scholarly journals Sensory adaptations reshaped intrinsic factors underlying morphological diversification in bats

BMC Biology ◽  
2021 ◽  
Vol 19 (1) ◽  
Author(s):  
J. H. Arbour ◽  
A. A. Curtis ◽  
S. E. Santana
Keyword(s):  
Morphological Evolution ◽  
Allometric Relationships ◽  
Geometric Morphometric ◽  
Anatomical Structures ◽  
Intrinsic Factors ◽  
Skull Shape ◽  
Evolutionary Allometry ◽  
Biological Form ◽  
Potential Impact ◽  
Sensory Adaptations

Abstract Background Morphological evolution may be impacted by both intrinsic (developmental, constructional, physiological) and extrinsic (ecological opportunity and release) factors, but can intrinsic factors be altered by adaptive evolution and, if so, do they constrain or facilitate the subsequent diversification of biological form? Bats underwent deep adaptive divergences in skull shape as they evolved different sensory modes; here we investigate the potential impact of this process on two intrinsic factors that underlie morphological variation across organisms, allometry, and modularity. Results We use comparative phylogenetic and morphometric approaches to examine patterns of evolutionary allometry and modularity across a 3D geometric morphometric dataset spanning all major bat clades. We show that allometric relationships diverge between echolocators and visually oriented non-echolocators and that the evolution of nasal echolocation reshaped the modularity of the bat cranium. Conclusions Shifts in allometry and modularity may have significant consequences on the diversification of anatomical structures, as observed in the bat skull.

scholarly journals Geometric morphometric analysis of skull morphology reveals loss of phylogenetic signal at the generic level in extant lagomorphs (Mammalia: Lagomorpha)

2015 ◽  
Vol 84 (4) ◽  
pp. 267-284 ◽  
Author(s):  
Deyan Ge ◽  
Lu Yao ◽  
Lin Xia ◽  
Zhaoqun Zhang ◽  
Qisen Yang
Keyword(s):  
Dna Sequences ◽  
Shape Change ◽  
Morphological Evolution ◽  
Phylogenetic Signal ◽  
Lateral View ◽  
Skull Morphology ◽  
Generic Level ◽  
Geometric Morphometric ◽  
Skull Shape ◽  
Long Time

The intergeneric phylogeny of Lagomorpha had been controversial for a long time before a robust phylogeny was reconstructed based on seven nuclear and mitochondrial DNA sequences. However, skull morphology of several endemic genera remained poorly understood. The morphology of supraorbital processes in Lagomorpha is normally used as a diagnostic characteristic in taxonomy, but whether shape change of this structure parallels its genetic divergence has not been investigated. In this study, we conducted a comparative analysis of the skull morphology of all 12 extant genera using geometric morphometrics. These results indicated that no significant phylogenetic signal is observed in the shape change of the dorsal and ventral views of the cranium as well as in the lateral view of the mandible. The supraorbital processes also show insignificant phylogenetic signal in shape change. Similarly, mapping the centroid size (averaged by genus) of these datasets onto the phylogeny also showed insignificant phylogenetic signal. Aside from homoplasy caused by convergent evolution of skull shape, the massive extinction of lagomorphs after the late Miocene is proposed as one of the main causes for diluting phylogenetic signals in their morphological evolution. Acknowledging the loss of phylogenetic signals in skull shape and supraorbital processes of extant genera sheds new light on the long-standing difficulties for understanding higher-level systematics in Lagomorpha.

scholarly journals Morphological diversity in tenrecs (Afrosoricida, Tenrecidae): comparing tenrec skull diversity to their closest relatives

2015 ◽  
Author(s):  
Sive Finlay ◽  
Natalie Cooper
Keyword(s):  
Quantitative Analysis ◽  
Quantitative Methods ◽  
Morphological Diversity ◽  
Lateral View ◽  
Ecological Niches ◽  
Diverse Group ◽  
Geometric Morphometric ◽  
Skull Shape ◽  
Morphometric Analyses ◽  
The Family

Morphological diversity is often studied qualitatively. However, to truly understand the evolution of exceptional diversity, it is important to take a quantitative approach instead of relying on subjective, qualitative assessments. Here, we present a quantitative analysis of morphological diversity in a Family of small mammals, the tenrecs (Afrosoricida, Tenrecidae). Tenrecs are often cited as an example of an exceptionally morphologically diverse group. However, this assumption has not been tested quantitatively. We use geometric morphometric analyses of skull shape to test whether tenrecs are more morphologically diverse than their closest relatives, the golden moles (Afrosoricida, Chrysochloridae). Tenrecs occupy a wider range of ecological niches than golden moles so we predict that they will be more morphologically diverse. Contrary to our expectations, We find that tenrec skulls are only more morphologically diverse than golden moles when measured in lateral view. Furthermore, similarities among the species-rich Microgale tenrec Genus appear to mask higher morphological diversity in the rest of the Family. These results reveal new insights into the morphological diversity of tenrecs and highlight the importance of using quantitative methods to test qualitative assumptions about patterns of morphological diversity.

scholarly journals Individual variation of the masticatory system dominates 3D skull shape in the herbivory-adapted marsupial wombats

