scholarly journals Cranial shape evolution of extant and fossil crocodile newts and its relation to reproduction and ecology

2020 ◽  
Vol 237 (2) ◽  
pp. 285-300 ◽  
Author(s):  
Peter Pogoda ◽  
Marcus Zuber ◽  
Tilo Baumbach ◽  
Rainer R. Schoch ◽  
Alexander Kupfer
Keyword(s):  
Shape Evolution ◽  
Cranial Shape

Do convergent ecomorphs evolve through convergent morphological pathways? Cranial shape evolution in fossil hyaenids and borophagine canids (Carnivora, Mammalia)

Paleobiology ◽  
2011 ◽  
Vol 37 (3) ◽  
pp. 470-489 ◽  
Author(s):  
Zhijie Jack Tseng ◽  
Xiaoming Wang
Keyword(s):  
Convergent Evolution ◽  
Shape Change ◽  
Morphological Evolution ◽  
Shape Evolution ◽  
Deep Time ◽  
Phylogenetic Constraint ◽  
Mechanisms Of Adaptation ◽  
Evolutionary Pathways ◽  
Length Reduction ◽  
Cranial Shape

Cases of convergent evolution, particularly within ecomorphological contexts, are instructive in identifying universally adaptive morphological features across clades. Tracing of evolutionary pathways by which ecomorphological convergence takes place can further reveal mechanisms of adaptation, which may be strongly influenced by phylogeny. Ecomorphologies of carnivorous mammals represent some of the most outstanding cases of convergent evolution in the Cenozoic radiation of mammals. This study examined patterns of cranial shape change in the dog (Canidae) and hyena (Hyaenidae) families, in order to compare the evolutionary pathways that led to the independent specialization of bone-cracking hypercarnivores within each clade. Geometric morphometrics analyses of cranial shape in fossil hyaenids and borophagine canids provided evidence for deep-time convergence in morphological pathways toward the independent evolution of derived bone-crackers. Both clades contained stem members with plesiomorphic generalist/omnivore cranial shapes, which evolved into doglike species along parallel pathways of shape change. The evolution of specialized bone-crackers from these doglike forms, however, continued under the constraint of a full cheek dentition and restriction on rostrum length reduction in canids, but not hyaenids. Functionally, phylogenetic constraint may have limited borophagine canids to crack bones principally with their carnassial instead of the third premolar as in hyaenids, but other cranial shape changes associated with durophagy nevertheless evolved in parallel in the two lineages. Size allometry was not a major factor in cranial shape evolution in either lineage, supporting the interpretation of functional demands as drivers for the observed convergence. The comparison between borophagines and hyaenids showed that differential effects of alternative functional “solutions” that arise during morphological evolution may be multiplied with processes of the “macroevolutionary ratchet” already in place to further limit the evolutionary pathways available to specialized lineages.

scholarly journals Crocodylomorph cranial shape evolution and its relationship with body size and ecology

2019 ◽  
Author(s):  
Pedro L. Godoy
Keyword(s):  
Body Size ◽  
Cranial Morphology ◽  
Shape Evolution ◽  
Shape Variation ◽  
Crown Group ◽  
Early Peak ◽  
Group Members ◽  
Phylogenetic Hypotheses ◽  
And Shifts ◽  
Cranial Shape

AbstractCrocodylomorpha, which includes living crocodylians and their extinct relatives, has a rich fossil record, extending back for more than 200 million years. Unlike modern semi-aquatic crocodylians, extinct crocodylomorphs exhibited more varied lifestyles, ranging from marine to fully terrestrial forms. This ecological diversity was mirrored by a remarkable morphological disparity, particularly in terms of cranial morphology, which seems to be closely associated with ecological roles in the group. Here, I use geometric morphometrics to comprehensively investigate cranial shape variation and disparity in Crocodylomorpha. I quantitatively assess the relationship between cranial shape and ecology (i.e. terrestrial, aquatic, and semi-aquatic lifestyles), as well as possible allometric shape changes. I also characterise patterns of cranial shape evolution and identify regime shifts. I found a strong link between shape and size, and a significant influence of ecology on the observed shape variation. Terrestrial taxa, particularly notosuchians, have significantly higher disparity, and shifts to more longirostrine regimes are associated with large-bodied aquatic or semi-aquatic species. This demonstrates an intricate relationship between cranial shape, body size and lifestyle in crocodylomorph evolutionary history. Additionally, disparity-through-time analyses were highly sensitive to different phylogenetic hypotheses, suggesting the description of overall patterns among distinct trees. For crocodylomorphs, most results agree in an early peak during the Early Jurassic and another in the middle of the Cretaceous, followed by nearly continuous decline until today. Since only crown-group members survived through the Cenozoic, this decrease in disparity was likely the result of habitat loss, which narrowed down the range of crocodylomorph lifestyles.

3D SHAPE EVOLUTION IN GRASS SILICA SHORT CELL PHYTOLITHS: TAXONOMIC PATTERNS IN BAMBUSOIDEAE AND OTHER LINEAGES

2017 ◽  
Author(s):  
Ashly Senske ◽  
◽  
Claire Marvet ◽  
Sultan Akbar ◽  
Silishia Wong ◽  
...  
Keyword(s):  
Shape Evolution ◽  
Short Cell ◽  
3D Shape ◽  
Taxonomic Patterns

Shape Evolution and Growth Mechanisms of 3D-printed Nanowires

2021 ◽  
pp. 102076
Author(s):  
Robert Winkler ◽  
Jason D. Fowlkes ◽  
Philip D. Rack ◽  
Gerald Kothleitner ◽  
Harald Plank
Keyword(s):  
Shape Evolution ◽  
Growth Mechanisms ◽  
3D Printed

Shape Evolution of Octahedral and Triangular Platelike Silver Nanocrystals from Cubic and Right Bipyramidal Seeds in DMF

2009 ◽  
Vol 9 (11) ◽  
pp. 4700-4705 ◽  
Author(s):  
Masaharu Tsuji ◽  
Yoshinori Maeda ◽  
Sachie Hikino ◽  
Hisayo Kumagae ◽  
Mika Matsunaga ◽  
...  
Keyword(s):  
Shape Evolution

Mechanics of shape evolution of particle aggregates in viscous sintering

2021 ◽  
Vol 41 (1) ◽  
pp. 797-810
Author(s):  
Fumihiro Wakai ◽  
Yuta Numanami ◽  
Tomoki Sekiya ◽  
Norimasa Nishiyama
Keyword(s):  
Shape Evolution ◽  
Particle Aggregates ◽  
Viscous Sintering

Substrate evaporation induced neck-shape evolution of a liquid/solid interface

2007 ◽  
Vol 9 (5) ◽  
pp. 338-343 ◽  
Author(s):  
Shmuel Barzilai ◽  
Michael Aizenshtein ◽  
Marina Lomberg ◽  
Natalie Froumin ◽  
Nachum Frage
Keyword(s):  
Shape Evolution ◽  
Solid Interface
Sign in / Sign up

Export Citation Format

Share Document