroposterior” and “neurodermatocranial” hypotheses) of ventral cranial modularity were confirmed. At the evolutionary level, the “neurodermatocranial” hypothesis was confirmed for the ventral cranium, which is in accordance with the pattern observed at the ontogenetic level. The observed pattern of static modularity could be driven by functional demands and can be regarded as adaptive. Ontogenetic modularity and evolutionary modularity show the same developmental origin, indicating conservatism of modularity patterns driven by developmental constraints.

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Section: Introductionmentioning

confidence: 99%

Multilevel assessment of the Lacertid lizard cranial modularity

Urošević

Ljubisavljević

Ivanović

2018

J Zool Syst Evol Res

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“…An anatomical report on the ossification of lacertid skull shows that the bones of the snout region (premaxilla, maxilla and nasal bones) ossify before those of the skull roof, and the posterior region of the frontal areas ossifies before the anterior region of the parietals (Barahona and Barbadillo, 1998). An equivalent of similar antero-posterior growth gradient, associated with a differential allometric rate, has been described in several lacertids, as well as in other lizard taxa, in both the skull (Monteiro and Abe, 1997) and the cephalic scales (Bruner et al, 2005;Bruner and Costantini, 2007). The fronto-parietal suture, which is positioned under the fronto-parietal scales, has been hypothesized to be a relevant pace-maker of the head growth and development .…”

Section: Introductionmentioning

confidence: 79%

“…All the individuals were recovered around Rome, between 1999 and 2005. Of each species, we included in this study three males and three females chosen from a larger sample (Bruner et al, 2005;Bruner and Costantini, 2007) in order to have a head size gradient (i.e., from small to large) for each sex and for each species, respectively. The specimens were scanned using a high-resolution X-ray microtomography (lCT-80, Scanco Medical, Switzerland), at 45 kV X-ray tube voltage, 88 lA, 0.35 degree rotation step and $800 ns exposure time per individual shadow projection.…”

Section: Materials and Methods Sampling And Lct Analysismentioning

confidence: 99%

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The Relationship Between Cephalic Scales and Bones in Lizards: A Preliminary Microtomographic Survey on Three Lacertid Species

Alonso

Moazen

Bruner

2010

The Anatomical Record

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In the last two decades, there has been a great deal of interest in the morphology and anatomy of the lizard skull in an ecological and evolutionary perspective. However, the relationship between variations in many key anatomical features remains largely unknown. Using microtomography and geometric morphometrics, we examined the relationship between bones and scales associated with the parietal foramen in the three lizards species most common in the Italian peninsula: Podarcis muralis, P. sicula, and Lacerta bilineata. The imprints of the scales are clearly recognizable on the outer bone surface, and this may suggest a structural interaction between these elements. The temporal osteoderms are visible in the larger males and in the larger females of L. bilineata, but they are absent in the smaller specimens of L. bilineata and in all Podarcis specimens. Two parallel rows of pterygoid teeth are present in all the specimens of L. bilineata and are absent in the smaller male of L. bilineata and in both Podarcis species. Cheek osteoderms occurred only in the largest specimens of our sample (i.e., large L. bilineata), being possibly related to hyperostotic processes and densitometric thresholds more than to phylogeny. Minor differences may be also associated with the form of the parietal foramen. In absolute terms the parietal foramen tends to be largest in L. bilineata but in relation to skull length the foramen tends to be larger in P. muralis. In this latter species the foramen is also more elongated. In all three species the fronto-parietal suture occupies a similar location relatively to the scale spatial organization. A shared allometric pattern shows that the main vault enlargement can be localised at the areas anterior to the fronto-parietal suture, providing further information on the possible morphogenetic dynamics associated with the interaction between scales and bones around this structure. Anat Rec,

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“…The tight developmental connection between scales and bones is also supported by their shape variation. The variation of the cephalic scales is largely characterized by a size-related pattern associated with negative allometry of the anterior region (frontal scales) and positive allometry of the posterior region (occipital, parietal, and interparietal scales; see Monteiro and Abe, 1997;Bruner et al, 2005;Bruner and Costantini, 2007). This anteroposterior growth gradient matches the pattern of ossification of the underlying cranial bones (Barahona and Barbadillo, 1998).…”

Section: Sensitivity Analysis In a Lizard Suturementioning

confidence: 88%

A Sensitivity Analysis to the Role of the Fronto‐Parietal Suture in Lacerta Bilineata: A Preliminary Finite Element Study

Moazen

Bruner

2012

The Anatomical Record

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Cranial sutures are sites of bone growth and development but micromovements at these sites may distribute the load across the skull more evenly. Computational studies have incorporated sutures into finite element (FE) models to assess various hypotheses related to their function. However, less attention has been paid to the sensitivity of the FE results to the shape, size, and stiffness of the modeled sutures. Here, we assessed the sensitivity of the strain predictions to the aforementioned parameters in several models of fronto-parietal (FP) suture in Lacerta bilineata. For the purpose of this study, simplifications were made in relation to modeling the bone properties and the skull loading. Results highlighted that modeling the FP as either an interdigitated suture or a simplified butt suture, did not reduce the strain distribution in the FP region. Sensitivity tests showed that similar patterns of strain distribution can be obtained regardless of the size of the suture, or assigned stiffness, yet the exact magnitudes of strains are highly sensitive to these parameters. This study raises the question whether the morphogenesis of epidermic scales in the FP region in the Lacertidae is related to high strain fields in this region, because of micromovement in the FP suture. Anat Rec, 296:198-209, 2013. V C 2012 Wiley Periodicals, Inc.Key words: biomechanics; lizard; skull; finite element analysis Sutures are sites of bone deposition and growth, which undergo many changes in terms of their stiffness and form over the growth and development of the skull (Herring, 2008). However, the role and function of sutures in the adult skull has been the subject of debate among functional morphologists and palaeontologists. In fact, in a lot of taxa, many sutures do not fuse after the growth and developmental processes have effectively terminated, and the possible biomechanical roles of these elements during ontogeny and phylogeny are still not fully understood (

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Head morphological variation in Podarcis muralis and Podarcis sicula: a landmark-based approach

Cited by 21 publications

References 12 publications

Multilevel assessment of the Lacertid lizard cranial modularity

Multilevel assessment of the Lacertid lizard cranial modularity

The Relationship Between Cephalic Scales and Bones in Lizards: A Preliminary Microtomographic Survey on Three Lacertid Species

A Sensitivity Analysis to the Role of the Fronto‐Parietal Suture in Lacerta Bilineata: A Preliminary Finite Element Study

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