2019 ◽  
Author(s):  
Vera Weisbecker ◽  
Thomas Guillerme ◽  
Cruise Speck ◽  
Emma Sherratt ◽  
Hyab Mehari Abraha ◽  
...  
Keyword(s):  
Individual Variation ◽  
Principal Component ◽  
Individual Variability ◽  
Shape Variation ◽  
Mandibular Ramus ◽  
Geometric Morphometric ◽  
Skull Shape ◽  
Marsupial Species ◽  
Masticatory System ◽  
The Individual

AbstractBackgroundWithin-species skull shape variation of marsupial mammals is widely considered low and strongly size-dependent (allometric), possibly due to developmental constraints arising from the altricial birth of marsupials. However, species whose skulls are impacted by strong muscular stresses – particularly those produced through mastication of tough food items – may not display such intrinsic patterns very clearly because of the known plastic response of bone to muscle activity of the individual. In such cases, shape variation should not be dominated by allometry; ordination of shape in a geometric morphometric context through principal component analysis (PCA) should reveal main variation in areas under masticatory stress (incisor region/zygomatic arches/mandibular ramus); but this main variation should emerge from high individual variability and thus have low eigenvalues.ResultsWe assessed the evidence for high individual variation through 3D geometric morphometric shape analysis of crania and mandibles of thre species of grazing-specialized wombats, whose diet of tough grasses puts considerable strain on their masticatory system. As expected, we found little allometry and low Principal Component 1 (PC1) eigenvalues within crania and mandibles of all three species. Also as expected, the main variation was in the muzzle, zygomatic arches, and masticatory muscle attachments of the mandibular ramus. We then implemented a new test to ask if the landmark variation reflected on PC1 was reflected in individuals with opposite PC1 scores and with opposite shapes in Procrustes space. This showed that correspondence between individual and ordinated shape variation was limited, indicating high levels of individual variability in the masticatory apparatus.DiscussionOur results are inconsistent with hypotheses that skull shape variation within marsupial species reflects a constraint pattern. Rather, they support suggestions that individual plasticity can be an important determinant of within-species shape variation in marsupials (and possibly other mammals) with high masticatory stresses, making it difficult to understand the degree to which intrinsic constraint act on shape variation at the within-species level. We conclude that studies that link micro- and macroevolutionary patterns of shape variation might benefit from a focus on species with low-impact mastication, such as carnivorous or frugivorous species.

Geometric morphometric study of the skull shape diversification in Sciuridae (Mammalia, Rodentia)

2014 ◽  
Vol 9 (3) ◽  
pp. 231-245 ◽  
Author(s):  
Xuefei LU ◽  
Deyan GE ◽  
Lin XIA ◽  
Chengming HUANG ◽  
Qisen YANG
Keyword(s):  
Morphometric Study ◽  
Geometric Morphometric ◽  
Skull Shape

Morphometric variation of fish scales among some species of rattail fish from New Zealand waters

2018 ◽  
Vol 98 (8) ◽  
pp. 1991-1998
Author(s):  
A. L. Ibáñez ◽  
L. A. Jawad
Keyword(s):  
New Zealand ◽  
Discriminant Analysis ◽  
Morphological Evolution ◽  
Procrustes Analysis ◽  
Fish Scales ◽  
Geometric Morphometric ◽  
Morphometric Variation ◽  
Generalized Procrustes Analysis ◽  
Morphometric Methods ◽  
Components Analysis

New Zealand rattail fish are of great interest both to biologists who study their phylogenetics and in fisheries. In contrast, their morphological evolution is little studied and poorly understood. Geometric morphometric methods based on scale shape were applied in this study to determine differences among species and genera. Scale shapes were described using seven landmarks, the coordinates of which were subjected to a generalized Procrustes analysis, followed by a principal components analysis. A cross-validated discriminant analysis was applied to assess and compare the size-shape (centroid size plus shape variables) efficacy in the species and the discrimination of the genera. Two main phenetic groups were identified: cluster no. 1 with eight species and cluster no. 2 with six species. Coelorhinchus aspercephalus and Mesovagus antipodum were more separated from the other species in the first cluster. The cross-validated canonical discriminant analysis correctly classified 74% at the genus level, with most misclassifications occurring between Coelorhinchus and Coryphaenoides, whereas the best classified genera were Mesovagus and Trachyrincus. The discrimination of correctly classified species ranged from 41.2 to 100%. The highest correct classification rates were recorded for Coryphaenoides armatus, Coelorhinchus innotabilis, Trachyrincus longirostris and Mesovagus antipodum.

scholarly journals Ecomorphological diversification in squamates from conserved pattern of cranial integration

2019 ◽  
Vol 116 (29) ◽  
pp. 14688-14697 ◽  
Author(s):  
Akinobu Watanabe ◽  
Anne-Claire Fabre ◽  
Ryan N. Felice ◽  
Jessica A. Maisano ◽  
Johannes Müller ◽  
...  
Keyword(s):  
Morphological Evolution ◽  
Habitat Preferences ◽  
Reproductive Mode ◽  
Phenotypic Integration ◽  
Common Pattern ◽  
Skull Shape ◽  
Rates Of Evolution ◽  
Rapid Changes ◽  
Developmental Variations ◽  
Jaw Musculature

