Constraint and adaptation in the evolution of carnivoran skull shape

Paleobiology ◽  
2011 ◽  
Vol 37 (3) ◽  
pp. 490-518 ◽  
Author(s):  
Borja Figueirido ◽  
Norman MacLeod ◽  
Jonathan Krieger ◽  
Miquel De Renzi ◽  
Juan Antonio Pérez-Claros ◽  
...  
Keyword(s):  
Morphological Plasticity ◽  
Shape Space ◽  
Cranial Morphology ◽  
Skull Morphology ◽  
Skull Shape ◽  
Olfactory Sense ◽  
History Of ◽  
Proximate Source ◽  
Brain Processing ◽  
Iterative Evolution

The evolutionary history of the Order Carnivora is marked by episodes of iterative evolution. Although this pattern is widely reported in different carnivoran families, the mechanisms driving the evolution of carnivoran skull morphology remain largely unexplored. In this study we use coordinate-point extended eigenshape analysis (CP-EES) to summarize aspects of skull shape in large fissiped carnivores. Results of these comparisons enable the evaluation of the role of different factors constraining the evolution of carnivoran skull design. Empirical morphospaces derived from mandible anatomy show that all hypercarnivores (i.e., those species with a diet that consists almost entirely of vertebrate flesh) share a set of traits involved in a functional compromise between bite force and gape angle, which is reflected in a strong pattern of morphological convergence. Although the paths followed by different taxa to reach this “hypercarnivore shape-space” differ because of phylogenetic constraints, the morphological signature of hypercarnivory in the mandible is remarkably narrow and well constrained. In contrast, CP-EES of cranial morphology does not reveal a similar pattern of shape convergence among hypercarnivores. This suggests a lesser degree of morphological plasticity in the cranium compared to the mandible, which probably results from a compromise between different functional demands in the cranium (e.g., feeding, vision, olfactory sense, and brain processing) whereas the mandible is only involved in food acquisition and processing. Combined analysis of theoretical and empirical morphospaces for these skull data also show the lower anatomical disparity of felids and hyaenids compared to canids and ursids. This indicates that increasing specialization within the hypercarnivorous niche may constrain subsequent morphological and ecological flexibility. During the Cenozoic, similar skull traits appeared in different carnivoran lineages, generated by similar selection pressures (e.g., toward hypercarnivory) and shared developmental pathways. These pathways were likely the proximate source of constraints on the degree of variation associated with carnivoran skull evolution and on its direction.

scholarly journals New specimen of <i>Cacops woehri</i> indicates differences in the ontogenetic trajectories among cacopine dissorophids

Fossil Record ◽  
2015 ◽  
Vol 18 (1) ◽  
pp. 73-80 ◽  
Author(s):  
N. B. Fröbisch ◽  
A. Brar ◽  
R. R. Reisz
Keyword(s):  
Morphological Changes ◽  
Lower Permian ◽  
Ecological Diversity ◽  
Large Specimen ◽  
Skull Morphology ◽  
Skull Shape ◽  
Ontogenetic Trajectories ◽  
Ontogenetic Trajectory ◽  
Taxic Diversity

Abstract. The Lower Permian Dolese locality has produced numerous exquisitely preserved tetrapod fossils representing members of a lower Permian upland fauna. Therein, at least nine taxa of the clade Dissorophoidea, ranging in size from the large predaceous trematopid Acheloma to the miniaturized amphibamid Doleserpeton, highlight the great taxic and ecological diversity of this anamniote clade. Here we describe a large specimen of the dissorophid Cacops woehri, which was previously only known from the juvenile or subadult holotype skull. Another member of the genus Cacops present at the Dolese locality, Cacops morrisi, is also represented by specimens spanning juvenile, subadult, and adult stages, allowing for a comparison of morphological changes taking place in the late phases of the ontogenetic trajectory of cacopine dissorophids. The new find shows that, in contrast to C. morrisi and C. aspidephorus, C. woehri only undergoes relatively subtle changes in skull morphology in late ontogeny and retains the overall more gracile morphology into adult stages. This includes retention of the rather shallow skull shape as well as a pattern of sculpturing consisting of elongate ridges and grooves and a large occipital flange. This suggests somewhat different functional demands in C. woehri than in other known species of Cacops, possibly associated with a different ecology paralleling the great taxic diversity of dissorophoids at the Dolese locality.

