scholarly journals Upper molar morphology, homologies and evolutionary patterns of chinchilloid rodents (Mammalia, Caviomorpha)

2018 ◽  
Vol 234 (1) ◽  
pp. 50-65 ◽  
Author(s):  
Luciano Luis Rasia ◽  
Adriana M. Candela
Keyword(s):  
Evolutionary Patterns ◽  
Molar Morphology ◽  
Upper Molar

Uniquely derived upper molar morphology of Eocene Amphipithecidae (Primates: Anthropoidea): Homology and phylogeny

2013 ◽  
Vol 65 (2) ◽  
pp. 143-155 ◽  
Author(s):  
Pauline Coster ◽  
K. Christopher Beard ◽  
Aung Naing Soe ◽  
Chit Sein ◽  
Yaowalak Chaimanee ◽  
...  
Keyword(s):  
Molar Morphology ◽  
Upper Molar

Reassessment of Lower Eocene Seggeurius amourensis: aspects of primitive dental morphology in the mammalian order Hyracoidea

1993 ◽  
Vol 67 (5) ◽  
pp. 889-893 ◽  
Author(s):  
Nicholas Court ◽  
Mohamed Mahboubi
Keyword(s):  
Dental Material ◽  
Dental Morphology ◽  
Crown Height ◽  
Lower Eocene ◽  
Precise Characterization ◽  
Molar Morphology ◽  
Upper Molar ◽  
Lower Molar

New lower dental material of the fossil hyracoid mammal, Seggeurius amourensis Crochet, 1986, from Eocene deposits of the Southern Atlas in Algeria, has prompted a reevaluation of the genus. The dentition as a whole is first described in detail, thus providing a more precise characterization of the genus than has hitherto been available. Peculiarities, particularly in upper molar morphology, are sufficient to uphold a generic distinction. However, based largely on lower molar morphology Seggeurius amourensis is transferred from the subfamily Geniohyinae to Saghatheriinae. In the upper molars, absence of a postmetacrista and the presence of a preprotocrista continuous with the parastyle are interpreted as primitive features in hyracoids. In the lower molars, extreme reduction of the paracristid and the presence of a mesoconid are also considered primitive for hyracoids. These features together with small size, bunodonty, low crown height, and very simple premolar morphology indicate that Seggeurius amourensis is the most primitive hyrax yet recovered.

scholarly journals Upper molar morphology and relationships among higher taxa in bats

2011 ◽  
Vol 92 (2) ◽  
pp. 421-432 ◽  
Author(s):  
Maria Paula Aguiar Fracasso ◽  
Leandro de Oliveira Salles ◽  
Fernando Araújo Perini
Keyword(s):  
Higher Taxa ◽  
Molar Morphology ◽  
Upper Molar

Variability, selection, and constraints: development and evolution in viverravid (Carnivora, Mammalia) molar morphology

Paleobiology ◽  
1998 ◽  
Vol 24 (4) ◽  
pp. 409-429 ◽  
Author(s):  
P. David Polly
Keyword(s):  
Tooth Development ◽  
Phenotypic Variability ◽  
Evolutionary Change ◽  
Stabilizing Selection ◽  
Developmental Constraints ◽  
Evolutionary Patterns ◽  
Evolutionary Response ◽  
And Function ◽  
Molar Morphology ◽  
The Relationship

Developmental constraints presumably operate by influencing patterns of variability: when development causes some features to vary more than others and when the level of variability is correlated with evolutionary change, then development can be said to constrain evolution. This idea was tested by examining the relationship between tooth variation and three other factors: developmental processes, tooth function, and evolutionary change. Data came from two lineages of viverravid carnivorans (Viverravidae, Carnivora) from the Paleogene of North America. Variability in cusp position was significantly correlated with position in the developmental cascade, with the amount of intercusp growth (when growth is relatively greater in some cusps than others), and with amount of evolutionary change. This indicates that tooth development exerts a local constraint on phenotypic variability and on the evolutionary response to functional selection, but comparative data suggest that the developmental constraint itself may evolve. Intense directional or stabilizing selection may modify the developmental cascade so that the constraint is either removed or modified to permit new evolutionary patterns. Thus development does not constrain evolution in an absolute sense, but rather introduces modifiable patterns of covariance among crown features. Both development and function seem to play important, intertwined roles in coordinating evolutionary change in mammalian molars.

Upper molar morphology of the early oligocene egyptian anthropoidQatrania wingi

2015 ◽  
Vol 159 (4) ◽  
pp. 714-721 ◽  
Author(s):  
K. Christopher Beard ◽  
Pauline M. C. Coster
Keyword(s):  
Early Oligocene ◽  
Molar Morphology ◽  
Upper Molar

Evolutionary Patterns of Retinal-Binding Pockets of Type I Rhodopsins and Their Functions†

2006 ◽  
Vol 82 (6) ◽  
pp. 1426 ◽  
Author(s):  
Larisa Adamian ◽  
Zheng Ouyang ◽  
Yan Yuan Tseng ◽  
Jie Liang
Keyword(s):  
Type I ◽  
Evolutionary Patterns ◽  
Binding Pockets

Comparative Analysis of Genetic and Morphological Variation within the Platanthera hyperborea Complex (Orchidaceae)

2020 ◽  
Vol 45 (4) ◽  
pp. 767-778
Author(s):  
Eranga Wettewa ◽  
Nick Bailey ◽  
Lisa E. Wallace
Keyword(s):  
North America ◽  
Diploid Species ◽  
Morphological Characters ◽  
Evolutionary Patterns ◽  
Founding Population ◽  
Multiple Origins ◽  
Geographic Structure ◽  
Species Complexes ◽  
Nuclear Its ◽  
Cryptic Taxa

Abstract—Species complexes present considerable problems for a working taxonomy due to the presence of intraspecific variation, hybridization, polyploidy, and phenotypic plasticity. Understanding evolutionary patterns using molecular markers can allow for a more thorough assessment of evolutionary lineages than traditional morphological markers. In this study, we evaluated genetic diversity and phylogenetic patterns among taxa of the Platanthera hyperborea (Orchidaceae) complex, which includes diploid (Platanthera aquilonis) and polyploid (Platanthera hyperborea, P. huronensis, and P. convallariifolia) taxa spanning North America, Greenland, Iceland, and Asia. We found that three floral morphological characters overlap among the polyploid taxa, but the diploid species has smaller flowers. DNA sequence variation in a plastid (rpL16 intron) and a nuclear (ITS) marker indicated that at least three diploid species have contributed to the genomes of the polyploid taxa, suggesting all are of allopolyploid origin. Platanthera convallariifolia is most like P. dilatata and P. stricta, whereas P. huronensis and P. hyperborea appear to have originated from crosses of P. dilatata and P. aquilonis. Platanthera huronensis, which is found across North America, has multiple origins and reciprocal maternal parentage from the diploid species. By contrast, P. hyperborea, restricted to Greenland and Iceland, appears to have originated from a small founding population of hybrids in which P. dilatata was the maternal parent. Geographic structure was found among polyploid forms in North America. The area of Manitoba, Canada appears to be a contact zone among geographically diverse forms from eastern and western North America. Given the geographic and genetic variation found, we recommend continued recognition of four green-flowered species within this complex, but caution that there may be additional cryptic taxa within North America.

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