Factors intrinsic and extrinsic to organisms dictate the course of morphological evolution but are seldom considered together in comparative analyses. Among vertebrates, squamates (lizards and snakes) exhibit remarkable morphological and developmental variations that parallel their incredible ecological spectrum. However, this exceptional diversity also makes systematic quantification and analysis of their morphological evolution challenging. We present a squamate-wide, high-density morphometric analysis of the skull across 181 modern and extinct species to identify the primary drivers of their cranial evolution within a unified, quantitative framework. Diet and habitat preferences, but not reproductive mode, are major influences on skull-shape evolution across squamates, with fossorial and aquatic taxa exhibiting convergent and rapid changes in skull shape. In lizards, diet is associated with the shape of the rostrum, reflecting its use in grasping prey, whereas snakes show a correlation between diet and the shape of posterior skull bones important for gape widening. Similarly, we observe the highest rates of evolution and greatest disparity in regions associated with jaw musculature in lizards, whereas those forming the jaw articulation evolve faster in snakes. In addition, high-resolution ancestral cranial reconstructions from these data support a terrestrial, nonfossorial origin for snakes. Despite their disparate evolutionary trends, lizards and snakes unexpectedly share a common pattern of trait integration, with the highest correlations in the occiput, jaw articulation, and palate. We thus demonstrate that highly diverse phenotypes, exemplified by lizards and snakes, can and do arise from differential selection acting on conserved patterns of phenotypic integration.

scholarly journals Do island populations differ in size and shape compared to mainland counterparts?

2019 ◽  
Vol 101 (2) ◽  
pp. 373-385 ◽  
Author(s):  
Sergio Ticul Álvarez-Castañeda ◽  
Laura A Nájera-Cortazar
Keyword(s):  
Geometric Morphometric ◽  
Island Populations ◽  
Terrestrial Vertebrates ◽  
Skull Shape ◽  
Skull Size ◽  
Morphometric Analyses ◽  
Interpopulation Variation ◽  
Pocket Mouse ◽  
Shape Analyses ◽  
Insular Populations

Abstract Adaptation and evolution of terrestrial vertebrates inhabiting islands have been the topic of many studies, particularly those seeking to identify trends or patterns in body size in mammals, albeit not necessarily in shape, in relation to mainland populations. The spiny pocket mouse, Chaetodipus spinatus, is distributed in the Baja California peninsula and its surrounding islands. Insular populations became isolated ~12,000 due to changes in sea level; these populations’ matrilinear (mitochondrial) DNA shows minor interpopulation variation. We tested the hypothesis that adaptation and evolution in these island populations involve variation in both skull size and skull shape (using geometric morphometrics) relative to mainland populations, rather than only in size as previously assumed. A total of 363 specimens from 15 insular and peninsular populations were used in analysis of the skull length and geometric morphometric analyses. Our findings revealed significant differences related to skull size among population. The skull shape analyses showed two significantly different morphotypes: one for all island specimens and one for all mainland samples. Our analyses support the hypothesis that insular populations may not only vary in size relative to mainland populations, but may also show variations in shape, regardless of differing conditions across islands.

scholarly journals Are you what you eat? A geometric morphometric analysis of gekkotan skull shape

2009 ◽  
Vol 97 (3) ◽  
pp. 677-707 ◽  
Author(s):  
JUAN D. DAZA ◽  
ALEXANDRA HERRERA ◽  
RICHARD THOMAS ◽  
HÉCTOR J. CLAUDIO
Keyword(s):  
Morphometric Analysis ◽  
Geometric Morphometric ◽  
Skull Shape ◽  
Geometric Morphometric Analysis

scholarly journals Walk the line: 600000 years of molar evolution constrained by allometry in the fossil rodent Mimomys savini

2014 ◽  
Vol 369 (1649) ◽  
pp. 20140057 ◽  
Author(s):  
Cyril Firmat ◽  
Iván Lozano-Fernández ◽  
Jordi Agustí ◽  
Geir H. Bolstad ◽  
Gloria Cuenca-Bescós ◽  
...  
Keyword(s):  
Iberian Peninsula ◽  
Morphological Traits ◽  
Growth Regulation ◽  
Rodent Species ◽  
Evolutionary Divergence ◽  
Allometric Relationships ◽  
Evolutionary Allometry ◽  
Dental Measurements ◽  
Lower Molar

The allometric-constraint hypothesis states that evolutionary divergence of morphological traits is restricted by integrated growth regulation. In this study, we test this hypothesis on a time-calibrated and well-documented palaeontological sequence of dental measurements on the Pleistocene arvicoline rodent species Mimomys savini from the Iberian Peninsula. Based on 507 specimens representing nine populations regularly spaced over 600 000 years, we compare static (within-population) and evolutionary (among-population) allometric slopes between the width and the length of the first lower molar. We find that the static allometric slope remains evolutionary stable and predicts the evolutionary allometry quite well. These results support the hypothesis that the macroevolutionary divergence of molar traits is constrained by static allometric relationships.

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