scholarly journals The limits of convergence: the roles of phylogeny and dietary ecology in shaping non-avian amniote crania

2021 ◽  
Vol 8 (9) ◽  
pp. 202145
Author(s):  
Keegan M. Melstrom ◽  
Kenneth D. Angielczyk ◽  
Kathleen A. Ritterbush ◽  
Randall B. Irmis
Keyword(s):  
Functional Morphology ◽  
Feeding Ecology ◽  
Cranial Morphology ◽  
Skull Shape ◽  
Morphological Convergence ◽  
Morphometric Methods ◽  
Central Regions ◽  
Dietary Ecology ◽  
Amniote Phylogeny ◽  
Cranial Shape

Cranial morphology is remarkably varied in living amniotes and the diversity of shapes is thought to correspond with feeding ecology, a relationship repeatedly demonstrated at smaller phylogenetic scales, but one that remains untested across amniote phylogeny. Using a combination of morphometric methods, we investigate the links between phylogenetic relationships, diet and skull shape in an expansive dataset of extant toothed amniotes: mammals, lepidosaurs and crocodylians. We find that both phylogeny and dietary ecology have statistically significant effects on cranial shape. The three major clades largely partition morphospace with limited overlap. Dietary generalists often occupy clade-specific central regions of morphospace. Some parallel changes in cranial shape occur in clades with distinct evolutionary histories but similar diets. However, members of a given clade often present distinct cranial shape solutions for a given diet, and the vast majority of species retain the unique aspects of their ancestral skull plan, underscoring the limits of morphological convergence due to ecology in amniotes. These data demonstrate that certain cranial shapes may provide functional advantages suited to particular dietary ecologies, but accounting for both phylogenetic history and ecology can provide a more nuanced approach to inferring the ecology and functional morphology of cryptic or extinct amniotes.

scholarly journals The largest known cowrie and the iterative evolution of giant cypraeid gastropods

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Stefano Dominici ◽  
Mariagabriella Fornasiero ◽  
Luca Giusberti
Keyword(s):  
Species Richness ◽  
Evolutionary History ◽  
Western Europe ◽  
Negative Relationship ◽  
Species Selection ◽  
Biogeographic Patterns ◽  
Large Size ◽  
Northeastern Italy ◽  
History Of ◽  
Iterative Evolution

AbstractBased on the fossil record, we explore the macroevolutionary relationship between species richness and gigantism in cowries (Cypraeidae), the best-studied family of gastropods, with a global diversity distribution that parallels that of tropical corals, mangroves and seagrasses. We introduce Vicetia bizzottoi sp. nov. based on a Priabonian fossil found in northeastern Italy, the largest documented cowrie found so far and the youngest of a lineage of Eocene Gisortiinae species. The Gisortiinae stratigraphic record in western Europe indicates that species selection favoured large size and armouring of the shell. Palaeoecology and per-stage species richness suggest that gigantism occurred in peripheral habitats with respect to diversity hotspots, where smaller species were favoured. The Eocene–Oligocene boundary was marked by a turnover and the Chattian global warming favoured small-sized species of derived clades. Species selection leading to gigantism is further documented in Miocene lineages of Zoila and Umbilia, in the southern hemisphere, two extant genera distributed at the periphery of modern diversity hotspots, suggesting that the negative relationship between size and diversity is a recurring pattern in the evolutionary history of cowries. This palaeontological evidence is projected onto the existing hypotheses that explain analogous biogeographic patterns in various other taxa. Likewise, body size-species richness negative relationship was possibly driven in cowries by physiological, ecological and life history constraints.

scholarly journals Comparing size of morphospace occupation among extant and cretaceous fossil freshwater mussels using Elliptical Fourier Analysis

2014 ◽  
Author(s):  
Matt Burton-Kelly ◽  
Joseph H Hartman
Keyword(s):  
Fourier Analysis ◽  
Confidence Intervals ◽  
Freshwater Mussels ◽  
Morphological Plasticity ◽  
Geographic Area ◽  
Future Research ◽  
Fossil Assemblage ◽  
Elliptical Fourier Analysis ◽  
Modern Species ◽  
History Of

Background. Freshwater mussels of superfamily Unionoidea are a diverse group with an evolutionary history of at least 360 million years. Many fossil and modern species exhibit a generally unsculptured, roughly elliptical shell outline. Such morphology results in difficulties when attempting to identify or classify fossil material, as only hard parts are preserved. Several latest-Cretaceous fossil localities over a small geographic area in southwestern North Dakota contain poorly preserved edentulous freshwater mussels that effectively lack all but shell outlines. This paper discusses methods that were used to attempt to determine how many fossil taxa were present in one of these assemblages. Methods. Elliptical Fourier Analysis was performed on two-dimensional shell outlines of both edentulous fossils and modern taxa to create Fourier scores representing outline shape. Morphospace occupation, or the amount of variation within a sample of shell outlines, was calculated using two methods: within-group dispersion and sum of variance. Morphospace occupation was compared among each of the modern taxa (at both generic and specific levels) and fossil assemblage using confidence intervals, ANOVA, and Tukey’s HSD tests. Results. The amount of outline variation within the fossil assemblage tested is more than some modern genera and species and less than others. Morphospace occupation and confidence intervals are defined for the modern taxa (nine genera and 24 species) that were examined. Discussion. Although results were inconclusive, discussion points are presented to drive future research. Methodological improvements are suggested including choice of extant (comparative) genera, ontogeny and size, morphological plasticity, phenotypic convergence, taphonomic deformation, and general geometric morphometrics.

The Natural History of Cranial Morphology in Sagittal Craniosynostosis

2018 ◽  
Vol 29 (4) ◽  
pp. 852-855 ◽  
Author(s):  
Sultan Al-Shaqsi ◽  
Elizabeth Zellner ◽  
Jessica Ching ◽  
Chirstopher Forrest ◽  
John Phillips
Keyword(s):  
Natural History ◽  
Cranial Morphology ◽  
Sagittal Craniosynostosis ◽  
History Of

scholarly journals Beyond the carapace: skull shape variation and morphological systematics of long-nosed armadillos (genus Dasypus)

2017 ◽  
Author(s):  
Lionel Hautier ◽  
Guillaume Billet ◽  
Benoit De Thoisy ◽  
Frédéric Delsuc
Keyword(s):  
Morphological Variation ◽  
Distinct Species ◽  
Morphological Characters ◽  
Molecular Data ◽  
Guiana Shield ◽  
Shape Variation ◽  
Skull Morphology ◽  
Geometric Morphometric ◽  
Skull Shape ◽  
Shape And Size

Background. The systematics of long-nosed armadillos (genus Dasypus) has been mainly based on a handful of external morphological characters and classical measurements. Here, we studied the pattern of morphological variation in the skull of long-nosed armadillos species, with a focus on the systematics of the widely distributed nine-banded armadillo (D. novemcinctus). Methods. We present the first exhaustive 3D comparison of the skull morphology within the genus Dasypus, based on µCT-scans. We used geometric morphometric approaches to explore the patterns of the intra- and interspecific morphological variation of the skull with regard to several factors such as taxonomy, geography, allometry, and sexual dimorphism. Results. We show that the shape and size of the skull vary greatly between Dasypus species, with D. pilosus representing a clear outlier compared to other long-nosed armadillos. The study of the cranial intraspecific variation in D. novemcinctus evidences clear links to the geographic distribution and argue in favour of a revision of past taxonomic delimitations. Our detailed morphometric comparisons detected previously overlooked morphotypes of nine-banded armadillo, especially a very distinctive unit circumscribed to the Guiana Shield. Discussion. As our results are congruent with recent molecular data and analyses of the structure of paranasal sinuses, we propose that D. novemcinctus should be regarded either as a polytypic species (with three to four subspecies) or as a complex of several distinct species.

THE HISTORY OF THE WORD FOR CACAO IN ANCIENT MESOAMERICA

2007 ◽  
Vol 18 (2) ◽  
pp. 193-237 ◽  
Author(s):  
Terrence Kaufman ◽  
John Justeson
Keyword(s):  
Central America ◽  
Theobroma Cacao ◽  
Cultural Context ◽  
Reasonable Doubt ◽  
Intergroup Interaction ◽  
Basin Of Mexico ◽  
History Of ◽  
Proximate Source ◽  
Mesoamerican Languages ◽  
Shed Light

AbstractThe word *kakaw(a) (‘cacao’, Theobroma cacao) was widely diffused among Mesoamerican languages, and from there to much of lower Central America. This study provides evidence establishing beyond reasonable doubt that this word originated in the Mije-Sokean family; that it spread from the Mije-Sokean languages in or around the Olmec heartland into southeastern Mesoamerican languages; that its diffusion into Mayan languages took place between about 200 B.C. and A.D. 400; and that it spread from a Mije-Sokean language in or near the Basin of Mexico into languages in the region. It shows that each of the arguments presented by Dakin and Wichmann (2000) against a Mije-Sokean origin is either unworkable, is based upon false premises, or is not relevant; and that their proposed alternative — that it originated in and spread from Nawa into other Mesoamerican languages — conflicts with the mass of evidence relevant to the issue.This study also discusses the linguistic details of vocabulary for drinks made from cacao; shows that no proposed etymology for the word chocolate is correct, but agrees with Dakin and Wichmann that its proximate source is a Nawa form chikola:tl; and discusses the history of words for Theobroma bicolor (‘Nicaragua chocolate tree; pataxte’) and their use.The linguistic data are pertinent to issues of intergroup interaction in pre-Columbian Mesoamerica, but do not shed light on the nature or the cultural context of the diffusion of cacao in Mesoamerica, nor on its uses.

Past Scents

2014 ◽  
Author(s):  
Jonathan Reinarz
Keyword(s):  
Group Identity ◽  
People Of Color ◽  
Modern Times ◽  
Community Or ◽  
The World ◽  
Olfactory Sense ◽  
History Of ◽  
Global North

This book offers a historiography of smell from ancient to modern times. Synthesizing existing scholarship in the field, it shows how people have relied on their olfactory sense to understand and engage with both their immediate environments and wider corporal and spiritual worlds. This broad survey demonstrates how each community or commodity possesses, or has been thought to possess, its own peculiar scent. Through the meanings associated with smells, osmologies develop—what cultural anthropologists have termed the systems that utilize smells to classify people and objects in ways that define their relations to each other and their relative values within a particular culture. European Christians, for instance, relied on their noses to differentiate Christians from heathens, whites from people of color, women from men, virgins from harlots, artisans from aristocracy, and pollution from perfume. This reliance on smell was not limited to the global North. Around the world, the book shows, people used scents to signify individual and group identity in a morally constructed universe where the good smelled pleasant and their opposites reeked. The book is a useful and entertaining look at the history of one of our most important but least-understood senses.

scholarly journals Severe population bottleneck and cranial morphology change in the Mednyi Island subspecies of Arctic fox Vulpes lagopus (Carnivora: Canidae)

Mammalia ◽  
2020 ◽  
Vol 84 (2) ◽  
pp. 162-170
Author(s):  
Miguel Prôa ◽  
Olga Nanova
Keyword(s):  
Demographic History ◽  
Population Bottleneck ◽  
Cranial Morphology ◽  
Arctic Fox ◽  
Vulpes Lagopus ◽  
Morphometric Traits ◽  
Arctic Foxes ◽  
History Of ◽  
Bering Island ◽  
Two Populations

AbstractArctic foxes, Vulpes lagopus living on Mednyi Island suffered a drastic decline in population size in the late 1970s due to an outbreak of mange epizootic. This dramatic fall in numbers rendered the subspecies endangered, and the concomitant loss of variability resulted in a population bottleneck. Here, we investigate whether differences in cranial morphology between Mednyi Island Arctic foxes and Bering Island Arctic foxes could be attributed to the severe population bottleneck suffered by the Mednyi population in the 1970s. We used morphometric traits as proxies for genetic data to provide estimates of FST. Results show higher FST estimates for the Mednyi population than for the Bering population, which we interpret as a bottleneck signature. FST results also indicate a pattern of divergence between the two populations consistent with random genetic drift. Bottleneck detection is critical for the interpretation of the demographic history of the endangered Mednyi Island Arctic fox, with consequences for conservation management.

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